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Discussion Starter · #1 ·
Has anyone tried running ReplayTV recorded files that have been run through a GOP/PTC fixer (like in Womble)? I'm wondering if those fixes would create any incompatibilities. I did try running a file that had been altered to show 16:9 AR instead of 4:3 AR, and the Replay seemed to work just fine (although my TV didn't automatically show it 16:9, as I was hoping).
 

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Wow, you got an altered file to stream back onto the replay?


That's a new one.
 

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Discussion Starter · #3 ·
Yes. The only changes to the file were with DVDPatcher; the file was not editted (i.e., nothing was cut or added). Of course, I only tried this once, since the end result wasn't what I wanted, but the file seemed to play o.k. Maybe I'll try one with the GOP/PTC corrections tonight and see what happens.
 

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Although I've never added modified mpegs "back" to the RPTV Box, I have had extensive experience dealing with the extracted Mpegs. The Mpeg "EN"- coding engine in the RPTV Box produces what I like to call a "RAW" mpeg. There is no attention paid to any kind of compatibilty per se. You'll often find those PTS errors as well as GOP picture seqences over the DVD limit of 15 and video bit rate excursions beyond the DVD nomal rate as well.


Now the "DE"-coder in the RPTV box seems robust and flexible enough to handle all those problems without a hitch.


Ergo I'd have to suggest that any "improvement" to the original RPTV Mpeg isn't going to cause any kind of problem with the playback in the RPTV environment.


It looks as though the RPTV decoder can handle anything from 1/2 D1 up to full D1 for file frames. I'd be curious to see if it could handle SVCD frame sizes as well (480x480)


How are you getting the mpegs back into the RPTV box ??
 

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This is really the next big hack we need to focus on... Getting edited shows / home movies / downloaded adult content from Gnutella / etc to play on Replay!
 

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Discussion Starter · #6 ·
>>How are you getting the mpegs back into the RPTV box ?


I streamed it back with DVArchive, I didn't actually move it back.
 

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Discussion Starter · #8 ·
>> Have you played with getting editted files to play back via DVArchive?


Nope, I've assumed that it's not possible based on comments from others. Also, I don't understand the interaction with the ndx file, but presumably if the mpg is editted with cuts, additions, etc., then the ndx would get broken.


I did just try to play back a file after applying Womble's GOP/PTS fix. The file played, but was garbled. But it was garbled on the PC as well, so the fact that the Replay played it without barfing is promising (although I was dissappointed that Womble messed up the file instead of fixing it). I'm going to play around some more and see what happens. It looks like maybe if the base encoding is done by the Replay, the file will play back with some alterations.
 

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Discussion Starter · #9 ·
>>Nope, I've assumed that it's not possible based on comments from others.


Just tried to play an editted file. It tried to play, gagged and rebooted.


But it played an uneditted file that had 15k PTS errors fixed just fine.
 

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Hmmm, okay now the next question. Does the RPTV box make an index file for every program it records ... OR .. only for those where you've activated commercial skip. Or maybe the ndx file is different for a commercial skip save than normal recording without that feature.


I would try doing a recording without commercial skip enabled, then export that, edit it and import it back into the RPTV BOX. If you were modifying the internal mpeg features or settings, I don't think you'd have a problem, but if the file length was altered by removing commercials or what-ever, then the index file wouldn't find the end of the mpeg or match up which I guess would cause all kinds of problems.


Just my guess here ..
 

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I've been playing with edited replay mpegs and have found that as long as you don't reencode the mpeg file, everything works just fine. The replay seems to ignore the time code information completely, simply playing the audio and video streams it finds from beginning to end. This is a nice feature because it makes removing chunks (of, say, three minutes or so...:)) very easy -- just delete the GOPs you don't want without touching the rest of the file and the replay is perfectly happy. As for the ndx files, every replaytv mpeg file has one to allow for better random access (it seems it uses this file in lieu of the time coding information), so they're not just for mpegs with commercials. Creating an ndx file is a fairly trivial task; you can use jtl's replaypc program "build-ndx" to create one for any mpeg-ps file.
 

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Quote:
Originally posted by Rich A
Hmmm, okay now the next question. Does the RPTV box make an index file for every program it records ... OR .. only for those where you've activated commercial skip. Or maybe the ndx file is different for a commercial skip save than normal recording without that feature.
Commercial Advance is always on at the recording level. You can just choose to turn off its playback.
 

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Discussion Starter · #13 ·
>>I've been playing with edited replay mpegs and have found that as long as you don't

>>reencode the mpeg file, everything works just fine.


Are you creating your own ndx files, or are you getting them to play without that? Have you tried it with any files where you have cut material from the very beginning?
 

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Quote:
Originally posted by RandyL712
This is really the next big hack we need to focus on... Getting edited shows / home movies / downloaded adult content from Gnutella / etc to play on Replay!
Have you looked at MyTv? http://pages.sbcglobal.net/mytv
 

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Quote:
Originally posted by pmcneill
I've been playing with edited replay mpegs and have found that as long as you don't reencode the mpeg file, everything works just fine. The replay seems to ignore the time code information completely, simply playing the audio and video streams it finds from beginning to end. This is a nice feature because it makes removing chunks (of, say, three minutes or so...:)) very easy -- just delete the GOPs you don't want without touching the rest of the file and the replay is perfectly happy. As for the ndx files, every replaytv mpeg file has one to allow for better random access (it seems it uses this file in lieu of the time coding information), so they're not just for mpegs with commercials. Creating an ndx file is a fairly trivial task; you can use jtl's replaypc program "build-ndx" to create one for any mpeg-ps file.
If I'm reading this correctly, you're saying that you can:


1) Copy mpg from Replay to PC

2) Cut sequences from mpg file (Womble, GOPChop, etc).

3) Create a new ndx file using build-ndx

4) Copy new mpg & ndx from PC to Replay

5) Play modified mpg on Replay


Is this correct?
 

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Quote:
Originally posted by RandyL712
I believe the only playback has been via DVArchive.
I don't know the answer to this since I've got a 5040 and DVArchive doesn't yet work with the 5000's:


Does DVArchive use the ndx files from the Replay? If not, I don't understand why creating them (w/build-index) is necessary? If it does use them, how do you import them into DVArchive? If I recall correctly the Import function just looks for the mpg file (but I could be mistaken).


Scott
 

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Discussion Starter · #19 ·
DVArchive does download the ndx files.


As to the other questions above, I have been able to serve shows from DVArchive and play them on a Replay when the aspect ratio info in the headers was changed, and after fixing GOP/PTC errors. I have not been able to run shows that have been clipped. I haven't spent a lot of time trying to do either, so I'm not sure how representative my results are.
 

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acourvil: I'm creating new ndx files with the replaypc "build-ndx" program. It'd also be pretty easy to write a program that would strip out the records corresponding to the removed GOPs. Neither the mpg or the ndx files are much for headers, so pulling pieces out doesn't make much of a difference. I've also successfully played files where I removed the beginning (in one instance, I even downloaded the circular buffer and just saved a piece of it with no problems).


zabolots: you're correct, except I used dvarchive to stream back to the replay (as RandyL said).


It seems that the replay doesn't care at all about headers or the GOP time coding. As long as the GOP was created by a replay, it's perfectly happy to play it back for you. The problems occur when you reencode the GOPs -- at that point either the decoder chip or the software driving it chokes.
 
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