I have found a pretty helpful article for ffmpeg recompile: http://fozzolog.fozzilinymoo.org/tech/2009/11/recompiling-ffmpeg-for-fedora-12-to-add-faac-support.html . However, it looks like the instructions were incomplete.
Get Codec and/or Stream Information of Media Files in Linux
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Normally, it’s a pain finding stream, codec or bitrate information for media files.
Multiplex Audio and Video Streams
The below joins audio and video streams into one MPEG1 or 2 file.
Create Video Preview Thumbnails with Ffmpeg
See http://blog.prashanthellina.com/2008/03/29/creating-video-thumbnails-using-ffmpeg/ ffmpeg -ss -4 -i test.avi -vcodec mjpeg -vframes 1 -an -f rawvideo -s 320×240 test.jpg ffmpeg -itsoffset -4 -i test.avi -vcodec mjpeg -vframes 1 -an -f rawvideo -s 320×240 test.jpg