Controlling channel volumes in 12 channel AIFF file

FMOD Engine
1

I have a 12 channel AIFF file withe 6 stereo pairs that I am trying to control using chan->setMixLevelsInput. I cannot control anything past the first 4 stereo pairs ( channels index (0 → 7). Other comments in the forum references to using the speaker map (AllStereo) in the FMOD_CREATESOUNDEXINFO, but that has been deprecated. I’m sure that there must be a way to ensure that all 12 channels are addressable, but I can’t find any documentation or code examples as to how to make that happen. Any help or guidance would be greatly appreciated.

2

Thank you for reporting, I have reproduced this issue with the latest version and there appears to be a bug in Channel::setMixLevelsInput. Are you mapping your 12 channel file to 12 different outputs or just down to stereo?
You can try using ChannelControl::setMixMatrix to map the input mix levels to your desired outputs. Here is an example of mapping a 12 channel file to a stereo output:

system->playSound(sound1, 0, true, &channel);

// 2 output rows, 12 input columns
float matrix[2][12] = {
	{1.0f, 0.1f, 0.2f, 0.3f, 0.4f, 0.5f, 0.6f, 0.7f, 0.8f, 0.9f, 0.5f, 0.3f},   // Channel 1 left speaker full, ch2 10%L, ch3 20%L, ch4 30%L etc
	{0.0f, 0.9f, 0.8f, 0.7f, 0.6f, 0.5f, 0.4f, 0.3f, 0.2f, 0.1f, 0.5f, 0.3f},   // Channel 1 mute right, ch2 90%R, ch3 80%R, ch4 70%R etc
};

channel->setMixMatrix(&matrix[0][0], 2, 12);
3

Using the latest download of fmod and fmod studio. Thanks for verifying this behaviour. The speaker matrix solution is a workable stop gap, but it would even more user friendly to have an “all stereo” mode for a channel that would override the automatic mapping to the various surround formats and allow mixes for multiple parallel stereo pairs in multichannel audio files with more than 8 channels. Thanks!

4

At the moment it looks like it just does a 1-1 mapping of n channels to n speakers; I agree it would be nice to have a downmix option on setMixLevelsInput which lets you test on whatever output device you have available. Thanks for the suggestion, I will pass it along to the dev team.