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

[Tseveendorj O.]

Hi Moritz,

Thank you very much. Good product. Keep going


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 ?

Command

 ffmpeg -i Untitled.avi -vcodec mpeg2video -filter_complex
"[0:1:a]channelsplit[left][right];[left]asplit=4[a1][a2][a5][a6];[right]asplit=4[a3][a4][a7][a8]"
-map 0:v:0 -map "[a1]" -map "[a2]" -map "[a3]" -map "[a4]" -map "[a5]" -map
"[a6]" -map "[a7]" -map "[a8]" -c:v mpeg2video -c:a:1 pcm_s24le -b:a:1
1152k -ar:1 48000 -c:a:2 pcm_s24le -b:a:2 1152k -ar:2 48000  -c:a:3
pcm_s24le -b:a:3 1152k -ar:3 48000  -c:a:4 pcm_s24le -b:a:4 1152k -ar:4
48000 -c:a:5 pcm_s24le -b:a:5 1152k -ar:5 48000 -c:a:6 pcm_s24le -b:a:6
1152k -ar:6 48000 -c:a:7 pcm_s24le -b:a:7 1152k -ar:7 48000 -c:a:8
pcm_s24le -b:a:8 1152k -ar:8 48000 -flags +ildct+ilme -vf
colormatrix=bt601:bt709 -top 1 -r 25 -g 12 -bf 2 -pix_fmt yuv422p -minrate
50000k -maxrate 50000k -b:v 50000k -vtag xd5e -f mxf output.mxf

mediainfo

Audio #1
ID                                       : 3
Format                                   : PCM
Format settings, Endianness              : Little
Format settings, wrapping mode           : Frame (AES)
Codec ID                                 : 0D01030102060300
Duration                                 : 10s 400ms
Bit rate mode                            : Constant
Bit rate                                 : 768 Kbps
Channel(s)                               : 1 channel
Sampling rate                            : 48.0 KHz
Bit depth                                : 16 bits
Stream size                              : 975 KiB (1%)




On Thu, Mar 5, 2015 at 6:41 PM, Moritz Barsnick <barsnick at gmx.net> wrote:

> On Thu, Mar 05, 2015 at 18:01:20 +0800, Tseveendorj O. wrote:
>
> > ffmpeg version 1.2.6-7:1.2.6-1~trusty1 Copyright (c) 2000-2014 the
> FFmpeg developers
> >   built on Apr 26 2014 18:52:58 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
>
> You do realize that this version is very old, especially feature-wise?
>

Installed ffmpeg for test purpose. I will install it from tarball of latest
version.


>
> > sudo ffmpeg -i Untitled.avi -vcodec mpeg2video -filter_complex
> "[0:1:a]channelsplit[a1][a2][a3][a4]" -map 0:v:0 -map "[a1]" -map "[a2]"
>
> What do you need sudo for? Are you reading from or writing to a
> location not accessible as a normal user?
>

Yes. I just changed permission of folder. It is working fine.


>
> That said:
>
> > I'm trying to split one stereo channel to eight mono channels. I don't
> know
> > it is possible. I tried below command but get error
>
> From the channelsplit filter documentation, I would say it splits an
> input stream into separate mono streams, e.g. stereo into two monos.
> Since your audio input is stereo, channelsplit will have two output
> streams. Therefore, your [a3] and [a4] are undefined.
>
> You will need to split out the channels:
> [0:1:a]channelsplit[left][right]
> and then split the desired channel into four (you wrote eight but your
> example shows four) identical streams:
> [left]asplit=4[a1][a2][a3][a4]
>
> In combination:
> [0:1:a]channelsplit[left][right];[left]asplit=4[a1][a2][a3][a4]
>
> (Untested.)
>
> I just tested. It is working well. I can split audio to 8 channels.


> HTH,
> Moritz
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> ffmpeg-user at ffmpeg.org
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>



-- 
*Best Regards,*
*Tseveendorj O*
*System Engineer*
*KhulanContent LLC*
*Website: http://www.khulancontent.mn <http://www.khulancontent.mn>*
*Phone: 99083297*