[FFmpeg-user] How to crop extra audio channels?

[Deron]

On 3/17/12 5:46 AM, Carl Eugen Hoyos wrote:
> Deron<deron<at>  pagestream.org>  writes:
>
>> ffmpeg -i "file.mov" -f s8 -vn -ac 2 -ar 48000 -acodec pcm_s8 -y
>> "file.audio"
> Sorry for my first comment, please try the following and report back:
> ffmpeg -i file.mov -f s8 -map_channel 0.0.1 -map_channel 0.0.2 file.audio
>
> As explained in ticket #1088, -ac 2 would downmix from 16 to two channels,
> since the layout for 16 channels is unknown, this is generally impossible.
>
> Carl Eugen
>
>

Thanks for the suggestion, but it still output the full 16 channels!

I guess I need to simply(?) export the full 16 channel to raw audio, 
write a little program to strip out the 2 channels, and then mux it back in?

Deron