音频单元RemoteIO设置交错浮动给kAudioUnitErr_FormatNotSupported

Question

我正在与音频单元RemoteIO的工作，以获得一个低延迟音频输出。我的问题是AFAIK音频单元只接受几种音频格式，这取决于硬件。我的问题是，我有一个C++ DSP声音引擎，它与浮动交织PCM工作。我不想实现格式转换器，因为它可以在远程IO回调中减慢速度。我尝试获得具有以下格式的低延迟音频单元：

AudioStreamBasicDescription const audioDescription = {
            .mSampleRate        = defaultSampleRate,
            .mFormatID          = kAudioFormatLinearPCM,
            .mFormatFlags       = kAudioFormatFlagIsFloat,
            .mBytesPerPacket    = defaultSampleRate * STEREO_CHANNEL,
            .mFramesPerPacket   = 1,
            .mBytesPerFrame     = STEREO_CHANNEL * sizeof(Float32),
            .mChannelsPerFrame  = STEREO_CHANNEL,
            .mBitsPerChannel    = 8 * sizeof(Float32),
            .mReserved          = 0
        };
        
        status = AudioUnitSetProperty(audioUnit,
                                          kAudioUnitProperty_StreamFormat,
                                          kAudioUnitScope_Input,
                                          kOutputBus,
                                          &audioDescription,
                                          sizeof(audioDescription));

这在错误代码kAudioUnitErr_FormatNotSupported -10868中失败。如果我试图获得一个浮动PCM非交错音频流与以下内容：

AudioStreamBasicDescription const audioDescription = {
            .mSampleRate        = defaultSampleRate,
            .mFormatID          = kAudioFormatLinearPCM,
            .mFormatFlags       = kAudioFormatFlagIsFloat | kAudioFormatFlagIsPacked | kAudioFormatFlagIsNonInterleaved,
            .mBytesPerPacket    = sizeof(float),
            .mFramesPerPacket   = 1,
            .mBytesPerFrame     = sizeof(float),
            .mChannelsPerFrame  = STEREO_CHANNEL,
            .mBitsPerChannel    = 8 * sizeof(float),
            .mReserved          = 0
        };
        
        status = AudioUnitSetProperty(audioUnit,
                                          kAudioUnitProperty_StreamFormat,
                                          kAudioUnitScope_Input,
                                          kOutputBus,
                                          &audioDescription,
                                          sizeof(audioDescription));

一切都很好。然而，我想获得一个交错的音频流，让我的DSP引擎工作，没有格式转换。这有可能吗？

PS。等待hotpaw2引导我:)

Answer 1

您的错误可能是由于这一行：

.mBytesPerPacket    = defaultSampleRate * STEREO_CHANNEL,