[FFmpeg-user] reduce file size: extract audio from mp4 (video)
zaphod at berentweb.com
Tue May 27 17:04:04 CEST 2014
I have several video files that I would like to convert to audio-only.
Is there a simple ffmpeg command to extract the audio as-is from the
video file, AND achieve file size reduction? For example,
"$ ffmpeg -i vidoe.mp4 -vn -acodec copy audio.mp3" naturally fails with:
"[mp3 @ 0x80d03f020] Invalid audio stream. Exactly one MP3 audio stream
is required. Output #0, mp3, to 'audio.mp3':
Metadata: major_brand : isom, minor_version : 512,
compatible_brands: isomiso2mp41, encoder : Lavf55.19.104
Stream #0:0(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, 99 kb/s"
Other methods advised by google mostly have bitrate-type solutions
"$ ffmpeg -i video.mp4 -vn -ar 44100 -ac 2 -ab 192 -f mp3 music.mp3"
I have tried some of these, but the resulting files are larger than the
original mp4, which makes absolutely no sense.
More information about the ffmpeg-user