[FFmpeg-user] ProRes -> 1stream (pcm_s24le) 16ch audio -> invalid channel layout

Podium B.V. mailinglist at podiumbv.nl
Fri Oct 18 11:18:49 CEST 2013

Hi All,

first of all, and I can't say it enough, what is FFMpeg a GREAT tool!
I work on the IT-department of a Video Broadcast Company, and where
the "video-people" want to buy all kinds of expensive (windows) software.
We almost everytime can script it cheaper, better and much faster!!
(on a good machine FFMpeg is FAST!) then the proprietary software.

But there is one little problem, wich could us save much time in our
workflows, where I can't find a good solution for...

In the broadcast video world (not ENG) it is very default to asume
that when there is one video signaal there could be 16 (mono) audio 
This is because of the spefication of the SDI protocol we use between 

And the way these mov-containers most of the time are recored is:
Stream# 0.0 Video
Stream# 0.1 Audio -> with 16 diffrent (mono) channels!
Stream# 0.2 Data

With a lot of testing I did find out, when there are more than 8 
channels (7.1 surround)
it's not longer possible to extract the audio or split channels to 
diffrent stream.
Not with: -map / -map_channel / -filter_complex channelspilt / pan / etc...
Also not with the latest build (yesterday, 17th), the build of 1st of 
July or the latest
static build (2.0.1)...

Our workarround for now is first open the recored file in a proprietary 
application. Extract 8 audio channels, save the file without a render 
(which still can
take up to a hour!?!) and start the desired FFMpeg script...

A quote from the creativecow forum 

"/I think your right. I created a test file with a video and a 16 
channel audio stream.//
//I created it with ffmpeg btw. It can _create_ the 16 channel audio 
stream, but the//
//filter subsystem doesn't like it when I feed it back in to try to 
split the channels out.//
//Gives errors about invalid channel layout./"

My question:
* Do I maybe overlooked something?
* Or is this a (new) feature not (yet) implemented?
* Or is this a "problem" which is not easy to fix cause of the way 
ffmpeg is build?

I am not a programmer, so I really have no idea how to proceed...
...even if I could get my boss to hire a programmer to help solve this 
for everybody out there, I don't know if it is even possible...

Kind regards,

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