在 IOS 中使用 AUGraph 在 AudioUnit 中播放立体声

问题描述

我想在 ios 中使用 AUGraph 使用 Audiounit 播放立体声，但我面临的问题是“当我想以 48000 采样率以立体声模式播放时，我的声音播放速度很快”。但它适用于单声道声音（单声道）。

这是我的代码。

import Combine
import AudioUnit
import Foundation
import AudioToolBox
import AVFoundation

@objc protocol AudioUnitDataChannelPlayoutDelegate
{
    func performInput(
        _ ioActionFlags: UnsafeMutablePointer<AudioUnitRenderActionFlags>,inTimeStamp: UnsafePointer<AudioTimeStamp>,inBufNumber: UInt32,inNumberFrames: UInt32,ioData: UnsafeMutablePointer<audiobufferlist> ) -> Osstatus
}

private let AudioController_InputCallback: AURenderCallback =
{
    (
        inRefCon,ioActionFlags,inTimeStamp,inBufNumber,inNumberFrames,ioData
    )-> Osstatus in
    
    let delegate = unsafeBitCast(inRefCon,to: AudioUnitDataChannelPlayoutDelegate.self)
    
    let result = delegate.performInput(ioActionFlags,inTimeStamp: inTimeStamp,inBufNumber: inBufNumber,inNumberFrames: inNumberFrames,ioData: ioData!)
    return noErr
}

class AudioUnitDataChannelPlayout
{
    
    private static var instance: AudioUnitDataChannelPlayout?
    
    public class var sharedInstance: AudioUnitDataChannelPlayout
    {
        if instance == nil
        {
            instance = AudioUnitDataChannelPlayout()
        }
        return instance!
    }
    
    static let audioBuffer = CircularBuffer(size: 25003904)
   
    let kInputBus: UInt32 = 1
    let kOutputBus: UInt32 = 0
    var status: Osstatus?
    var flag: UInt32 = 1
    
    var ioFormat = CAStreamBasicDescription(
        sampleRate: Double(48000.0),numChannels: 2,pcmf: .int16,isInterleaved: true )
    
    var timePitchFormat = CAStreamBasicDescription(
        sampleRate: Double(48000.0),numChannels: 1,// if chnges to 2 nothing happens
        pcmf: .float32,isInterleaved: false ) // if change to true then error occurs
    
    var graph: AUGraph?
    var firstConverterNode: AUNode = 0
    var timePitchNode: AUNode = 0
    var secondConverterNode: AUNode = 0
    var outputNode: AUNode = 0
    var firstConverterUnit: AudioUnit?
    var timePitchUnit: AudioUnit?
    var secondConverterUnit: AudioUnit?
    var outputUnit: AudioUnit?
    
    
    init()
    {
        configureAudioSession()
        setupRecordingUnit()
        playAudio()
    }
    
    private func setupRecordingUnit()
    {
        check(error: NewAUGraph(&graph),description: "Failed to create AUGraph")
        
        var output_desc = AudioComponentDescription(
            componentType: OSType(kAudioUnitType_Output),componentSubType: OSType(kAudioUnitSubType_VoiceProcessingIO),componentManufacturer: OSType(kAudioUnitManufacturer_Apple),componentFlags: 0,componentFlagsMask: 0 )
        
        var converter_desc = AudioComponentDescription(
            componentType: OSType(kAudioUnitType_FormatConverter),componentSubType: OSType(kAudioUnitSubType_AUConverter),componentFlagsMask: 0 )
        
        var varispeed_desc = AudioComponentDescription(
            componentType: OSType(kAudioUnitType_FormatConverter),componentSubType: OSType(kAudioUnitSubType_NewTimePitch),componentFlagsMask: 0 )
        
        check(error: AUGraphAddNode(graph!,&output_desc,&outputNode),description: "Failed to Add Node Audio Node")
        
        check(error: AUGraphAddNode(graph!,&converter_desc,&firstConverterNode),description: "Failed to Add converter node")
        check(error: AUGraphAddNode(graph!,&varispeed_desc,&timePitchNode),description: "Failed to Add Node varispeed Node")
        check(error: AUGraphAddNode(graph!,&secondConverterNode),description: "Failed to Add converter node")
        
        check(error: AUGraphOpen(graph!),description: "Failed to open AUGraph")
        
        check(error: AUGraphNodeInfo(graph!,outputNode,nil,&outputUnit),description: "Failed to get Info of audioUnit")
        check(error: AUGraphNodeInfo(graph!,firstConverterNode,&firstConverterUnit),description: "Failed to get Info of converterUnit")
        check(error: AUGraphNodeInfo(graph!,timePitchNode,&timePitchUnit),description: "Failed to get Info of VarispeedUnit")
        check(error: AUGraphNodeInfo(graph!,secondConverterNode,&secondConverterUnit),description: "Failed to get Info of converterUnit")
        
        check(error: AudioUnitSetProperty(outputUnit!,kAudioOutputUnitProperty_EnableIO,kAudioUnitScope_Output,kOutputBus,&flag,MemoryLayoutStride.SizeOf32(flag)),description: "Failed to set enable IO for Playing.")
        
        check(error: AudioUnitSetProperty(firstConverterUnit!,kAudioUnitProperty_StreamFormat,kAudioUnitScope_Input,&ioFormat,MemoryLayoutStride.SizeOf32(ioFormat)),description: "Failed to set property of firstConverter Unit")
        
        check(error: AudioUnitSetProperty(firstConverterUnit!,&timePitchFormat,MemoryLayoutStride.SizeOf32(timePitchFormat)),description: "Failed to set property of firstConverter Unit 1")
        
        check(error: AudioUnitSetProperty(timePitchUnit!,description: "Failed to set property of varispeed unit")
        
        check(error: AudioUnitSetProperty(timePitchUnit!,description: "Failed to set property of Varispeed Unit 1")
        
        check(error: AudioUnitSetProperty(secondConverterUnit!,description: "Failed to set property of firstConverter Unit")
        
        check(error: AudioUnitSetProperty(secondConverterUnit!,description: "Failed to set property of firstConverter Unit 1")
        
        
        check(error: AudioUnitSetProperty(outputUnit!,description: "Failed to set property of Output Unit")
        AUGraphConnectNodeInput(graph!,0)
        AUGraphConnectNodeInput(graph!,0)
        
        
        var recordingCallback = AURenderCallbackStruct(
            inputProc: AudioController_InputCallback,inputProcRefCon: UnsafeMutableRawPointer(Unmanaged.passUnretained(self).toOpaque()) )
        
        check(error: AUGraphSetNodeInputCallback(graph!,&recordingCallback),description: "Failed to set inPutCallback")
        
        AUGraphInitialize(graph!)
    }
    
    func check(error: Osstatus,description: String)
    {
        if error != noErr
        {
            fatalError("\(description) : \(error)")
        }
    }
    
    func startSpeakerUnit()
    {
        check(error: AUGraphStart(graph!),description: "Error Failed to start AUGraph")
        print("initializing the speaker unit")
    }
    
    func stopSpeakerUnit()
    {
        check(error: AUGraphStop(graph!),description: "Error Failed to stop AUGraph")
        AudioUnitDataChannelPlayout.instance = nil
    }

    private func playAudio()
    {
        AudioUnitSetParameter(self.timePitchUnit!,kNewTimePitchParam_Rate,kAudioUnitScope_Global,AudioUnitParameterValue(1.0),0)
    }
    
}

extension AudioUnitDataChannelPlayout: AudioUnitDataChannelPlayoutDelegate
{
    func performInput(_ ioActionFlags: UnsafeMutablePointer<AudioUnitRenderActionFlags>,ioData: UnsafeMutablePointer<audiobufferlist>) -> Osstatus
    {
        
        let playbackPointer = ioData[0].mBuffers
        
        print("SECOND POINTER: \(playbackPointer)")

        let bytesTocopy = ioData[0].mBuffers.mDataByteSize

        
        var bufferTail = AudioUnitDataChannelPlayout.audioBuffer.getTail()
        
        print(AudioUnitDataChannelPlayout.audioBuffer.getAvailableBytes())

        let bytesToWrite = min(bytesTocopy,AudioUnitDataChannelPlayout.audioBuffer.getAvailableBytes())
        
        memcpy(playbackPointer.mData,bufferTail,Int(bytesToWrite))
        
        print("playing...\(bytesTocopy)")
        AudioUnitDataChannelPlayout.audioBuffer.consume(samples: bytesToWrite)
        
        return noErr
    }
    
}

在这堂课中，我只是播放立体声的波形文件。在这方面的任何帮助将不胜感激。

解决方法

我在那里编写的播放器代码没有错误。但是以快速模式播放音频的主要原因是，在将数据插入播放器时，我提供了立体声数据，但将其视为单声道（因为我只填充了一半的帧数）。我在分配内存时将帧数与通道数相乘，结果成功了。