SDI, is it all that?

Discussion in 'Projectors, Screens & Video Processors' started by Gordon @ Convergent AV, Aug 29, 2001.

  1. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    A post Event POSTING:

    I have so much I feel I need to tell you all but I have little time as this week is hectic. So I thought I'd start with a little discussion about the above.

    SOme while ago, when Uwe Sperling of Vigatec launched the modded 737 with SDI out on us all I played it in to a modded VC1280 Vigatec processor against the standard analogue component outputs. I used a s/h Sony1251Q CRT with the output resolution of Vigatec set to 800 x 600. The result, was to my eyes, quite substantial. The SDI removed a layer of haze and brought out detail making text on clothing and fine detail in backgrounds more obvious.

    This weekend I did a similar thing, except this time I had the company of Richard Ansell of Snell and Wilcox, a CineMAX 9" CRT projector and about 80 like minded individuals. We used an analogue component output from the TAG DVD32r and played it against an SDI out from the modded 737. Both fed direct to a Snell and Wilcox Interpolator Gold. We did it in three session before stopping as no-one could really see much difference. I would agree with them too. It was miniscule compared to what I'd seen with the Vigatec.

    So, what does this mean. Well, to me it says the DVD32r has a great analogue component output and that the Interpolator is exceptional at its video processor of component video signals. I'd guess dealing with analogue is harder than digital when it comes to video.

    Any comments?

    Gordon
     
  2. Couch Potato

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    That's why I want the DVD32R!!

    Only £30K to find now for the Interpolator <img src="biggrin.gif" border="0">

    Steve
     
  3. Nic Rhodes

    Nic Rhodes
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    Gordon

    I was quite surprized by this as well. It was my first projector experience with SDI and I expected much. I have seen it looking stunning on a plasma.

    I agree totally with you observation that the SDI was only marginally better than analogue. I wasn't too bother by the difference. Certainly at the event there were other things that made a far bigger difference.

    Is something to do with possible the best interlaced analogue signal available against a mass market DVD with after market mod, complete with jitter? I don't know the answer but I went away with a content Tag feeling.
     
  4. JohnAd

    JohnAd
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    Gordon

    I agree with you, I think this says more about the TAG's D/A and the S&W's A/D convertors than it tells us about SDI. On the high end stuff it seems feasible that you can basically recover the full DVD stream. On lower end stuff as with the Vigatec it should make a difference but only because you're removing the need to two very expensive convertions.

    John
     
  5. Blade

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    I was speaking to Jenz last night about the Event and he mentioned the Vigatec/SDI option.

    He said that he is awaiting the SDI Input for the Rock+ as being his next Image improvement.

    I was under the impression though that SDI is "illegal" from the DVD Forum point of view. Aside from the modded Pioneer 737 what other Players have SDI?

    I'd certainly be interested in hearing about your Scaler Demo with a Vigatec/SDI and Rock+/SDi <img src="biggrin.gif" border="0">
     
  6. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    The Vigatefc D-I-Y mod is about 500EUROS I think. The cheapy D-I-Y US mod board is around $200ish.

    It's an extra £600-700 for every additional SDI input on a Vigatec.

    Gordon
     
  7. mart.stokes

    mart.stokes
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    It's funny how this thread has turned slightly. The initial comment regarding how good the Snell and Wilcox is (and can extract digital type performance from an analogue input) has been mostly ignored and people have homed in on the SDI Vigatec input. Great minds (and crap ones) think alike. The Event has got a lot of us thinking about the DVD(digital feed)-&gt;Vigatec-&gt;CRT route.

    The only thing is that Jenz obviously believes that the Rock+ was not set up as well as it could be and, in total system cost terms, there would be little between the Rock+ and Vigatec. This fact, coupled with a serious lack of the required amount of money, still leaves me pondering a little (and I'll probably be pondering a long time at this rate).

    [ 30-08-2001: Message edited by: mjs ]</p>
     
  8. Jeff

    Jeff
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    Another interesting thing about SDI is that it is natively supported by the bt8x8 chips so adding support to DScaler should be fairly easy. All we need is a card and something that outputs SDI (a modded Sky + box would be very nice) and a small code change to DScaler. After sorting out the internal IR for Kryton this is my next project.

    Jeff
     
  9. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    It would be interesting indeed. I think that the SDI on both these devices is the way to extract the last ounce of performance from them both.

    SDI is not allowed to be supplied by manufacturersa s standard for the reasons you say. Vigatec sell a mod kit now for Pioneer owners and there's a huge thread over at AVScience about DIY mods. TGhe favoured player over there seems to be a Denon DVD3300 as it has no chroma bug (although no-one saw a chroma problem on the afflicted 737 we played or any of the Arcams)and it's also easy to mod.

    So, there you go. I have spoken with my spies who fly to Indianapolis tomorrow for CEDIA USA. They will be visitng all display technology vendors in a never ending quest for video nirvana!

    Gordon
     
  10. Blade

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    Hwat sort of pricing are we talking about here Gordon as an indication?

    How much for an SDI Mod and how much for a Scaler Input Card with SDI Upgrade above and beyond say the Vigatec/Rock price?
     
  11. JohnAd

    JohnAd
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    Jeff

    If you don't mind I'll try and clarify the situation by complicating it some more <img src="smile.gif" border="0">

    The bt878 chips will allow you to input CCIR656 streams which is an 8 bit Cr Y Cb Y stream that is very close to what we process internally and similar to whats actually stored on DVD.

    SDI is natively 10 bit and also Cr Y Cb Y (I think). so to convert true SDI to CCIR656 you "should" dither and do other clever stuff to drop the 2 least significant bytes.

    In our situation where you have an MPEG decoder chip outputting CCIR656 or something similar that gets upconverted to SDI just by adding zeros it will be fine to just drop the zeros again at the other end.

    As far as DScaler is concerned there is already some code in there to support digital boards that was added by the guys at Connexant so it "should" just work once we get it all connected up.<br />So who's up for getting the chips metioned in the <a href="http://www.avsforum.com/ubb/Forum23/HTML/001178.html" target="_blank">AVS SDI for cheapskates thread</a> and having a bash at getting this working.

    Dan Schmelzer has done a lot of work playing about with this stuff, I don't know how far he's got. See this <a href="http://www.avsforum.com/ubb/Forum12/HTML/011702.html" target="_blank">AVS thread by Dan Schmelzer</a> where he found the Sasem card that exposes the digital in pins as a ribbon cable header which whould make prototyping easier.

    What we need is

    Sky Tuner -&gt; MPEGChip -&gt; CCIR656/Similar -&gt; ???? -&gt; SDI

    +

    SDI -&gt; ???? -&gt; CCIR656 -&gt; bt878 -&gt; DScaler -&gt; VGA

    = Yummy

    John

    [ 31-08-2001: Message edited by: JohnAd ]</p>
     
  12. Mr.D

    Mr.D
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  13. Blade

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    Didn't Jenz indicate that he, Gordon and B4 only had a very limited time to set up? Would love to see the Scaler Demo nearer London with just the three main units (Vigatec, Rock+, and HTPC).
     
  14. JohnAd

    JohnAd
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    Blade

    Yes, neither Jenz and Jeff had enough time to set up either the Rock or the HTPC properly for the environment.

    During the talk Jenz hinted that Gordon had longer to set up the Vigatec (*edit* this is wrong see below *edit*) and that may account for the superior perforamnce in the very dark scene from Unbreakable.

    I'd also love to see the scalers go head to head again, especially with some video material, as even half decently materered film is a bit easy for the big boys and there was very little to chose apart from judder between them.

    I'd also like to see the NR thrown in as well as I'd like to see if the pre/post-processing Faroudja do has and noticable effect on the picture.

    Jenz and I had a quick play with the Viatec<br />after the last demo and noticed that the Vigatec was taking about a second to switch from video mode to film mode compared with too fast to notice on the Rock+

    John

    [ 31-08-2001: Message edited by: JohnAd ]</p>
     
  15. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    OK,

    The scaler room at the event was just to show that there are differences to scalers other than de-interlacing ability. It was not to show which one was the best.

    Each devices has its own peculiarities and features. As I have said ideally we would have spent longer setting each up to it best.

    I didn't have longer to set up a Vigatec than the other units. I think in actual fact I pushed buttons on the front panel for a total of around 60 seconds. The Vigtec was set at standard default settings with an output of 1024 x 768 like all the rest. The Rock and HTPC were set to 72 Hz output. Which is fair as this is a feature you would expect to use when playing back NTSC film based DVD's.

    At some point I will get down to Jenz with our Vigatec. Then he and I and can spend a significant amount of time setting each up to it's best with his 808.

    Please do not assume from what happened at the event that a Rock+ is not as good as a Vigatec or ViceVersa. You should seek out a dem of each and work it out for yourself.

    Gordon
     
  16. JohnAd

    JohnAd
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    Gordon

    Sorry for casting aspersions....

    You're right that there is more to scalers than the simple demo that we saw could possible cover.

    The one aspect that was interesting was that on default settings the Vigatec output just looked better, more film like, whatever you want to call it, on that dark scene.

    This may have been caused by a variety of factors but to me the fact that it appeared better than the HCPC in that scene points to a better output stage or a gamma adjustment taking place somewhere.

    John
     
  17. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    John, don't worry about casting aspersions or otherwise.

    I think if the Vigatec seemed to have better black detail or whatever it was quite possibly due to good firtune more than anything else. I do believe the Rock, HTPC and Vigatec were better than Quad and Iscan's. They should be...at twice the price +.

    To me what was interesting was how bad folk thought the Runco was. I don't. However I too am going to have to go away and try it again in direct comparison to a Vigatec after setting both up properly....

    Gordon

    Gordon
     
  18. JohnAd

    JohnAd
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    Gordon

    I think the order that we viewed the equipment was important here. What came across on my first run through the set was that there was a massive detail drop between the Vigatec and the Runco, also the colours didn't seem as "good". The Rock and HTPC were a step up again from the Runco for similar reasons but I think most peoples perceptions of the Vigatec were partly due to position, the quadscan before and the runco after, the Vigatec stood out more than the Rock+ HCPC.

    On the second pass through I was trying to look past the order of viewing and tried to compare in a different way. I'm not sure I managed it, especially with Richard and Jenz pointing out the red push and the crushed blacks on the Runco.

    Lots of things could have affected this of course and I realise there is a massive problem area when you try and compare colours. But from that experience you really need to do a set of A-B comparisons rather than A-B-C-D-E-F.

    What was clear was that there are good cheap scalers that get a good image and there a higher up scalers that improve the image further but as you say it was impossible to pick the best/right for you scaler in those conditions.

    John
     
  19. Nic Rhodes

    Nic Rhodes
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    People seem to love the idea of a digital transmission standard, well what about DVI? It is far more capable (and supported) than SDI. It can do much more. Many new panel projectors have the required inputs.

    Tag and Meridian will announce updates using DVI interfaces soon. This is what I am interested in for DVD.

    Imagine a digital Progressive scan signal sent from a Tag DVD192R to their AV192R that then does scaling and only outputs to RGB at the very last minute.
     
  20. Jenz

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    Well there's quite a lot of statements here and Gordon hit the nail on the head. We were trying to show the benefits of deinterlacing, judder removal and scaler impact on colour.

    Its fair to say that the Runco, Vigatec, Rock+ and HTPC (mainly V-Sync) were not as well done as I'd have liked but it was still very worthwhile.

    I have almost completed the Scaler Presentation in HTML and I have enclosed post-event notes in there to that are particularly related to Runco/Rock+/Vigatec machines.

    I have supsequently recalibrated the Rock+ and got the results I expected. Even managed to kill of those Motion Artefacts on the Wooden Huts. Do you lot realise I see that Scene in my Dreams now! <img src="eek.gif" border="0">

    Jenz.
     
  21. Jeff

    Jeff
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    I'm not the only one then, I must have played the Insurrection and Unbreakable scenes about 20-30 times by now. I'm now back to nice normal 60hz judder on Star Trek and I now have all the detail the vigitec had on Unbreakable. I wasn't happy with Krytons performance on the day, trying 72Hz for the first time probably wasn't the greatest idea. Vigitecs performance on Unbreakable opened my eyes and as a result it has helped me retune brightness and gamma levels to match its performance. Now I'm putting both DVDs away and I won't be playing them for a while. I might even watch a whole film. <img src="smile.gif" border="0">

    Jeff
     
  22. Gordon @ Convergent AV

    Gordon @ Convergent AV
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