Help: Multi-Channel Audio (5.1 Surround Sound) on iOS


#1

We are trying to get multi-channel audio (5.1 surround sound) to playback on iOS.

We have developed an app that is mapping 5.1 .wav files perfectly, but when the same files are encoded to ALAC, AAC or AC3, all channels are mapped to Front Left & Front Right only.

Hardware is iPad Pro → Lightning to USB 3 Camera Adapter → miniDSP U-DAC8

Lightning to USB 3 Camera Adapter:

miniDSP U-DAC8:
https://www.minidsp.com/products/usb-audio-interface/u-dac8

More details and test files here:
https://hydrogenaud.io/index.php/topic,114640.0.html

We can pay a little money to anyone that can help.

Thanks.


#2

Sorry, I’m a little confused - the iOS audio device only writes data to the first two channels, irrespective of the audio format, so what behaviour is different with wav files?


#3

Edited post to clarify playback.


#4

It’s late on a Friday here, so perhaps I’m tired, but I’m afraid I’m still not sure what problem you are reporting!

No audio will play back using more than 2 channels with JUCE on iOS. It doesn’t matter how you supply the audio - JUCE’s software iOS audio driver will only populate the first two channels.

What exactly is working fine with .wav but not with the other formats?


#5

More details and test files here:
https://hydrogenaud.io/index.php/topic,114640.0.html


#6

More details, but unfortunately not the crucial details.

What does this mean? Is it your app that is playing audio? If so, any audio produced by a JUCE app on iOS will only use the first two channels. The format of the audio file is irrelevant. Look here were we send audio data to the sound card:

You can see that if the number of channels is >= 2 then we only use the first two on iOS.

Are you somehow producing correct multichannel output on iOS (for any file format)? If so, how? I don’t see how you could do this using JUCE, so I still can’t work out what issue you are reporting.

We’re open to requests to support multichannel output on iOS, especially if there’s a financial incentive, but I think you might be talking about something else…