[FFmpeg-user] split 1 stereo channel to 8 mono channels

Moritz Barsnick barsnick at gmx.net
Thu Mar 5 13:27:43 CET 2015

Hi Tseveendorj,

On Thu, Mar 05, 2015 at 19:59:28 +0800, Tseveendorj O. wrote:
> I just tested. It is working well. I can split audio to 8 channels.

Excellent. :-)

> I have question.
> Converted audio channel #1 is always showed PCM 16bit and bitrate 768 Kbps.
> but I defined 24 bit and 1152 Kbps. Why is it ? What I did wrong ?

No matter how you count, ffmpeg's stream specifiers begin counting at
zero. As you did not define anything for -c:a:0 (you always begin with
:1), ffmpeg chose a default, which is different from yours. (ffmpeg
interestingly didn't complain about -c:a:8 which remains unused.)

So you either need to add:
  -c:a:0 pcm_s24le -b:a:0 1152k -ar:0 48000
or, even better, since the audio codec details are the same for all
your eight streams, just do this instead of specifying it eigtht times:
  -c:a pcm_s24le -b:a 1152k -ar 48000


More information about the ffmpeg-user mailing list