[FFmpeg-user] reduce file size: extract audio from mp4 (video)

c_14 ffmpeg at c-14.de
Tue May 27 17:21:38 CEST 2014

On 27/05/14 at 18:04, Beeblebrox wrote:
> "$ 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"
I think the problem is that you're trying to copy an aac audio stream
into an mp3 file. That won't work. Try:
ffmpeg -i video.mp4 -vn -c:a copy audio.m4a


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