利用AudioKit的AKHighPassFilter实现频率滤波
利用AudioKit的AKHighPassFilter实现频率滤波
提问于 2017-05-02 02:42:44
我正在尝试用AudioKit过滤掉低于指定阈值的频率。我正在使用AKHighPassFilter来完成这项工作。
func playSound(duration: Int, frequencyRange: Range<Double>) {
generator = AKOperationGenerator() { parameters in
let volume = AKOperation.sineWave(frequency: parameters[0]).scale(minimum: 0, maximum: 0.1)
let jitter = AKOperation.jitter(amplitude: parameters[1], minimumFrequency: lowerFrequency, maximumFrequency: upperFrequency)
return AKOperation.sineWave(frequency: jitter, amplitude: volume)
}
generator!.parameters = [baseFrequency, amplitude]
// Exception thrown at this line after method called 1 time
var highPassFilter = AKHighPassFilter(generator)
highPassFilter.cutoffFrequency = frequencyRange.lowerBound
highPassFilter.resonance = 0
AudioKit.output = highPassFilter
AudioKit.start()
generator?.play()
}我第一次调用playSound(duration:, frequencyRange:)时，它工作得很好。一旦我停止AudioKit并尝试第二次播放声音，就会在该行抛出一个异常：
var highPassFilter = AKHighPassFilter(generator)以下是崩溃的控制台输出：
2017-05-01 14:32:01.169 MyApp[18123:3459824] *** Terminating app due to uncaught exception 'com.apple.coreaudio.avfaudio', reason: 'required condition is false: [_nodes containsObject: node]'
*** First throw call stack:
(
0 CoreFoundation 0x0000000109ea7b0b __exceptionPreprocess + 171
1 libobjc.A.dylib 0x000000010990c141 objc_exception_throw + 48
2 CoreFoundation 0x0000000109eabcf2 +[NSException raise:format:arguments:] + 98
3 AVFAudio 0x000000010cdc3a9e _Z19AVAE_RaiseExceptionP8NSStringz + 158
4 AVFAudio 0x000000010cdc9cbb _ZN17AVAudioEngineImpl10DetachNodeEP11AVAudioNodeb + 421
5 AVFAudio 0x000000010cdc9ad0 -[AVAudioEngine detachNode:] + 67
6 AudioKit 0x0000000108d3bee4 _TToFC8AudioKit6AKNodeD + 84
7 libobjc.A.dylib 0x0000000109920b8e _ZN11objc_object17sidetable_releaseEb + 202
8 AudioKit 0x0000000108d39a99 _TToFC8AudioKit16AKHighPassFilterE + 25
9 libobjc.A.dylib 0x000000010990a9bc _ZL27object_cxxDestructFromClassP11objc_objectP10objc_class + 127
10 libobjc.A.dylib 0x0000000109916d34 objc_destructInstance + 129
11 libobjc.A.dylib 0x0000000109916d66 object_dispose + 22
12 AudioKit 0x0000000108d3bf1b _TToFC8AudioKit6AKNodeD + 139
13 libobjc.A.dylib 0x0000000109920b8e _ZN11objc_object17sidetable_releaseEb + 202
14 MyApp 0x00000001087301ec _TFC7MyApp11SoundPlayerClass9playSoundfT8durationSi14frequencyRangeGVs5RangeSd__T_ + 988
15 MyApp 0x000000010873a1a4 _TFC7MyApp18MainViewController13playFrequencyfCS_12FrostyButtonT_ + 2276
16 MyApp 0x000000010873a4fa _TToFC7MyApp18MainViewController13playFrequencyfCS_12FrostyButtonT_ + 58
17 UIKit 0x000000010ab63d22 -[UIApplication sendAction:to:from:forEvent:] + 83
18 UIKit 0x000000010ace825c -[UIControl sendAction:to:forEvent:] + 67
19 UIKit 0x000000010ace8577 -[UIControl _sendActionsForEvents:withEvent:] + 450
20 UIKit 0x000000010ace74b2 -[UIControl touchesEnded:withEvent:] + 618
21 UIKit 0x000000010abd149a -[UIWindow _sendTouchesForEvent:] + 2707
22 UIKit 0x000000010abd2bb0 -[UIWindow sendEvent:] + 4114
23 UIKit 0x000000010ab7f7b0 -[UIApplication sendEvent:] + 352
24 UIKit 0x000000011e3c075c -[UIApplicationAccessibility sendEvent:] + 85
25 UIKit 0x000000010b362adc __dispatchPreprocessedEventFromEventQueue + 2926
26 UIKit 0x000000010b35aa3a __handleEventQueue + 1122
27 UIKit 0x000000010b35bd08 __handleEventQueue + 5936
28 CoreFoundation 0x0000000109e4dc01 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
29 CoreFoundation 0x0000000109e330cf __CFRunLoopDoSources0 + 527
30 CoreFoundation 0x0000000109e325ff __CFRunLoopRun + 911
31 CoreFoundation 0x0000000109e32016 CFRunLoopRunSpecific + 406
32 GraphicsServices 0x000000010ecd4a24 GSEventRunModal + 62
33 UIKit 0x000000010ab620d4 UIApplicationMain + 159
34 MyApp 0x000000010872cb77 main + 55
35 libdyld.dylib 0x000000010fbaf65d start + 1
36 ??? 0x0000000000000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException在添加AKHighPassFilter之前，该方法运行良好。我欢迎建议re:如何解决这个崩溃。感谢您的阅读。
回答 1
Stack Overflow用户
发布于 2017-11-17 01:24:13
我认为这里的主要问题是，您在每次调用playSound时重新创建所有对象，并在每次调用时在play方法中设置AudioKit.output。您要做的是在初始化例程中创建对象链，然后根据需要更改参数。所有的连接只需要建立一次。一种技术是使用AKMixer作为输入或输出，并在其中添加和删除节点。例如，高通滤波器可以对AKMixer的输出进行滤波。这个混合器可以有任意数量的节点附加到它。对于在运行时删除或添加的节点，AVAudioEngine可能会有些敏感。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/43724558
复制相关文章
相似问题
腾讯云开发者
