FFmpeg - Convert Video to MP307 Apr 2016
FFmpeg can easily be used to extract the audio tracks from virtually all video files and save them to new audio files:
Copy audio track from video file:
This example assumes that the video’s audio track is already an MP3 so can be simply copied over without re-encoding.
ffmpeg - i video.mkv -acodec copy audio.mp3
Convert audio track to MP3 (CBR):
This example assumes that the video’s audio track is something other than MP3 (or whatever target format you want). FFmpeg will re-encode the audio track so you can also specify some additional quality options.
ffmpeg -i video.mkv -b:a 192K -vn audio.mp3
In this command we specify the that the bit rate of the new audio file will be a constant 192kb/s (CBR).
Convert audio track to variable bit rate MP3 (VBR)
This command creates a variable bit rate (VBR) MP3 instead of the CBR file as in the above example. This will reduce the size of the new MP3, but may sacrifice some quality.
ffmpeg -i video.mkv -q:a 0 -map a audio.mp3