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How to determine the speaker configuration/number of channels at runtime?

0 votes

I'd like to find out the number of speakers/channels configured at runtime for Wwise (Windows in this case). Is there a simple way to do so? Ideally it would be something we could query periodically and update in case the output device changes in Windows.

Thank you,

asked May 3 in General Discussion by Brent S. (140 points)

1 Answer

0 votes
We are using Unreal (older integration) so I'll post my answer here if someone else needs it.

I added a call to register the bus volume callback for the master audio bus in the initialization routine.

    if (AK_Success != AK::SoundEngine::RegisterBusVolumeCallback(MASTER_AUDIO_BUS, AkMasterBusSpeakerVolumeMatrixCallback))
        UE_LOG(LogInit, Warning, TEXT("Could not register the master bus volume callback."));

Then had the callback set the rtpc based on the number of channels, removing the low frequency effects channel in the count if found.    


static const AkUniqueID MASTER_AUDIO_BUS = 3803692087U;
void FAkAudioDevice::AkMasterBusSpeakerVolumeMatrixCallback(AkSpeakerVolumeMatrixCallbackInfo *in_pCallbackInfo)
    static unsigned long LastNumChannels = 0xffffffff;

    if (in_pCallbackInfo
        && (in_pCallbackInfo->outputConfig.uNumChannels != LastNumChannels))
        auto AudioDevice = FAkAudioDevice::Get();
        if (!AudioDevice)

        LastNumChannels = in_pCallbackInfo->outputConfig.uNumChannels;

        const FString& ChannelRtpc = GetDefault<UAkSettings>()->SpeakerChannelRtpcName;
        if (ChannelRtpc.Len())
            // remove the .1 low frequency effects channel from the reported channel count
            const bool HasLFE = in_pCallbackInfo->outputConfig.HasLFE();
            const unsigned long ReportedChannels = LastNumChannels - (HasLFE ? 1 : 0);

            UE_LOG(LogAkAudio, Display, TEXT("Number of audio channels found: %d%s"), ReportedChannels, (HasLFE ? TEXT(".1") : TEXT("")));

            AudioDevice->SetRTPCValue(*ChannelRtpc, ReportedChannels);
answered May 15 by Brent S. (140 points)