Questions about audio

General
1

Hi!

I’m working on a casparcg client that is directed towards live events/corporate shows with custom resolutions for led walls. I know its not designed for it, but for now it’s a fun project.

I’d like to be able to work with multiple audio output channels, but less than 16. Is it possible to set a hard limit in the config for example to 8ch?
I tried using ffmpeg consumer to output audio to alsa, but it always says that the channel count is less than 16 and uninitializes the consumer.
Are there any other options I could try?
I tried searching for answeres, but most posts i found are quite old and seem to be already deprecated.

2

Just for understanding: Why would it be essential to be able to set a limit?

3

My main workflow right now is connecting display port output from a media server to screen management system and getting the video as well as 8ch audio that I can route to Dante.

When I tried doing that with Casparcg I got the error that the consumer can’t handle 16ch and it uninitialize.

Maybe there is a workaround for it that I couldn’t find.

4

Aha, so you use the Screen Consumer and System Audio, right? They only support two channels of audio. the trick would be to use one ore multiple Decklink cards. They support embedded audio up to 16 channels.

5

That’s what I fell back to.

I was trying to get more audio outputs by using ffmpeg consumer but as stated before couldn’t get it to work.

6

Oh, I forgot. If anyone is interested here is the repo for the client I’m working on.

Would love some pointers from more experienced.

7

I am waiting for @Julusian to accept my PR #1714 that enables multiple (stereo) outputs using OAL consumer. This is something I had an immediate need for, for a setup with two small LED walls and sound domes. Both are fed from one CCG Server with two Screen + OAL consumers running on two channels.

I’ve fixed a few issues in the OAL consumer and it’s now actually usable for simple stereo setups with Screen + OAL through HDMI out. No need for fancy cards.

There is also a PR #1720 by @gmeisel that introduces multi-channel PortAudio consumer. It needs a bit of a clean-up and simplification (sorry @gmeisel :wink: ) I was going to take a look at it at some point and/or use it as a starting point.

@Julusian indicated he likes PortAudio, so maybe at some point it will replace the OAL consumer.

8

BTW if anyone wants to test run my build, I have Debian and Ubuntu packages here:

9

Nice!

This is exactly what I needed. Will test it when I’ll be back at the warehouse.