音频录制和实时处理在iOS开发中是非常重要的功能,它们可以用于实现语音聊天、音频处理应用等。本文将介绍iOS中的音频录制和实时处理,并提供一些示例代码供参考。
音频录制
iOS提供了AVAudioRecorder类来实现音频录制功能。下面是一个简单的示例代码,演示了如何使用AVAudioRecorder录制音频:
import AVFoundation
class ViewController: UIViewController, AVAudioRecorderDelegate {
var audioRecorder: AVAudioRecorder!
override func viewDidLoad() {
super.viewDidLoad()
setupAudioRecorder()
}
func setupAudioRecorder() {
let audioSession = AVAudioSession.sharedInstance()
do {
try audioSession.setCategory(AVAudioSessionCategoryPlayAndRecord)
try audioSession.setActive(true)
let basePath = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true).first!
let audioURL = URL(fileURLWithPath: basePath).appendingPathComponent("audio.m4a")
let recordSettings: [String: Any] = [
AVSampleRateKey: 44100.0,
AVNumberOfChannelsKey: 2,
AVEncoderAudioQualityKey: AVAudioQuality.high.rawValue
]
audioRecorder = try AVAudioRecorder(url: audioURL, settings: recordSettings)
audioRecorder.delegate = self
audioRecorder.prepareToRecord()
} catch let error {
print("Failed to setup audio recorder: \(error.localizedDescription)")
}
}
@IBAction func startRecording() {
audioRecorder.record()
}
@IBAction func stopRecording() {
audioRecorder.stop()
}
}
以上代码首先设置了音频会话,然后通过NSSearchPathForDirectoriesInDomains
方法获取存储路径,创建一个音频URL。接着,我们设置录制的参数,并使用URL和参数创建AVAudioRecorder实例。最后,通过调用record
方法开始录制,调用stop
方法停止录制。
实时音频处理
iOS的音频处理功能可以使用AudioUnit框架来实现。下面是一个简单的示例代码,演示了如何使用AudioUnit实现实时音频处理:
import AudioToolbox
class AudioUnitPlayer {
var audioUnit: AudioUnit!
init() {
var audioComponentDescription = AudioComponentDescription()
audioComponentDescription.componentType = kAudioUnitType_Output
audioComponentDescription.componentSubType = kAudioUnitSubType_RemoteIO
audioComponentDescription.componentManufacturer = kAudioUnitManufacturer_Apple
audioComponentDescription.componentFlags = 0
audioComponentDescription.componentFlagsMask = 0
let audioComponent = AudioComponentFindNext(nil, &audioComponentDescription)
AudioComponentInstanceNew(audioComponent!, &audioUnit)
var enableIO: UInt32 = 1
AudioUnitSetProperty(audioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Output, 0, &enableIO, UInt32(MemoryLayout<UInt32>.size))
var inputStreamFormat = AudioStreamBasicDescription()
inputStreamFormat.mSampleRate = 44100.0
inputStreamFormat.mFormatID = kAudioFormatLinearPCM
inputStreamFormat.mFormatFlags = kAudioFormatFlagIsFloat | kAudioFormatFlagIsNonInterleaved
inputStreamFormat.mBytesPerPacket = 4
inputStreamFormat.mFramesPerPacket = 1
inputStreamFormat.mBytesPerFrame = 4
inputStreamFormat.mChannelsPerFrame = 2
inputStreamFormat.mBitsPerChannel = 32
AudioUnitSetProperty(audioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, 0, &inputStreamFormat, UInt32(MemoryLayout<AudioStreamBasicDescription>.size))
let renderProc: AURenderCallback = { (inRefCon, ioActionFlags, inTimeStamp, inBusNumber, inNumberFrames, ioData) -> OSStatus in
// 处理音频数据
let audioBuffer = UnsafeMutableAudioBufferListPointer(ioData)
for buffer in audioBuffer {
let floatData = buffer.mData?.assumingMemoryBound(to: Float.self)
if let data = floatData {
for i in 0..<Int(buffer.mDataByteSize / 4) {
data[i] = data[i] * 2 // 将音量放大2倍
}
}
}
return noErr
}
var callbackStruct = AURenderCallbackStruct(inputProc: renderProc, inputProcRefCon: nil)
AudioUnitSetProperty(audioUnit, kAudioUnitProperty_SetRenderCallback, kAudioUnitScope_Input, 0, &callbackStruct, UInt32(MemoryLayout<AURenderCallbackStruct>.size))
AudioUnitInitialize(audioUnit)
AudioOutputUnitStart(audioUnit)
}
func stop() {
AudioOutputUnitStop(audioUnit)
AudioUnitUninitialize(audioUnit)
AudioComponentInstanceDispose(audioUnit)
}
}
以上代码首先创建了一个AudioUnit实例,并通过AudioUnitSetProperty
方法设置了音频输入流的参数。接着,我们定义了一个渲染回调函数,在该函数中可以处理音频数据。在示例代码中,我们将音频的每个样本的值放大2倍。最后,通过调用AudioOutputUnitStart
方法开始实时音频处理。
总结
本文介绍了iOS中的音频录制和实时处理的基本实现方法,通过AVAudioRecorder和AudioUnit可以很方便地实现这些功能。希望本文对大家有所帮助。
本文来自极简博客,作者:琉璃若梦,转载请注明原文链接:iOS中的音频录制和实时处理