Written by Gordon Fraser,

posted with permission from:

http://www.convergent-av.co.uk/article4.html

Note: originally written for PAL, but also quite relevant for NTSC.

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Scalers: Many folk seem confused as to what scalers actually are. The common belief is that they just de-interlace SD material and then rescale it to some other resolution. Indeed when discussing scalers often the comments are usually about what de-interlacing chipset is used above anything else. It's true that those are main features of scalers but there is more to it than that. How they go about these tasks matter, as do some of the other features a scaler can have that may offer increases in performance over in built video processing. Here's some of the things we believe scalers should do.

Scalers are the glue that binds together a video system. Modern displays are not able to display our old and new television standards without some form of processing being involved. Most of our video systems at home will have a large and disparate range of sources with varying output resolutions and refresh rates. None of these sources are likely to actually output a resolution or refresh rate that is optimum for our display! Good scalers are able to be configured to optimise the capture and processing of all these signals and to then output them at the most appropriate resolution and refresh rate for the source material and the display. Here are some examples:

Sources:

Satellite TV: 576i usually by SCART or svideo
VCR: PAL, Composite video
DVD: Region1, 480i@60Hz via Component or possibly HDMI
DVD: Region2, 576i@50Hz via Component or possibly HDMI
ProgDVD: R1, 480P@60Hz via Component, HDMI or DVI
ProgDVD: R2, 576P@50Hz via Component, HDMI or DVI
HD Tape: 1080i@60Hz via Component or HDMI
HD Satellite: 1080i@50Hz or 720P@50Hz via component or DVI HDCP/HDMI

Displays:

SD plasma's... and clones : 852x480
HD 42" plasma... : 1024x768
50" plasma and clones : 1366x768
Alis panels and clones : 1024x1024
Pioneer 43" plasma: 1024x768
Pioneer 50" plasma : 1280x768
DLP: 1280x720 or 1024 x576
DILA: 1365x1024 or 1400x800 or 1920x1080
SXRD : 1920x1080
LCD : 1280x720, 1920x1080, 1366x768
CRT Front Projection : Variable from 480P up to 1080P or more!

If you compare the source output resolutions with the displays actual resolutions you can see why we need scalers.

Standard definition signals in composite, s-video, component or SCART (RGBcvS) should be able to be processed alongside HDMI, DVI, RGBHV, or High Definition component. These analogue signals should be sampled at a very high rate in order to get good, accurate information to the front end of the system. The Digital inputs meanwhile should be capable of accepting the full range of signals available from current sources from 480i up to 1080i.

Advanced greyscale, gamma and colour decoding combined with careful adjustment of input sizing should allow for each source to be optimised for the most accurate and detailed playback. Over-scanning of the incoming signals can be minimised and active picture area being sent to the display should be adjustable to allow the full picture resolution to be displayed on screen. Digital video levels on input and output should be selectable for PC or VIDEO dependant on source as required in order to gain maximum contrast with minimal banding artefacts.

Multiple inputs should allow direct connection of each source to the scaler, removing the need for switching of video elsewhere which could degrade the signal quality and which would mean many components would have to share the same input (compromising one or all of their picture quality).

Advanced powerful detection algorithms should work out whether the video material is from original progressive content (film or PC graphics) or from interlaced video cameras and appropriate processing then should take place. Original progressive images should be re-constituted to their full resolution frames then sent on to be up or downscaled to the required resolution of the display. Accurate frame rate conversion should then be able to output the progressive frames at the most appropriate rate eliminating judder and other temporal artefacts. Clever filtering should be employed to remove harsh digital artefacts like mosquito noise, where appropriate. Chroma filtering should be assignable on a per source basis for digital sources with mpeg decoders that suffer from the famous, chroma bug.

Fast processing and as little buffering of the video signal as possible should be applied in order to minimise potential lip-sync errors that may require the use of expensive audio delays. This processing should be able to be updated to add further feature sets or to aid product compatibility.

If possible multiple memories should be available to allow quick and simple adjustments for more than one display or perhaps for day and night-time viewing. The unit, once set up, should be extremely simple to use.

Advanced RGB gamma and overall LUMA adjustments may be available on a per input and memory basis. This would allow ISF calibrators to make very accurate adjustments for greyscale where the capability wasn't present in the display or where non linear tracking after calibration required further tweaking.

As we have a mixture of analogue and digital displays still it'd be wise for the scaler to have analogue outputs that could be configured for RGB or YPrPb output, preferably on high quality 75ohm BNC connectors where high resolution displays are going to be used. For digital displays DVI-D or HDMI outputs should be available. The output resolution and timing parameters of the scaler should be adjustable in order to create the perfect timings required to minimise artefacts on screen. In built test patterns should be available to help in set up and confirmation of ideal scaler/display configuration.

With the advent of High Definition broadcasts about to start in the UK we'd expect that high definition inputs should be available. These inputs should not just pass through an HD signal. There are many displays that are not compatible with either the resolutions or the refresh rates of HD broadcasts. Good video processing should be able to capture these HD signals and frame rate convert them and scale to allow compatibility with older displays.

Thanks for the overview. I found this to be very helpful!

But ultimately what is the configuration set up using a scaler as part of an AV system? Do all sources conect into the scaler or AV preamp (assuming I have separates)?

Given the advent of HDMI, what is the ideal conection configuration for an AV system?

TwoFeathers,

All video goes through scaler, all audio goes through receiver.

When you need lipsync delay, audio can also be routed through scaler...

Which then requires the user to toggle both the scaler and receiver when switching between multiple sources?

Well to use mine as an example (and maybe a mod can split this off as a thread?)

I put most audio through my scaler (VP30) which also does the audio delay/lipsync, so the amp is only ever on the scaler input. Actually I rarely need to switch scaler input either as the auto-detection/prioritisation seems to work very well.

Otherwise, when forcing a selection manually, my pronto is programmed to switch both the scaler & amp.

I am new to scalers and have become intrigued by them. Thank you for starting this thread as it did answer some questions.

This may sound stupid, but I like my TV and its picture. I see nothing wrong with it. I also love technology and have no problem dishing out $2000 for an external scaler. I read in Home Theater Magazine that my TV's internal scaler incorrectly deinterlaces 1080i. After reading the article I began researching external scalers. Granted, I think the picture looks great, but now when I look at CSI: Miami, I know something is missing. This site kinda has that impact on me. Because of the education this site has given me, I see Macro Blacking and care about black level. Had I never found the site I would a regular Joe buying whatever I was told was the best. I would see something was wrong and know what it was.

You answered, "Why I need a scaler", but a scaler is already present in our digtal TV's. Can you please, please, plase explain to me/us how to recognize limitations in our TV's Scaler and WHEN an external scaler is necessary?

Scalers have much better processors and Algorithms. And they can be used to calibrate your TV to its fullest potential. i had a calibrator come and do my CRT mitsubishi and am very happy with what he has done. here ares ome links that might hepl you out

http://www.cir-engineering.com/index.php

http://www.hometheaterspot.com/htsthreads/showflat.php/Cat/0/Number/810772/an/0/page/0#Post810772

Athanasios

CIR has been contacted. I hope he get enough business my way for a trip. The closest calibrator I could find was an hour and a half away and wasn't interested.

Thank you,
V

I recently purchased a PHP-4270HD, now I blew the wad on the plasma, however I will shortly be looking into more appropriate sources for this truely awesome plasma. Currently I don't have HD service or for that matter any other source that gives me anything better than a 480p signal.

Now knowing the benefits of a scaler, should I for go the up grades to HD cable service, and an upconversion DVD player?

It would certainly pay for its self within a short time. Not to mention the scalers processes should be much better than any reasonibly priced DVD player...yes/no?

Thanks

I know the plasma/LCD TV has a built-in scaler.
IF I buy an external scaler (e.g. Crystallio II, iScan etc), how can I make sure that the output from the external scaler will by-pass the built-in scaler and go to the plasma/LCD panel directly?

Tony

I know the plasma/LCD TV has a built-in scaler.
IF I buy an external scaler (e.g. Crystallio II, iScan etc), how can I make sure that the output from the external scaler will by-pass the built-in scaler and go to the plasma/LCD panel directly?

Tony

You need to do 1:1 pixel mapping. That is, if your plasma is 768P you need to output 768P from the scaler. Although this can be done on many TV's, not all of them allow you to bypass the internal scaler. You need to find out if yours will first. Even those that do sometimes have to have specific timings in order to bypass the TV's internal scaler. My Panasonic TH-50PHD8UK is a good example. The display is 1366x768P. The only way to achieve 1:1 is to use specific timings and use a DVI card. It will not do 1:1 through the HDMI card.

For me the biggest benefit to an external scaler is that it helps to fight off the urge to purchase expensive Blu-Ray and HD-DVD discs to replace the already existing library.

I have a VP30 with the later-upgraded deinterlacer being fed SDI from a Denon 3910 to an ISF calibrated SXRD. And while my Blu-Ray and HD-DVD player do look better, on many discs it is not dramatic enough. So by making the most of my old DVDs, I am saving money by only purchasing the HD discs which are must-own reference discs. I still buy ordinary DVDs, which are as little as $3.99 new at local megastores. Much better than $35 per disc.

And it is a convenient video hub since I am not limited to SDI and can send HDMI from my HD sources through that. Except for the Monoprice HDMI switchers, they seem so expensive that it's worth the little extra money to get some video processing with my switcher.

I've been reading here, and I see lots of flexibility in external scalers.
But like mhsens I'm primarily interested in playing DVD's into my RP DILA JVC 1080i/p, and the new RS-1 when it comes next month.

The cheap Toshiba upconverting DVD player looks quite good, with rare artifacts, on the 61" screen. And I'm thinking the newer Oppo upscaling DVD will be even better.
If I'm happy with these, and have HD DishTV (and I continue to ignore the 1100 vhs analog tapes) ..... will I really benefit from an external scaler?

S

The cheap Toshiba upconverting DVD player looks quite good, with rare artifacts, on the 61" screen. And I'm thinking the newer Oppo upscaling DVD will be even better.
If I'm happy with these, and have HD DishTV (and I continue to ignore the 1100 vhs analog tapes) ..... will I really benefit from an external scaler?

S


First time to the forum, though I've been following several threads for about 6 mos. Glad to see this one on scalers.

My question is similar to Stew M.

I too have HD Dish TV--I'm mostly pleased with the content esp. HD (though admittedly still viewing via 32" CRT Sony Wega), even SD is quite good most of the time.

However, I'm considering a 46-52" LCD (waiting/hoping for prices to drop even further) and will be sitting approx. 7 feet away. I'm mostly concerned about SD and the amount of artifact I'll be able to notice. Expect that the larger the display the more noticeable will be any artifacts.

a) Can a scaler help to "stablize" the SD image for this viewing distance? b) And will it work with the DishDVR (ViP622)? I have a Yamaha 2700 AVR which has an ABT 1010 chip (I believe its a chip?) but the DVR will only allow "passthrough" on the AVR and I can't seem to utilize the ABT scaler in the Yammy. I wouldn't want the same thing to occur with a dedicated scaler.

(I realize there are several issues here and there are other threads I haven't yet completely been able to read through. Apologies for any fumble)

Thanks in advance.

PS: Stew, can't speak for the Toshiba, but I have the Oppo 981 and it works great.

My plasma only has one HDMI input and I prefer to use that for my Dish HD Vip622 receiver. That being said, I either have to purchase an HDMI switcher and program my remote to change the picture settings on my panel every time I switch from DVD to Dish, or I have to purchase a DVD player that upconverts over component. Those are getting increasingly rare and usually involve a hack that doesn't always yield optimal results. Of course, the third option, the one that brings me to this thread is the use of a scaler to upconvert a component signal to my panels resolution of 1024 X 768. I saw a processor that ViewSonic makes:
ViewSonic NextVision N6 (http://www.viewsonic.com/support/accessories/tvvideoprocessors/nextvisionn6/index.htm) and wondered if this would do what I am looking for. It appears to take a component signal and convert it to a variety of resolutions and refresh rates. It's certainly cheaper than the DVDO and high-end processors. I suppose I could expect an audio sync issue at the very least. One final thought, the scaler in my HP PL4260N might do an admirable job. I'm not sure. I've been warned that upconverting DVD players even over HDMI can actually degrade the image if the scaler in the player isn't as good as or better than the one in the panel itself.

Thanks in advance,
Jeff

This thread does not give answers. I posted on here with hopes for some feedback on scalers with no avail. Save your efforts for some other site. Maybe some pro forum. Threads like these are pointless. The individual that started this thread I believe did for sake of search engine hits, and has no interest in helping those with questions.

Consider yourself for warned... :(

I have looked around and have not found this information elsewhere. If you send 1080p to a 1080i/720p display, how is this displayed? Is it able to convert to 1080i or does it downconvert to 720p?

If the display does not accept 1080p, it will display nothing. Whatever you throw at it has to be specified as a supported input format on the specific input used in order to be displayed.

My plasma only has one HDMI input and I prefer to use that for my Dish HD Vip622 receiver. That being said, I either have to purchase an HDMI switcher and program my remote to change the picture settings on my panel every time I switch from DVD to Dish, or I have to purchase a DVD player that upconverts over component. Those are getting increasingly rare and usually involve a hack that doesn't always yield optimal results. Of course, the third option, the one that brings me to this thread is the use of a scaler to upconvert a component signal to my panels resolution of 1024 X 768. I saw a processor that ViewSonic makes:
ViewSonic NextVision N6 (http://www.viewsonic.com/support/accessories/tvvideoprocessors/nextvisionn6/index.htm) and wondered if this would do what I am looking for. It appears to take a component signal and convert it to a variety of resolutions and refresh rates. It's certainly cheaper than the DVDO and high-end processors. I suppose I could expect an audio sync issue at the very least. One final thought, the scaler in my HP PL4260N might do an admirable job. I'm not sure. I've been warned that upconverting DVD players even over HDMI can actually degrade the image if the scaler in the player isn't as good as or better than the one in the panel itself.

Thanks in advance,
Jeff

I am most certainly in the same situation and I was loking forward to a reply to the previous question ,
But I guess the the question will not be answered since they will only reply to what they feel is worth it,
what a bunch of hot air..

Hi: This is an question about a very old post of yours. I have a one year old 55" Hitachi plasma and have tried two different scalers (one Genesis by Faroujada) and can get no improvement in picture quality. I keep reading comments by other people how great scalers are but cannot make it work for me. Any suggestions? Thanks for the help, gene

Hi: This is an question about a very old post of yours. I have a one year old 55" Hitachi plasma and have tried two different scalers (one Genesis by Faroujada) and can get no improvement in picture quality. I keep reading comments by other people how great scalers are but cannot make it work for me. Any suggestions? Thanks for the help, geneWhat kind of a problem specifically are you having with the picture?

If it's compression artifacts or "noise" on digital satellite or cable channels, maybe something like the Algolith Flea would help better. It's noise reduction capabilities "cleans up" the artifacts in the signal, where most scaler/deinterlacers aren't specifically designed to do that.

Hi Raminski: Thanks for the quick reply. The images are fuzzy and colors are poor unless I am playing DVDs or HD cable channels.

Question for anybody. Would you run you HD dvd player though your scaler or would you just connect it directly to your tv? I just purchase a A35 hd player from toshiba and was wondering if I should connect it to my key digital video scaler which is connected to my panasonic dlp tv. Any suggestions?

In most cases a good scaler does a better job than either the DVD player or the TV, but you would have to try it all three ways to find out.

Wow, this thread looked so promising and I started reading it with anticipation. Somethimes months go by without anybody posting. I guess that says all that needs to be said about the subject. Peeps are "voting with their feet".

Terrific overview!!!
Under sources though, Laserdisc was not mentioned.

It was mentioned in one thread that high-def dvds look better than standard dvds that have been upconverted - I would like to hear more about that subject. Is that universally agreed? Is it true of all converters, or do the best ones match the output from original high-def dvds? Will it always be true? (i.e., I assume scaler technology is improving).

With things between Blu-Ray and HD-DVD still unresolved, and combo players at $800+, I'm wondering if upscaling standard dvds might be a better option.

I am looking at purchasing a Pioneer Elite 92TXh. I am lost when it comes to the benefits, reliability, feasibility and general usefulness of the Faroudja DCDi 1080p output feature.

Has anyone ever connected their DTV HR20/21 DVR using component with a 480p output and/or their standard 480p DVD player to the receiver thru component and output the signal using the HDMI 1080P option with their receiver?

Is their a discernible difference? Will it clean up a signal that is coming in on an MPEG2 channel and gets pixelated with transitions or poor compression? Is it even necessary with the 1080P processor in the television already?

Any help or information regarding this would be greatly appreciated.

Thanks,

Pauper

Dean:

Laserdisc: 576i OR 480i, composite video at 50 and 60Hz respectively. These players often have svideo outputs as well but the info on the disc is composite so if you are using the svideo output you are just choosing to do the composite to Y/C(svideo) conversion in player.

skvinson: It is extremely unlikely that any scaler, no matter how great the manufacturer claims, can make an SD DVD look as good as a decent HD-DVD/BD....The exceptions being the early BD discs as I saw Fifth Element and it was really, really bad.

Hello,
As you can see I am new here. I have one question. I have Sony's very first plasma monitor -42". I paid a whopping $8k for it. It has 2 vga outputs. I have DTV's newest HD DVR. It only has HDMI or RGB. I was going to just run a vga to RGB conversion cable. Is this OK or do you think I would need a video scaler for it? Any thoughts are appreciated.

Thanks,
Sam

anyone?

ahhhhhh c'mon. Someone has to know. -LOL!

Hello,
As you can see I am new here. I have one question. I have Sony's very first plasma monitor -42". I paid a whopping $8k for it. It has 2 vga outputs. I have DTV's newest HD DVR. It only has HDMI or RGB. I was going to just run a vga to RGB conversion cable. Is this OK or do you think I would need a video scaler for it? Any thoughts are appreciated.

Thanks,
Sam

That's easy. Go ahead and run the conversion cable (a whole lot cheaper than springing for a scaler), and if you are satisfied with the resulting images, then you don't need a scaler. If you are dissatisfied, then you may either want a scaler or a whole new display (any of which will have more-sophisticated video processors than your first-generation unit, Id venture to say).

Then let us know what it looks like.

Maybe I'm being a little contentious, but as I watch mostly BluRay discs at native 1080/24p into my AE2000 projector, what benefit (if any) would a scaler add to my picture quality?

I could use a scaler (but it would have to be cheap) to produce a 'resolution within a resolution' to allow me to 'fit' a 16:9 image into my (zoomed) 2.35:1 image for when viewing the intial menu and trailers. If anyone knows of such a device I'd like to look into it.:) It would be neat to allow a remote button press to change from 2.35:1 to 16:9 even if the 16:9 would be lower quality it wouldn't matter just for trailers and menus. When watching a whole 16:9 film, I'd just zoom back and use the full resolution of the PJ anyway.

Given the above, I either need a very cheap scaler/processor to achieve my instant AR change, or if there would be a worthwhile improvement to the main feature picture quality, then I'll have to look at the more upmarket models.....

Is Windows/MacOS base PC a much better option afterall?!

I find that the higher end video processors are so much more expensive compared to other products. One of the contributing factor for higher cost is the production line. As video processors are not usually produced in very high volume like other AV devices.

My question is, are they really worth what they are priced? just because they are rare? Can we easily replace them with a HTPC/MacMini?

Hello all, I can't seem to get much help posting in the scalers forum so I thought I would ask here.

I live in an apartment and they are not going to put up a high def dish. We only haave a 3LNB dish so I only get about 8 HD channels. Everything I watch is unfortunatly not on the HD channels.

Will a scale......scale my 480i signal from my DirecTV hr-21 to 1080i/P?

Its really a bummer watching SD on my Samsung 46" lcd.

Oh and when I say scale, I mean double or possibly more than double the resolution.

Any help will be greatly appreciated.

dudeman

Hello all, I can't seem to get much help posting in the scalers forum so I thought I would ask here.

I live in an apartment and they are not going to put up a high def dish. We only haave a 3LNB dish so I only get about 8 HD channels. Everything I watch is unfortunatly not on the HD channels.

Will a scale......scale my 480i signal from my DirecTV hr-21 to 1080i/P?

Its really a bummer watching SD on my Samsung 46" lcd.

Oh and when I say scale, I mean double or possibly more than double the resolution.

Any help will be greatly appreciated.

dudeman
Dudeman,
Yes. By your description of your current video setup you could greatly benefit from a scaler. You would set the output of the scaler to the native resolution of your display so it is possible that your lines of resolution will more than double on certain content.

Since I do not see it addressed much in this forum I thought I would mention that scalers are creating information that is not there to match your display's resolution. These images will look much improved but will not look as detailed as say a Blu-ray since those pixels are actual and not interpolated. An HD source will have a higher resolution to start with and require less scaling and possibly none with a 1080P source. Even these images may be improved by correction of overscan to fit your display better so that less image is lost off the screen.

I hope this answered some of your questions. Since I am new to the forums I don't expect to have instant credibility but am a Lumagen dealer, so if I don't have the answer, I can get it.

Matt

Howdy.

I've been searching for a ranked list of scalars / a ranked list of devices to help choose where I should be doing my scaling. Does such a list exist? For instance, I have a Kuro 9G, PS3, and Yamaha 3900. Where to scale?

My google fu is weak today.

Thanks.

I have a Kuro 9g display hooked up to Verizon FiOS and an Oppo BDP-83. Those are my only sources for video. Right now both are routed through my Integra 7.8 receiver and then to the Kuro display all by via HDMI. I was thimking of ugrading to an Anthem d2v video/audio processor, but will I really notice a difference? The picture quality and audio quality are both already very good. Will a processor like the Anthem make a noticeable improvement in PQ or AQ?

Nice post, very helpful. Thanks.

I have a Lumagen XD running into a Pioneer 150FD 8th gen 60" Kuro. I thought that my picture could'nt get better, until I tested the Lumagen. I calibrated my display using Calman and an i1pro. Then I calibrated it with the XD's CMS and Greyscale and WOW!!! My STD content looks great and my HD content almost looks 3D. Even my wife saw the difference !!! I have 2 XD's factory sealed for sale check out the AV classified for info.
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