FFMPEG AVI (XVID) to IPOD Mp4, AUDIO OUTPUT is 2x Normal Speed, HELP!

[jiulonghks]

Hi

I've sucessfully coverted other Xvids to IPOD format, but for some reason, for this one particular video, the audio of the coverted file plays back at 2x the normal speed. The video is fine. I don't know how to fix this. I've tried to encode twice now, same problem. Any suggestions?

I'm using ffmpegx 0.0.9x for osx. I'm running a 10.5.4.

the source video is:

avi
mpeg4, yuv420p, 496x368
ac3, 48000 hz, mono, 192 kb/s

thanks !

[tomlee59]

I haven't encountered this problem during the particular operation you're attempting, but I have occasionally run into similar ones during some other conversions. In those cases, it was due to a bug in the way mono vs. stereo was handled. I notice that your source audio is mono (or that's what ffmpegx thinks, anyway).

Check that ffmpegx is choosing the output audio characteristics properly; if not, override its selection as needed. Or experiment with mono vs. stereo (e.g., if ffmpegx has chosen stereo, change it to mono, and vice-versa).

If that doesn't work, you may have to convert the audio in two steps. In the first step, you create a stereo track that is simply two mono channels. In the second step, you convert as you were originally attempting to.

Perhaps others have encountered your problem, and know what causes it (and more importantly, how to fix it). But no one else has chimed in yet, so I figured I'd share what little I have to offer.

Good luck! And I hope someone else provides you with more definite assistance.