问题
In Objective-C, recording and playing audio simultaneously is fairly simple. And there are tonnes of sample code on the internet. But I want to record and play audio simultaneously using Audio Unit/Core Audio in Swift. There are vary small amount of help and sample code on this using Swift. And i couldn't find any help which could show how to achieve this.
I am struggling with the bellow code.
let preferredIOBufferDuration = 0.005
let kInputBus = AudioUnitElement(1)
let kOutputBus = AudioUnitElement(0)
init() {
// This is my Audio Unit settings code.
var status: OSStatus
do {
try AVAudioSession.sharedInstance().setPreferredIOBufferDuration(preferredIOBufferDuration)
} catch let error as NSError {
print(error)
}
var desc: AudioComponentDescription = AudioComponentDescription()
desc.componentType = kAudioUnitType_Output
desc.componentSubType = kAudioUnitSubType_VoiceProcessingIO
desc.componentFlags = 0
desc.componentFlagsMask = 0
desc.componentManufacturer = kAudioUnitManufacturer_Apple
let inputComponent: AudioComponent = AudioComponentFindNext(nil, &desc)
status = AudioComponentInstanceNew(inputComponent, &audioUnit)
checkStatus(status)
var flag = UInt32(1)
status = AudioUnitSetProperty(audioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Input, kInputBus, &flag, UInt32(sizeof(UInt32)))
checkStatus(status)
status = AudioUnitSetProperty(audioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Output, kOutputBus, &flag, UInt32(sizeof(UInt32)))
checkStatus(status)
var audioFormat: AudioStreamBasicDescription! = AudioStreamBasicDescription()
audioFormat.mSampleRate = 8000
audioFormat.mFormatID = kAudioFormatLinearPCM
audioFormat.mFormatFlags = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked
audioFormat.mFramesPerPacket = 1
audioFormat.mChannelsPerFrame = 1
audioFormat.mBitsPerChannel = 16
audioFormat.mBytesPerPacket = 2
audioFormat.mBytesPerFrame = 2
status = AudioUnitSetProperty(audioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Output, kInputBus, &audioFormat, UInt32(sizeof(UInt32)))
checkStatus(status)
try! AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayAndRecord)
status = AudioUnitSetProperty(audioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, kOutputBus, &audioFormat, UInt32(sizeof(UInt32)))
checkStatus(status)
// Set input/recording callback
var inputCallbackStruct: AURenderCallbackStruct! = AURenderCallbackStruct(inputProc: recordingCallback, inputProcRefCon: UnsafeMutablePointer(unsafeAddressOf(self)))
inputCallbackStruct.inputProc = recordingCallback
inputCallbackStruct.inputProcRefCon = UnsafeMutablePointer(unsafeAddressOf(self))
status = AudioUnitSetProperty(audioUnit, kAudioOutputUnitProperty_SetInputCallback, kAudioUnitScope_Global, kInputBus, &inputCallbackStruct, UInt32(sizeof(UInt32)))
checkStatus(status)
// Set output/renderar/playback callback
var renderCallbackStruct: AURenderCallbackStruct! = AURenderCallbackStruct(inputProc: playbackCallback, inputProcRefCon: UnsafeMutablePointer(unsafeAddressOf(self)))
renderCallbackStruct.inputProc = playbackCallback
renderCallbackStruct.inputProcRefCon = UnsafeMutablePointer(unsafeAddressOf(self))
status = AudioUnitSetProperty(audioUnit, kAudioUnitProperty_SetRenderCallback, kAudioUnitScope_Global, kOutputBus, &renderCallbackStruct, UInt32(sizeof(UInt32)))
checkStatus(status)
flag = 0
status = AudioUnitSetProperty(audioUnit, kAudioUnitProperty_ShouldAllocateBuffer, kAudioUnitScope_Output, kInputBus, &flag, UInt32(sizeof(UInt32)))
}
func recordingCallback(inRefCon: UnsafeMutablePointer<Void>,
ioActionFlags: UnsafeMutablePointer<AudioUnitRenderActionFlags>,
inTimeStamp: UnsafePointer<AudioTimeStamp>,
inBufNumber: UInt32,
inNumberFrames: UInt32,
ioData: UnsafeMutablePointer<AudioBufferList>) -> OSStatus {
print("recordingCallback got fired >>>")
return noErr
}
func playbackCallback(inRefCon: UnsafeMutablePointer<Void>,
ioActionFlags: UnsafeMutablePointer<AudioUnitRenderActionFlags>,
inTimeStamp: UnsafePointer<AudioTimeStamp>,
inBufNumber: UInt32,
inNumberFrames: UInt32,
ioData: UnsafeMutablePointer<AudioBufferList>) -> OSStatus {
print("playbackCallback got fired <<<")
return noErr
}
With that code, only recordingCallback
method is getting called. And playbackCallback
method is not being fired at all. I sure that i am going something wrong here. Can someone please help me with this. I am banging my head over this problem.
回答1:
You are setting the InputCallback
and RenderCallback
method incorrectly. Other settings seems OK. So your init
method should be like this.
init() {
var status: OSStatus
do {
try AVAudioSession.sharedInstance().setPreferredIOBufferDuration(preferredIOBufferDuration)
} catch let error as NSError {
print(error)
}
var desc: AudioComponentDescription = AudioComponentDescription()
desc.componentType = kAudioUnitType_Output
desc.componentSubType = kAudioUnitSubType_VoiceProcessingIO
desc.componentFlags = 0
desc.componentFlagsMask = 0
desc.componentManufacturer = kAudioUnitManufacturer_Apple
let inputComponent: AudioComponent = AudioComponentFindNext(nil, &desc)
status = AudioComponentInstanceNew(inputComponent, &audioUnit)
checkStatus(status)
var flag = UInt32(1)
status = AudioUnitSetProperty(audioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Input, kInputBus, &flag, UInt32(sizeof(UInt32)))
checkStatus(status)
status = AudioUnitSetProperty(audioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Output, kOutputBus, &flag, UInt32(sizeof(UInt32)))
checkStatus(status)
var audioFormat: AudioStreamBasicDescription! = AudioStreamBasicDescription()
audioFormat.mSampleRate = 8000
audioFormat.mFormatID = kAudioFormatLinearPCM
audioFormat.mFormatFlags = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked
audioFormat.mFramesPerPacket = 1
audioFormat.mChannelsPerFrame = 1
audioFormat.mBitsPerChannel = 16
audioFormat.mBytesPerPacket = 2
audioFormat.mBytesPerFrame = 2
status = AudioUnitSetProperty(audioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Output, kInputBus, &audioFormat, UInt32(sizeof(UInt32)))
checkStatus(status)
try! AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayAndRecord)
status = AudioUnitSetProperty(audioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, kOutputBus, &audioFormat, UInt32(sizeof(UInt32)))
checkStatus(status)
// Set input/recording callback
var inputCallbackStruct = AURenderCallbackStruct(inputProc: recordingCallback, inputProcRefCon: UnsafeMutablePointer(unsafeAddressOf(self)))
AudioUnitSetProperty(audioUnit, AudioUnitPropertyID(kAudioOutputUnitProperty_SetInputCallback), AudioUnitScope(kAudioUnitScope_Global), 1, &inputCallbackStruct, UInt32(sizeof(AURenderCallbackStruct)))
// Set output/renderar/playback callback
var renderCallbackStruct = AURenderCallbackStruct(inputProc: playbackCallback, inputProcRefCon: UnsafeMutablePointer(unsafeAddressOf(self)))
AudioUnitSetProperty(audioUnit, AudioUnitPropertyID(kAudioUnitProperty_SetRenderCallback), AudioUnitScope(kAudioUnitScope_Global), 0, &renderCallbackStruct, UInt32(sizeof(AURenderCallbackStruct)))
flag = 0
status = AudioUnitSetProperty(audioUnit, kAudioUnitProperty_ShouldAllocateBuffer, kAudioUnitScope_Output, kInputBus, &flag, UInt32(sizeof(UInt32)))
}
Try with this code and let us know if that helps.
来源:https://stackoverflow.com/questions/36968813/how-to-record-and-play-audio-simultaneously-in-ios-using-swift