ffmpeg/libav is a bundle of open source software in command line that permit to manage audio or video streams. With ffmpeg/libav, we can make recordings, readings or making corrections with filters, or transcode media from a format to an other.
libav is a fork of ffmpeg that we can find in the Debian repositories. If you want to use ffmpeg, you will have to change the word "avconv" to "ffmpeg" in the different commands lines, the rest stay the same.
The package libav is available in the main repository :
# apt-get install libav-tools
The package ffmpeg is available in the multimedia repository :
# apt-get install ffmpeg
FFmpeg or Libav can be use from GUI like:
Or direcly from the command line interface