录音

使用AVAudioRecorder录制音频数据

1. 包含头文件#import <AVFoundation/AVFoundation.h>

2. 创建属性：录音对象、播放对象、存放录音文件的URL

@property (nonatomic, strong) AVAudioRecorder *recorder;
@property (nonatomic, strong) AVAudioPlayer *player;
@property (nonatomic, strong) NSURL *recordURL;　

3. 设置支持AVAudioSession支持录音和回放功能

[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayAndRecord error:nil];

4. 录音前准备和设置工作

    NSMutableDictionary *setting = [NSMutableDictionary dictionary];
    
    // 编码格式
    setting[AVFormatIDKey] = @(kAudioFormatAppleIMA4);
    // 采样率
    setting[AVSampleRateKey] = @(44100);
    // 声道数
    setting[AVNumberOfChannelsKey] = @2;
    // 量化位数
    setting[AVLinearPCMBitDepthKey] = @16;
    // 编码质量
    setting[AVEncoderAudioQualityKey] = @(AVAudioQualityHigh);
    
    NSError *error;
    _recorder = [[AVAudioRecorder alloc] initWithURL:self.recordURL settings:setting error:&error];
    
    if (error != nil) {
        NSLog(@"error >>> %@", error);
    }
    // 准备录制
    [_recorder prepareToRecord];

5. 懒加载

- (NSURL *)recordURL
{
    if (_recorder == nil) {
        NSString *docPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0];
        //当使用kAudioFormatAppleIMA4编码格式时，生成的文件格式为caf
        NSString *path = [docPath stringByAppendingPathComponent:@"test.caf"];
        
        _recordURL = [NSURL URLWithString:path];
    }
    return _recordURL;
}

- (AVAudioPlayer *)player
{
    if (_player == nil) {
        _player = [[AVAudioPlayer alloc] initWithContentsOfURL:self.recordURL error:nil];
        _player.numberOfLoops = 1;
        
        [_player prepareToPlay];
    }
    return _player;
}

6. 录音/播放控制

- (IBAction)startRecord:(UIButton *)sender {
    [_recorder record];  //开始录音
}
- (IBAction)startPlay:(UIButton *)sender {
    [self.player play];  //开始播放
}
- (IBAction)endRecord:(UIButton *)sender {
    
    [_recorder stop];    //结束录音
}
- (IBAction)endPlay:(UIButton *)sender {
    [self.player stop];  //停止播放
}