IOS AVFoundation的录音与播放

这是我第一次撰写博客，大部分内容都来自网络，写的不对地方还请多多指教，如果有摘录的地方与原作略有相同还请谅解说明。请多多支持。

1，AVAudioSession的使用

AVAudioSession是一个单例模式。在IOS7以前可以不用设置，在IOS7上不设置AVAudioSession则不可以录音。

一，设置AVAudioSession的类别（部分）及开启音频会话

Category（类别）作用

AVAudioSessionCategoryPlayback后台播放

AVAudioSessionCategoryRecord录音

AVAudioSessionCategoryPlayAndRecord后台播放及录音

具体代码如下：

//录音权限设置AVAudioSession * audioSession = [AVAudioSession sharedInstance];//设置类别只支持录音[audioSession setCategory:AVAudioSessionCategoryRecord error:nil];//启动音频会话管理，此时会阻断后台音乐的播放[audioSession setActive:YES error:nil];二，在录音或播放结束后，要关闭音频会话，来延续后台音乐的播放

AVAudioSession * audioSession = [AVAudioSession sharedInstance];[audioSession setCategory:AVAudioSessionCategoryPlayback error:nil];[audioSession setActive:NO error:nil];

三，要想启用其他程序的后台音乐播放，则要用如下设置

AVAudioSession * audioSession = [AVAudioSession sharedInstance];[audioSession setCategory：AVAudioSessionCategoryPlayback error:nil];[audioSession setActive:NO withFlags:AVAudioSessionSetActiveFlags_NotifyOthersOnDeactivati??on error:nil];

2，AVAudioRecorder的基本使用

一，设置参数

重点作用值

AVFormatIDKey录音格式kAudioFormatMPEG4AAC，kAudioFormatLinearPCM ...

AVSampleRateKey录音采样率

影响音频的质量8000,44100,96000

AVNumberOfChannelsKey录音通道数1或2

AVLinearPCMBitDepthKey线性采样位数8,16,24,32

AVEncoderAudioQualityKey录音质量AVAudioQualityMin，AVAudioQualityLow，

AVAudioQualityMedium，AVAudioQualityHigh，

AVAudioQualityMax

二，保存路径的网址设置

// CFUUID每次都会产生一个唯一号CFUUIDRef cfuuid = CFUUIDCreate（kCFAllocatorDefault）;NSString * cfuuidString =(NSString *)CFBridgingRelease(CFUUIDCreateString(kCFAllocatorDefault, cfuuid));NSString * catchPath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];NSString * audioRecordFilePath = [catchPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.AAC”，cfuuidString];NSURL * url = [NSURL fileURLWithPath：audioRecordFilePath];

三，AVAudioRecorder初始化

NSError *error = nil;AVAudioRecorder *recorder = [[AVAudioRecorder alloc] initWithURL:url settings:recordSetting error:&error];

四，所有代码如下：

//录音参数设置设置NSMutableDictionary * recordSetting = [[NSMutableDictionary alloc] init];//设置录音格式[recordSetting setValue:[NSNumber numberWithInt:kAudioFormatMPEG4AAC] forKey:AVFormatIDKey];//设置录音采样率[recordSetting setValue:[NSNumber numberWithFloat:44100] forKey:AVSampleRateKey];//录音通道数[recordSetting setValue:[NSNumber numberWithInt:1] forKey:AVNumberOfChannelsKey];//线性采样位数[recordSetting setValue:[NSNumber numberWithInt:16] forKey:AVLinearPCMBitDepthKey];//录音的质量[recordSetting setValue:[NSNumber numberWithInt:AVAudioQualityHigh] forKey:AVEncoderAudioQualityKey];//录音文件保存的网址CFUUIDRef cfuuid = CFUUIDCreate(kCFAllocatorDefault);NSString *cfuuidString = (NSString *)CFBridgingRelease(CFUUIDCreateString(kCFAllocatorDefault, cfuuid));NSString *catchPath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];NSString *audioRecordFilePath = [catchPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.AAC", cfuuidString];NSURL *url = [NSURL fileURLWithPath:audioRecordFilePath];NSError *error = nil;//初始化AVAudioRecorder_recorder = [[AVAudioRecorder alloc] initWithURL:url settings:recordSetting error:&error];if (!error）{ //NSLog(@"初始化录音错误:%@", error);} else { if ([_recorder prepareToRecord]){ //录音最长时间设置 [_recorder recordForDuration:20]; //委托事件 _recorder.delegate = self; [_recorder record]; //开启音量检测 _recorder.meteringEnabled = YES; //开启定时器，音量监测 _timer = [NSTimer scheduledTimerWithTimeInterval:0.05 target:self selector:@selector(volumeMeters:) userInfo:nil repeats:YES]; }}#pragma mark 实时监测音量变化定时器任务- (void)volumeMeters:(NSTimer *)timer{ //刷新音量数据 [_recorder updateMeters]; double lowPassResults = POW(10, (0.05 * [_recorder peakPowerForChannel:0])); if（0 <lowPassResults <= 0.14）{ }else if(0.14 <lowPassResults <= 0.28){ }else if(0.28 <lowPassResults <= 0.42){ }else if(0.42 <lowPassResults <= 0.56){ }else if(0.56 <lowPassResults <= 0.7){ }else if(0.7 <lowPassResults <= 0.84){ }else if(0.84 <lowPassResults <= 0.98){ }else{ }}// AVAudioRecorder委托事件- (void)audioRecorderDidFinishRecording(AVAudioRecorder *)recorder successfully:(BOOL)flag{ //录音结束}- (void)audioRecorderEncodeErrorDidOccur:(AVAudioRecorder *)recorder error:(NSError *)error{ //录音编码错误}

3，AVAudioPlayer的使用

主要用于音频文件的播放，它主要有两个初始化方法：initWithData与initWithContentsOfURL。两个一般都可以使用，但在使用initWithContentsOfURL时要注意传入文件的文件名的格式，稍有不同，则无法播放，如：aac文件，如果后缀名为大写AAC，则无法播放。

// initWithContentsOfURLNSURL * urlAudio = [NSURL fileURLWithPath:audioPath];AVAudioPlayer * _player = [[AVAudioPlayer alloc] initWithContentsOfURL:urlAudio error:nil];// initWithDataNSData * dataAudio = [NSData dataWithContentsOfFile:audioPath];NSError *error = nil;AVAudioPlayer *_player = [[AVAudioPlayer alloc] initWithData:dataAudio error:&error];//属性设置[_player prepareToPlay]; //准备播放[_player play]; //播放[_player pause]; //暂停播放[_player stop]; //停止播放_player.duration; //播放持续时间，只读_player.volume = 0.8; //设置音量大小_player.currentTime = 15.0; //设置当前播放时间_player.numberOfLoops = 3; //循环播放时间_player.delegate = self; //委托事件// AVAudioPlayer委托事件- (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag{ //音频文件播放结束}- (void)audioPlayerDecodeErrorDidOccur:(AVAudioPlayer *)player error:(NSError *)error{ //音频文件解码错误}

注：录音类AVAudioRecorder最好设置为全局变量。如果为局部变量，当销毁掉时将结束录音

附：据此写出的仿微信录音框架：点击打开链接