Conversion out of sync

Steve Walsh · Member Joined: 09 Feb 2004 Location: United Kingdom

@ guns1inger

The weirdness continues...

The "stretched" audio file (from Audacity) is not consistently out-of-sync. Using MPC I was able to get the start of the film in sync (-1750ms) but it VERY soon went out of sync again.

Going back to the original (demuxed with vdub) uncompressed wav and adding this to the (HCEnc encoded) m2v (or the original avi) I get no sync issues - even though the file lengths are not the same (see previous post or just down a bit).
However, all is not perfect yet...
Converting the WAV to AC3 or MP2 with BeSweet, I am able to mux the m2v and AC3 (or MP2) using ImagoMPEG-Muxer and I get a nice in-sync MPEG file (or VOB)
As per my initial post, GUI for DVDauthor does not successfully mux these files - it complains about a time length mismatch (video = 1:42.59, audio = 1:39.37)

Next try to author a DVD using the Imago output.
Using the segmented vob's from Imago, I've attempted with IfoEdit using the "create IFO files" function.
The IfoEdit IFO file reports a running time of 2:12:33.09 !
The resulting DVD is very jerky.

I was going to try various other solutions to author a DVD using the output from Imago - ideas I found from this post : http://www.videohelp.com/forum/archive/how-do-i-make-an-mpeg-2-dv ... 65284.html

Would I get similar issues to those seen from my IfoEdit DVD ?
Would PGCedit let me change the running time of the IfoEdit files ? (and would this help the jerky DVD?)

What is the "best" way to convert a working MPEG2 file to a DVD ?

Another question I have from this experience -
Could the reported file length times be wrong ? (I've used AVIcodec and GSpot and they agree, vdub reports the same for video, audio is not correct though - because of original VBR MP3 ? VLC plays the file to 1:42.59)

Thanks,
Steve

guns1inger · Member Joined: 01 Apr 2004 Location: Miskatonic U

I have had VBR MP3 behave oddly a few times, with at least one instance where I could not do anything useful with the audio at all.

I would start by opening the file in AVI Demux, and when it asks to build a time map, say yes. Test play to make sure that everything is still in sync. Leave the video set to copy, and change the audio to WAV LPCM. Save a new version of the video (remembering to put the .avi file extension on the file name), and test this to make sure the audio is still in sync. If it is, use the new video for your conversion.
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Steve Walsh · Member Joined: 09 Feb 2004 Location: United Kingdom

Thanks for the prompt reply and for letting me know I'm not going mad - I've done many avi -> DVD conversions in the past and never had issues like this (even with previous VBR audio files).

Opening the file in AviDemux and choosing to build the time map brings up another box - Index is not up to date. It gave the option to do it now so I went ahead.... Followed the rest of your instructions and got myself a new avi.
When I look at the new avi in AviDemux (file > properties) the same problem still exists !

Video is 1:42.59, Audio is 1:39.37

Any thoughts ?

Cheers,
Steve

guns1inger · Member Joined: 01 Apr 2004 Location: Miskatonic U

Take the new AVI file into Media Player Classic and try to sync it to find the delay. if you can get the start lined up and play the file through in sync from that point, then you should be able to apply this delay in AVI Demux to fix the AVI, and convert from there.

However if you cannot get the two in sync, you might just have to accept that downloading AVI files from places unknown is a risk, and the results can sometimes be less than satisfactory. It may simply be that the original file is corrupt or so badly made that there is nothing you can do with it other than delete it and move on. It happens.
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turkey702 · Member Joined: 23 Jun 2009 Location: United States

Hi, I'm having sync issues also, with the Xvid Codec. Admittedly, I'm not a video expert, so please be easy on me.

guns1inger said:

2. Starts in sync and drifts further out of sync over time.

Perfectly describes the issue. All the files play perfectly in vlc player and wmp. When I say all, this happened with three separate files from different sources all using the Xvid codec. I first noticed a problem when I started loading Xvid videos into Adobe Premiere and gradually the audio got out of sync as the file progressed. I then tried other project settings for frame rates, and region encoding. Didn't seem to make any difference. Tried replacing the audio track with uncompressed wav audio. No. The one time I approached some success was when I adjusted the pitch in Sound Forge to the wav audio. The audio stayed in sync, but the video stuttered every couple seconds. I figured it was Premiere, but then I uncompressed the video with virtualdubmod, using full processing mode. I was somewhat surprised to discover that the uncompressed video also plays out of sync the same way, in wmp and vlc. I successfully converted the videos to SVCD using TMPGEnc, with the audio track uncompressed into wav. Virtualdubmod says the Xvid videos contain no errors. What am I doing wrong here? A video uncompressed with vdub from my experience shouldn't do this. Maybe I'm doing it wrong.

guns1inger · Member Joined: 01 Apr 2004 Location: Miskatonic U

Xvid is a video codec and does not cause audio sync issues.

Premiere/Vegas etc are NOT the tools to be playing with Xvid/Divx encoded video. Xvid/Divx is NOT intended for editing, and these semi-professional editors are NOT designed to edit this type of video.

The most likely cause of your problem is Variable BitRate MP3 audio tracks. Use MediaInfo to confirm.

You are wasting your time concentrating on the video side of this, as the issue is one of audio compression.
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turkey702 · Member Joined: 23 Jun 2009 Location: United States

Yay! It worked. Thanks for the quick reply. I guess what I did wrong before was I didn't set the *audio* to full processing mode. Now the video is working fine.

Steve Walsh · Member Joined: 09 Feb 2004 Location: United Kingdom

AviDemux doesn't seem to be doing anything different to the file.
The initial AVI was in-sync, and the resulting AVI (after running through AviDemux) is still in sync.
However, the audio is still almost 3 minutes shorter than the video when demuxed from both AVI files.
Meaning I have the same issue as I started with.

It's just REALLY strange that it worked properly as an AVI in the first place !

As for the conversion to DVD, I've chopped off almost 3 mins of the end title credits - shrinking the video length to match the audio length - and this seems to have "fixed" the problem for the DVD.

(dvdauthor engine in Gui for dvdauthor still fell over and complained about a frame mismatch, but using muxman in Gui for dvdauthor, the files were successfully muxed and I got an in-sync DVD out of the application)

Thanks for your advice and patience.
Steve

carlos28355 · Member Joined: 14 Jun 2009 Location: United States

guns1inger · Member Joined: 01 Apr 2004 Location: Miskatonic U

The audio drops out of sync half way through after being in sync the rest of the time then generally the issue is corruption in the source. It doesn't take much to cause sync problems. It could be some missing frames in the video, or a glitch in the audio. The only fix is to use an editor to try to cut and re-align the audio. I like Vegas because you get a nice visual representation which makes it easier to sync things up.
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carlos28355 · Member Joined: 14 Jun 2009 Location: United States

ya thats correct its on an anime series 3 part disk the weird thing is that it does it on all 3 discs? which i find kind of odd. im not good with all this editing stuff lol ill try vegas out hopefully i can get it to work.

how would that work like when u say cut do you mean i actually have to cut some of the audio out of there or just move it around to align it?

also if it makes a difference i scaned in virtualdubmod for errors and none found

oh another thing im curious about lets say that it is corruption of the source. is there a reason that can be explained as to why it would work perfect with original files and not after the conversion. i dont know all the inner workings of this stuff but seems to me that it would be off in original files too? or is it something kind of like if u make a copy of a copy of a copy then eventually you just start to lose quality of the file?

carlos28355 · Member Joined: 14 Jun 2009 Location: United States

* is there a free version of Vegas? if not what else would you recommend? hows audacity? i think you recommended it in the past to someone else but i think it was an old post..thanks (=

guns1inger · Member Joined: 01 Apr 2004 Location: Miskatonic U

There is a free, 30 day demo of Vegas . . .

The difficulty of working purely in an audio editor is you have nothing to sync with. Audacity is more than capable of editing the audio, but you need to see what you are doing.

You could look at Reaper. It can load video and allows you to edit the audio while watching the clip. That might be worth a try.
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carlos28355 · Member Joined: 14 Jun 2009 Location: United States

if its a 30 day no restriction trial alot of programs restrict what you can do until you buy it but ill give it a shot...i dunno what im doing but ill try lol

Smico · Member Joined: 30 Sep 2009 Location: Germany

Heyho,
I've got a weird Problem with a mp4-Conversion.
The created mp4-file plays perfectly on Quicktime Player in OSX and on Media Player on WinXP/Vista.

But...if played on Quicktime-Player on Windows, the sound is out of sync.

I've tried endless different ways of conversion...different bitrates (even 400kbit and worse), resolutions, converters (VisualHub, Canopus, Free Video Converter, MPEG Streamclip, FCP Studio Compressor), PCs...it's always the same. Even converting the footage to wmv and then to mp4 doesn't work.

Anyone got a clue?

Thanks in advance