AVI to mp4, no audio or video much faster than audio

[michaelab]

I've been trying to convert some AVIs to MP4 for viewing on my iPhone using the "iPhone" preset. If I use the preset "as is" I get video but no audio. If I view the original AVI in Quicktime it also plays with no audio (allthough VLC and mplayer have no problem) so I unchecked the "Decode using Quicktime" option. That resulted in an MP4 where the audio was fine but the video was way too fast, at least double speed at a rough guess. Any ideas??

I've used EasyWMV to convert the same files to iPhone MP4 format and it has no problems but I would prefer to use ffmpegX! Once thing I noticed though is that EasyWMV is reducing the audio sample rate from 48kHz to 44.1kHz, but I doubt that's relevant.

The original audio appears to be encoded in vanilla MP3 (stereo, 128Kbps, 48kHz).

[michaelab]

OK, I 'fixed' this by installing Perian. That got the audio to play in Quicktime and hence I could revert to using the "Decode using Quicktime" option and the converted file then had audio. However, the audio is out of sync with the video, and this gets progressively worse such that at the end of the 42 minutes the audio is almost a second ahead of the video.

When I look at the "info" that ffmpegX provides it says the audio codec is "framecopy"?? Wtf? Next try will be to change the sample rate from 48kHz to 44.1kHz in the coversion to see if that changes anything...

[Case]

However, the audio is out of sync with the video, and this gets progressively worse such that at the end of the 42 minutes the audio is almost a second ahead of the video.

You could try to stretch the audio to the video length, by using a tool like Audacity or Amadeus.

When I look at the "info" that ffmpegX provides it says the audio codec is "framecopy"?? Wtf?

It is not the 'framecopy' that is of interest (that's just ffmpeg lingo) here. After 'framecopy' it should list 'format' with a number, where 'format=55' is an identifier for MP3 audio.