Ios 当AvaudioInTimePitch改变播放速率时,如何使用AVAudioEngine执行脱机音频处理?
我学会了如何使用AVAudioEngine将音频处理成文件,只要我不使用AVAudioUnitTimePitch改变播放速率,我的代码就可以工作 更改速率时,渲染音频的长度与原始音频的长度相同(速率不变)。因此,如果音频减慢(速率<1),部分音频将被修剪,如果音频加速(速率>1),渲染音频的最后部分将静音 代码如下:Ios 当AvaudioInTimePitch改变播放速率时,如何使用AVAudioEngine执行脱机音频处理?,ios,swift,avfoundation,avaudioengine,Ios,Swift,Avfoundation,Avaudioengine,我学会了如何使用AVAudioEngine将音频处理成文件,只要我不使用AVAudioUnitTimePitch改变播放速率,我的代码就可以工作 更改速率时,渲染音频的长度与原始音频的长度相同(速率不变)。因此,如果音频减慢(速率1),渲染音频的最后部分将静音 代码如下: // engine: AVAudioEngine // playerNode: AVAudioPlayerNode // audioFile: AVAudioFile open func render(to destinat
// engine: AVAudioEngine
// playerNode: AVAudioPlayerNode
// audioFile: AVAudioFile
open func render(to destinationFile: AVAudioFile) throws {
playerNode.scheduleFile(audioFile, at: nil)
do {
let buffCapacity: AVAudioFrameCount = 4096
try engine.enableManualRenderingMode(.offline, format: audioFile.processingFormat, maximumFrameCount: buffCapacity)
}
catch {
print("Failed to enable manual rendering mode: \(error)")
throw error
}
do {
try engine.start()
}
catch {
print("Failed to start the engine: \(error)")
}
playerNode.play()
let outputBuff = AVAudioPCMBuffer(pcmFormat: engine.manualRenderingFormat,
frameCapacity: engine.manualRenderingMaximumFrameCount)!
while engine.manualRenderingSampleTime < audioFile.length {
let remainingSamples = audioFile.length - engine.manualRenderingSampleTime
let framesToRender = min(outputBuff.frameCapacity, AVAudioFrameCount(remainingSamples))
do {
let renderingStatus = try engine.renderOffline(framesToRender, to: outputBuff)
switch renderingStatus {
case .success:
do {
try destinationFile.write(from: outputBuff)
}
catch {
print("Failed to write from file to buffer: \(error)")
throw error
}
case .insufficientDataFromInputNode:
break
case.cannotDoInCurrentContext:
break
case .error:
print("An error occured during rendering.")
throw AudioPlayer.ExportError.renderingError
@unknown default:
fatalError("engine.renderOffline() returned an unknown value.")
}
}
catch {
print("Failed to render offline manually: \(error)")
throw error
}
}
playerNode.stop()
engine.stop()
engine.disableManualRenderingMode()
}
//引擎:AVAudioEngine
//播放节点:AVAudioPlayerNode
//音频文件:AVAudioFile
打开func渲染(到destinationFile:AVAudioFile)抛出{
playerNode.scheduleFile(音频文件,at:nil)
做{
让buffCapacity:AVAudioFrameCount=4096
尝试engine.enableManualRenderingMode(.offline,格式:audioFile.processingFormat,最大帧数:buffCapacity)
}
抓住{
打印(“无法启用手动呈现模式:\(错误)”)
抛出错误
}
做{
试试引擎启动()
}
抓住{
打印(“启动引擎失败:\(错误)”)
}
playerNode.play()
让outputBuff=AVAudioPCMBuffer(PCM格式:engine.manualRenderingFormat,
帧容量:发动机。手动渲染最大帧数)!
而engine.manualRenderingSampleTime
我试图通过渲染与播放速率成反比的样本量来解决这个问题。这只解决了速率大于1时的问题。由于没有人回答,而且很多天过去了,我将分享我是如何解决这个问题的 事实证明,渲染与播放速率成反比的样本量是有效的。起初,这种方法不起作用,因为我做错了 以下是如何获得要渲染的正确采样数:
let framesToRenderCount = AVAudioFramePosition(Float(audioFile.length) * 1 / rate)
这回答了你的问题吗?