The DIY VGA to component transcoder is a very successful thread that is still going on in finishing the PCI version.

In the meantime I have received a number of requests for a Component to VGA transcoder. I think that we could start this design ending in the same results:

1) A freely available design database plus full description including PCB's for all forum members.
2) An assembled converter with warranty available from me.

At this time I would like to get some idea's on the options that people are interested in and I need to investigate how the design should look.

Please feel free to comment

This sounds like a great project idea. I have built and tinkered with circuits since the 1970's. I would be happy to help with testing of such a device. The 'options' that first come to my mind are actually 'features':
-Able to handle video from 15 kHz through 1920x1080
-Able to be powered by the VGA device, if there is power available on any of the HD15 pins

Thanks-

Chris,

The first should be doable, the second I need to investigate. The VGA port is an output, so I doubt that the input on the other side has any power on it.

One of the key things for HDTV compatibility is proper tri-level to bi-level sync conversion.

yep, I agree. This is actually not too difficult, the most interesting problem is horizontal picture shift.


Kim

In addition to proper tri-level to bi-level sync conversion, the transcoder should be able to remove all traces of sync from the RGB output, or at least have the option available.

I would personally like to have a separate converter for converting tri-level sync to bi-level sync only, because my RPTV seems operates at its best using YPrPb+HV (5 inputs) with bi-level sync.

steve,

Stripping all the sync from the RGB output is exactly the plan, now I just have to figure out how to do it.

When we have the sync stripped and converted it should not be too hard to make it available including a YPrPb pass through.


Kim

(1) I would like to see two inputs- one that is compoent to be transcoded to rgbhv, and a second input that can be configured either as a second component to be transcoded, or as a rgbhv pass-thru. Switching between inputs would either be via ir or rs-232.

(2) Able to handle 480i, 480p, 720p, 1080i and 1080p. In this regard, please note that I currently have a transcoder made by Current Design that transcodes well, but has an annoying quirk. I receive hdtv signals via an OTA stb in all formats, which is fed to a front projector. When the input signal switches from 1080i to 720p, the projector will not sync up, and I get an image on the left half of the screen and an identical image on the right side of the screen. Going from 720p to 1080i does not exhibit this problem. I know the quirk is with the transcoder, because when i connect the rgbhv output of the stb to the projector, this problem does not occur.

(3) selectable tri-level or bi-level output.

(4) ability to strip out 7.5 ire when a digital version of an ntsc signal is inputted.

(5) ability to strip out macrovision.

(6) compatibility with the jvc dvhs recorders.

Steve

Is there a website on that Current design transcoder so I can look it up, I can only find kayaks under that name.

This is an interesting feature list that you would like to see and at first glance it will not be in the $100 range anymore.


Kim

Current Design is an off-shoot of Progressive Labs, the maker of the CA-1 color analyzer. They never had a website, AFAIK.

Steve

Progressive Labs no. is 201-342-1235. I think I may have contact info (e.g., who designed it) on Current design at home. I will try to find it.

Steve

This Colorimiter Walks on Water AFAI Concerned.

Originally posted by steve
(1) I would like to see two inputs- one that is compoent to be transcoded to rgbhv, and a second input that can be configured either as a second component to be transcoded, or as a rgbhv pass-thru. Switching between inputs would either be via ir or rs-232.

...

(Steve

I second this part with a bit more constraint...

It would be great if the RGBHV in and out were BNC and if the switch bandwidth were high enough not to kill the benifits of an MP1 moded card.

Would it be possible to have it auto switch with selectable priority and override.

By the way is Mike involved in this project at all? I know he discussed a transcoder design previously as well.

Briands,


I don't know if Mike is reading these posts. BNC inputs is definately an option and bandwidth should end up around 160MHz or so.

Let me ask another important thing. How much should this thing cost in the end. Do we want to make the mother of all transcoders, just a simple one or one that can be expanded with different options?

I've spoken to several HT owner who have the same problem. Most of us own a Front Projector TV with RGBHV input. Several pass through a processor/doubler/transcanner that only proceses 480i input information. All of these units have a passthrough RGBHV directly to the projector. This passthrough is a selectable input via a remote control. In this case, it is the only means for providing HDTV info to a data grade monitor. Several of us have RGBHV switchers to select between different RGBHV HDTV inputs. The switcher's RGBHV output goes to the RGBHV input/passthrough of the Transcanner. In order to accomodate newer STB's, PVR's and Progressive scan DVD Players, a remotely switchable transcoder to process YPbPr to RGBHV is required. The switch would select between the RGBHV input to the unit for passthrough to its RGBHV output or would select the YPrPb input for transcoding to its RGBHV output. For upgrade, the unit could be offered with 1,2,or3 YPbPr inputs and the RGBHV passthrough. Please keep it simple. Plug it in and select. Try to keep dip switch setting to a minimum. Thankyou!! I'll offer to buy or test the first unit if you need an old physicist whose played with this stuff for 50 years.

beun-

I would rather see a simple, small, low-cost device. Keep any multi-input or auto-switching circuits as a separate project.

I do not know what the parts for the RGB-to-component project cost, but I'd like to see this one be less than US$50 not including case or power supply, but including the circuit board (and maybe connectors). The one 'option' that I'd like is separate versions/boards/layouts for multi-BNC outputs versus HD15 ("VGA connector") output. Thanks!

Update-

I had only glanced at the RGB-to-component discussion at its beginning and I had seen a simple schematic with a few TTL chips and op amps. Now, I have seen the Crescendo product and schematic-it is obviously a much more complex device than in the beginning. So, the $50 price is probably not likely, but I am interested anyway.

Mike has his own transcoder that he is putting together. I should have one to test on Saturday. Based on Mike's previous work, I expect it will be a higher end unit.

When Mike already has a transcoder that does everything there may not be a need for a new one.

I will however see if can make some time today to draw up a simple block diagram that captures the ideas from your recent postings. It will consist of a basic transcoder that does the sync-stripping and the color matrix ( both of them) with optional input and output switching. I will try to avoid a microcontroller (programming issues) but if anyone would like to see remote control that is probably unavoidable.

Originally posted by beun

When Mike already has a transcoder that does everything there may not be a need for a new one.


Yes there could still be a need for what you're doing. I'm doing something a little different. I'm putting emphasis on performance, so I've not considered some of the request that are listed on this thread. My unit will only have two component inputs, but all in's and outs will be true 75 ohm BNC's. And the inputs will be selected from a front panel switch.

I'm not into bells and whistles. So I've spent my time tweaking and tuning for performance, so my unit will be very straight forward.

However, I really like what you've done with the other transcoder. And it's a blessing to have someone like you around to make things like this available to many. And of course I really like how you've made it available to those who could not assemble one themselves.

Keep up the good work;) !

Here is a site with some schematics that show a couple different versions of YUV to RGB conversion.
http://elm-chan.org/works/yuv2rgb/report.html
Some more complex than others. There are also a lot of new high bandwidth op amps out there designed for these video applications with built in sync strippers.
http://www.intersil.com/data/an/an9513.pdf
From my perspective it would be important to have the transcoder either calibrated or to have the ability to calibrate the RGB output properly. In the end, the reason we are doing this is to get the black levels correct. My STBs output RGB and Component, if indeed the component is the most accurate of the OTA and Satellite HD formats, then accuracy of that conversion to RGBHV is critical.
..Doyle

Hmmm.....

Seems this thread went dead. Are we still thinking this is a good idea? I for one am up for a kit or at least PCB of a good Component to RGBHV transcoder. I can't do the > $200 dollar deal.

..Doyle

I hope it is not dead. I have put off buying a ready made transcoder expecting the gentleman who offered to build one and sell it to do so. I'll pay up to $300 for remotely switchable Component to RGBHV with RGBHV passthrough. as I discussed in my previous posting.

No the thread is not dead, it is just that I have a lot to do and so little time to do it.

What I would be proposing is the following.

1) make a modular system, with the component->VGA transcoder as the core. This one will do the sync-stripping and the color conversion. There will be dipswitches or so to select the color matrix. This one can be had separately.

2) Create a front-end switcher. Depending on the requests it can be relatively simple but high quality using relays, or it can be a fancy (and expensive) cross-point switch that will have slightly reduced bandwidth (200MHz for the simple one vs 100MHz for the cross-point).

3) Create a backend switcher for those that want to do fancy things with the recovered sync.

4) Anything fancy requires a microcontroller as the IC's to use need to be serially programmed. This microcontroller can than also be used to receive remote control.

This design is going to be a fairly lengthy process. The core transcoder probably needs 3 months of design and first round printed circuit boards. I myself am very bad in programming microcontrollers so I would need some help there .

This is rather disheartening. I guess those readily available transcoders for $199 aren't such a bad deal.

John,

So youare getting MP's transcoder this weekend?? Can't wait to see it!!

Terry

Art,

The transcoder core which will be comparable to the AA or KD transcoder and put in its own case can be designed and made for a price that will be very competitive. It is all the switching functions that drive up the costs.

I own an AA transcoder, you do not want one that performs so poorly. Snych stripping and accurate color output should be the core, so true HD black levels can be maintained. Its sooo disheartening to have an HD source and not be able to use it because there is no affordable transcoder that can adequately display the signal.
My vote, both in words and with real money, is for a very basic transcoder that outputs an RGB signal with all of the correct levels of synch(ie. none on the RGB) and correct color signals in order to result in a fully detailed HD image on my front projectors. There are TONS of good switchers already available on ebay for very little, we need a good transcoder ONLY.
If MP can sell his for $300. or less, I'll buy one of his. But I would also support this effort, as it doesn't sound like MP is heading anywhere near that price point.

I've had the MP transcoder for a few days and my initial impression is very very positive, much better than the inexpensive units.

That is GREAT news, but only if he'll be able to sell it for an affordable amount. Like a Faroudja scaler, it doesn't really matter if its the best if I'll never be able to afford one. Any word on pricing or availability yet ?

No word on pricing and as to availability I believe it is still in the testing phase.

I vote for conversion only and no switching/passthrough.

Mark

Any advantage over the ATI Dongle?
Since I am building a HTPC and haven't decided on a Video Card yet, I would like to know if there is any advantage using the Transcoder over the ATI dongle?

Thanks for your reply

JAH

JAH,

for the answer look in the special deals area.


Kim

Pardon my ignorance, but how do you use component to VGA in the HTPC world?
VGA to component is quite clear to me, but not the other way around...
Thanks.

galileo2000
Every one of us with a glorious CRT front projector sorely needs a component to vga transcoder to transcode the component output of HD STB's and HD D-VHS vcr's. We need a good transcoder which will not rob the signal of its full black extension. Cheap transcoders leave the synch signal on the RGB signals and thereby rob them of their full bandwidth, which leaves the blacks from any HD source crushed.

Aaah, thanks...I have Sony 61HS10 and no HD devices, so it was a mystery to me...

so front CRT's don't have comp inputs, only VGA, correct?

Correct.
Any CRT front projector I've ever had has the capability to lock to EVERY form of RGB signal, but only a very few can take a component signal directly, and the two I've had that could, didn't do a very good job with component, likely just had a cheap built in transcoder, but I don't know for sure.

Thanks GN2. Since we are here, can you tell me what is the best Cheapest front CRT projector in your opinion?

My Sony 61HS10 is limited to very few VGA signals, but I still need, quoting you, "any kind of VGA signal"....

Another reason to have this device is for people (like me) who have an all-RGB switching system, even if their display device could accept a component signal in addition to RGB. Having an inexpensive component-to-RGB xcoder means I could buy things like the JVC DVHS VCR, or 'any' Panasonic consumer HD device, and just figure in the xcoder cost for each new device.

I too would like just a 'core' transcoder - Component to RGBHV, with full sync stripping only - and have it for less money. The switching can go later :).

<I too would like just a 'core' transcoder - Component to RGBHV, with full sync stripping only - and have it for less money. The switching can go later>

Yes I agree but RGBHV passthrough is essential. Many have systems already configured for RGBHV switching and prefer that signal go to the monitor since it is far better than PbPrY. With the monitor looking for a sync pulse, do you need active swiching or just isolation of the two inputs?

If further votes are needed, I too vote for PQ over whistles at a =<$250.00 price point if possible. RGBHV passthrough is very nice, but if it means I settle for crushed blacks or can't afford it, drop it. I suspect passthrough is easy though, and probably not expensive at all to incorporate.

Yes, a passthrough is fairly easy and doesn't cost much extra, it only takes up some board real estate.


Kim

But for me the best would be:

1. a component to RGBHV transcoder- for HDTV settop box
2. another component to RGBHV transcoder, and-for my STB dvd player
3. a RGBHV pass through -so I can use the MP-1 output from my comp'r

or I can mix and match, but at least 1 of the first two and three would be great....

And I'd volunteer for testing too....

Are we making any progress on this? My cable company is supposed to be rolling out the new HDTV box w/ HD and SD PVR in early December. I have no way to use it until this or Mike's transcoder are available.

I am a bit overworked at the moment, but a basic version can be ready at the end of the year.


Kim

Kim -

One more vote for a simple device from a front-projection CRTer, especially if you can do it for near the price of the VGA-component box that you've already done. - Pat

A simple device is definately possible for around that price. I already started some initial design work.


Kim

Originally posted by budiman
I too would like just a 'core' transcoder - Component to RGBHV, with full sync stripping only - and have it for less money. The switching can go later :).

I realize that the Key Digital KD-CTCA3 does a bit more than that, and costs $279, but does it meet the PQ requirements? (I ask on behalf of those who may not be able to wait.)

The core of the transcoder is actually quite simple, I will check what extra things the KD-CTCA3 does to find out what warrants the additional cost.


Kim

I am not as technologically savvy as the rest of you. I hope I understand everything correctly.

My preference is for the following device:

I have a direct view monitor which receives 1080i HDTV signals only through a DB 15 VGA port. I need to be able to connect with a cable company set top box which outputs HD only through component outputs. I am told that I need a component to VGA (DB-15) transcoder.

I don't believe I need any pass through, and I respectfully request that the price be kept near the $125 price of your VGA to component device.

Thank you,
Stu

I would like to add my vote for a simple but quality YPbPr component to RGBHV transcoder. ie: No added cost for switching or passthrough even.

I would envisage something that looks pretty much like your RGBHV to component transcoder, but which works in reverse, at around the same price point.

Only addition I would request is the option of BNC RGBHV output connectors, instead of HD15 (in the interests of signal quality etc.)

Would also be interesting to know what most people are intending to use this for. eg: Would it be fair to guess that perhaps a good percentage are looking to connect their D-VHS 1080i component output into their RGBHV only CRT Projectors? If so, this may assist optomising the design for this specific purpose (including the -ve sync requirement of older Barco PJ's).

A reasonable priced simple (but quality design) transcoder optimised for this purpose might help more CRT owners move to D-VHS / D-Theater setups, who are currently put-off by the need to buy an expensive transcoder on top of the D-VHS deck cost.

Just my thought for the day. ;)

Greg

Let me stress again the absolute need for a passthrough. Most of us have STB's or other equipment that we selected for use specifically with our RGBHV only monitors. Unless we plan to dump all those devices a passthrough is necessary for the older equipment. New devices will benefit from the transcoder. If you can not see this, you must be planning to dump your present input devices.

One more vote for simple, best PQ for the buck (i.e. as inexpensive as possible with quality PQ and no bells).


As for multiple devices, since there seems to be a majority in favor of simple, quick and inexpensive, can't you just switch your current RGB lines with a cheap mechanical ganged switch using the 'new' transcoder as one input and your current rgb lines as the other input? Higher quality switching could be added as per taste of each individual, but the cost of the 'new' transcoder could be minimized and time to market sped up.
kb

Let me stress again the absolute need for a passthrough

Use a dedicated distribution amp, it will provide more outputs and better quality then trying to shoehorn one into a transcoder.

I now have the first cut of a component -> RGBHV transcoder ready. I have attached the schematic (in ExpressPCB format) and printouts in PDF format. This transcoder has a component pass-though as it comes virtually for free. I have to give credit to Mike Parker for pointing me to the right sync separator. I hope that I will ever get around to finishing the picture shift function that I promised him.

This transcoder does the reverse of the high def (540p/720p/1080i) color matrix. In formula's:

B = Y+1.8556*Pb
R = Y+1.5748*Pr
G = 1.3982*Y-0.2973*R-0.1010*B = Y-0.4682*Pr-0.1874*Pb

If everybody can agree on the first iteration of this thing then I can work on the PCB during the Xmas holiday. These prototype boards will have RCA and VGA connectors because I have these ones in abundance. When enough people request it I will use BNC's for the final product.


Kim

I'm not sure why anyone would want to pass through RGB (Component). I thought I explained the need for RGBHV passthrough. Without an RGBHV passthrough, all existing RGBHV will require additional RGBHV switching. Another $200.00 box.

Good Job!!!!!!!! I'll buy one even without the RGBHV passthrough.

Please put me on the list of early adopters.
I'd prefer BNC's but if it means I get one in a matter of weeks instead of months, I'll make due with RCA's.

I'm not sure why anyone would want to pass through RGB (Component).

I'm not sure why anyone would think that RGB is a component signal, Component is Y, R-Y, B-Y...a different colour space.

I thought I explained the need for RGBHV passthrough.

There is no need for a VGA passthrough in this transcoder, that's why I said a distribution amp would be better.
I'm not sure why you keep referring to a switcher when you're describing a distribution amp anyway.

If some people think that a VGA (RGBHV) passthrough (like implemented in the KD-CTCA3) is so important, I can do that as an option. The description of how it is supposed to work is not quite clear by the way. The websites talk about 2 VGA outputs, but the hookup diagram clearly talks about a VGA passthrough input. It looks like they are mixing up the CTCA2 description with the CTCA3 connection diagram


Kim

Beun,

If you could offer an RGBHV in that passes through except when there is an H or V sync fron your RGB component in, then a monitor would sync on the RGBHV passthrough or the RGB component transcoded RGBHV. It would be nice if selection could occur without user intervention however a simple switch would work. In Line has RGBHV switchers that sense the presence of the input sync and give that input priority. Don't ask me how. Mine is a manual unit.

Ok,

Attached the updated schematic as before, now with VGA passthrough that automagically switches in when there is no valid sync on Y.

Hi,
Newbie question. Hope it is not too stupid:
My Barco actually syncs just fine by plugging the Y signal (from a DISH 811) directly into the green input (port 4 which is sync on green). I get a 'beautiful' green picture. The only problem is that blue and red are extremely dim. I am guessing that is the magic of your formulas and your amplifier circuit - to get the right mix of RGB without washing out the B and R getting them up to the same level as the G.

My question is, could I get by without using all the sync extraction portion of your design and leave the sync on green (which the barco seems to be able to extract just fine)?

I am thinking I should just be able to throw together a very simple wirewrap board using your amplifier design without bypass and without sync extraction and have this thing working tomorrow - real down and dirty just to see if it works.

I have about 2 weeks to get my money back from DISH if I can't get my new 811 interfaced to my Barco. So, I can't wait for your full design and kit to come out and I don't want to spend $400 just to test the 811 (I'm not even sure it will work ever work with my BD800).

Your DIY approach is my only hope to resolve my problem in time. It sounds like the only way to go - I am just pressed for time. If I can 'prove the concept' with a quick breadboard test, then I can be confident in going for the full kit in the future.

Thanks,
KB

Thanks very much for all the help you have provided already on this forum.

Beun,

That is perfect. Sign me up. I'll buy the first one.

KB,

You actually made me think about the sync portion that is on Y (I had forgotton about that) and I am beginning to feel that this might already be a problem in the current design. Let me do a few simululations and I will get back to you.


Kim

Count me in to.
I've tried to make a transcoder myself but gave up due to my lack of knowledge and most of all TIME!!.

Is the idea to send it as a DIY kit or as a put together little machine??
Will it be able to handle 230 volts??
If not can you ship without transformer and I will be able to put one in myself??

The primary use will be from my HK dvd25 to my E-home 3500. Just to be able to use the progressive scan.

If it checks out fine after some testing you got yourself a buyer.

Thanks

Kim,
Thanks for the consideration. I hate to be a total parasite - I am new to this video game, but I learn quick. If you could direct me to some relevant literature on component and rgb video design, I would like to become helpful.

One quick question: I am guessing that the simplest design would just need to implement your formulas - summers and multipliers. I suspect that will give proper levels on the gains for each color, but does this maintain the black levels black? It must not be easy since that seems to be the problem (according to posts on this forum) with the COTs products out there.
Also, at the risk of revealing serious ignorance, what exactly does 'crushed black level' mean? Every body talks about it, but what is it really?

Thanks,
KB

Crushed Blacks refers to the inability to see detail in the dark areas. The dark areas go from gray to totally black as the brightness level is turned down. IRE levels of 20-30 are not visible.

KB,

The fastest info that you can get is look at some application examples for video opamps. You can find a number of (simple) examples on the Linear technology website The datasheet of the LT1399 and the like is a good start. Although they don't quite implement the right formulas, they give you some idea.

I am not quite sure how the projector handles the black-levels, a good one will do black-level restoration I guess. I noticed that the component outputs of my DVD player is AC-coupled, so either my transcoder has to clamp black, or the projector has to.


Patrik,

You can either buy a kit, or for something like $25 more an assembled one. The power supply is external, 9-12VAC on a 3.5mm audio connector I am pretty sure you can find these in Sweden.

Beun: I hope you aren't saying your transcoder will be like the other cheap ones and only produce HD material with crushed blacks ?
Crushed blacks is most definitely NOT caused by the "projector" but rather a result of the poor quality of the lower priced component to VGA converters. I've got a couple of HD sources that can be set to output either VGA or component, and on the component output, when transcoded using my cheap AA transcoder, there is no black detail. Whereas, when I output using the VGA of the sources, black extension is correct and shadow detail is very good. Trying to get away from the "crushed blacks" issue is the ONLY reason why I need another transcoder, as is the case with all of your CRT projector owning customers(I'd wager).
Can you please clarify if your transcoder will be a simple copy of other cheap ones or one that will NOT crush blacks so beautiful HD imgages are unwatchable ?

Let's be clear. Were not trying to see blacker than black are we? My DWIN Transcanner will not pass blacker than black but if you go through the RGBHV bypass directly to the projector blacker than black is clearly visible. But who needs blacker than black? It is just for set up. Someone please comment.

I'm not lookin for blacker than black.
It would be nice to have a transcoder that passed the subtle gradations that are found in HD, thats all.

Paul, Art,

I see no reason why any transcoder should produce crushed blacks or couldn't produce blacker than black. Crushed blacks is usually produced by an insuffient number of bits available in digital processing. This is an analog transcoder and can reproduce anything from -100 IRE (if it would exist) to at least 150 IRE.

However there are two other things to consider.

1) Setup, the component out of eg. a DVD player usually has its black level at +7.5 IRE (other players don't adhere to this NTSC convention and may therefore look too dark). As designed now, this transcoder just passes everything as is, and black would then also be at 7.5 IRE at the VGA output. If anything else is desired, please tell me.

2) black level restoration. The component output of many sources is AC coupled (The transcoder itself actually is DC coupled). I haven't done any simulations on this item yet (I am now fixing our shower, tiling and all during my days off), but I am beginning to suspect that before processing the color-matrix I need to do a black level clamp on the back-porch in order to set a reference. As soon as I have this shower thing behind me and get some real time of from the wife, I will dive into this. It shouldn't make much of a difference where the black level restoration is done (either the transcoder of the projector), but I will verify this.


Kim

What is the status on this (component to vga transcoder)? Seems to have gone dead for a while. Did it move to a new thread or something?
Thanks,
kb

kb,

No it's not dead. Unfortunately I have to redo the bathroom because of leakage. This is taking way longer than I expected, and tiling a big portion of wall is not something that I do on a daily basis so it goes sloooooow.

As soon as I have this mess finished, I am back on the transcoder.

Kim

Are you soldering copper pipe ? The trick is to use emery cloth around the joint piece thats going inside(male end) so the scoring from the emery cloth is around the outside of the end of the pipe, also emery cloth the inside of receptacle piece(female end). Make sure to clean it well, then flux it well, put heat to one side of the joint and ONLY apply solder to the OPPOSITE side of the joint. This way, the solder will be drawn into the entire joint.
If you're working with PVC and/or ABS, make sure your joints are physically clean, AND chemically cleaned, and be sure you use the cement specified for the material. ABS cement will only work with ABS, etc. These basics(provided to me by my Dad, many years ago) shoud take care of your leaks.
And let you get back to the IMPORTANT things.

Paul,

Thanks for the tip. Luckily soldering is about the only thing I don't have to do. What went wrong is that water started to leak through the grout and over the years has eaten away the backer board and the sheetrock. The builders built it so cheaply that they didn't use a moisture barrier nor water resistant backer board. So I had to rip all that away, have a nest of carpenter ants exterminated that felt quite at home back there and dry out the soaked studs.

I am now in the final stages of tiling and hope to be finished by mid week.


Kim

Did you use cement board for a backer ? Its too late now but if you ever do it in the future, this stuff is GREAT. It can be immersed and not be damaged in the least. A little more expensive, but worth it and a great underlayment for ceramic tile.
Do you find tiling kind of fun ? My Dad was a general contractor who put ceramic tile EVERYWHERE. He felt it was so much better than the alternative and really quite easy to put in, I like tiling and find it is too easy to do and does its job too well to be replaced. Have fun with the job.

Yep, I used hardibacker cement board with a moisture barrier behind it.

This is my first time tiling and it is not too bad. The problem is, I am a electronics engineer and a perfectionist so it doesn't go quite fast because I want to do it right, you may know the feeling :)

Well the other shoe has been dropped by MP in regards to his platinum plated transcoder, so the hopes are all pinned on you now.

I did some internet searching the last few hours, and I found an easy way to do the black level restoration. This will mean that when I have some time of tomorrow before I start grouting I can finish the design.

By the way, are you saying that MP isn't finishing his transcoder or that it is way too expensive?

$799.list.

Paul,

Where did you find that, I didn't see it on MP's own website.

http://www.avsforum.com/avs-vb/showthread.php?s=&threadid=274865&pagenumber=2

Well,

The 19" case definately makes it more expensive. I noticed that it usually is't the electronics that makes up the price but the mechanics.

I read in his thread that he has a picture shift, is that important?

NO.

Neither is a 19" case or a burled walnut shifter or a milled titanium plated faceplate.
An affordable working example is much more desirable.

I can't speak for anyone else, but I don't need/want ANY bells and whistles, just value.

Originally posted by gn2
NO.

Neither is a 19" case or a burled walnut shifter or a milled titanium plated faceplate.
An affordable working example is much more desirable.

I can't speak for anyone else, but I don't need/want ANY bells and whistles, just value.

An "affordable working example" should be your goal, and you should use care to NOT talk against a product that you have no real knowledge of its value.

The next time you look to purchase a product, don't go where you can't afford. That way you won't find yourself wasting time blaming someone else for what you're not willing to spend money for. Myself, I would feel rather stupid posting negative comments about a product, simply because it's out of my budget range.

By the way, there are no bells or whistles on the transcoder. It has only two switches on the front, and there's nothing fancy about the case, which has very little to do with the cost.

It's what's inside that counts, and as you can see from the reports from those who've seen it in action - "it's worth every penny"

gn2 wrote:
> Neither is a 19" case or a burled walnut shifter or a milled titanium plated faceplate. An affordable working example is much more desirable. <

Paul, I understand where you're coming from, but I have to agree with Mike that this sounds like an unwarranted knock on his product. Mike has put a huge amount of time and effort into research and testing of numerous circuit designs to solve a multiplicity of technical problems, and come up with his trademark "super clean" implementation.

While everyone might wish it were cheaper, compared with other products in its price range it apparently does a significantly better job, and is cheaper to boot. That's real value, and for those who can afford it, a real bargain. We're lucky to have someone like Mike investing his time into creating products of this nature that solve real problems, and deliver impressive results. He deserves kudos for those efforts. And I hope he sells a bunch of them. (And I'm sure he will, from comments here in the Forum.)

OTOH, I'm in the same (poor man's) boat as you are. I can't afford one. :( But I still need a decent transcoder at an affordable price. That's why I'm happy to see Beun working on _his_ design. I hope he pulls it off, and it solves the major problems of the existing off-the-shelf low-priced transcoders. But I'm not kidding myself that it will be in the same league as Mike's transcoder. I think there's more than enough room for both of them to co-exist and meet the needs of different buyers.

Mike has been kind enough to post encouraging words here in the DIY thread, and I appreciate that. Who knows... since he's already solved the problems, he may share some tidbits of knowledge that will be useful to Beun. Regardless, I don't think that insulting and alienating Mike (or anyone, really) is a great approach.

Now, if Beun can just get that plumbing problem out of the way... :)

- Tim

While the technical folks seem to be reading....

Can anyone give a quick primer on the difference between RGB and RGBhv?

Personally I need a device that will let me watch my HTDV signals on my Viewsonic 22" computer monitor. This lets me only use the DLP bulb for movies.

The only device that I have seen in this category is the Viewsonic Nextvision N6. Is what you are designing similar? If so I would vote for just a straight dongle. Switching is easy enough that even I have a design. What you are talking about may be far more than I need.

Best to get experts opinions on this though...

THX
Chris

Chris-

The term "RGB" is often used just to distinguish signals with true individual colors (red, green, blue of course) from signals that mix colors with each other (component, s-video, composite). Video signals require horizontal and vertical sync signals as well as the picture information. RGBHV has the three colors and two sync signals on five separate wires. Computer ("VGA") signals are handled this way. RGBS has H and V sync mixed, with four wires carrying signals total. RGsB, also called "sync on green", mixes the H and V sync and adds it onto the green signal for three wires total. Component video also puts H/V sync onto one of its signals (Y).

The comments in posts 65 and 67 of this discussion refer to removing the sync from the Y component signal in addition to using it to create separate H and V outputs.

If this appears twice, I am sorry. James bond is on to "Die Another Day".

So if I follow what you are saying. My NEC LT-240 that can accept component and "RGB" would be both RGBS and RGBHV. It would also follow that there is circuitry in the pj to convert the RGBHV to RGBS?

So if I wanted to use an external scaler it must output 1024 x 768, which is my native format. For the monitor which can go far higher would be easier or harder for you guys to create a transcoder? Also would this be more or less helpful for the PJ? Bypassing the on-board converters?

Being a nerd in the Silicon Valley of the North, I am pretty confident that I could pass the word about an inexpensive Component (progressive) to VGA conversion / transcoder tool. I mean, it only took five minutes to convert me after seeing the Viewsonic Nextvision N6! This sounds even easier to use too.

Hope all goes well with the design.

THX
Chris

I have just finished the grouting (there is still more to do) and I am back on the transcoder. I had a few very technical revealing PM's with VideoGrabber and he pointed me to a few interesting websites. The conclusion is that I need to implement black level clamping (I have already done that) but I also need to do sync stripping and make sure that MacroVision doesn't screw up my system. I will keep you guys updated.


Kim

http://www.audioauthority.com/aacconsumers/9a62detc.html

Beun,

The above transcoder does do 1080i.

MrHifi commented:
> The above transcoder (AA 9A62) does do 1080i. <

I'm not sure where you got that impression, Art? I read in another thread that a rep from AA flat out stated that it did not handle anything beyond 480p. Also, Copperbox is a reseller of this unit, and this is what they had to say...

09A62 Updated 02-17-2003 info: The 09A62 supports input formats of 480i and 480p. 720p, 1080i, PAL, SECAM, and other formats are not supported. 480i support is limited. Many RGB display devices do NOT support this format. Before ordering, read the documentation included with your source device and display device to confirm support for 480i and 480p. Do not order this product if you need support for 720p/1080i or PAL 576p.Lastly, several members here (IIRC, Paul (gn2) among them) have indicated that the AA unit was a disappointing performer.

- Tim

<I'm not sure where you got that impression, Art? >

Please read the 4DTV Forum messages 3231.1-3231.9.

http://forums.satforums.com/SatForumMaster/index.php?webtag=4DTV&msg=3231.9

Hey guys, this would be my backup device. It does 1080i as well. They also have the revese.

http://www.ramelectronics.net/html/PC-TV_video.html#hd

Just my two CDN cents.
Chris

Art wrote:
> Please read the 4DTV Forum messages 3231.1-3231.9. <

Well, it's hard to argue with somebody who's actually doing it. :) Some of Nat's comments were a bit confusing and contradictory, but "my 1080i images on the 106 inch screen are unbelievably awesome. I have done comparisons, feeding the signal directly via VGA and using the RGB converter and can see no difference." sounds pretty definitive.

I just wonder if there's something unusual about the component video output from the HDD200, or the RGB inputs on his Runco PJ. It may have something to do with the fact that his PJ also has direct component video input support, and the VGA circuits have some special tolerance.

But it certainly sounds like the AA 9A62 is passing 1080i just fine. Perhaps Paul (gn2) will chime in here and re-iterate his experiences with the AA unit.

- Tim

P.S. Paraclipse 12, eh? Sweet.

Any other confirmed successes with the aa 9a62?
Barco success would be even better to hear about.
Thanks,
KB

One more vote for very simple design. Creeping elegance will kill me (and likely most of the others who just want to see thier christmas presents work - I am currently watching Leno in green monochrome feeding Y directly into my barco's Gs input just cause I can't take not seeing my new 811 do anything - BTW, I can tell just by watching the monochrome that it is pretty dang nice - I can't wait to see it with colors ;) (but I sure can't justify $1000 to do it - I would have to figure out how do it myself before I would pay that much, or much better, buy into Kim's design for DIY) ).

I just want to decode the component signal to RGB. I want to do it before I get too antsy and start trying the cheaper COTS solutions (i.e. AA). I think the majority feeling is that we all need something inexpensive and quick.

Kim's first design he put out looked like a great start. Can't we get that one to work (simple Y Pb Pr to RGB conversion) and *then* start adding features?

Thanks,
KB

I looked long and hard at the problem of sync-stripping and I have reached the conclusion that the only really right way of doing it is to use a micro-controller. In order to test the rest and to see the true necessity for sync-stripping I will make a few prototypes of what I have now. The transcoder now does:

1) Black level clamping at the input
2) Correct Sync separation for bi- and tri-level sync
3) A 720p/1080i color matrix
4) Automatic RGBHV bypass is there is no sync detected on the YPrPb input
5) RGBHV output with positive/ negative sync or composit sync on H

What I still have to do is finish the PCB, this will probably take me a week. I will keep you posted on the progress.

In the meantime I will teach myself micro-controller programming again, this will show my age but the last time I played with one it was called 8085.


Kim

Beun,

Sounds like exactly what the doctor ordered. You are a gentleman. Would that doctors acted as professionally as engineers do. If I can help test the prototype or whatever, I'll be happy to. I currently feed an RGBHV from my 4DTV/HDD200 and another RGBHV from a DTC 100 through a manual RGBHV switch. I could instead use the RGB outputs from the HDD200 into your transcoder and the RGBHV from the DTC100 through the passthrough RGBHV of your transcoder. The RGBHV out would go to the input ogf the Transcanner directly to the front projector. Let me know.

Art,

When you mean the YPrPb outputs of the HDD200 than yes, it would work. I am planning to built 4 prototypes, one is for me and you guys can fight over the remaining three :) .


Kim

Beun wrote:
> I have reached the conclusion that the only really right way of doing it is to use a micro-controller. <

If you share what functionality the mcu will be performing, perhaps some of us can lend a hand in the programming, or even possibly suggest ways to avoid it entirely.

> you guys can fight over the remaining three <

I think Paul (gn2) is most desperate ;) and he has experience with other transcoders to compare it to. Art (MrHifi) would be another good candidate.

- Tim

Originally posted by CRG64
So if I follow what you are saying. My NEC LT-240 that can accept component and "RGB" would be both RGBS and RGBHV. It would also follow that there is circuitry in the pj to convert the RGBHV to RGBS?
I do not know which RGB variations your NEC will accept-if it is not in the manual, you could ask in the projector forum. I would only "assume" that it can accept RGBHV, since that is the most 'universal' of them all.

An 'internal conversion' would only be from the "S" (composite sync) into separate H and V sync signals, not the reverse, since those two separate signals are needed in two different circuits in most display devices.

Tim


The problem is the following. In order to strip the sync, I need a signal that starts a little before the sync-pulse and ends a little after the sync-pulse. The output of the sync-separator is of cause a little delayed (about 110ns for a 720p signal) in the default mode of the sync-separator. When I use this to strip the sync, I will have a remaining needle (apart from some other minor issues).

The solution is the following: The Sync-IC can be programmed (3 wire bus) to output 512xHsync on one of its pins. This signal can be used to count to just before the next H-sync thereby making it possible to precisely strip the sync.

I am planning to use a simple PIC to do this, the PIC seems simple to program and there is a lot of stuff for it out there.


Kim

Kim,

I hope I'm not asking too much but... Could a version of your circuits be made available without the VGA or the Component pass throughs and without the sync stiping?

My Projector can do sync on green and I am looking for a DIY transcoder that can convert YPrPb to RGB, the simpler the better.


-Brian

You don't need any complex circuits to do the sync strip. Just use a modern video OP-amp with RRIO and a single supply. There are application notes in the data sheets from several manufacturers describing this. A RRIO (rail to rail input and output) OP-amp will limit the output to the power supply even if the inputs are driven slightly outside, so a small negative sync level will be limited to ground if the OP-amp is used as a buffer.

By the way...

I've been study-ing the circuits and it looks like there are some components are listed as resistors when they should really be capacitors. For example R10 R11 and R12 call for resistors with a value of 4.7. I think these are actually supposed to be capacitors with a value of 4.7micro-farads.

-Brian

Pucco,

Thanks for your input. (I'm not sure if your comment was a response to my question or just for the general discussion but if it was a resonse to me then My point is for now I'm not interested in sync stipping no matter if it's easy or not.)

I just want to convert a YPrPB signal as simply as possible to a RGsB signal.

I think, from a bunch of circuits I've found including the ones given here, I may be able to do this with only a few compontents.

-Brian

Brian,

No, those are resistors. They are just there to isolate the opamp a bit. They are probably not needed, it is just a security matter. What you want is not too difficult, the current design does this although the sync is output separately and not on green.


Pucco,

The problem with those things is that they only clip the negative portion, the positive part of the tri-level sync will still be there. I have been pointed to some evidence that the lense flare of this big (light gray/white) pulse just outside the visible area is still a problem.

Beun,

Your drafted circuits look very nice. Any chance of a maximally simplified circuit that only converts YPrPb to RGsB with no passthroughs?

Thanks and Good Luck,

Brian

p.s. I will be interested in the full circuit after I make something that will let me get by.,

Beun,

Tri-level sync, I had to check what it was before replying again. :D
I looked in to your schematics and the data sheet for EL4511 and one solution for the blanking could be a RRIO OP-amp to clip the negative part and then use a SR flip flop with SYNCOUT (EL4511) as set and BACKPORCH (EL4511) as reset and force blanking during SET.

Beun,

You can make a SR flip flop with one of the spare buffers, a resistor, a diode and a transistor. :D :D :D

Brian,

Sure I just have to leave out some stuff from the board.

Pucco,

I will look into that and hope that there isn't a needle left. Also, do you have a recommendation for a rail to rail video amp with a bandwidth of at least 200MHz?

Beun,
One perfect candidate would be AD8061 from Analog Devices, it has examples of sync stripping and video buffering in the data sheet.

Beun wrote:
> The problem with those things is that they only clip the negative portion, the positive part of the tri-level sync will still be there. <

That's true, and I was about to make the same point. However, if such an OA can adequately handle removal of the negative portion of the tri-level sync (which precedes the +300 mV sync pulse), the leading edge of the negative sync could trigger gating/clamping for sufficient duration to eliminate the positive sync, without requiring a high timing resolution programmable counter to establish its temporal location.

- Tim

[NB: I started writing this during lunch, and just got back to finish it now.]

Kim,

I realize that what I'm looking for just calls for leaving stuff out.. But, what I was asking is could that circuit be described so that I can go build it?

-Brian

Ditto to all Brian is saying. I would be very happy to leave sync on green and jsut get the color space issue resolved (i.e. get from Y Pb Pg to RGsB).
I still think your original design was nearly there. I have even considered just going to get a couple of single channel video amps from radio shack to boost red and blue and see what happens (likely some bandwidth problems with cheap COTS amps at RS but worth a try - I am sure getting tired of watching green monochrome Leno ;) ).

Brian, if you are interested, I would be up to starting to try to get Kim's initial desing going. I have no lab setup at all - I am on vacation and can't even tinker at work. But I have a feeling we could get fairly reasonable results with a little help here and there from Kim. I am pretty rusty ( I let myself get sucked into 'management - i.e. brain freeze' and haven't touched a resistor in years - I am apparantly from the same era as Kim as I fondly recall playing with the 80xx family as well - I didn't feel too old tell he pointed out that knowing what an 8086 is makes you so. But, I am desperate enough to jump in and try. I am on the verge of ordering one of the cheap, crushed black units everyone is saying work fine.

Anyway, I think if we can trust the formulas Kim put on his first design and implement them, it should work. I have noticed that when I put the Y directly into my Gs input, I get a very strong clear (green only) picture that is apparantly at nearly the correct level. My Barco is also doing a little bit of transcoding (actually it is probably only rgb balancing) such that I get quite a bit of red information and very slight blue. If I hook up Yb to blue and Yr to red, the levels increase significantly and I can actually see them if I turn brightness up (way up) but then green gets too bright and red and blue get 'washed' out (but visible). It thus seems to me that the sync issue (while possible relevant to bandwidth robbing issues) is not critical. If we can just get the color balance correct without washing out any colors and maintaining a black level, we will be mostly there.


If the sync really is an issue, won't the 4511 in Kim's second design take care of it?

What can I do to help? Again, I am rusty, but eager. Let me know what I might be able to do to get a quick and simple test breadboarded.

KB

KB

I can throw you a simple transcoder schematic tomorrow. It will have the black level clamping at the input, sync separation, the color matrix and sync on green. This should probably be Ok for you you to start building and to recognize a resistor again :)

Well,

I'm set to start building. I'm also in the same boat as KB... My Christmas present isn't going to work without a transcoder. I think I may start a DIY transcoder thread in the DIY forum and post my experience in trying to realize one.

From what I've read... If you don't strip the sync you get the crushed blacks unless you have a projector (or monitor) that can Sync on Green. Well, I have a projector that can sync on green so I think I can get by with leaving the sync on green.

-Brian

Originally posted by Brian Hampton
From what I've read... If you don't strip the sync you get the crushed blacks unless you have a projector (or monitor) that can Sync on Green. Well, I have a projector that can sync on green so I think I can get by with leaving the sync on green.

Brian,

If your projector supports sync on green, wouldn't one of the cheap CTCA2 clones work for you?

http://www.dcslinks.com/catalog/product_info.php?products_id=452

Bob

Yep,

I guess it would. But.. I don't know if it will be good enough. There doesn't seem to be a power supply for those units so I don't know how they work.

My hope was to build something similar to one of those units for now and then to build something eventually that does the whole sync stripping to provide RGBHV.

I may go ahead and order one of those anyway though, could be easier.

-Brian

<There doesn't seem to be a power supply for those units so I don't know how they work. >

It says it comes with a power supply.

http://www.dcslinks.com/catalog/product_info.php?products_id=452

I wonder if we could purchase one, take it apart and see what you get for $54.00 + shipping. How does it differ from the Key Digital for $279.00 + shipping

<http://www.digitalconnection.com/Products/Video/kdctca3.asp>?

This one also looks interesting.

http://www.zektor.com/hds4/index.htm

But I wonder if they all rely on the same electronics?

These are three units that will do the job. Beun, I believe you need to see how their designers solved the problem.

Hi,

Well it looks like I could get a working solution for $74 shipped but I don't really have that much for the Home theater budget just now. (Having just bought a DVD player and x-mass presents and so on.) So If I go that route it has to wait. But, if I do go that route I'll certainly take the device apart to see what's in it.

On the other hand, from study-ing Kim's circuits (both revisions) I think I can derive what's needed to make the adapter and it looks to be a simple enough project that I can get started. I plan to build the circuit to be inserted into a DVD player and use the power supply inside the player which should simplify things ever further.

Good Luck,

Brian

MrHifi wrote:
> These are three units that will do the job. <

That's just the problem, Art... they don't do the job. The Zektor HDS4 isn't even a transcoder at all, it's a passive component video switcher. The "VGA Box" from DcsLinks is similar to the A2, and has mixed reports of "sorta working" on some CRTs and poor performance on others. It does NOT strip syncs.

The A3 is newer and sounds better on paper. We also know from Cary's scope capture that it does a decent job of stripping tri-level sync (though it does leave significant spikes behind). Whether this is really adequate is still questionable, and even though it's an "inexpensive" unit by perfectionist standards, it still costs more than my JVC 30K D-VHS HDTV VCR, and the other refurb decks many of us were lucky enough to get.

I'm anticipating that Beun's final design will be both a better performer, and cost about half as much.

Brian wrote:
> Well, I have a projector that can sync on green so I think I can get by with leaving the sync on green. <

You might be able to, since it would certainly depend on your PJs' input circuits, but keep in mind that the RGsB sync the PJ is expecting is bi-level, not tri-level. Also, my understanding is that HiDef component video has tri-level sync on ALL 3 of the signal lines. So it might not work as well as you're anticipating. It's worth a try though, even if just to confirm or refute the need for more sophisticated signal conditioning.

- Tim

I included the HDS4 for those who are trying to solve a "system" installation roadblock. I realize it is not a transcoder and should have been more selective in my description. The A2 and A3 are used widely. I realize the limitations but before trying to reinvent the wheel, I always at least performed a "literature" search to see if I could avoid developing a new device or test method where one already existed.

Attached you will find a very simple circuit that performs the black level clamp, the color transcoding function and the sync on green generation. Everything else has been removed.

Please realize that the circuit isn't perfect, I just now see how large the residual sync on the outputs actually is.


Kim

Kim,

Thanks. I can't read SCH files though.. what program is used for them?

I started a thread about DIY transcoders in the DIY forum too in case you want to check it out.

Thanks and Good Luck,

Brian

Brian,

The program used is the free software from www.ExpressPCB.com

I will look at our new thread.


Kim

Kim,

Actually... this is your show so if you want to start a thread there (or have this one moved there) then I'll remove mine. That way you can give it the direction you like,

-Brian

Have you eliminated the RGBHV passthrough?

Brian,

I don't think it is my show, it is our show. I am just the starter of the thread and perhaps the most experienced designer ;) but I value anyone's input, hardware design wise, software design wise and high level specification wise. It may be that I started the thread in the wrong group and I certainly don't think that a second or third thread will take away anything from this group effort. (I just saw a typo in my previous reply, I meant to say "I will look at your new thread", might this be the reason of your remark?)

MrHifi,

Not at all, I just put a simplified schematic out there for the people that would just like sync on green and nothing else. I am still going on with the original one, first produce a test board that has everything on there except the sync-stripping and atfer that design one with perfect sync stripping. I am already PM'ing with a member that is experienced in uP programming and who is interested in lending his experience.


Kim

Kim,

I just re-read this entire thread and thought I would post my suggestion...

You should go ahead with a simple version that has component in and VGA (RGBVH) out and put it up for sale ~$150 if possible.

I'll certainly be interested in buying one regardless of how my own DIY attempts pan out.

I don't think anyone wants any type of passthrough or switching except for MrHiFi and It sounds like he need a switcher and a transcoder.

I'm sorry I detracted from this thread in looking to cut a few quality corners for my own needs. I think there is a real market for an enexpensive quality simple unit that does nothing but sync stripping and color space conversion.

If I can help... I would love too. And I seriously want to order one today.

-Brian

<I don't think anyone wants any type of passthrough or switching except for MrHiFi and It sounds like he need a switcher and a transcoder.>

You are just flat wrong. Check the following messages:

Steve 10/08/03
Briands 10/09/03
BGPGuy 11/11/03
Gordf 11/12/03

They appear to want a passthrough also.

I was quite clear on what I needed and explained why I and others needed it.
For your sake and for those who may have missed it, I will again attempt to clarify/restate the issue so that you do not have to interpret my words--"...sounds like he needs...".

Situation

Owners of monitors with RGBHV inputs have been using input devices with RGBHV outputs. These include devices like Progressive scan DVD players, HD satellite decoders and OTA ATSC receivers. Some may have only one device, others systems may incorporate multiple RGBHV output devices. In order to choose between the various input devices, a switcher with multiple RGBHV inputs and at least one RGBHV output is necessary. Many of us bought or built a device to perform the RGBHV selection function. The fact is that most owners of projectors are going to have input devices with RGBHV outputs already connected to their monitors/projectors.

Problem

Owners of RGBHV output equipment want to continue using one or more existing RGBHV output devices while incorporating into their systems newer input sources which have only component outputs--3 wire RGB--. One can not connect these to a monitor with RGBHV inputs without a component to RGBHV transcoder.

Transcoder

The existing RGBHV device's/switcher's output would go to the RGBHV input/passthrough of the transcoder. Component output devices would be connected to the component input of the transcoder. When there is no active component imput, the RGBHV passes through. Alternatively, the circuit could be designed so that if there is an active RGBHV input, it passes through to the RGBHV output of the transcoder.

The passthrough permits seamless incorporation of previous equipment.

Summary

Most existing users will have devices with RGBHV outputs and want to incorporate into their system newer equipment with Component only outputs.
A Component to RGBHV Transcoder with an RGBHV passthrough is the only practical solution.

Afterthought

Owners may still need to use an RGBHV switcher. Most of us have RGBHV switchers whose inputs are completely used. The transcoder can be used either before or after the switcher. I will agree, however, that if the RGBHV switcher's inputs are not fully utilized, a device without passthrough can be utilized. No matter how you incorporate a transcoder, you need a passthrough in order to accomodate existing equipment.

"Most of us have RGBHV switchers whose inputs are completely used."

Are you making this stuff up. I own a projector with RGBHV input but If I want to have more than one input I can buy a switcher. A transcoder doesn't need to also be a switcher.

I wonder who this "most of us" is.

What I see is a petty attempt to save a few dollars holding back a great idea from comming to market.

Face the fact that you want transcoder+switcher. Switchers can be bought serperatly and are easily available. If most of us have switchers with inputs used up, and I am clearly not in that catagory, then we need more switchers or switchers with more inputs.

"No matter how you incorporate a transcoder, you need a passthrough in order to accomodate existing equipment."

Wrong. For example, If I want to keep my HTPC and also run progressive scan dvd player I can transcode the component output of the progressive scan dvd player into RGBHV and then hook them both to a switcher or I can use my second RGBHV input on my projector. Two ways to accomodate existing equipment.

Both BGPguy and Gordf stated in thier posts that a transcoder with pass through would be nice but they would be happy to have just a transcoder if that was easier. In the words of BGPguy "RGBHV passthrough is very nice, but if it means I settle for crushed blacks or can't afford it, drop it."

-Brian

MrHiFi,

I imagine that some users want the pass through because thier MP1 modded PC could then be used with the component sources which are switched by a AV Receiver.

In that case the pass through will be a great thing to simplify stuff.

I personally don't need or want a passthrough but ... I guess it doesn't add much complexity to the system and so it's mute point.

-Brian

Although this is probably Newbie hubris (& risks derailing the thread in the hope of not derailing the thread), why not use Belkin Omniview SE Plus as a VGA switcher? LA Audiofile Review, Sept 2003.

Brian wrote:
> I don't think anyone wants any type of passthrough or switching except for MrHiFi <

I can back Art up that this is not a correct statement. Having an RGB passthrough will be useful to many folks, simplify the system operation (since it's fully automatic), and minimize extra components/stages for switching. It's not like this feature is either difficult to design or implement, will add significantly to the cost, or will slow down the release process in any way. Other factors are responsible for that. So I think it's a big win to include it.

OTOH, I also think that Art overstates the case with several of his comments, similar to "an RGBHV passthrough is the only practical solution" indicating this feature is an absolute requirement. Those with an extra input port on an existing RGB switcher wouldn't need it (though the transparent switching of a passthrough would still be a big win in my book). Those without RGB switchers could add one for far less than the $200 figure Art mentioned. New KVM switchers with 200 MHz bandwidth and a full set of cabling are under $70, and used 4-port switchers with 100-150 MHz bandwidth can be had on eBay for $10-20.

> it doesn't add much complexity to the system and so it's mute point. <

I agree (it's also moot ;)). Let's keep things cordial here, and not alienate those who have needs slightly different than our own. We can all come out satisfied, and dropping minor tweaks isn't going to accelerate the process for those anxious to get a unit immediately. Kim will release a product when the sync issues are resolved satisfactorily, so we have a high-quality solution that's not a compromise like many off-the-shelf options. If you can't wait that long, and I realize that some can't, you can breadboard or wirewrap your own unit using the info in the schematics already posted. The passthrough circuitry is trivial to excise.

- Tim

I guess it's not the inclusion of the pass through that would possibly hold things up it's the IR /RS232 switching since that calls for a microprocessor and Kim has mentioned this would be an area where he would need help.

I do plan on using the scematics and building a version (without passthrough) because I don't want to wait (and because it sounds like fun.) But I would likely be interested in buying the finished product as well is the price was low enough.

Kim,

What kind of power supply would be used with this? I see the circuits for the internal supply but what would the external (Wall Wart) specifications be?

I think Radio Shack does have everything I need to build a simple version (no sync stripping, no clamping.) Maybe thier opamps are crap but I could build a simple prototype and then order better components after.

-Brian

Brian,

It uses a walwart supply, it is a 9-12VAC output that you can buy from digikey or mouser (AC output is important here, don't use one with DC output). Internally, two diodes rectify and the regulators make it a nice +5 and -5V supply.


Kim

I would be interested in this even without the passthru, but I thought it was a pretty easy add. If the passthrough bandwidth is impacted though I would rather buy seperate switch.

Maybe we should start a thread for a DIY RGBHV hi bandwidth switch. Granted there are Extron units on ebay all of the time, but I really don't need an 8 chanel switch.

I can draw up the schematic of those switches in a very short time if anybody is interested, were you looking for 2 and 4 input.


Kim

Does no one understand my point? Any RGBHV output equipped device must still be connected to the monitor. You must have something that selects either the old RGBHV output equipped devices or the new component output equipped devices. That is why the devices already for sale have the passthrough. It's not rocket science guys. There is a practical reason for the passthrough. The passthrough's addition is inconsequential to whether the transcoder's design achieves a better overall conversion than those already on the market. If you make the selection of component vs. RGBHV automatic by the monitors sensing a sync on the RGBHV, you have produced a transcoder that does what others now do but with a much higher level of picture quality. Beun, verify for me that the addition of the passthrough will add no more than a couple of percent to the final price. That seems to be everyone's main concern. Let me say finally that you never design a new product with less functionality than its predecessor. Quality is important but it still has to be functional.

Art,

I am fine with the passthrough function, the YPrPb passthrough is only 3 resistors and a connector, the RGB passthrough is a triple opamp a few resistors and a connector. It barely complicates the design and if anyone doesn't want it I can leave it off.

Originally posted by MrHifi
Does no one understand my point? Any RGBHV output equipped device must still be connected to the monitor. You must have something that selects either the old RGBHV output equipped devices or the new component output equipped devices. That is why the devices already for sale have the passthrough. It's not rocket science guys. There is a practical reason for the passthrough. The passthrough's addition is inconsequential to whether the transcoder's design achieves a better overall conversion than those already on the market. If you make the selection of component vs. RGBHV automatic by the monitors sensing a sync on the RGBHV, you have produced a transcoder that does what others now do but with a much higher level of picture quality. Beun, verify for me that the addition of the passthrough will add no more than a couple of percent to the final price. That seems to be everyone's main concern. Let me say finally that you never design a new product with less functionality than its predecessor. Quality is important but it still has to be functional.

I agree. I prefer it as well, but if it adds unnecessary complexity or seriously degrades the quality of the passthrough signal it may not be worth it. There will always be a compromise on the autoselect feature as well. I plan to pass my HTPC via the RGBHV and connect a Motorolla 6208 HD PVR cable box to the componant. I do not know what will happen when I am watching a DVD from the HTPC when the PVR comes on in the background to record. I do not know if "background recoding" activates its output. Will it "steal" the switching? I would probably benifit more if the passthrough priority was given to the RGBHV because I can easily switch the output of my graphics card with an IR command.

Kim,
Thanks for the new link to your new drawings. I just started looking them over. Why the change in amps from your first couple of releases (I'm just trying to learn and watching your development process can help).

I couldn't take it any more. I had to see my christmas present work somehow so I broke down and ordered a korean kd knockoff. Unfortunately, I did it for $70 before I saw the link someone put above for the $54 one. Dang it.

Anyway, when it comes, if you see any serious value in looking inside it, could try breaking it open. From the picture, it looks like a molded case so it would take a pretty destructive open procedure. If you really think it would help as some have indicated above, I could give it a try.

I am still going to try wirewrapping the design from your last link. Thanks for the link to the drawing package. I was wondering why you were giving us you microsoft scheduler files ;) (they wouldn't open with Scheduler - obviously).

One thought since we seem to be debating if this is going to be a do all box - the knock off has a dip switch for neg/pos sync. Reports are that it works for getting into a barco without need for an additional box (extron or altinex sync conditioner). Seems like an easy addition to eliminate another $200 box (I already have one, but the fewer I have to put in the line of processors the better).

Let me know if you want to see whats inside the kd knockoff when it comes.
KB

Krbennett,

That is the kind of positive, constructive recommendation that makes a product more useful without compromising its real value/

Beun,

The dip switch idea sounds like a good one. It certainly will make the tanscoder more universally acceptable.

krbennet wrote:
> Thanks for the new link to your new drawings. <

Was this via private communications? I haven't seen any new links in this thread for a while (the Dec18 schematics).

> the knock off has a dip switch for neg/pos sync. Reports are that it works for getting into a barco without need for an additional box (extron or altinex sync conditioner). Seems like an easy addition to eliminate another $200 box <

Kim's design already has jumpers to select postive or negative syncs, so this capability is already in place. DIP switches are convenient, but for something that gets set once and never touched, having jumper headers is superior because they can be placed local to each circuit (rather than all routed over the PCB to the central DIP switch), and changed with a 0.1 cent jumper.

- Tim

Tim,

The schematic for the simplified transcoder (no passthrough) is in post #129. you are right, the design already has jumpers for pos/neg/comp sync, when it is in a case I might change it to DIP switches and a mux.

KB,

I changes the opamps at the input because they do black level clamping, thereby solving one of our problems. Can you send me the link the the real cheapo knockoff, I may just buy it to open it up myself.


Kim

beun wrote:
> The schematic for the simplified transcoder (no passthrough) is in post #129. <

Thanks. I was confused because previous posts had the schematics in PDF form, as well as SCH, which I mistakenly assumed was some form of PCB layout image.

> Can you send me the link the the real cheapo knockoff, I may just buy it to open it up myself. <

Art already posted this one a while back, from DCSlinks...

http://www.dcslinks.com/catalog/product_info.php?products_id=452

It's $54, plus around $20! for shipping. May take a while to receive, since it's shipped from overseas. That's the cheapest one I've seen, and still seems to be available, unlike the Canadian options.

Before you go to the trouble and expense of ordering one though, you might inquire here if anyone already has one that they're willing to part with.

- Tim

Well, it looks like I spoke too soon. Currently, DCSlinks has no units in stock, with no indication of if/when they anticipate getting more in.

- Tim

The lack of availability tells me that this is a high demand item. Think about it. There are two decades worth of projectors out there that need such a device to be compatible with most of the newer equipment.

This one made for Xbox component to VGA but you can just cut the connector off and rewire it with RCA jacks.

I think these get shipped from China/Taiwan so there is shipping charge of $10-$20.

resolution suggested the x2vga:
> This one made for Xbox component to VGA but you can just cut the connector off and rewire it with RCA jacks. <

An interesting option. Thanks for the reference, which for those not already familiar with it, has info available at x2vga.com. One alternative I'd suggest is that rather than hacking off the XBox connector, make a breakout cable from XBox to RCAs (assuming connector availability). That way, when the Beun-transcoder is complete, you can sell the x2vga on fleaBay. :)

From the sound of their website hype, backed up by several reviews, they seem to have solved the sync/brightness issues. Check out a glowing review here... http://www.xbox1.com/article-expand.asp?i=835

> I think these get shipped from China/Taiwan so there is shipping charge of $10-$20. <

$13. Total cost $78. Plus they'll throw in a 2-port RGB (mechanical) switch for an extra $5 shipping charge. Delivery to the US, 1-2 weeks.

- Tim

Kim,
Where can I find a data sheet for the new amp on line? I searched for a while with no luck.

Also,
As others have said, the $54 one (KD knockoff) linked higher in this thread is gone. If you want a $69 one (best buy I could find without some bizzare payment and shipping requirements) I ordered one from a guy on ebay (just happened to be 30 minutes from the end of an auction when I searched for it so I grabbed it - sure he has plenty more he'll sell for the same price if you email him - his
buy now was $99, whatever)
Try an email to: Super_deal4u@ hotmail.com

BTW, jumpers are fine by my vote also - I'm wirewrapping anyway so I plan to cut every corner like that there is. Wife messed up payment on the box I ordered so it will be a few days longer and I want to see that 811 run so I guess I will for sure be building tomorrow or at least looking for parts.

Tim,
The 'simplified version' has no jumpers or neg sync capability (deleted from the original Dec 18 version) from what I could see - but then that was the point - simple. BTW, it is also dated Dec 18 on the schematic (but likely a couple weeks more recent than that). From Kim's comments above, I assume it will be part of the final full design. He was nice enough to give the impatient among us something easy to start playing with (thanks again Kim).

KB

Kim,

I hate to keep asking for status update, but I keep reading (in the Local HD thread) all of the guys gloating about their new HD PVR cable boxes. I just wonder the status of this. I've looked over the schematics and (though I've never done that kind of thing) I think it might be fun to try. What do you anticipate for a ship date for the finished unit and the parts kit (board and enclosure)? Do you anticipate a version with BNCs for the RGBHV in and out?



If it will be a while, maybe you can answer the following:

I found the pars list in the .sch file, but is there any additional info for the componants? Have specific tolerances been assigned ( as well as say ... types of caps) I know there are different types and grades, etc...

The only other part of the prints that has me a bit confused is on the sync sheet (p2 of 3 on the simple version). On the little part at the bottom, where do the nodes 4, 6,8,10 and 12 connect?

Where would you recommend getting the parts? What would you expect the whole kit of parts to cost (for each version?)

If a board is not available, how would you recomend building it?

Can you reccomend a nice safe test that will not result in letting the magic smoke out of any connected devices ie projector or HD cable box???

Thank for all of your help.

The datasheet for the opamps with black level restoration can be found as follows (for some reason Zetex doesn't show the URL)

1) go to www.zetex.com
2) type in 4089 into the search box
3) follow the links


The resistors are 1% yageo (I use surface mount, you probably want through-hole), and the capacitors are film type, use panasonic ( the not too expensive ones) or BC components. All these can be ordered from digikey. The opamps are surface mount they don't come in through-hole. The additional inverter outputs go nowhere, just leave them open, I just have to connect the inputs because CMOS inputs cannot be left open.

I just realized that in order to partly strip off the sync for R and B another opamp could be chosen that is powered between 0 and 5V (instead of -5V and 5V). The opamp to use here would be the suggested AD8061. This would at least strip off the negative portion of the sync on R and B. I will see how soon I can update the schematic for that purpose.

As for a status update I will do my best to get it done as fast as possible, but unfortunately there is lot of stuff going on at my regular job so my time is limited (whose isn't).

Thanks Kim.
Appreciate your guidance.
Will start trying to get stuff together.
Any suggestions on how to get a surface mount chip into a wirewrap socket or breadboard somehow? How do you even get them onto a PCB without flow soldering?
KB

Originally posted by krbennett
Any suggestions on how to get a surface mount chip into a wirewrap socket or breadboard somehow? How do you even get them onto a PCB without flow soldering?
KB

You can solder small pieces of stripped wire wrap wire to the legs of an SM part fairly easily. There are some SM -> DIP adapters available (perhaps pomona make some) which you can then set into a wire wrap socket. I suspect they will be expensive however.

To solder an SM part to a board, you just place the part on a board, apply some flux and solder the regular way. I usually use SM parts in my design because my opinion is they are much easier to work with than many of the through-hole parts.

The only parts that really need one of the process soldering methods are the ball-grid array (BGA) packages. For prototyping with those, you can purchase BGA->PGA adapters, just in case you cook the parts.

Thanks, I'll give it a try.

Originally posted by krbennett
Any other confirmed successes with the aa 9a62?
Barco success would be even better to hear about.
Thanks,
KB

I tried this solution to go from my Samsung T-151 to my Loewe 30" Aconda as was recommended by my local dealer. At 480P the picture looks very good and the colors seem dead on in comparison to the other connections. However, if I switch the T-151 to 1080i the resolution on the TV is AMAZING but the colors are off towards green and the picture is much darker. It is watchable but not ideal by any stretch. I tried correcting it but I just could not get the color to be correct. I am wondering if this is why it is only rated at 480P.

It may also be of interest to note that I also tried a couple of Key Digital adapters that did not work at all (xbox version and the ctca- 2). The only one that Loewe says will work with my display is the newest ctca- 3 adapter (which is the only one I have not tried).

I am going to stick with the AA option for now as I have already spent way too much on various adapters and I was not all that impressed with the Key Digital build quality.

Just thought I would add my .02.

First of all, I would like to say thank-you for this thread. It has given me a lot of answers to questions that I've been trying to resolve lately.

I've been reviewing the schematics (most recently the sync on g with vga pass-throug) and I have a question: what part of the circuit does the blanking of the sync puleses so that they don't end up on the rgb outputs? Also, I have an older projector that is rgbs (no hv sync), do I need the el4511 and 74ac240's? Can I use an lm1881 to pull the composite sync off of Y to feed the sync output?

Thank-you again for freely sharing your time and efforts.

Roger

Roger,

There are two schematics in this thread. One with YPrPb and VGA passthrough that has no sync on green but does RGBHV and RGBS and there is a simplified schematic with sync on green that has no pass-throughs. Neither has any sync stripping yet. This is still something that has to be designed. I know how I want to do it (uP) but I still have to do the work. The advantage of the EL4511 is that is handles tri-level sync correctly, the LM1881 being much older doesn't do that.


Kim

Wow, thanks for the fast reply.

Do I need to worry about tri-level sync on an older machine? I don't need the HV sync, just a composite. Can the EL4511 provide composite sync as well? I've reviewed the schematics, and the only option for sync output is a jumper setting for normal/inverted sync.

Is there much interference on the output imposed by not blanking the sync pulses? How many off the shelf units provided a blanking generator in the design?

Roger

ok, I found the jumper (jp5 jp6) to select RGBHV or RGBS.

How complicated is it to implement a blanking generator into this design?

Roger,

The EL4511 provides the composite sync output and when I remember correctly, there is also a jumper for composite sync. You need to worry about the tri-level sync, because that is what the off-air/satellite HD-receiver produces and this needs to be correctly converted to HV or S sync.

In my opinion the remaining sync in the RGB signal should not be a problem if a correct black level clamping is performed, apparently many projectors do not do this.


Kim

Oops you beat me to a reply. I plan to use a micro controller to generate the sync blanking pulse. It is not difficult, it is only counting clock edges. I am just a bit rusty on this so it may take a bit longer.


Kim

roger_ingram asked:
> Do I need to worry about tri-level sync on an older machine? <

I can't think of any reason why you wouldn't.

> Is there much interference on the output imposed by not blanking the sync pulses? <

Yes. Worse is that the positive-going pulse in the tri-level sync actually feeds into the color decoder matrix, shifts the level and skews the output.

> How many off the shelf units provided a blanking generator in the design? <

The CTCA3 is the only one we know for sure strips the syncs (at least mostly), though whether it uses a blanking generator or not is uncertain.

- Tim

again, I'm impressed.

On your first designs (yuv & rgb pass-through), you've passed the signals through two sets of op-amps (LT1399). On the simplified version, you've used the ZXFV4089 as the first stage. Is the later version for the dc restoration and black level clamp? Is this a better option than the LT1399 or are they interchangeable?

Correct me if I'm wrong, I'm still new on video circuit design:
Is the first stage compensating for the attenuation on the Pr & Pb signals to equalize them to the Y signal and the second stage is the math to restore the original rgb information?

I got the KD knockoff the other day and it worked great right out of the box! I have spent most of my spare time the last week tweeking my PJ to get it looking better with the new signals. Honestly, it looks so good, I don't know if I will build one now. It is cheaper than parts and didn't take any time to build. It may be worth a try for the cost. I didn't even need to break out an extron box to fix sync issues. It worked great without it (has a dip switch for neg/pos sync, but it worked so I didn't mess with it). I guess I am still not sure how to identify 'crushed black' since I see nothing wrong with this picture. I think I can see pretty good details on very dark objects - I think even better than with DVD (vs HDTV). The 'philes' will likely think I am too stupid to see how bad my picture is, but it looks pretty dang good to me and that is all that really matters (BTW, I *am* very picky - I have been tweeking my barco several times a week for 6 years and have been designing flight simultors with Barcos for 17 years so I actually do have a decent eye - I am just the kind of guy that takes the side of radio shack cable vs Kimber Kable every time - my spectrum analyzer can't be wrong ;)).

I paid $70 so I could get it off ebay through a US located distributor. You can find links on this forum to get them for $54 with some odd shipping and payment issues if you like living on the edge.

Kim,
If you think it would help you any, I could crack it open and look inside. Someone else reported that they had done this and the numbers were scratched off the chips so it didn't help much. If you want me to try, I could, but I hate to take a chance on damageing it if you don't see a real serious benefit. I would be anxious to try an A/B test with one of Kim's designs at some point just to see if there really is a difference. I would be the first to buy one if there is.

I think what Kim is doing is great - incredible! There are many who will find that there is not an inexpensive COTS solution to getting component to work on their display (I hope I didn't use all my lifetime's remaining luck on this one). I am willing to bet that when Kim is done, his DIY will provide a great solution at a cost that most can live with. I bet 99 out of 100 people won't be able to see the difference between his and the $1000+ transcoders (extron, altinex, etc.).

And he seems to be doing it just to help. What a great guy. Thanks Kim.
kb

Originally posted by krbennett
I got the KD knockoff the other day and it worked great right out of the box! I have spent most of my spare time the last week tweeking my PJ to get it looking better with the new signals. Honestly, it looks so good, I don't know if I will build one now.

krbennett,

What projector are you using? I'm wondering if it's because yours handles clamping that you can use the cheap transcoder.

Thanks,
Bob

Roger,

The ZXFV4089 that I use in the later schematics does the blacklevel clamping (the LT1399 doesn't do that so they are not interchangeable). The first stage with a gain of 2 is there for buffering and as passthrough amplifier (two birds with one stone) The following stage indeed takes care of the color matrix.


KB,

I am glad you found a transcoder that works. I just received a KD-XB and when I opened it up I saw that all IC markings had been filed off. I therefore assume that in yours it will be the same. Please don't destroy it just out of curiosity, I think I know what to do, I just have to do it. I didn't have the time yet to do some measurements on it to see what it does to the sync but I will soon.

I will continue with the design as started here not only because I just like doing it but also because I think that there is room out there for an affordable and technically sound design.

I also ordered one of the Key Digital Clones on ebay for $69.99. It should be here tomorrow according to UPS tracking.

I wanted to build one or buy Beun's model ("who can resist a project called AVS transcoder"?) but I think this cheap versions going to be just fine.

MrHiFi is right... It's sold out in some places because of the great demand for this type of device. (Surprizingly, it's in demand even though it doesn't have a pass through:cool:.)

Good Luck to those still working to make this happen.

-Brian

What is the effect of no sync blocking on the output? jitter? what?

I'm going from an NTSC-RGB decoder to a component-RGB decoder, so either way, I should notice a HUGE improvement. Not only that, but I will be able to enable to progressive scan on the DVD.

Originally posted by cerulean
krbennett,

What projector are you using? I'm wondering if it's because yours handles clamping that you can use the cheap transcoder.

Thanks,
Bob

I have a Barco BD800 - bottom of the 8" line (but I still love it ;)). I have also tried it successfully on a 1208 at work (btw, I like my 800 picture much better than the 1208 - don't know why. Some folks say the filters on the 800s are better for video. Don't know if that is it or just that I have spent 1000000000 hours tweeking my 800 and not a lot of time on the 1208, but I would not trade it for the 1208 - ok maybe I would (it's much sharper - 800 is pretty soft)). I have spent 17 years designing flight simulators using Barcos for the display systems. Every time I build a new simulator, I go check out the competition and every time Barco comes out best (IMHO). My 800 dang near works with component input directly into the RGB (just some color mapping problems but it syncs fine). The barco rep seems sure that 's' models should work great directly connected to component signals (unadvertised feature).

I think the knockoff must actually be an improvement on the KD-CTCA2, which many report will not work on a barco. The 'knockoff' I got from ebay appears to be more of a KD-CTCA2 than the XB. The 'knockoff' I got worked great right out of the box. Has 9 dip switches to set up for your machine (pos/neg sync, RGsB/RGBH/RGBHV, etc). Didn't even need to stack on the extron to resolve sync issues. Search for transcoder on ebay and look for a $69 unit - sold by someone like deals4you.com for something with *4you.com in the name. Got it in a couple of days, shipped from California, paid with paypal - all very easy and fairly safe (at least it seemed safer than some of the wierd shipping/payment options from the cheaper korean distributors).

good luck.
kb

KRBENETT,

Your description was pretty good but I can't find the transcoder on ebay (Even searched previous auctions).
Can you dig up the name of the seller or name of the product as it listed.

Thanks !
SR

http://cgi.*********/ws/eBayISAPI.dll?ViewItem&item=2980927530&category=21169

Originally posted by srej
KRBENETT,

Your description was pretty good but I can't find the transcoder on ebay (Even searched previous auctions).
Can you dig up the name of the seller or name of the product as it listed.

Thanks !
SR

SR,

Search for item number 2981197626 on ebay. (You can put the number right in the search field.)

Bob

KB

Does the item in this web site match your unit?

http://www.audiotechcity.com

Andy

I'm not KB but that's the one.

Let me give you guys a quick update on the progress.

I am now programming a PIC micro (16F628) to do what I need. I have already finished the subroutine to talk to the EL4511 and I can now set it in the right mode.

Next up is the interrupt routine to count down to just before the next H-sync.

This is the guy I got mine from (found his link on EBAY and emailed him directly to avoid the auction crap - he should sell it to you for $69, at least he did me).

Super_deal4u@ hotmail.com

All the pictures seem to look the same. I would guess they are all coming from the same manufacturer. The one I have says "XBOX to VGA" on it in white letters.

I got a really goofy cable with mine that made no sense coming with a video processor. My guess is that it is a breakout cable to allow you to connect an 1/8" headphone jack to the RCA outputs on your receiver. It has red & white RCA phono plugs/jacks & an 1/8th in plug at one end. Don't know why it was incuded with a transcoder, but it might identify that it came from same manufacurer. BTW, they did not provide any useful cables (like a VGA to RGB breakout or component video cables) ;).

kb

Hey,

I bought this transcoder to use with my NEC Xtra and I'm not impressed....perhaps I need to change dipswitch settings...I'll experiment with it and see. Otherwise someone can buy it off me for a good price because I think I need a transcoder that strips the tri-level sync!

Which brings up another question...does the ctca3 strip tri-level sync??? If so, why aren't people buying it? Is it too expensive or do we believe that this DIY option will work better??

Thanks,

Ben

Any headway on this? I have had the "Cheapo" transcoder from fleabay and Motorolla 6208 for a couple weeks and I am not impressed. I will try to get some pictures to post over the weekend. Using it in "Auto" mode, the image was shifted extremely left and I had wraparound on the right side. There was a lot of noise in the image and a pretty bright magenta spot at the bottom center of the image in the overscan area. On dark scenes it became appearant that this is lighter but still present in about 10 places up through the image.

When I switch the unit to 1080i mode, the centering is better and I can eliminate the wrapping, but there is a LOT of light and dark banding that comes and goes throuout the picture. I have observed all of these on both a monitor and my projector. As I said, I'll try to get some screen shots this weekend to clarify.

To make a long story short, this is not an acceptable final solution for me so I await one of the "improved" transcoder alternatives.

Man this forum moves fast...

Has anyone built your own yet?

Buen - Have you gotten the sync stripping working?

Brian,


I have a first cut program running on a PIC micro and I am in the process of creating a schematic for a test board. This will be a basic transcoder, no pass-through's of any kind, just component->VGA, sync separation and sync stripping using the PIC. I expect to go through a few iterations of the program before it will work.


Kim

RE: post 165 by Brian.

(((Maybe we should start a thread regarding the korean knockoff. Hate to detract from the DIY line. If it bugs anybody to talk about it here, please move it out (and leave a post here saying where it went). I am also waiting to see how Kim's DIY turns out as I will likely want one too, just not as urgently as I was before the Korean knockoff came along. At least I can see HDTV now.)))

With the korean knockoff (with dish 811 and barco), I have not had any problems with noise or magenta spots, picture is very clear and nice.

I have a minor warp on left side. I can blank the right side about 1/2" and not see it (1/2" from 8' isn't much of a loss but it bugs me I had to do it). (one Barcoism that I might take to the CRT PJ forum is that using genlocked grid adjustment with 811/transcoder as source, the warp is nearly unnoticeable, but when I go back to image, it is much more noticeable, any ideas why?). So, I tried setting to 1080 mode (from auto) and turning pot. All that happens as I turn the pot is I get a very faint dark vertical line at the right edge that moves into the pic (toward the left) as I turn the pot. The whole picture stays where it is at. No effect on the left edge warp.

One odd thing that I didn't expect is that in 1080 mode, the progressive scan DVD player still worked (480P). Does yours (480p work with xcoder in 1080 mode)? I am wondering if my unit is 'stuck' in auto mode and thus restricting effect of the pot. The instructions printed on the unit are somewhat contradictary with the ones on the paper in the box. Printed on the unit implies that the pot is inactive in auto mode. In box says try pot in auto first and if not enough change, go to manual modes and try again for more adjustment potential.

Also, I am getting what could be described as light and dark banding as you describe, so I bet it is the same. What it appears is that if there is an object at the far left of screen that differs significantly in brightness from the rest of the raster to its right, it tries to hold the brightness at its level, mixing with the level of the raster across the right to either make it lighter or darker. What could this be? Some sort of level clamping apparantly going awry. Anybody figured out how to fix it? This will be the problem that if not solved will drive me to building the DIY.
It only seems to happen on fairly dark scenes and doe not happen at all with DVD (480p) throught the same xcoder - so apparantly only happens on 1080 signals. The picture - colors, clarity, sharpness, blacks, etc are incredible if only I could eliminate the occasional 'streaking'.

Any ideas?

Originally posted by krbennett
RE: post 165 by Brian.

Also, I am getting what could be described as light and dark banding as you describe, so I bet it is the same. What it appears is that if there is an object at the far left of screen that differs significantly in brightness from the rest of the raster to its right, it tries to hold the brightness at its level, mixing with the level of the raster across the right to either make it lighter or darker. What could this be? Some sort of level clamping apparantly going awry.

Any ideas?

First- the post number listen in the profile portion of the screen changes with every post so you may want to reference the thread post number from footer at the bottom of the posting.

The banding you describe is exactly what I was getting in Manual mode with seperate sync. I have changed to RGsB and now I seem to be back to the non centered image (shifted to the left) but the banding is gone. The level is still MUCH lower than MyHD card and I have to run the contrast up to 95 to get any light in the image. I do still have the magenta spot at the bottom center.

I'll try some pics this afternoon.

Brian,
I am using RGsB and have bands. Have not tried other syncs. Mine worked great (except for the bands, which I didn't notice at first - they only show up in certain conditions, I would say it happens in about 1/3 of the movies I have watched and I can't see it on sit coms or sports) out of the box so I didn't mess with it until I started noticing the bands.

What are your dip switch settings when you have no bands?

I would like to get where you are without any banding and then I think I could resolve centering/brightness issues with projector adjustments. If I can't get rid of the bands, I like you will be trying to build one.
Thanks,
kb.

Off
Off
On
On
On
Off
Off
Off

This is manual 1080i with composite sinc (+)

Even with this setting, I can not center (projector controls) without getting retrace on the right edge though. BTW I onle connect the RGB cables otherwise I get the bands.

Status update??? I know I am a pain to keep asking, but this is one of the last pieces in the HT puzzle (video anyway).

Originally posted by Briands
BTW I onle connect the RGB cables otherwise I get the bands.

Thanks for reply.

What do you mean by this exactly? My interpretation is that if you connect 3 wires (with sync on green) you get no banding, but if you connect 4 (or 5) wires (with sync still on green - i.e. there should not be a signal on H or V wires so I am not sure why you would do this) you get banding. Is that what you mean? Or do you change the dip switches to go to 4 or 5 wire and then bands occur?

I have never connected more than 3 wires and have bands. I hope I have misinterpreted you comment and that you have a key to getting rid of bands that I don't yet understand.

KB

KB sorry for the delay. I missed your reply.

I had originally used RGBHV and auto on the transcoder. When I swithed it to 1080i I got improved position but the dark banding made it impossible to watch. It's been a while, but I think I switched it to RGsB and still had the banding until I removed the HV cables. Unfortunately, now it is back to being shifted to the left where we started. I may go through the iterations again this weekend and maybe catch something that I missed the last time.


I REALLY want a transcoder that works. I am holding off on the version 3 of the KD though I have heard that it works well for everyone. I was hoping one Beun or Petr would have a solution where I could get BNC outputs and eliminate another connector in the chain.

I have about lost my patiance and will go ahead with the KD if we don't get some word from Buen or Petr this week.

For every one,


I just received the PIC programmer from Digikey, so when I can find some time I can start burning micro's


Kim

Kim-

It sounds good-I hope you are successful with this project. I am looking forward to trying out your plans and feeding various CRT, LCD, and DLP devices that I have. This will be my first HTPC hardware project since the UIR device. (That one also required that I build my own cheap-and-dirty PIC programmer.) With the HD DirecTivo and other upcoming items not including RGB, your timing is perfect!

Yep. It does sound good. Anyone make one yet?

Hey guys this is a little bit off the subject but perhaps one of you could offer a thought.

i bought an LGE 3410A HD PVR. It's OK but the brightness level shifts evry time there is a large area of dark or bright in the field. I run two other devices through the same path and they work perfectly. The LGE does not exhibit this behavior in other modes, S or composite. Only in RGBHV is there a problem. I have never seen anything like this before and I've already had 2 units that exhibit the same behavior. No one else has seen it even those who use CRT projectors. It is very annoying, you're watching a scene, a bright window fills part of the field, then all the blacks in the picture get brighter, like 20 IRE. I've replace cables and tried different resolutions. Always does the same thing.

Sounds like a very weak ps, but I'm NOT a tech and I'm just speculating based on what I've read.

Originally posted by Briands
KB sorry for the delay. I missed your reply.

I had originally used RGBHV and auto on the transcoder. When I swithed it to 1080i I got improved position but the dark banding made it impossible to watch. It's been a while, but I think I switched it to RGsB and still had the banding until I removed the HV cables. Unfortunately, now it is back to being shifted to the left where we started. I may go through the iterations again this weekend and maybe catch something that I missed the last time.


I REALLY want a transcoder that works. I am holding off on the version 3 of the KD though I have heard that it works well for everyone. I was hoping one Beun or Petr would have a solution where I could get BNC outputs and eliminate another connector in the chain.

I have about lost my patiance and will go ahead with the KD if we don't get some word from Buen or Petr this week.

Biran,
Did you ever "I may go through the iterations again this weekend and maybe catch something that I missed the last time"? I still cannot get rid of my 'streaking' problem no matter the dip settings. In the previous post by Art (above) he describes what sounds like a similar problem associated with a PVR. My problem, like his, only occurs with HD source material (from Dish 811 in my case). I have no streaking whatsoever in SD source from same 811 or from a DVD, all playing through same transcoder. But, even if I put it into manual modes using the DIPs, I see no change. If I put it in 480 manual modes, I still get HD signal to work (with streaks).

Any ideas? You seem to have at least been successful in getting rid of streaks.
Thanks,
KB

Streaks sounds like a bandwidth problem. Likely something in your chain from the HD source to the projector is not able to pass the necessary full bandwidth of the HD signal, hence the streaking. Could you your cable or a connector, or a device in the chain. Termination can be a source of streaking too, is there an unterminatied input on the transcoder ?

beun : Do you have a working example of a transcoder yet ? I think one thing you should include is contrast/brightness/saturation controls.

I think these controls are vital, as I've noticed differences in output of HD material in RGB from two different HD sat systems which were using the EXACT same HD signal. This would indicate that not all HD sources output the HD signal exactly the same. Specifically, I was watching CSI from the same CBS HD feed, only one signal was from my DTV HD receiver, and the other was from my BEV HD receiver. The BEV's output was noticably brighter than the DTV receiver. This would indicate to me that various HD sources have varying black levels. If this is the case, having brightness/contrast/saturation control in the transcoder would make it possible to adjust each HD source to the same output level.

Originally posted by gn2
Streaks sounds like a bandwidth problem. Likely something in your chain from the HD source to the projector is not able to pass the necessary full bandwidth of the HD signal, hence the streaking. Could you your cable or a connector, or a device in the chain. Termination can be a source of streaking too, is there an unterminatied input on the transcoder ?

Thanks for the reply.
3 RCA cables (Y, Pb, Pr) from 811 to transcoder. High density 15 pin VGA DB connector (output from xcoder) to BNC RGB adapter cable into BNC RGB port on Barco800. All commercially produced cables. Have not checked, but would assume solid connections. There are no impedance settings on any of the devices (or thier I/O) except for the Barco which only has them on the composite and S-video inputs, neither of which are being use.

If I run the Y directly from the 811 to the barco (i.e. no xcoder) the resulting monochrome image does not appear to have the streaking, however, it could be there just not noticable because of the monochrome. Without the transcoder, the blue and red (direct hook up to PJ) are way too dim to show the streaking. It is hard to see the streaking on any of the colors by themselves through the xcoder. It actually only shows up ever on very dark scenes. If I had to venure a guess, I would say it appears to be some flaw in some AGC logic in HD mode. It appears only when the raster line(s) begin at the far left edge with a bright image, followed to the right by dark images, which are then overly brightened. Just as a description, the best I can use is that it has the appearance of what you see in the real world if you are sitting in the shade of a tree and can see beams of light leaking through the branches causing brightened streaks in your view. I could try to take a pic, but I doubt it will show up. It is really not a huge change in brightness, just enough to barely notice and bug the crap out of you.

I have actually tried different cables in all connections, but to no affect.

Since Brian has been successful in eliminating the streaks in his using different dip settings, I suspect I may have a defective unit. Maybe I could send mine to Brian to see if it functions differently than his.

Thanks,
KB

gn2,


I now have a schematic and a PIC-micro program finished to test the principle. I am working on the PCB layout. I already bought the programmer and all the part so I can get going as soom as I have the board. Sorry for the slow respons and progress but my job is killing me.


Kim

Originally posted by krbennett
Biran,
Did you ever "I may go through the iterations again this weekend and maybe catch something that I missed the last time"? KB

I got rid of the streaks using either the full auto mode with RGBHV or fixing a scan rate and using RGsB. In both cases the image is about the same. Compared to MyHD card, it is VERY DARK. and the image is shifted to the left by about 15% of a screen width.

The streaking I see may be associated with black level clamping / tri level sinc. I don't fully understand this, but is it possible that the black level (full off) for each scan line would be controlled by the signal in the front porch where there should be no picture information. If, however there is some thing there, it may mess up the black level for that scan line and thus you get horizontal banding corresponding to picture information on the edge of the image.

Anyway, I have given in and ordered a KD CTCA3 yesterday. It seems that a several people have had good luck with it on their NEC PGs. I was really hoping to get one that would have BNC outs, but none of those have become available yet and I have gotten pretty good at making my own breakout cables now.

I'll post back when I get the KD installed.

Kim: I'm glad to hear you are making some progress, I'll be interested to see your final result. I think if you can, you should have brightness/contrast controls on it.

Brian: Post your impressions of the CTCA3 when you get it, as it is *supposed* to have synch stripping down pat, which should eliminate crushed blacks.

Attached you will find the testbed that I am going to use for this development. At the moment it does not have any brightness/contrast controls in them but that would be relatively easy to do. All this entails is a gain/offset adjustment.

The important thing for me to see is the quality of the sync-stripping, so I designed a minimum transcoder, no pass-throughs of other funky things. Next on the to-do list is to m ake a PCB for this one.


Kim

Do not despair, there is still movement. I have just finished the board belonging to the schematic as posted above. I will go over it one more time and than order some samples.


Kim

Kim

When you get this finished put me on the list for whatever will be available... PCB's, kits, or whatever you are going to make available for those of us in dire need.

Now where did I put those holo3d posts??????

Walt

beun - I am very interested as well.

I will most likely order 4 or so test boards, no soldermask or silkscreen just to test the PIC program and to see if everything works. I will post the PCB layout and the BOM soon and the PIC program when it works. I will need at least one board. As for the remaining three .......


Kim

OOOOOH.....me...me...me....

Anyone with grandchildren will understand.

Walt

Attached the schematic and PCB of the testbed I am going to use.


Kim

beun,
Thanks for all of your awesome work on this project. I am planning on buying one of the MP-5 units but I am currently unemployed. I really want to build one of yours. (I have plenty of time and solder. LOL!) Will you be able to make a kit available? If not a full kit, how about a PCB and the PIC?

BTW, shouldn't the PCB layout say YPrPb to VGA, not the other way around?

Thanks again.

Later,
Ben

Ben,

Yes you can always get a board from me and I can throw in a PIC as well. Your are correct about the text, I think I paid more attention to the layout that the rest.


Kim

Cool, that works. How far along are you with the testing? In other words, when will I be able to order a PCB and PIC? ;)

Also, wiil the unit be able to do 480p? I remember something earlier in the thread talking about 720p and 1080i. I have a RCA MM36100 EDTV monitor that currently only accepts 480p via a VGA connection.

Thanks,
Ben

Ben,

The boards should be in at the end of the week. If the PIC program works as it is intended to, the transcoder is insensitive to scanrate, meaning that it should work as well at 480p or 1080i. Depending on how much time I have left (I do have a business trip abroad coming up) I could do the testing in a week or so. In case you can burn PIC's yourself you can even get going sooner because I can just send you a board and the source code and you can modify (share back with me and everyone else here) the program and test it yourself.


Kim

Kim,
Sounds like it is time to start playing! Nice job.
What is exact part number for PIC? (assume you are using the 18 pin PDIP version, but want to be sure to match what you are doing exactly).
Do you have parts you would like to sell that you may have purchased (or are planning to purchase) in bulk?
What is cost of PCB, source code and any other parts you might have?
Thanks!
kb

kb,

The PIC I use is the 16F628-20/P in a 18pin DIP. Looking at the Mouser website, these are now considered "not for new designs". In order to develop the program I will just keep on useing them these until I have the time to look at the new versions. My guess is that it is not going to make much difference.


Kim

Any time guesstimate on a working model ? Especially one with basic contrast/brightness/saturation controls ?
What about a cost range guess, I would image its gone up quite a bit because of all this extra research ?

Kim,
Unfortunately, I don't have any experience with PICs. I'll have to get a burned one from you when testing is complete.

I've compiled a parts list (http://home.wi.rr.com/buttonpuncher/temp/Component%20to%20VGA%20Parts%20List.doc). Could you look it over and see if everything looks OK?

Also, I came up with a few questions while putting together the list...

Who stocks the EL4511CU?
Do all of the resistor values need to be 0.1% tolerance?
Will the Component RCA jack that I found work with the current PCB layout?
Will the VGA jack work?
Will the 3.5mm jack work?

Thanks again for all of your AWESOME work.

BTW, for everyone concerned, the parts cost alone is about $50. (This doesn't include the PCB, EL4511 chip, or the programmed PIC.)


Ben

Paul,

The extra research is not a factor in the final price since I am not running a real for profit business. I only use the parts cost as a factor in this formula. When this prototype works as intended than adding contrast/brightness/saturation controls is not a big step anymore although it will increase the parts cost and complicate the choice of case.


Ben,

Fantastic that you have taken the time to compile a BOM. I will go over it carefully and compare some prices. Historically I have mostly used Digikey and I seem to remember that the component and 3.5mm jacks have to be from Digikey. The VGA jack from Mouser is the 156-3315 (have a new shipment lying in front of me). When I am not mistaken than the EL4511 is either carried by Digikey or Newark. I will use this info to compile a final BOM soon.


Kim

That is great news Beun, I REALLY look forward to the day you start making these, as my present transcoder, while working properly, has no way to compensate for the varying levels of the different HD sources its hooked to. Contrast/brightness/saturation level control is more important than I imagined, and I can't wait till I can match them for all HD sources so they all look equally good.

I am still working on the BOM update so please be patient. The El4511 can be bought from Avnet but only in multiples of 55 (yeah...55). Since I needed them I now have a few left for the experimenters amongst us.


Kim

Kim-

I am glad to hear you are making good progress on this project. I also want a board (and whatever other parts you will have available) when ready. Thanks!
(The HD Tivo is coming out soon, without RGB...)

Beun,

Would you please comment on this. I just returned the second LGE HD PVR because every time the peak white level changed in a portion of a scene, the whole field's brightness increased or decreased. It was very annoying. I used the units VGA output, RGBHV. It occurred at all resolutions through this output. There was no such shift through the S or analog outputs even when HD material was downconverted to 480i. I speculated that they used a cheap transcoder to provide the VGA, RGBHV output. The unit had a YPrPb output. I loved the unit otherwise. I would consider using your transcoder if that coud be the source of this problem. Can stray syncs cause this phenomenon? The new Sony HD PVR's have no RGBHV output, only RGB and DVI. I am considering one of these with your transcoder.

Art,

It looks like your projector expects a nice fixed DC out RGB signal like from the output of a video card. Unfortunately most consumer outputs are AC coupled meaning that the projector has to do black level clamping otherwise it will look how you describe it. This is a seperate phenomenon from sync remnants but this design also does the black level clamping for you.


Kim

<most consumer outputs are AC coupled >

I run an RCA DTC100 and a Motorola HDD200 through the same path without any problem. Of course both of these were designed in the mid 90's. Has there been a change in design philosophy or standardization? I wonder if the implementation of DVI has had any role in the incompatibility.

Art,

I don't know about the HDD200, but the DTC100 I think was specifically designed with RGB in mind, it is well possible that for the PVR it was a not well thought out afterthought.


Kim

All,

I just received the PCB's fot the experiment but I am still waiting on the EL4511 and I think I need to order a few other parts. I will start as soon as possible and I will keep you guys informed.


Kim

Hi all. I'm sort of a newb to this scene.

I'm coming at all this from a different perspective, but also want to be able to build a fancy Component to RGBHV transcoder.

I started researching because I was trying to get a VGA image out of a Microsoft XBOX, whichwhen hacked, outputs a Sync on Green RGB signal. But, I'd rather build the transcoder you've all been talking about over the past year so that I can use it for anything - progressive DVD players, projecters and whatnot.

So to contribute a bit, a couple of years ago, one guy created a box that converted the XBOX Component Video to VGA. He oroginally started out like this forum, and provided a schematic, but I suppose has pulled it since he began selling finished versiosn of his box.

http://members.cox.net/kgasper/xboxvga/home.html

I haven't been able to find any sort of schematics until I found this thread here at AVS Forum.

Similar componentry is used chipwise.

So this is partly a bump to this thread, and partly finding out if there is a simpler box, without the fancy VGA passthrough, but with the VESA standard separate Horizontal and Vertical Sync?

I've created a small circuit just for the XBOX using the LM1881 chip, but it only uses the sync in green to output H and V syncs, but doesn't actually strip them from the Green.

Cheers!

[Quick Edit/PS]

And just in case this might be useful, but I think it's the same thing. I found in through my "research." But according to this schematic, I don't understand where the sync signals go.

http://home.att.net/~billhudson/rybyrgb.pdf

That design would pass through the sync to ( I think ) all outputs. This should work ok if your unit does sync on green.

So in addition to that Bill Hudson transcoder link above, would be a sync stripper? Which I'm supposing is what's going on in this forum. I only took a quick look at the schematics.

So, the first PDF schematic from early on - without the VGA passthrough - I'm supposing that's a sound circuit? and by sound, I mean, it's useable, no? The only thing I think I read about it is that it is only a sync on green.

The design as posted last is an experimental vehicle to test the transcoding function and the sync-stripping function and will output RGBHV. The is no provision for sound whatsoever. The final version will have nore functionality like for examples inverted syncs, sync on green and various passthroughs.

Currently I am on business trip so I have limited access to the internet.


Kim

Well, I didn't imagine there would be any provision for sound whatsoever - it would be unecessary to have so many cables in such a box.

A quick question for anyone out there though, this LT1339 chip - is it actually stripping sync out of Y/Green? As in, is it actually taking the sync signal away from the Y, or is it just using it to output to the Horizontal and Vertical sync splitter?

I've created a box that makes use of the LM1881 chip and it merely makes use of the sync information in the Y signal, rather than stripping it out completely. The problem I've found is that if a monitor that supports Sync-On-Green gets both a H and V signal and a Sync-On-Green signal, it has problems holding sync for obvious reasons. So I created a switch that turns the power off and on from the LM1881 chip.

Summary: The LT1339 chip STRIPS the HV sync signals from Y? Or the LT1339 chip just taps into the HV sync signals in Y? I'm guessing so far it's a sync STRIPPER.

The LT1399 is an Opamp and doesn't strip the sync. This function is done by the 4316 switch controlled by the PIC micro which gets its information from the EL4511 sync separator.

The EL4511 takes the sync of Y because this is where the sync always is on a component signal.

Kim

So there isn't any other way to strip sync besides a custom microcontroller? That kinda sucks. Although, it's lovely that you're working on it. I'm sure there has got to be a chip out there that does this off the shelf - it just seems like something that screams out as a useful application that one of the semiconductor companies would make it.


me

[edit]
Look what I found?

http://www.si87.com/Products/Cabling/Adapters/ss1spec.html
So if anyone has come across any of these, discovering the chip types used in products like these I guess would be helpful.

[edit]
Another chip

http://www.necel.com/digital_av/english/3dyc/d64011b.html

I'm unsure what its output is. It takes in a YCrCb input, and outputs what it calls a digital output, Y,R, B and "timing output." Maybe timing output means sync?

And what does this chip do?
http://www.intersil.com/products/deviceinfo.asp?pn=EL4583

And this one comes close, but I don't think it does it either.
http://www.intersil.com/products/deviceinfo.asp?pn=EL4511

The second reference looks like the circuit they employed in my DWIN transcanner to get RGBHV out of a YCrCb. Unfortunately it only is good for 480i.

I am back from my business trip and after having filled in my expense form I had some time to start soldering. This is the state so far.

I have put everything together except for the PIC with the result that the circuit does basic transcoding. For some reason I see some fuzz on the Y signal after it went through the input clamp, this may have something to do with the fact that this signal connects to the sync separator. I will have to investigate this, in the extreme case I may have to buffer this signal before I hook it up to the EL4511.

It looks like I need to gate the backporch signal with the Vblank signal because it goes a bit wrong during the vertical sync interval. I will set up my PIC programmer next and try to get the sync stripping to work.


Kim

Thanks for the update Kim. I'm looking forward to building one of these.

Kim-

Welcome back, and thanks for the update!

Some more information,

I think I have finished the PIC program to cut out the sync signal. It seems to work pretty well and nicely strips the sync. What is left to do now is to fix the black level clamping.


Kim

And add in the contrast, brightness, saturation controls ???............
Sorry to bug you about this, but you'll see they are necessary after you try it out on different HD boxes.

Guys,


I am still working on this and noticed that the sync separator IC has some issues with non-standard timing that I need to work around. I will keep you guys informed.


Kim

Thanks for keeping us updated, Kim.

After looking at this for quite a while now, I have reached the conclusion that the ZXVF4089 black level clamping IC doesn't work for high-def TV. I have a few other ideas that I will try out. This isn't over yet.


Kim

So what's the progress with this thread lately?

As a side note, one of the reasons I've been watching this thread is to build a transcoder to use an XBOX on the VGA port of a large NEC Plasma. (It's evil, my satellite has DVI out, and the NEC has DVI, but I can't use it because the satellite receiver outputs in HDCP and the newish NEC does NOT support HDCP. This copyright protection stuff p*sses me off). Anyhow, my friend bought a transcoder, a KeyDigitalSystems one. It's the KD-XB Xblaster, made for game systems and mostly for the XBOX. It's realtively cheap, and I don't understand what makes it exactly lower quality, but it seems not to work well. When hooked up to the (commercial grade) plasma, the screen is sort color warped. Dark green areas, dark blackish areas, it's all just sort of the wrong hue, but in bands. I dont' know why, and now it's a paperweight. I decided to open it up to see what chips it used, and the tops of all the chips are SCRATCHED OFF! HOW EVIL THEY ARE! I thought I could try reproducing the little box, but my way, or sharing what's inside with you all in this thread, but I guess I won't be doing that anytime soon.

Anyone know why it's not working on that NEC plasma? I hooked it up to a computer LCD and it worked just fine.

It's Video output is RGBHV, 0.7V p-p, 75OHM terminated at source
Output at sync is negative polarity, and says TTL during game console use.

The plasma accepts negative sync, and some pictures shows up, but just all wrong. any idea why? Any I sitll wanna build my own transcoder just to say that I can/did. So when are we all?


me

<After looking at this for quite a while now, I have reached the conclusion that the ZXVF4089 black level clamping IC doesn't work for high-def TV. I have a few other ideas that I will try out. This isn't over yet.>

Beun,

I have passed up a couple of input devices because of the incomptibility issue. You will remmember I have a DWIN 700, Transcanner, etc. I really need to get from Component to RGBHV. The Key Digital device CTCA043 if I remember right, $255.00, does not appear to work properly. I there a fundamental incompatibility issue--is it going to be impossible to build this device or should I just keep using my VCR's until you build a working unit? My experience with the LGE LST3410A HD PVR has made me leary of all newer input devices.