实现思路

利用系统框架AVFoundation实现录音和录音播放

AudioSession简介

iOS 通过sessions和AudioSession APIs处理音频行为

//获取session
[AVAudioSession sharedInstance]

设置Category 通过调用音频会话对象的setCategory:error:实例方法，来从iOS应用可用的不同类别中作出选择

/* set session category */
- (BOOL)setCategory:(NSString *)category error:(NSError **)outError;
/* set session category with options */
- (BOOL)setCategory:(NSString *)category withOptions: (AVAudioSessionCategoryOptions)options error:(NSError **)outError NS_AVAILABLE_IOS(6_0);

//Category 的类型

* AVAudioSessionCategorySoloAmbient 
  会停止其他程序的音频播放。当设备被设置为静音模式，app也同样被停止

* AVAudioSessionCategoryRecord
  仅用来录音，无法播放音频

* AVAudioSessionCategoryPlayback 
 会停止其它音频播放，并且能在后台播放，锁屏and静音模式下均可

* AVAudioSessionCategoryPlayAndRecord
  能播也能录，播放默认声音是从听筒出来

* AVAudioSessionCategoryAmbient
  app的声音可与其它app共存，但锁屏和静音情况会被停止，除非当前app是唯一播放的app

录音核心的代码如下:

 AVAudioSession *session =[AVAudioSession sharedInstance];
    NSError *sessionError;
   
    [session setCategory:AVAudioSessionCategoryAmbient error:&sessionError];
    
    if (session) {
            [session setActive:YES error:nil];
    }else{
            NSLog(@"%@",[sessionError description]);
    }
    
    self.session = session;
    
    
    //1.获取沙盒地址
    NSString *path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    filePath = [path stringByAppendingString:@"/record.wav"];
    
    NSLog(@"path : %@",filePath);
    
    //2.获取文件路径
    self.fileUrl = [NSURL fileURLWithPath:filePath];
    
    //设置参数
    NSDictionary *recordSetting = [[NSDictionary alloc] initWithObjectsAndKeys:
                                     //采样率  8000/11025/22050/44100/96000（影响音频的质量）
                                   [NSNumber numberWithFloat: 8000.0],AVSampleRateKey,
                                   // 音频格式
                                   [NSNumber numberWithInt: kAudioFormatLinearPCM],AVFormatIDKey,
                                   //采样位数  8、16、24、32 默认为16
                                   [NSNumber numberWithInt:16],AVLinearPCMBitDepthKey,
                                   // 音频通道数 1 或 2
                                   [NSNumber numberWithInt: 1], AVNumberOfChannelsKey,
                                   //录音质量
                                   [NSNumber numberWithInt:AVAudioQualityMax],AVEncoderAudioQualityKey,
                                   nil];

    
    self.recorder = [[AVAudioRecorder alloc] initWithURL:self.fileUrl settings:recordSetting error:nil];
    
    if (self.recorder) {
        
        self.recorder.meteringEnabled = YES;
        [self.recorder prepareToRecord];
        [self.recorder record];
        
        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(60 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
            [self stopRecord:nil];
        });
        
    }else{
        NSLog(@"无法初始化recorder");
    }

播放核心代码如下:

    [self.recorder stop];
    if ([self.player isPlaying]) {
      return;
    }
    self.player = [[AVAudioPlayer alloc] initWithContentsOfURL:self.fileUrl error:nil];
    [self.session setCategory:AVAudioSessionCategoryPlayback error:nil];
    [self.player play];
    

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