I know that flv and mp4 files contain aac audio, while avivideo usually mp3 audio streams.
What command (avconv, ffmpeg) would extract the audio without transcoding it?
2 Answers
ffmpeg -i video.mp4 -vn -acodec copy audio.aac
Here’s a short explanation on what every parameter does:
-ioption specifies the input file.-vnoption is used to skip the video part.-acodec copywill copy the audio stream keeping the original codec.
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1while the mp4 video contains aac audio, not mp3, is that keeping the audio stream without transcoding?– user32012Nov 28, 2014 at 9:26
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1Didn't take care of output file extension, my mistake. Updated the answer. Anyway, if you read the full answer, you will find that -acodec copy, this avoid transcoding.– jherranNov 28, 2014 at 9:28
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1i suggest m4a (container for aac) instead of aac, because it seems that is not easy to play– user32012Nov 28, 2014 at 9:35
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is it possible, while ussing ffmpeg or avconv, to have a command without mentioning the real names of input/output files, so that the command be used as such? (i would like to use that in a context menu action in nemo file manager)– user32012Nov 28, 2014 at 9:39
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1You might want to use a variable or something like that, but is better is you ask a question with all specific details.– jherranNov 28, 2014 at 9:42
As a complementary answer, with a command that doesn't need the specific name of the file.
For a video containing aac audio:
ffmpeg -i "$0" -map 0:1 -c:a copy "${0%%.*}".m4a
To use in a context menu command, a form like this works:
bash -c 'ffmpeg -i "$0" -map 0:1 -c:a copy "${0%%.*}".m4a' %f
Replace with corresponding audio format output for other video format input.
Initial source here.