Audio extract misses some streams

[mrlimbic]

When using stream export to extract audio to WAV/integer uncompressed, the WAV seems to only include 1st audio stream by default and doesn't seem to provide a way to specify which audio streams if more than 1.

Video produced by cameras often provide audio via 2 mono streams rather than 1 stereo.

I would like to extract all streams, either to separate files, or combine both into 1 stereo WAV, or multichannel AIF.

Is this possible with VLC or is this a bug?

[bat999]

Video produced by cameras often provide audio via 2 mono streams rather than 1 stereo.
I would like to extract all streams, either to separate files, or combine both into 1 stereo WAV, or multichannel AIF.

Hi
I don't think that VLC can do this,
but maybe I'm wrong.

Are you trying to extract the audio from camera feeds on-the-fly?
Or
Are you trying to extract the audio from recorded files?

[mrlimbic]

They are recorded files in MOV containers. They contain 4 streams: 1 video, then 2 audio, then 1 timecode.

I just want to extract the audio streams, either as separate files, or combined. I don't care about the video or timecode streams.

I found out that I can extract each separately using ffmpeg, so may have to use that unless I can find a more convenient way in future.

These commands worked on my test files to get each stream out into wavs..

ffmpeg -i dual-mono.mov -map 0:1 -vn stream1.wav
ffmpeg -i dual-mono.mov -map 0:2 -vn stream2.wav

Its a bit of hassle though as you have to work out the stream numbers before making the right command. You can find out which streams are contained and what their index is with this

ffmpeg -i dual-mono.mov

Stream #0.0(eng): Video: mpeg2video (Main), yuv420p, 1920x1080 [PAR 1:1 DAR 16:9], 35000 kb/s, 25 fps, 25 tbr, 2500 tbn, 50 tbc
Metadata:
creation_time : 2012-03-25 10:36:14
Stream #0.1(eng): Audio: pcm_s16be, 48000 Hz, 1 channels, s16, 768 kb/s
Metadata:
creation_time : 2012-03-25 10:36:14
Stream #0.2(eng): Audio: pcm_s16be, 48000 Hz, 1 channels, s16, 768 kb/s
Metadata:
creation_time : 2012-03-25 10:36:14
Stream #0.3(eng): Data: tmcd / 0x64636D74, 0 kb/s
Metadata:
creation_time : 2012-03-25 10:36:14

[bat999]

or combined.

For this can use FFmpeg too, with SoX:-

Code: Select all

ffmpeg -i dual-mono.mov -vn -map 0:1 -c:a copy temp1.wav && \ ffmpeg -i dual-mono.mov -vn -map 0:2 -c:a copy temp2.wav && \ sox -M temp1.wav temp2.wav stereo.wav && \ rm temp1.wav temp2.wav

Or with mkvmerge:-

Code: Select all

ffmpeg -i dual-mono.mov -vn -map 0:1 -c:a copy temp1.wav && \ ffmpeg -i dual-mono.mov -vn -map 0:2 -c:a copy temp2.wav && \ mkvmerge -o multi.mka temp1.wav temp2.wav && \ rm temp1.wav temp2.wav

EDIT
Maybe one pass will do it:-

Code: Select all

ffmpeg -i dual-mono.mov -vn -map 0:1 -map 0:2 -c:a:0 copy -c:a:1 copy multi.mka

[mrlimbic]

Thanks. I tried that but I get.

Unrecognized option 'c0'

Any ideas? Typo?

[bat999]

... Unrecognized option 'c0'...

Different version FFmpeg
(ffmpeg version git-2012-07-26-d5d5e3d)

Code: Select all

ffmpeg -i dual-mono.mov -map 0:1 -map 0:2 -acodec copy multi.mka

EDIT
The method with SoX doesn't work because FFmpeg won't allow type pcm_s16be in wav format.
It's easy to work around though if you prefer a 'stereo' wav/flac file instead of the 'multi' mka file.