AVAudioEngine:过滤实时音频
AVAudioEngine:过滤实时音频
提问于 2021-12-17 15:39:35
我已经通过了苹果的用vDSP实现音频均衡的示例代码，在那里的音频文件过滤在AVAudioSourceNode和复制。
我的目标是做完全相同的事情，但不是从音频文件中获取音频，而是从麦克风中实时获取音频。在AVAudioEngine中可以这样做吗？这样做的几种方法是基于installTap或AVAudioSinkNode，如第一策略和第二策略部分所述。
到目前为止，我已经接近了我的目标，有以下两个策略。
第一策略
// Added new class variables
private lazy var sinkNode = AVAudioSinkNode { (timestep, frames, audioBufferList) -> OSStatus in
let ptr = audioBufferList.pointee.mBuffers.mData?.assumingMemoryBound(to: Float.self)
var monoSamples = [Float]()
monoSamples.append(contentsOf: UnsafeBufferPointer(start: ptr, count: Int(frames)))
self.page = monoSamples.
for frame in 0..<frames {
print("sink: " + String(monoSamples[Int(frame)]))
}
return noErr
}
// AVAudioEngine connections
engine.attach(sinkNode)
// Audio input is passed to the AVAudioSinkNode and the [Float] array is pased to the AVAudioSourceNode through the _page_ variable
engine.connect(input, to: sinkNode, format: formatt)
engine.attach(srcNode)
engine.connect(srcNode,
to: engine.mainMixerNode,
format: format)
engine.connect(engine.mainMixerNode,
to: engine.outputNode,
format: format)
// The AVAudioSourceNode access the self.page array through the getSinalElement() function.
private func getSignalElement() -> Float {
return page.isEmpty ? 0 : page.removeFirst()
}这种方法使通过AVAudioSourceNode播放音频成为可能，但是，音频在几秒钟后停止播放(尽管我仍然成功地在AVAudioSourceNode中获得了self.page数组)，并且应用程序最终崩溃了。
2战略
在类似的方法中，我使用了installtap engine.attach(srcNode)
engine.connect(srcNode,
to: engine.mainMixerNode,
format: format)
engine.connect(engine.mainMixerNode,
to: engine.outputNode,
format: format)
input.installTap(onBus: 0, bufferSize:1024, format:formatt, block: { [weak self] buffer, when in
let arraySize = Int(buffer.frameLength)
let samples = Array(UnsafeBufferPointer(start: buffer.floatChannelData![0], count:arraySize))
self!.page = samples
})
// The AVAudioSourceNode access the self.page array through the getSinalElement() function.
private func getSignalElement() -> Float {
return page.isEmpty ? 0 : page.removeFirst()
}第二种策略实施后的结果与第一种策略相同。使这些方法失败的问题是什么？
回答 2
Stack Overflow用户
发布于 2021-12-17 15:51:24
您可以使用AvAudioEngine().inputNode，如下所示：
let engine = AVAudioEngine()
private lazy var srcNode = AVAudioSourceNode { _, _, frameCount, audioBufferList -> OSStatus in
return noErr
}
// Attach First
engine.attach(srcNode)
// Then connect nodes
let input = engine.inputNode
engine.connect(input, to: srcNode, format: input.inputFormat(forBus: 0))使用input.inputFormat(...)作为格式类型非常重要。
Stack Overflow用户
发布于 2022-05-20 13:06:46
do{
try audioSession.setCategory(.playAndRecord, mode: .default, options: [.mixWithOthers, .defaultToSpeaker,.allowBluetoothA2DP,.allowAirPlay,.allowBluetooth])
try audioSession.setActive(true)
} catch{
print(error.localizedDescription)
}
engine.attach(player)
//Add this only you want putch
let pitch = AVAudioUnitTimePitch()
// pitch.pitch = 1000 //Filtered Voice
//pitch.rate = 1 //Normal rate
// engine.attach(pitch)
engine.attach(srcNode)
engine.connect(srcNode,
to: engine.mainMixerNode,
format: engine.inputNode.inputFormat(forBus: 0))
engine.connect(engine.mainMixerNode,
to: engine.outputNode,
format: engine.inputNode.inputFormat(forBus: 0))
engine.prepare()
engine.inputNode.installTap(onBus: 0, bufferSize: 512, format: engine.inputNode.inputFormat(forBus: 0)) { (buffer, time) -> Void in
// self.player.scheduleBuffer(buffer)
let arraySize = Int(buffer.frameLength)
let samples = Array(UnsafeBufferPointer(start: buffer.floatChannelData![0], count:arraySize))
self.page = samples
print("samples",samples)
}
engine.mainMixerNode.outputVolume = 0.5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/70395504
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