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So I have a quicktime file with proxy video content and 8 audio tracks. I need to extract the audio into a single multichannel wave file. I think this is probably pretty simple, but I can't find the solution.

What I have: ffmpeg -i input.mov -c:a copy output.wav

This gives me just a single channel, so there must be some mapping issue going on.

Jonas Kvist Jensen
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1 Answers1

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Without -map, ffmpeg will pick one audio stream from among all inputs for output.

You need to specify multiple outputs and map one stream per output.

ffmpeg -i input.mov
       -map 0:a:0 -c:a copy stream0.wav
       -map 0:a:1 -c:a copy stream1.wav
       -map 0:a:2 -c:a copy stream2.wav
       -map 0:a:3 -c:a copy stream3.wav
       -map 0:a:4 -c:a copy stream4.wav
       -map 0:a:5 -c:a copy stream5.wav
       -map 0:a:6 -c:a copy stream6.wav
       -map 0:a:7 -c:a copy stream7.wav

Command shown on multiple lines for clarity.

For a single multichannel output, you have to first merge the streams.

ffmpeg -i input.mov -filter_complex "[0:a:0][0:a:1][0:a:2][0:a:3][0:a:4][0:a:5][0:a:6][0:a:7]amerge=8" multichannel.wav
Gyan
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