Transcoding and audio synch...

[lajams]

Hey Guys,
For some years now I've been ripping my DVDs to MPG2 and converting the audio from AC3, so I could stream to the MVP. I've noticed that with these videos, the movies play great from beginning to end. However, if I try to do the skip-forward function, the audio nearly always gets out of synch with the video. After skipping back and forth a few times, I can usually get it back in synch. This also happens if I stop the video, and then try to resume it later. The audio is out of synch again.

I thought maybe my transcoding was nerfed, so I decided to play with autoGK and give the XVid path a shot. I converted an episode of The Tick from one of my DVDs to XVid. I followed a popular guide to do the conversion, and it went great. I had to use GBPVR to play the video, as the Hauppage software refused the audio. BUT....same issue as my MPEG2 files.

SO....I dove into the VOB scene with xDVD a few days ago. These play just fine...I can skip around, resume, etcetera, and the audio is just fine. Also....recordings done by my PVR150 play fine too....I can skip forward and back with no loss of audio synch.

Know this is probably a worn subject, but is this strictly an issue with the chip in our MVPs, or is there something I can add into the transcoding sequence that would allow the MVP to track the audio/video synch a little better? It is obviously only affecting my transcoded stuff.

Thanks in advance.

[zehd]

Hey Guys,
For some years now I've been ripping my DVDs to MPG2 and converting the audio from AC3, so I could stream to the MVP. I've noticed that with these videos, the movies play great from beginning to end. However, if I try to do the skip-forward function, the audio nearly always gets out of synch with the video. After skipping back and forth a few times, I can usually get it back in synch. This also happens if I stop the video, and then try to resume it later. The audio is out of synch again.

I thought maybe my transcoding was nerfed, so I decided to play with autoGK and give the XVid path a shot. I converted an episode of The Tick from one of my DVDs to XVid. I followed a popular guide to do the conversion, and it went great. I had to use GBPVR to play the video, as the Hauppage software refused the audio. BUT....same issue as my MPEG2 files.

SO....I dove into the VOB scene with xDVD a few days ago. These play just fine...I can skip around, resume, etcetera, and the audio is just fine. Also....recordings done by my PVR150 play fine too....I can skip forward and back with no loss of audio synch.

Know this is probably a worn subject, but is this strictly an issue with the chip in our MVPs, or is there something I can add into the transcoding sequence that would allow the MVP to track the audio/video synch a little better? It is obviously only affecting my transcoded stuff.

Thanks in advance.

First, any MPG recording done with your tuners will be good and ready to playback on the MVP.

If you use most any transcoder out there to get a source video into an MVP MPG, unfortunately you will lose sync often when shuttling ff/rw.

This is known to happen quite often with Transcoding on the fly, avi to mpg, using either ffmpeg, mencoder or vlc.

I have noticed that it seems to be case by case. I have some avis that play in sync with ffmpeg, but not with vlc, etc...

If you have a DVD rip to mpeg transcoder, it will undoubtedly be using a transcoder that is outputting a file with the same symptoms. I would hazard a guess that the program is using one of the three transcoders mentioned...

There have been many suggestions. I have tried most of them, in my search for the best all around remedy to add to my Transcode program, ZProcess.

People have tried output dimensions, bitrate, DVD,VCD,SVCD profiles, faster and faster computers, different transcoders... I have done a lot of testing and I have not found any one solution that seems to work with everything on my harddrive. Nor does any or all of these tewaks that work great for one user, work for another user...

I have used AutoGK to rip several DVDs, and most transcode into something else (mostly MVP MPG) very well. I have ripped my Shrek DVDs with AutoGK too, and try as I might I cannot get it to transcode with anything other than ffmpeg at vcd settings...

I know that it's a choice in AutoGK that is making the output file sort of incompatible. Just don't know what it is...

I have tried xDVD too, and it uses much the same mechanism as ZProcess, and the transcodes do not work for me even though others swear by it.

Could be the codec suite installed...

[lajams]

90% of my files are MPEG2 ripped from DVD. The rest are tv recordings from my PVR150, and a few direct rips to VOB for testing, and a couple of XVids.

My DVDs are ripped as follows:

1) Rip with my favorite ripping program
2) Use DVD Shrink to reauthor to main movie and DD 5.1 English track.
3) Strip audio out of movie with DGIndex
4) Recode to MPEG2 with TMPEG Enc.

Thats about it. They play great on the puter (skip forward, fast-forward/rewind). I think its only when I stream them to the MVP that I start seeing issues, which is kinda strange to me.

And *I think* the only on-the-fly transcoding I may be doing is when I stream the XVid and the VOBs (audio only has to be converted on the VOBs I think). My DVD rips have MPEG audio after the encoding process above, so those should be streaming natively to the MVP for display.

I've been doing research, and I saw something about "PST Jumps" in relation to audio-sync. Something to the effect that "in the event of a dropped video frame, the audio plays continuously". So if I'm forwarding/reversing or skipping forward/back, and there's a dropped frame involved, there are no "blank" spots in the audio to match the video now, so its out of synch. Does that make sense? I would assume that the encoding process would have to drop the frames in the first place to cause this, but I don't know....

[nitrogen_widget]

I think the archive plug-in allows you to rip a DVD to mpeg.
I used to do that when I used my MVP more & I never had a problem with anything.

[zehd]

90% of my files are MPEG2 ripped from DVD. The rest are tv recordings from my PVR150, and a few direct rips to VOB for testing, and a couple of XVids.

My DVDs are ripped as follows:

1) Rip with my favorite ripping program
2) Use DVD Shrink to reauthor to main movie and DD 5.1 English track.
3) Strip audio out of movie with DGIndex
4) Recode to MPEG2 with TMPEG Enc.

There's your transcoder. And it will also create MPGs that look great on the computer and not on the MVP.

I want you to know that this has been hashed, and not solved...

As I said, doing everything exactly the same, can have success and failure movie to movie. Go figger

[lajams]

Thanks much. Was hoping this skip-forward/skip-back thing had been solved. I'll keep digging.

Btw, the videos look GREAT on the MVP. I used to encode at full DVD quality, but had to save some space, so I went with SVCD at high quality. Still looks really great. Maybe the way to go is to find player that does VOBs natively and just stop recoding stuff.

Anyway, thanks much everyone for your input.

[pBS]

hmm, so what is your 'favorite dvd ripper' ? usually they are the cause...

it sounds like the bad dvd sectors copy protection scheme, and your ripper probably isn't correcting them...happens all the time with cheesy rippers..works on some movies and not on others..you can rip the movie and it may play well on a dvd player because of the internal compensations for scratches, but when transcoding, the files aren't actually correctly structured and create sync issues..

i can rip most dvd's with mencoder without any help, but they will contain errors,as with any older ripping program..sure, you can watch it ok, but there will be hairline skips that you won't see much while watching...but they are there..[it really messes up the pts and timelines]

to get perfect rips i use Anydvd decrypter...it fixes those 'missing sector errors' copy protection schemes like dvd-decrypter does, plus the newer protections it can't fix..then you can use dvd shrink to rip directly from disc without errors

most dvd's nowdays use about 8-10 copy protection schemes so you need a quality ripper to adjust for them all or you'll get glitches in your rips and hard to transcode files... the glitches might not be noticeable while viewing..

now all this only works for dvd rips, you shouldn't have any problems with capture card stuff, tho some drivers will create bad timelines..[the newest ones are good tho] and web downloads are usually problematic cuz of bad original encodes..

[pBS]

have you tried the MVPMC dongle? it can play vobs directly, even ac3 audio..!
there's a thread on it here somewhere..
[native MVP dongle replacement that works with gbpvr also]
then you woudnlt have to rip the files at all..[but no menus]

[lajams]

[quote=pBS]hmm, so what is your 'favorite dvd ripper' ? usually they are the cause...

I use DVDFab. I have two kids, and can't be swapping DVDs all the time, nor worry about them trashing them. We have quite a collection of them too...I should own stock in Disney at the rate my wifey buys them!

Usually I'll just rip the whole shebang, then take the main movie and audio track 1 with DVD Shrink. Then the fun begins...DGIndex to strip the audio to wave (and I think this probably causes some of the problems) and then mux the VOBS and audio to an MPEG2-compliant SVCD file in high quality using TMPEG Enc. I use fairly popular methods to do this, and don't have any audio-sync issues on the computers....they fast-forward, skip forward-back all day long with no issues. But streamed to the MVP....thats kinda why I thought maybe there was something in the hardware on that end.

I didn't think about the dongle part though. I'll look into that. I just tested another SVCD creation (using CBR instead of VBR to see if that helped...didn't). And the xDVD stuff works perfectly, so kinda tells me that messing with the video and audio track together may consumate the issue. *sigh*. I'll look into the AnyDVD as well. I used it a long time ago, but there were too many freeware utilities so when my trial ran out.....

I love this streaming media stuff, and don't want spindles all over the house. Just too much for an old ex-SA to deal with, LOL! Thanks much.

[lajams]

have you tried the MVPMC dongle? it can play vobs directly, even ac3 audio..!
there's a thread on it here somewhere..
[native MVP dongle replacement that works with gbpvr also]
then you woudnlt have to rip the files at all..[but no menus]

If I load the MVPMC dongle in GBPVR would I have to do all the TFTP server stuff as well? I looked into that some time ago when it was starting up but that kinda set me off.

Thanks much.