ffmpegX 0.0.9u audio sync issue with H264

[mrmyster]

I have been experimenting with ffmpegX for a few weeks and this is my first post. I have used version 9s -9u to try converting .avi movies to something more playable [QuickTime vs VLC] and smaller. The H264 codec does an outstanding job in terms of quality but I too am experiencing the audio sync problem I've seen mentioned in the forums. Using the H264 mencoder option, att the end of a movie [1 hour 45 mins] the audio was running about 1 second ahead of the video [I don't know a good way of accurately measuring the actual discrepancy].

I've found it works quite a bit better using the 264 x264 codec. The video quality is excellent, the filesize is about 1/2 of what the original .avi file was, and the audio is nearly perfectly in sync. It -looks- like it might be off by a small fraction of a second at the end of the movie but its hard to tell.

I'm wondering if the sync problem has to do with the external mencoder binary rather than with ffmpegX?


Thanks for a fine tool. Looks like its coming along nicely.

Michael

[TheBum]

I've had the same experience with mencoder H.264 encoding of VIDEO_TS folders in 0.0.9u. It's a little better than 0.0.9t but still not fixed. Unfortunately, I can't easily test the x264 encoder because it doesn't yet process VIDEO_TS folders and I don't how to encode the individual VOB files and then merge them (suggestions?).

[stshipley]

As of last night, running tests on the mencoder H.264, I have an audio sync delay of about 0.6 seconds through out the test.

The X.264 H.264 does NOT HAVE THIS PROBLEM.

If the X.264 did two pass encoding it would be the gold standard as far as I'm concerned.

Also, on a 1.8GHz SP PowerMAc G5, I get between 4.5 and 5 fps using mencoder H.264, and between 5.5 and 6 fps using the X.264 version. If I could only use 2 pass encoding on the X.264, this would be the only codec and program I'd use.

To use the mencoder version, I have to use Audacity to alter the audio to achieve proper sync. Then to re-mux, I have to use a third program QTMF.

-STS

[major]

Yes the sync problem is due to mencoder as reported earlier and yes x264 does not have this problem. For PAL sources both engines does not have any sync problem. I'll add two pass support for x264 engine. To join VOBs check here https://www.videohelp.com/forum/viewtopic.php?p=1056853#1056853 or just extract as a single VOB.

[compufix2]

DO you know if there are any plans on a fix for Mencoder (which I know you are not responsible for) that will allow direct VOB-MP4 conversion without the sync delay? I use handbrake for my DVD-MP4 needs, but for the few that Handbrake does not like, I use MTR and FFMPEGX. 9 out of 10 VOB files (I do extract as one VOB file) I need to go Mencoder DIVX first, then convert that file to MP4 for iPod and it works great. It is twice the time, and I hate going from one compression format to another.

I was just wandering if there is anything that can be done, or somwhere I can go to pleade my case. I guess there is a mencoder forum somewhere...

[mrmyster]

Now I'm getting files where the video is running ridiculously fast and the audio appears to be more or less nominal. I've tried varying the framerate but am getting the same result every time.

[mrmyster]

FOLLOWUP- Does anyone know what this message from the 'Process Information' report means:

"error, non monotone timestamps 0 >= 3003"

I'm getting thousands of these entries on a couple of very disimilar files I'm converting.

[Leighgion]

Now I'm getting files where the video is running ridiculously fast and the audio appears to be more or less nominal. I've tried varying the framerate but am getting the same result every time.

Just posting to confirm I'm running into this issue too when trying to transcode AVI files with Xvid video and mp3 audio. The encoding progress bar hits around 40% and prematurely goes into audio encoding. The resulting file appears to have normal sound, but the video plays at what looks like about double speed even though the framerate is ostensibly correct. Video runs out and goes to white screen in Quicktime player while the audio cheerfully marches on.