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@christofluethi
Last active April 1, 2024 22:10
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Convert m4a to mp3 on OS X command line using ffmpeg
brew update
brew link yasm
brew link x264
brew link lame
brew link xvid
brew install ffmpeg
ffmpeg wiki:
https://trac.ffmpeg.org/wiki/Encode/MP3
lame option Average kbit/s Bitrate range kbit/s ffmpeg option
-b 320 320 320 CBR (non VBR) example -b:a 320k (NB this is 32KB/s, or its max)
-V 0 245 220-260 -q:a 0 (NB this is VBR from 22 to 26 KB/s)
-V 1 225 190-250 -q:a 1
-V 2 190 170-210 -q:a 2
-V 3 175 150-195 -q:a 3
-V 4 165 140-185 -q:a 4
-V 5 130 120-150 -q:a 5
-V 6 115 100-130 -q:a 6
-V 7 100 80-120 -q:a 7
-V 8 85 70-105 -q:a 8
-V 9 65 45-85 -q:a 9
ffmpeg -i in.m4a -codec:a libmp3lame -qscale:a 1 out.mp3
@seamusdemora
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I wonder why the size increases so much?

I had an m4a of size: '124943', and the output of the command given above produced an mp3 of size: '518403'
Seems odd.

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