我想在 iOS 设备上实现我的均衡器,它似乎可以通过 kAudioUnitSubType_NBandEQ 实现。但是,在我设置了每个频段的增益后,我听到的声音没有任何变化。
我使用 BandEQDemo 的示例代码(https://github.com/springlo/BandEQDemo)
OSStatus TOAUGraphAddNode(OSType inComponentType, OSType inComponentSubType, AUGraph inGraph, AUNode *outNode)
{
AudioComponentDescription desc;
desc.componentType = inComponentType;
desc.componentSubType = inComponentSubType;
desc.componentFlags = 0;
desc.componentFlagsMask = 0;
desc.componentManufacturer = kAudioUnitManufacturer_Apple;
return AUGraphAddNode(inGraph, &desc, outNode);
}
TOAUGraphAddNode(kAudioUnitType_Effect,
kAudioUnitSubType_NBandEQ,
graph,
&eqNode);
AUGraphNodeInfo(graph,
eqNode,
NULL,
&equalizerUnit);
// @[ @32, @64, @128, @256, @512, @1025, @2048, @4096, @8192, @16384 ]
然后在我设置增益并通过这两个函数再次检查之后:
- (AudioUnitParameterValue)gainForBandAtPosition:(NSUInteger)bandPosition
{
AudioUnitParameterValue gain;
AudioUnitParameterID parameterID = kAUNBandEQParam_Gain + bandPosition;
TOThrowOnError(AudioUnitGetParameter(equalizerUnit,
parameterID,
kAudioUnitScope_Global,
0,
&gain));
return gain;
}
- (void)setGain:(AudioUnitParameterValue)gain forBandAtPosition:(NSUInteger)bandPosition
{
AudioUnitParameterID parameterID = kAUNBandEQParam_Gain + bandPosition;
TOThrowOnError(AudioUnitSetParameter(equalizerUnit,
parameterID,
kAudioUnitScope_Global,
0,
gain,
0));
NSLog(@"After set gain@[%d]->%f", bandPosition, [self gainForBandAtPosition:bandPosition]);
}
当我设置后得到每个频段的增益值(-96dB ~ 24dB),它确实对应于我设置的值。但我听不出声音有什么不同。