AVAudioMixerNode: sample conversion

Hello,


I had some issues with AVAudioMixerNode. As a reminder, AVAudioMixerNode is supposed to work with inputs and outputs of any sample rate and take care of the sample rate conversions. Hence, it is a handy tool to convert the audio input's data format and especially its sample rate, when it does not conform to the internal processing format of the AVAudioEngine.


Summarized scenario:

Inside an AVAudioEngine,

- connect the input node to an AVAudioMixer (let's call it myMixer), using the input node's input format (AVAudioInputNode is not supposed to perform format conversion)

- connect myMixer to the main mixer (which is itself automatically connected to the output node), using a sample rate different than the audio session's sample rate (the hardware sample rate),

the audio signal won't go through from input to output unless there is some audio coming from another source (for example an AVAudioPlayerNode) to myMixer.


Details:

All details, with several test projects, are available on the following GitHub repo:

https://github.com/AudioScientist/AVAudioMixerNodeIssues


My question:

Is it a bug or something I do wrong?


Thank you all 🙂


Tom


PS: I already submitted it on Apple's bug report platform

Replies

Any luck? I'm having the same issues. What did Apple say about this bug?