ios audiounit实现录音分贝
时间: 2024-03-26 18:39:19 浏览: 129
实现 iOS AudioUnit 录音分贝检测,可以参考以下步骤:
1. 配置音频会话
在使用 AudioUnit 之前,需要先配置音频会话。可以设置为录音模式,同时指定要使用的音频输入设备。
```objc
AVAudioSession *audioSession = [AVAudioSession sharedInstance];
NSError *error;
[audioSession setCategory:AVAudioSessionCategoryRecord error:&error];
[audioSession setPreferredSampleRate:44100.0 error:&error];
[audioSession setPreferredIOBufferDuration:0.005 error:&error];
[audioSession setActive:YES error:&error];
```
2. 创建 AudioUnit
使用 `AudioComponentFindNext` 函数来查找可用的音频组件,并使用 `AudioComponentInstanceNew` 函数创建 AudioUnit 实例。
```objc
AudioComponentDescription desc;
desc.componentType = kAudioUnitType_Output;
desc.componentSubType = kAudioUnitSubType_RemoteIO;
desc.componentManufacturer = kAudioUnitManufacturer_Apple;
desc.componentFlags = 0;
desc.componentFlagsMask = 0;
AudioComponent inputComponent = AudioComponentFindNext(NULL, &desc);
AudioComponentInstanceNew(inputComponent, &_audioUnit);
```
3. 配置 AudioUnit
设置 AudioUnit 的音频格式和 IO 属性,并启用录音和回放功能。
```objc
// 设置音频输入格式
AudioStreamBasicDescription audioFormat;
audioFormat.mSampleRate = 44100.0;
audioFormat.mFormatID = kAudioFormatLinearPCM;
audioFormat.mFormatFlags = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked;
audioFormat.mFramesPerPacket = 1;
audioFormat.mChannelsPerFrame = 1;
audioFormat.mBitsPerChannel = 16;
audioFormat.mBytesPerPacket = 2;
audioFormat.mBytesPerFrame = 2;
// 设置 AudioUnit 输入流 IO 属性
AudioUnitSetProperty(_audioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, 0, &audioFormat, sizeof(audioFormat));
UInt32 enable = 1;
AudioUnitSetProperty(_audioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Input, 1, &enable, sizeof(enable));
// 设置 AudioUnit 输出流 IO 属性
AudioUnitSetProperty(_audioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Output, 1, &audioFormat, sizeof(audioFormat));
AudioUnitSetProperty(_audioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Output, 0, &enable, sizeof(enable));
// 启用录音和回放功能
AURenderCallbackStruct input;
input.inputProc = recordingCallback;
input.inputProcRefCon = (__bridge void *)(self);
AudioUnitSetProperty(_audioUnit, kAudioOutputUnitProperty_SetInputCallback, kAudioUnitScope_Global, 0, &input, sizeof(input));
AudioUnitSetProperty(_audioUnit, kAudioUnitProperty_SetRenderCallback, kAudioUnitScope_Global, 0, &input, sizeof(input));
```
4. 实现录音回调函数
在录音回调函数中,可以获取录音数据的分贝值,用来检测录音音量大小。
```objc
static OSStatus recordingCallback(void *inRefCon,
AudioUnitRenderActionFlags *ioActionFlags,
const AudioTimeStamp *inTimeStamp,
UInt32 inBusNumber,
UInt32 inNumberFrames,
AudioBufferList *ioData) {
AudioUnitRender(AudioUnitRecorder.audioUnit, ioActionFlags, inTimeStamp, 1, inNumberFrames, ioData);
float decibels = 0.0;
if (ioData->mNumberBuffers > 0) {
AudioBuffer buffer = ioData->mBuffers[0];
// 计算分贝值
int channels = buffer.mNumberChannels;
float peak = 0;
for (int i = 0; i < inNumberFrames * channels; i++) {
SInt16 sample = ((SInt16 *)buffer.mData)[i];
float sampleValue = sample / 32768.0;
if (sampleValue < 0) {
sampleValue = -sampleValue;
}
if (sampleValue > peak) {
peak = sampleValue;
}
}
decibels = 20.0 * log10(peak);
}
NSLog(@"Decibels: %f", decibels);
return noErr;
}
```
5. 启动 AudioUnit
启动 AudioUnit,开始录音。
```objc
AudioUnitInitialize(_audioUnit);
AudioOutputUnitStart(_audioUnit);
```
通过以上步骤,就可以实现 iOS AudioUnit 录音分贝检测。
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