Audio Mix Configuration on the fly

General
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1

Hi, is it possible somehow to create audio mix configuration on the fly at the moment I want to start playing out some file?

I would like to have stereo output all the time (only L and R channel on SDI output).
But a have a lot of files where many main audios are on different channels… on channel 3 and 4 or 5 and 6 etc.

So I would like to perform something like this:
PLAY 1-1 audioFile MIXCONFIG 0=2,1=3

It is possible, or which approach do you use? I know that I can preset some mix configs, but I would like to select audio channels them according to some setup on playout.

Thanks

2
3

Yes I am familiar with that, but there is only description how to set CHANNEL LAYOUT on the fly. You have to have predefined mix configurations and layouts. But I am looking for a way how to set that MIX CONFIG on the fly.

4

No way to do that over AMCP unless you’d use AF. It shouldn’t take you long to configure all the needed channel layout variations in casparcg.config to use this method.

5

Thanks for clarification. What is an AF please?

There will be unlimited variations of channel layouts. Sometimes we need to play only specific tracks and map them to output ch1 and ch2. If I am counting right, there are 16^16 combinations possible :slight_smile:

6

If you have up to 16 input channels and just 2 outputs that would be max 240 (excluding using the same channel more than once etc). IIRC CCG 2.3 only supports 8 channels.

AF is for audio filters in ffmpeg. Something like this:
PLAY 1-1 audioFile AF “pan=stereo|c0=c6|c1=c7”
might work to output CH6 as 1 and CH7 as 2.

7

Oh, I see, you are right on that combination counting.
So on 2.3 it is possible to use ffmpeg audio filters, but only up to 8 channels.
And on <=2.1 it should work with predefined ~240 channel layouts with media up to 16 channels. Right?

8

Yes. You might also be able to use CHANNEL_LAYOUT “stereo: 5 6” (or BR DL - don’t remember if numbers work and if they start from 0 or 1) - if that works it would probably be your simplest option.

9

Hi again Hreinn, I have to solve similar problem in one legacy project. If there a way how to put FFmpeg AUDIO filter in CasparCG 2.0.7?
I have tried
PLAY 1-1 demo FILTER volume=1
but is says that
Media type mismatch between the 'filter_buffer' filter output pad 0 (video) and the 'Parsed_volume_0' filter input pad 0 (audio)

Cannot create the link buffer:0 -> volume:0

Seems that only video filters are allowed in 2.0.7