我正在尝试将kAudioUnitSubType_Reverb2类型的AudioUnit添加到AUGraph，并在-10868 (kAudioUnitErr_FormatNotSupported)上收到AUGraphInitialize支持的错误。我的出发点是Apple的iPhoneMixerEQGraphTest示例应用程序，我基本上只是为混响添加了一个新的AudioUnit，但无法让它工作。
这是代码 -
- (void)initializeAUGraph
{
printf("initializeAUGraph\n");
AUNode outputNode;
AUNode eqNode;
AUNode mixerNode;
AUNode reverbNode;
printf("create client ASBD\n");
// client format audio goes into the mixer
mClientFormat.SetCanonical(2, true);
mClientFormat.mSampleRate = kGraphSampleRate;
mClientFormat.Print();
printf("create output ASBD\n");
// output format
mOutputFormat.SetAUCanonical(2, false);
mOutputFormat.mSampleRate = kGraphSampleRate;
mOutputFormat.Print();
OSStatus result = noErr;
// load up the audio data
[self performSelectorInBackground:@selector(loadFiles) withObject:nil];
printf("new AUGraph\n");
// create a new AUGraph
result = NewAUGraph(&mGraph);
if (result) { printf("NewAUGraph result %ld %08X %4.4s\n", result, (unsigned int)result, (char*)&result); return; }
// create three CAComponentDescription for the AUs we want in the graph
// output unit
CAComponentDescription output_desc(kAudioUnitType_Output, kAudioUnitSubType_RemoteIO, kAudioUnitManufacturer_Apple);
// iPodEQ unit
CAComponentDescription eq_desc(kAudioUnitType_Effect, kAudioUnitSubType_AUiPodEQ, kAudioUnitManufacturer_Apple);
// multichannel mixer unit
CAComponentDescription mixer_desc(kAudioUnitType_Mixer, kAudioUnitSubType_MultiChannelMixer, kAudioUnitManufacturer_Apple);
// reverb unit
CAComponentDescription reverb_desc(kAudioUnitType_Effect, kAudioUnitSubType_Reverb2, kAudioUnitManufacturer_Apple);
printf("add nodes\n");
// create a node in the graph that is an AudioUnit, using the supplied AudioComponentDescription to find and open that unit
result = AUGraphAddNode(mGraph, &output_desc, &outputNode);
if (result) { printf("AUGraphNewNode 1 result %lu %4.4s\n", result, (char*)&result); return; }
result = AUGraphAddNode(mGraph, &eq_desc, &eqNode);
if (result) { printf("AUGraphNewNode 2 result %lu %4.4s\n", result, (char*)&result); return; }
result = AUGraphAddNode(mGraph, &mixer_desc, &mixerNode);
if (result) { printf("AUGraphNewNode 3 result %lu %4.4s\n", result, (char*)&result); return; }
result = AUGraphAddNode(mGraph, &reverb_desc, &reverbNode);
if (result) { printf("AUGraphNewNode 4 result %lu %4.4s\n", result, (char*)&result); return; }
// connect a node's output to a node's input
// mixer -> eq -> output
result = AUGraphConnectNodeInput(mGraph, mixerNode, 0, eqNode, 0);
if (result) { printf("AUGraphConnectNodeInput result %lu %4.4s\n", result, (char*)&result); return; }
result = AUGraphConnectNodeInput(mGraph, eqNode, 0, reverbNode, 0);
if (result) { printf("AUGraphConnectNodeInput result %lu %4.4s\n", result, (char*)&result); return; }
result = AUGraphConnectNodeInput(mGraph, reverbNode, 0, outputNode, 0);
if (result) { printf("AUGraphConnectNodeInput reverb result %lu %4.4s\n", result, (char*)&result); return; }
// open the graph AudioUnits are open but not initialized (no resource allocation occurs here)
result = AUGraphOpen(mGraph);
if (result) { printf("AUGraphOpen result %ld %08X %4.4s\n", result, (unsigned int)result, (char*)&result); return; }
// grab the audio unit instances from the nodes
result = AUGraphNodeInfo(mGraph, mixerNode, NULL, &mMixer);
if (result) { printf("AUGraphNodeInfo result %ld %08X %4.4s\n", result, (unsigned int)result, (char*)&result); return; }
result = AUGraphNodeInfo(mGraph, eqNode, NULL, &mEQ);
if (result) { printf("AUGraphNodeInfo result %ld %08X %4.4s\n", result, (unsigned int)result, (char*)&result); return; }
result = AUGraphNodeInfo(mGraph, reverbNode, NULL, &mReverb);
if (result) { printf("AUGraphNodeInfo reverb result %ld %08X %4.4s\n", result, (unsigned int)result, (char*)&result); return; }
// set bus count
UInt32 numbuses = 2;
printf("set input bus count %lu\n", numbuses);
result = AudioUnitSetProperty(mMixer, kAudioUnitProperty_ElementCount, kAudioUnitScope_Input, 0, &numbuses, sizeof(numbuses));
if (result) { printf("AudioUnitSetProperty result %ld %08X %4.4s\n", result, (unsigned int)result, (char*)&result); return; }
for (int i = 0; i < numbuses; ++i) {
// setup render callback struct
AURenderCallbackStruct rcbs;
rcbs.inputProc = &renderInput;
rcbs.inputProcRefCon = &mUserData;
printf("set AUGraphSetNodeInputCallback\n");
// set a callback for the specified node's specified input
result = AUGraphSetNodeInputCallback(mGraph, mixerNode, i, &rcbs);
if (result) { printf("AUGraphSetNodeInputCallback result %ld %08X %4.4s\n", result, (unsigned int)result, (char*)&result); return; }
printf("set input bus %d, client kAudioUnitProperty_StreamFormat\n", i);
// set the input stream format, this is the format of the audio for mixer input
result = AudioUnitSetProperty(mMixer, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, i, &mClientFormat, sizeof(mClientFormat));
if (result) { printf("AudioUnitSetProperty result %ld %08X %4.4s\n", result, (unsigned int)result, (char*)&result); return; }
}
printf("get EQ kAudioUnitProperty_FactoryPresets\n");
// get the eq's factory preset list -- this is a read-only CFArray array of AUPreset structures
// host owns the retuned array and should release it when no longer needed
UInt32 size = sizeof(mEQPresetsArray);
result = AudioUnitGetProperty(mEQ, kAudioUnitProperty_FactoryPresets, kAudioUnitScope_Global, 0, &mEQPresetsArray, &size);
if (result) { printf("AudioUnitGetProperty result %ld %08X %4.4s\n", result, (unsigned int)result, (char*)&result); return; }
/* this code can be used if you're interested in dumping out the preset list
printf("iPodEQ Factory Preset List:\n");
UInt8 count = CFArrayGetCount(mEQPresetsArray);
for (int i = 0; i < count; ++i) {
AUPreset *aPreset = (AUPreset*)CFArrayGetValueAtIndex(mEQPresetsArray, i);
CFShow(aPreset->presetName);
}*/
printf("set output kAudioUnitProperty_StreamFormat\n");
// set the output stream format of the mixer
result = AudioUnitSetProperty(mMixer, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Output, 0, &mOutputFormat, sizeof(mOutputFormat));
if (result) { printf("AudioUnitSetProperty result %ld %08X %4.4s\n", result, (unsigned int)result, (char*)&result); return; }
printf("set render notification\n");
// add a render notification, this is a callback that the graph will call every time the graph renders
// the callback will be called once before the graph’s render operation, and once after the render operation is complete
result = AUGraphAddRenderNotify(mGraph, renderNotification, &mUserData);
if (result) { printf("AUGraphAddRenderNotify result %ld %08X %4.4s\n", result, (unsigned int)result, (char*)&result); return; }
printf("AUGraphInitialize\n");
// now that we've set everything up we can initialize the graph, this will also validate the connections
result = AUGraphInitialize(mGraph);
if (result) { printf("AUGraphInitialize result %ld %08X %4.4s\n", result, (unsigned int)result, (char*)&result); return; }
// ---- result here is error code 10868
CAShow(mGraph);
}
答案 0 :(得分：4)
由于某种原因，一些AU节点默认采用float格式的流格式，而其他节点则采用整数形式。如果流格式不匹配，则会出现此错误。因此，您需要在均衡器节点和混响节点之间添加格式转换器：
AudioComponentDescription convertUnitDescription;
convertUnitDescription.componentManufacturer = kAudioUnitManufacturer_Apple;
convertUnitDescription.componentType = kAudioUnitType_FormatConverter;
convertUnitDescription.componentSubType = kAudioUnitSubType_AUConverter;
convertUnitDescription.componentFlags = 0;
convertUnitDescription.componentFlagsMask = 0;
result = AUGraphAddNode (graph, &convertUnitDescription, &convertNode);
NSCAssert (result == noErr, @"Unable to add the converted unit to the audio processing graph. Error code: %d '%.4s'", (int) result, (const char *)&result);
确保将转换器节点输入的流格式设置为均衡器节点输出的格式：
AudioStreamBasicDescription eqStreamFormat;
UInt32 streamFormatSize = sizeof(eqStreamFormat);
result = AudioUnitGetProperty(eqUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Output, 0, &eqStreamFormat, &streamFormatSize);
NSAssert (result == noErr, @"Unable to get eq output format. Error code: %d '%.4s'", (int) result, (const char *)&result);
result = AudioUnitSetProperty(convertUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, 0, &eqStreamFormat, streamFormatSize);
NSAssert (result == noErr, @"Unable to set converter input format. Error code: %d '%.4s'", (int) result, (const char *)&result);
对转换器的输出执行相同操作，使用混响的输入格式进行设置。 这应该使您的图表初始化并运行，但如果您设法使混响节点实际执行某些操作，请告诉我，因为它对我不起作用。