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Discussion Starter · #1 ·
Can anyone outline a components breakdown for an HTPC based on the criteria listed below?


I have a number of Tivos, in fact more than 95% of my viewing of media is what's recorded on them. Obviously they're outputting something substantially less than 480 but if I'm watching on an HDTV I need to do something to clean up the signal and enhance it.


I am probably going to be purchasing the Pioneer 503 cmx and believe that based upon what I've read in these forums that the deinterlacer/scanner that the unit uses is not very good. This led me to think I should go with a Leeza or some such other video processor. However, if I can have the performance at a lower cost with an HTPC and potentially do other things with the HTPC that I can't do with the video processor then...
 

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I'm sort of in the same boat as you with the Tivo's. Check out this thread in the video processor forum.

http://www.avsforum.com/avs-vb/showt...threadid=47128


This is a discussion of modifying various devices for SDI output. This should give the best results as dscaler(htpc) gets a digital signal that has not undergone any digital to analog conversions. I have heard from some that the results on the Tivo is unbelievably good. I have also heard that there is little improvement.


If you are technically adept you may be able to pull this off yourself. If you check out the last page of the thread you can see that I am attempting to begin a new thread in the HTPC forum to address the specifics of do it yourself modifications. You can also have someone else do these modifications but at close to $600 per Tivo that would get pretty expensive for you.


I am still waiting for my National dev kit cards. When I get them, I am first going to do the Pany rp56 because it should be much more straight forward but after that I'm going to tackle the Tivo's. You might want to look to glimmie on this one as he has already done the rp56 and is working on the tivo.



Matt
 

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Discussion Starter · #3 ·
Thanks! Looks like a lot of helpful info, will have to digest it. Now totally a newbie with all of this processor madness so couple of questions:


I would be making a modification to the Tivo board to make the signal compliant. So regardless of what external devices I choose to use (leeza, faroudja, etc.) I'd still have to do this mod no matter what? Or if I were to use such a device I wouldn't need to do the DIY approach? I'm just not 100% clear on what I need to do to successfully feed my picture to the 503 cmx and have it cleaned up.
 

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Wow, that's a lot of DirecTivos.


Tom Strade at Immersive does SDI output modifications. You don't need to DIY! It's not cheap, but think about how much you watch TV...

Immersive's SDI Page


If you don't want to go that route, s-video will do (not as well, but it will do). There are several scalers that will do this at a good price, such as the new Focus Enhancement scaler.

If you are technically adept you may be able to pull this off yourself. If you check out the last page of the thread you can see that I am attempting to begin a new thread in the HTPC forum to address the specifics of do it yourself modifications.


Matt: I wish you luck, but I remember that it took several knowledgable people a lot of time and required some specialized hardware to SDI mod the DirecTivos. Can you program FPGAs?
 

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You could use the Tivo unmodified with an HTPC and any of the other devices you list. The problem with this is that you would be using an s-video connection and be inputting it as an analog signal into your device.


What happens in this scenario is.

1. The Tivo decodes the mpeg data

2. This data is then converted to an analog video signal

3. The analog signal is sent out the s-video port of the Tivo.

4. The HTPC (Leeza, Faroudja, etc...) converts the signal back to digital.

5. The line doubling (tripling, quadrupling) is done.

6. The processor converts the signal back to analog to output to your display device.


The problems with this solution are that the process of converting back and forth from digital to analog introduces artifacts into the signal. The signal also degrades during transport as an analog signal. Unless you have a display with a digital input, you cannot really avoid number 6.


The important thing is that all of these processors (HTPC, Leeza, Farouda, etc...) analyze the video signal and make their processing decisions based on what they find. Given a signal that has not undergone step 2 (digital to analog) and step 4 (analog to digital), the processor should be better able to analyze the signal. This is because it will have less conversion artifact to deal with.
 

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Dan,


I fully expect this to be difficult. I wouldn't be interested in doing it if I wasn't going to be learning something. I am currently just an ee student and I'm sure by myself I would never be able to figure this out.


I fortunatly have the advantage of being good friends with a couple of ee's at a medical imaging company who have done a little work with sdi.


I am definitely not suggesting that the DIY route is the way most people should go. I do think that I will try to make instructions that are as accessible as possible for people that would like to try this. I don't think that us diy guys will in any way affect Immersive's bottom line as I doubt most people that would be willing to try this are the types to drop $600 for someone else to do it.


I think that this is definitely the was to go for 480i sources but for some reason there is not a lot of buzz about it. I think that while the diy types are probably the exception as far as SDI is concerned, they are also the most likely to be vocal about the benefits. If there were several active threads talking about how great sdi modified Tivo's are, I think Immersive would probably be swamped with more orders than they could handle.


Of course, I could be wrong and nobody is really interested in this.


Thanks

Matt
 

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You're preaching to the choir! I love my SDI sources fed into the Silk and processed through DScaler. Please keep in mind though that it's a new technology to the home theater market (about a year), so that's part of why every other thread isn't about SDI.


And I didn't mean to impugn your knowledge (probably greater than mine) or your motivation in doing this. But IMO a DirecTivo isn't the best place to start on the output end. That's all.
 

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Discussion Starter · #8 ·
Ok DirecTivos (SDI modded) fed to Leeza or HTPC, which then feeds plasma tv.
 
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