[Richard Tywoniak]

The RP56 with SDI upgrade seems like an unbelievable bargain at approximately $650. Many higher priced options ($2500 and up) are available. The major difference that I see are power supply and dvd transport. Is there a difference in video quality. I suspect that there is a reliability difference but I could buy four of the cheap units versus 1 of the high end ones. Any thoughts on the benefits of one over the other.

 

[WynsWrld98]

What is SDI? What is it for? What does it do??

 

[Richard Tywoniak]

SDI stands for serial digital interface. The upgrade allows you to have a direct digital signal pass directly to your scaler as long as your scaler has an SDI input capability (Rock+ and Vigatech). The image is supposed to be HD-like in quality. Everyone I have talked to that has seen it says the quality is awesome. You basically bypass the digital to analog converter present in all DVD players. There is a company called Immersive that provides low cost upgrades ($450) to Panasonic DVD players. They chose Panasonic because these players do not have the Chroma bug. With a $180 purchase price on the DVD player the total comes out to about $650 including delivery. Taw offers a player for $2500. The differences I can see are in the power supply and the transport. Since the D/A converter is bypassed this does not even come into play which is ussually to high priced part of a DVD player. This is how I understand it, although I am not an expert.

 

[Daniel Hutnicki]

I might be all wrong, but from what I hear about high end dvd players is that their superiority is not so much based on their video but on their audio. I am sure that they are superior in video but the biggest attribute is their audio. Of course this is based on interlaced machines only. When you talk about progessive machines, its a different story. When I went to view the dwin transvion dlp, it was connected to a Meridian dvd player. The store owner told me (take with a grain of salt) that its audio capablity was what they liked in the player.

 

[Robert2413]

Quote:

Originally posted by Richard Tywoniak SDI stands for serial digital interface. The upgrade allows you to have a direct digital signal pass directly to your scaler as long as your scaler has an SDI input capability (Rock+ and Vigatech). The image is supposed to be HD-like in quality. Everyone I have talked to that has seen it says the quality is awesome. You basically bypass the digital to analog converter present in all DVD players. There is a company called Immersive that provides low cost upgrades ($450) to Panasonic DVD players. They chose Panasonic because these players do not have the Chroma bug. With a $180 purchase price on the DVD player the total comes out to about $650 including delivery. Taw offers a player for $2500. The differences I can see are in the power supply and the transport. Since the D/A converter is bypassed this does not even come into play which is ussually to high priced part of a DVD player. This is how I understand it, although I am not an expert.

I haven't seen an SDI connection myself, but basic physics suggests that this cannot be the "holy grail," making a huge difference in PQ. Why? Simply because EVERY progressive-scan DVD player _already_ has a direct digital connection between the MPEG decoder and the scaler chip. So I wouldn't expect an SDI connection to be any better than the output of a progressive DVD player with excellent D/A converters, provided you want a 480p output. The advantages of an SDI connection (to a high-end de-interlacer/scaler) over such a player are relatively subtle--mainly a direct digital connection between the 480p output of the deinterlacer and the input of the scaler. But until we have direct digital connections all the way to the display device, there will be at least one D/A and A/D conversion _somewhere_ in the path, the only questions being (1) where?, and (2) of what quality?


That being said, I am planning on having my Technics interlaced DVD player converted to SDI because I already have a Vigatec Dune with SDI input, and, in this case, the SDI connection will eliminate one set of conversions in the signal path. However, a Skyworth 480p output driving a plasma or CRT rear projector already gives me slightly better PQ than the Technics/Vigatec combination, probably due to one fewer conversions. So I don't expect miracles from the SDI connection, just a subtle improvement.

 

[Bosef]

Quote:

Originally posted by Robert2413 However, a Skyworth 480p output driving a plasma or CRT rear projector already gives me slightly better PQ than the Technics/Vigatec combination, probably due to one fewer conversions.

Do you use Skyworth for components or vga output?

Did you notice that Skyworth has problems in both kind of output?

The vga output has the max signal level for rgb wich is 20% lower than the standard output and the green offset wich is 6 times higher than the blue and the red, sa that the picture becomes greener with low light pictures.

The component output has dalays in the red and blue signals that won't match the Y component.


I couldn't ever watch Vigatec scaler with a sdi input and a dvd player without the chroma bug, but i do think that it could be really better than the Skyworth itself.


I agree that a good progressive dvd player can be better than a scaler with the analog inputs... i fully tested a Panasonic+Iscan Pro vs. Skyworth with Pal discs and the Skyworth is slightly better (exept for the chrome bug issue). Iscan Pro also nearly decrease the luminance dinamic.

 

[Brett]

Quote:

Originally posted by Robert2413 That being said, I am planning on having my Technics interlaced DVD player converted to SDI because I already have a Vigatec Dune with SDI input, and, in this case, the SDI connection will eliminate one set of conversions in the signal path. However, a Skyworth 480p output driving a plasma or CRT rear projector already gives me slightly better PQ than the Technics/Vigatec combination, probably due to one fewer conversions. So I don't expect miracles from the SDI connection, just a subtle improvement.

Hi Robert,


Could you report back to us, either in this thread or in another dedicated one to tell us how you feel you have, or have not gained much by going SDI?


Many thanks from all those contemplating going SDI.

 

[Robert2413]

Quote:

Originally posted by Bosef Do you use Skyworth for components or vga output? Did you notice that Skyworth has problems in both kind of output? The vga output has the max signal level for rgb wich is 20% lower than the standard output and the green offset wich is 6 times higher than the blue and the red, sa that the picture becomes greener with low light pictures. The component output has dalays in the red and blue signals that won't match the Y component. I couldn't ever watch Vigatec scaler with a sdi input and a dvd player without the chroma bug, but i do think that it could be really better than the Skyworth itself. I agree that a good progressive dvd player can be better than a scaler with the analog inputs... i fully tested a Panasonic+Iscan Pro vs. Skyworth with Pal discs and the Skyworth is slightly better (exept for the chrome bug issue). Iscan Pro also nearly decrease the luminance dinamic.

I use the Skyworth's VGA output, which shows no problems at all with the AVIA disk. That is, chroma delay is spot-on and the 6.75MHz pattern is clearly defined. I do not notice a problem with the gray scale, probably because I use a separate input to the projector and plasma for the Skyworth, and I have calibrated the white level and gray scale on these inputs to overcome any Skyworth-induced problems. (I can understand that there could be objections if there was no way to have a separate sets of calibrations for the Skyworth!)


I have never used the Skyworth's component outputs, simply because I already have the broadcast-grade VGA cables and the Skyworth's VGA output is known to have better chroma delay accuracy than the component outputs.


The only peculiar problem I have seen with the Skyworth for which I have not been able to compensate is a vertical "venetian blind" pattern that appears when I try to apply the Skyworth's VGA output to inputs 6, 7, or 8 of the Vigatec. The picture is normal and stable except for this fixed pattern that is visible, modulating the brightness. The effect is severe enough to render the picture irritating to watch.


Sooner or later, I should put the Skyworth's VGA output on an RF spectrum analyzer to find out if this patterning is caused by clock leakage or inadequate reconstruction filtering at the Skyworth's output. Oddly, I see no sign of it at all on the projector (Barco Retrographics 801s) and only the faintest trace on the plasma (JVC 50") when the Skyworth is connected directly to these display devices.

 

[Robert2413]

Quote:

Originally posted by Brett Hi Robert, Could you report back to us, either in this thread or in another dedicated one to tell us how you feel you have, or have not gained much by going SDI? Many thanks from all those contemplating going SDI.

I intend to report on this to the group. However, as yet I have received no feedback from Immersive on where I am in the queue, so the report is not going to come tomorrow...

 

[Brett]

Hi Robert,


Thanks for your candid reply. While I'm in no rush, I would like to eventually know how you perceive the improvement. I've got a Skyworth and a CRT projector, so I think we've got similar enough setups that your observations would be quite relevant to my situation.


I'm not yet signed up for the Immersive SDI output mod. However I will be getting an SDI input card which will be initially for digital satellite reception. Your feedback would help me decide whether to go all out, with a DVD output mod and an SDI switcher box...


Cheers,

 

[Bosef]

Thank you Robert.


i don't know what it could be that "venetian blind" problem but if you find out what it is, please keep us informed

I don't have problem with the gray scale either, the 20% lack of the rgb output can be fixed with the contrast control.

What i clearly see, since i was told about that by a friend, is the greenish black.

It is not a huge problem, but the skin and the fleshy tones are truly *strange*and i don't know why, but i didn't notice this at all before!

Try to take a look if you have a copy of American Beauty... the two girls heve different skin tones. Originally a girl is purple and the other one looks like a zombie. If i use the Skyworth, both seem to be zombie-like...

 

[dschmelzer]

"But until we have direct digital connections all the way to the display device, there will be at least one D/A and A/D conversion _somewhere_ in the path, the only questions being (1) where?, and (2) of what quality?"


Robert: there is a scenario that is completely digital and is the cheapest option of the bunch. DVD Player >--SDI--> SDI Input Card >--PCI Bus--> DScaler >--AGP Bus--> Graphics Card Overlay >--DVI--> Display device.


Good luck.

 

[DaViD Boulet]

Quote:

I haven't seen an SDI connection myself, but basic physics suggests that this cannot be the "holy grail," making a huge difference in PQ. Why? Simply because EVERY progressive-scan DVD player _already_ has a direct digital connection between the MPEG decoder and the scaler chip.

Actually, very few progressive scan DVD players have scalers.


They all have de-interlacing engines, which is not the same thing.


What makes the SDI path so promising is that the scaling engine...the algorithm that takes you from 480 x 720 pixels to 720 x 1200 or 1080 x 1920 whatever has a direct digital 480x720 source to work from (just like the scaling done in a HTPC).


You're right that a progressive-scan DVD player should be just as good with deinterlacing...but we're not talking about watching a 480P image on the screen here (other wise, all we'd need is a 480P DVD player). We're talking about *scaling* that image to synthesize HD resolutions.


-dave

 

[Robert2413]

Quote:

Originally posted by DaViD Boulet Actually, very few progressive scan DVD players have scalers. They all have de-interlacing engines, which is not the same thing. What makes the SDI path so promising is that the scaling engine...the algorithm that takes you from 480 x 720 pixels to 720 x 1200 or 1080 x 1920 whatever has a direct digital 480x720 source to work from (just like the scaling done in a HTPC). You're right that a progressive-scan DVD player should be just as good with deinterlacing...but we're not talking about watching a 480P image on the screen here (other wise, all we'd need is a 480P DVD player). We're talking about *scaling* that image to synthesize HD resolutions. -dave

Good point. I really should have written "de-interlacers." Although it might be argued that a 480i->480p conversion has also been commonly known as "line-doubling," which is an elementary form of scaling, I will nevertheless concede that most contemporary high-performance displays (except for 42" plasmas) require a true "scaler" for best performance.


[Disclaimer: Yes, I know that 42" plasmas actually _do_ need real scalers to do picture width and height adjustments. To accommodate overscan, they usually end up mapping slightly fewer than 480 lines to the 480 physical lines in the display.]


Nevertheless, the principle stands: do we put the D/A->A/D conversions before the de-interlacer, before the scaler, before the display, or do we dispense with it altogether? While there are a few displays now available that will accept a digital input, most of us still have to deal with analog inputs, at least for the moment.


Of course, CRT displays, being intrinsically analog devices, do not require an A/D conversion. But even systems driving a CRT display _must_ have a D/A conversion somewhere in the path.

 

[oferlaor]

dschmelzer,


Few problems:

1. I'm not at all sure that an SDI & DVI capable HTPC is the cheapest solution on the block. Both Radeon DVI and a custom SDI card cost a lot!. Add Infra/Red reception, a big harddrive a quiet case & fans, and a good non-SDI video input card, then a powerful processor and you're set back quite a few thousand bucks...


2. DScaler cannot do as well as some of the popular deinterlacers out there - like DCDi, or even the Genesis deinterlacer!


3. With 3/2 pulldown content - I assume your combination should give anything else out there a real run for its money!

 

[DaViD Boulet]

Quote:

Good point. I really should have written "de-interlacers." Although it might be argued that a 480i->480p conversion has also been commonly known as "line-doubling," which is an elementary form of scaling

"line doubling" is a venacular term that is more or less inaccurate when describing 3-2 pulldown for deinterlacing film. It does have some relation to what happens when one "deinterlaces" native 480I video...because in this case there is interpolation of some sort to fill in the missing scan-lines...so that could be thought of as an elementary form of "scaling" (because of interpolation).

Quote:

Nevertheless, the principle stands: do we put the D/A->A/D conversions before the de-interlacer, before the scaler, before the display, or do we dispense with it altogether? While there are a few displays now available that will accept a digital input, most of us still have to deal with analog inputs, at least for the moment.

It's very simple. Keep the signal digital as long as it's being digitally processed. Convert only to analog once the signal can stay that way.


For digital displays, the ideal would be to have an all-digital video path. For analog displays, the ideal would be to keep the signal digital through all the stages of processing (deinterlacing and scaling) and then only convert to analog before feeding the CRTs.


Same is true with audio. Why would I convert a PCM stereo track to analog only to convert it back to digital for ProLogic decoding in my pre-amp?


If I'm just playing back 2.0 stereo...I could convert it to analog before the pre-amp because it's going to stay that way.


-dave

 

[dschmelzer]

"I'm not at all sure that an SDI & DVI capable HTPC is the cheapest solution on the block. Both Radeon DVI and a custom SDI card cost a lot!. Add Infra/Red reception, a big harddrive a quiet case & fans, and a good non-SDI video input card, then a powerful processor and you're set back quite a few thousand bucks..."


Err... Quite a few thousand? I'm confused...


$900 PC, Including Radeon DVI + $400 SDI input card (includes 4 composite & 1 s-video) = $1,300

"2. DScaler cannot do as well as some of the popular deinterlacers out there - like DCDi, or even the Genesis deinterlacer!"


Wrt to the Genesis, Stacey Spears seems to think most emphatically otherwise . I haven't done a direct comparison. Have you?


Wrt DCDi, is there an SDI scaler available with this chip? And, if so, how much does it cost? Thanks.