Encode with FFmpegX XviD ignores QuickTime sync

[Metrophage]

Hi there, I am a new user of FFmpegX. I've wanted to try it, but just finally gotten around to buying an encoder card. Found an Aurora Fuse for $15, heard great things about these, but the MJPEG MOV it creates always has sound which goes out of sync. I found an app called Movie Sync which lets me choose points in the file to anchor where the sound should be and save the result to a new, properly synchronized MOV.

Now I am trying to use FFmpegX to convert these huge 30+GB files to XviD/MP3 AVIs at 700 MB. Configuring FFmpegX to do this with acceptable picture and audio quality has been easy. The big problem is that the resulting AVI file does not retain the sync information, it ignores it. Curiously, this has been the case even when I checked "Decode with QT", which I figured should fix it. Even when I try to preview my file with the built-in Mplayer, there is no sync. Towards the ends of my files the audio needs to be offset by -133 to -600 "units" for proper sync.

Of course, trying a different encoder card could alleviate the problem, but i cannot afford one at this time. And the output of it is otherwise acceptable, so I'd rather not. QuickTime does retain the timing data, but I have had problems with the XviD component ignoring my bit rate settings, resulting in huge files.

Is there some way I can use FFmpegX to properly transcode my syncronized QuickTime files? Or is there a built-in utility I can use for the audio offset? These 30+GB files are sitting heavy on my hard drive. Thanks for any suggestions!
M

[major]

You should use Quicktime Player to export as MPEG-4 for instance, and it should retain the sync.

[Metrophage]

Thanks for the reply.

After a good twelve hours of various transcodings, some good news and bad news. Good news is that using Quicktime to convert the file to MP4 did result in proper sync. I can now play it in VLC and Mplayer without any problems. The latest problem is that FFmpegX doesn't like the audio part of the file. It is in AAC 44.1khz stereo, 128kbps. AAC is the only audio option for MP4 export, so I don't know what else to do about it. When I choose in FF, the "info" no longer works, and when it uses Mplayer to play the file there is no audio. Weird since MplayerX has no trouble here. When I try to go ahead and transcode the file to XviD one of two things happen. With some audio settings selected, FFmpegX tells me that it has instantly finished, when it obviously has not. Or, with other audio settings FFmpegX goes ahead and transcodes the video well, but then it finished leaving a zero-byte audio file in the directory which it can't mux.

I don't have much experience with encoding video, but I hope I can sort this out. It's been so time consuming a trial and error process. Quicktime offers less options than FFmpegX, the encoding isn't so fast and the files look so-so for their size. I could try using QT to export H264 instead but that'd take about 24 hours on my machine, versus about 4 for MP4. I'd certainly love any and all advice on how I can prepare these files to be FFmpegX compatable.
M

[Metrophage]

Aha! Doing some searches on the forums here for missing audio, I discovered the situation about the stream order. So I did another encoding today with the audio invert box checked, and finally got a finished XviD/MP3 file which plays with sound!

But now there is another peculiarity with this file. The sound is smooth, but the video playback is very jerky, as if it is playing at two or three frames per second - but it is playing at full frame. It appears to have been encoded jerky! Since this is a non-realtime process it boggles me why this would be the case, as each frame should be processed in sequence.
Since I've got audio and video now I'm going to try other settings, like "decode from QT" and two-pass. This has been a frustrating learning experience, but interesting! I figure I'll play more with video.