Problem : Every time you try to encode a video using wiff ( GUI for FFMPEG) in Ubuntu, it would open the terminal and produce an “unknown encoder libxvid” error when you choose xvid encoding. None of the encodings work . Message is always “unknown encoder libxxxx” wher xxxx is the name of the encoder.
Why it happens : your system can’t find the encoders it requires to convert the video into a different format. I think these encoders are not open source so they are not included with standard intallation.
Solution : Install libavcodec-extra-53, which contains ffplay multimedia player, the ffserver streaming server and the Libav audio and video encoder.
I ran on my Ubuntu 12.10
sudo apt-get install libavcodec-extra-53
It deleted 2 packages, installed 3 new packages and now wiff works fine.