在iOS6中使用Arisraph的Varispeed audiounit
我正在学习iOS中的AudioUnits并试图实现这样的图形：
------------------- -----------------
| | | |
-->| FormatConverter | --->| bus 0 |
| (Varispeed) | | |
-------------------- | Multichannel |
-------------------- | Mixer Unit |
| | | | --------------------
-->| FormatConverter | --->| bus 1 | | |
| (Varispeed) | | | --->| Remote IO | ----->
-------------------- | | | Unit |
-------------------- | | | |
| | | | --------------------
->| FormatConverter | --->| bus 2 |
| (Varispeed) | | |
--------------------- | |
-----------------
首先，我尝试在没有kAudioUnitSubType_Varispeed Unit的情况下使用AudioUnits。 它工作正常，声音播放。 但是现在我想知道每个声音的音高（单独），这就是为什么我决定添加Varispeed单位来控制每个声音的音高。
我使用下面的代码：
OSStatus result = noErr;
//............................................................................
// Specify the audio unit component descriptions for the audio units to be
// added to the graph.
// I/O unit
AudioComponentDescription iOUnitDescription;
iOUnitDescription.componentType = kAudioUnitType_Output;
iOUnitDescription.componentSubType = kAudioUnitSubType_RemoteIO;
iOUnitDescription.componentManufacturer = kAudioUnitManufacturer_Apple;
iOUnitDescription.componentFlags = 0;
iOUnitDescription.componentFlagsMask = 0;
// Multichannel mixer unit
AudioComponentDescription MixerUnitDescription;
MixerUnitDescription.componentType = kAudioUnitType_Mixer;
MixerUnitDescription.componentSubType = kAudioUnitSubType_MultiChannelMixer;
MixerUnitDescription.componentManufacturer = kAudioUnitManufacturer_Apple;
MixerUnitDescription.componentFlags = 0;
MixerUnitDescription.componentFlagsMask = 0;
// Varispeed unit
AudioComponentDescription varispeedUnitDescription;
MixerUnitDescription.componentType = kAudioUnitType_FormatConverter;
MixerUnitDescription.componentSubType = kAudioUnitSubType_Varispeed;
MixerUnitDescription.componentManufacturer = kAudioUnitManufacturer_Apple;
MixerUnitDescription.componentFlags = 0;
MixerUnitDescription.componentFlagsMask = 0;
//............................................................................
// Add nodes to the audio processing graph.
NSLog (@"Adding nodes to audio processing graph");
AUNode iONode; // node for I/O unit
AUNode mixerNode; // node for Multichannel Mixer unit
AUNode varispeedNode0;
AUNode varispeedNode1;
AUNode varispeedNode2;
//............................................................................
// Create a new audio processing graph.
result = NewAUGraph(&processingGraph);
if (noErr != result) {[self printErrorMessage: @"NewAUGraph" withStatus: result]; return;}
//............................................................................
// Open the audio processing graph
result = AUGraphOpen(processingGraph);
if (noErr != result) {
[self printErrorMessage: @"AUGraphOpen" withStatus: result];
return;
}
//............................................................................
// Add the nodes to the audio processing graph
result = AUGraphAddNode(
processingGraph,
&varispeedUnitDescription,
&varispeedNode0);
if (noErr != result) {
[self printErrorMessage: @"AUGraphNewNode failed for varispeedNode0 unit" withStatus: result];
return;
}
result = AUGraphAddNode (
processingGraph,
&varispeedUnitDescription,
&varispeedNode1);
if (noErr != result) {
[self printErrorMessage: @"AUGraphNewNode failed for varispeedNode1 unit" withStatus: result];
return;
}
result = AUGraphAddNode (
processingGraph,
&varispeedUnitDescription,
&varispeedNode2);
if (noErr != result) {
[self printErrorMessage: @"AUGraphNewNode failed for varispeedNode2 unit" withStatus: result];
return;
}
result = AUGraphAddNode (
processingGraph,
&iOUnitDescription,
&iONode);
if (noErr != result) {
[self printErrorMessage: @"AUGraphNewNode failed for I/O unit" withStatus: result];
return;
}
result = AUGraphAddNode (
processingGraph,
&MixerUnitDescription,
&mixerNode);
if (noErr != result) {
[self printErrorMessage: @"AUGraphNewNode failed for Mixer unit" withStatus: result];
return;
}
当我运行应用程序时，出现以下错误：
2013-04-24 21:44:59.335 Drumpads[327:c07] *** AUGraphNewNode failed for varispeedNode0 unit error: ˇˇ¯+ 2013-04-24 21:44:59.338 Drumpads[327:c07] Error.domain = NSOSStatusErrorDomain, code=-2005, descr =Error Domain=NSOSStatusErrorDomain Code=-2005 "The operation couldn’t be completed. (OSStatus error -2005.)"
根据MacErrors.h -2005表示'badComponentType'。
所以看起来Varispeed Unit甚至不能添加到AUGraph中。 一切似乎都是正确的，所以我不知道为什么添加Varispeed节点会导致错误。
我使用了来自developers.apple.com代码的示例代码作为参考（我知道，这是针对OSx的，但Varispeed现在可用于iOS5和6，因此我决定使用此代码作为参考）。
我需要控制每个声音的音高变化。 我选择了Varispeed，但我也读过NewTimePitch节点。 我试过NewTimePitch（在同一张图中），但也没有成功。
有人知道我的代码有什么问题，以及为什么添加Varispeed节点会导致错误？
提前致谢！
经过一天的研究，并试图找到更多有关FormatConverter和Varispeed的信息，并阅读了很多信息，我终于找到了答案。
当然，修理它是非常困难的，但幸运的是我！ 大声笑
这是我以前的代码：
AudioComponentDescription varispeedUnitDescription;
MixerUnitDescription.componentType = kAudioUnitType_FormatConverter;
MixerUnitDescription.componentSubType = kAudioUnitSubType_Varispeed;
MixerUnitDescription.componentManufacturer = kAudioUnitManufacturer_Apple;
MixerUnitDescription.componentFlags = 0;
MixerUnitDescription.componentFlagsMask = 0;
这是新的：
AudioComponentDescription varispeedUnitDescription;
varispeedUnitDescription.componentType = kAudioUnitType_FormatConverter;
varispeedUnitDescription.componentSubType = kAudioUnitSubType_Varispeed;
varispeedUnitDescription.componentManufacturer = kAudioUnitManufacturer_Apple;
varispeedUnitDescription.componentFlags = 0;
varispeedUnitDescription.componentFlagsMask = 0;
所以...这是非常糟糕的组件类型（-2005），因为varispeedUnitDescription实际上没有正确描述。
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