Questions[ffmpeg](ubuntu)

I have a video I need to convert to mp3 (from the command line - not GUI): video.mp4

I tried:

ffmpeg -i -b 192 video.mp4 video.mp3

with no success. I get the following error:

WARNING: library configuration mismatch
Seems stream 0 codec frame rate differs from container frame rate: 59.83 (29917/500) -> 59.75 (239/4)
WARNING: The bitrate parameter is set too low. It takes bits/s as argument, not kbits/s 
Encoder (codec id 86017) not found for output stream #0.0

so I tried lame:

lame -h -b 192 video.mp4 video.mp3

I get:

Warning: unsupported audio format

Am I missing something?

I would like to use ffmpeg to transform an mp4 video file into avi but with the same quality, even if it takes up more space. If I simply do:

ffmpeg -i file.mp4 file.mp4.avi

The resulting avi file is very low-quality and pixelated. How can I do this transformation while keeping the video and audio quality?

I need to convert a video file from Matroska container into mp4 container. Matroska file contains one h.264 video track and one AC3 sound track. It should be possible to do this losslessly, but how to do it with native Ubuntu tools?

Transcoding is not an option.

On my desktop Ubuntu 10.4 I use ffmpeg to convert videos to a format my dvd-player understands. On my laptop running 10.10 I can't get the same command to work, what package(s) are missing?

ffmpeg -i infile.flv \
-threads 2 -vcodec mpeg4 -vtag divx -acodec libmp3lame \
outfile.avi

#...snip
Unknown encoder 'libmp3lame'

Using apt-cache search libmp3lame I'm told there exist libmp3lame0 and libmp3lame-dev, both of which I've installed. Using acodec libmp3lame0 doesn't work either.

I created a screencast using recordmydesktop which produced an .ogv file. I believe this is an OGG file encoded using the Theora codec. I'm wondering how can I convert this to MPEG4/H.264? I've tried to use FFmpeg in a naive way, as follows:

ffmpeg -i demo.ogv -f mp4 demo.mp4

However this produces an evil blob of dark greens and grays when trying to play it again in MPlayer. I then tried to get more sophisticated, using the command-line flags specified here:

ffmpeg -i demo.ogv \
       -s 352x288 -vcodec libx264 -vpre default \
       -acodec libmp3lame -ab 192k -ac 2 -ar 44100 -f mp4 \
       demo.mp4

But, the result was the same.

If anyone has any insight into what might be the best way to accomplish this task, I'd appreciate it if you could let me know.