iOS实现录音转码MP3及转码BASE64上传示例

NSLog(@"开始录音");[self startRecord];- (void)startRecord{  //删除上次生成的文件，保留最新文件  NSFileManager *fileManager = [NSFileManager defaultManager];  if ([NSTemporaryDirectory() stringByAppendingString:@"myselfRecord.mp3"]) {    [fileManager removeItemAtPath:[NSTemporaryDirectory() stringByAppendingString:@"myselfRecord.mp3"] error:nil];  }  if ([NSTemporaryDirectory() stringByAppendingString:@"selfRecord.wav"]) {    [fileManager removeItemAtPath:[NSTemporaryDirectory() stringByAppendingString:@"selfRecord.wav"] error:nil];  }    //开始录音  //录音设置  NSMutableDictionary *recordSetting = [[NSMutableDictionary alloc] init];  //设置录音格式 AVFormatIDKey==kAudioFormatLinearPCM  [recordSetting setValue:[NSNumber numberWithInt:kAudioFormatLinearPCM] forKey:AVFormatIDKey];  //设置录音采样率(Hz) 如：AVSampleRateKey==8000/44100/96000（影响音频的质量）, 采样率必须要设为11025才能使转化成mp3格式后不会失真  [recordSetting setValue:[NSNumber numberWithFloat:11025.0] forKey:AVSampleRateKey];  //录音通道数 1 或 2 ，要转换成mp3格式必须为双通道  [recordSetting setValue:[NSNumber numberWithInt:2] forKey:AVNumberOfChannelsKey];  //线性采样位数 8、16、24、32  [recordSetting setValue:[NSNumber numberWithInt:16] forKey:AVLinearPCMBitDepthKey];  //录音的质量  [recordSetting setValue:[NSNumber numberWithInt:AVAudioQualityHigh] forKey:AVEncoderAudioQualityKey];    //存储录音文件  recordUrl = [NSURL URLWithString:[NSTemporaryDirectory() stringByAppendingString:@"selfRecord.wav"]];    //初始化  audioRecorder = [[AVAudioRecorder alloc] initWithURL:recordUrl settings:recordSetting error:nil];  //开启音量检测  audioRecorder.meteringEnabled = YES;  audioSession = [AVAudioSession sharedInstance];//得到AVAudioSession单例对象  if (![audioRecorder isRecording]) {    [audioSession setCategory:AVAudioSessionCategoryPlayAndRecord error:nil];//设置类别,表示该应用同时支持播放和录音    [audioSession setActive:YES error:nil];//启动音频会话管理,此时会阻断后台音乐的播放.        [audioRecorder prepareToRecord];    [audioRecorder peakPowerForChannel:0.0];    [audioRecorder record];  }}

[self endRecord]; - (void)endRecord {   [audioRecorder stop];             //录音停止   [audioSession setActive:NO error:nil];     //一定要在录音停止以后再关闭音频会话管理（否则会报错），此时会延续后台音乐播放 }

- (void)transformCAFToMP3 {  mp3FilePath = [NSURL URLWithString:[NSTemporaryDirectory() stringByAppendingString:@"myselfRecord.mp3"]];    @try {    int read, write;        FILE *pcm = fopen([[recordUrl absoluteString] cStringUsingEncoding:1], "rb");  //source 被转换的音频文件位置    fseek(pcm, 4*1024, SEEK_CUR);                          //skip file header    FILE *mp3 = fopen([[mp3FilePath absoluteString] cStringUsingEncoding:1], "wb"); //output 输出生成的Mp3文件位置        const int PCM_SIZE = 8192;    const int MP3_SIZE = 8192;    short int pcm_buffer[PCM_SIZE*2];    unsigned char mp3_buffer[MP3_SIZE];        lame_t lame = lame_init();    lame_set_in_samplerate(lame, 11025.0);    lame_set_VBR(lame, vbr_default);    lame_init_params(lame);        do {      read = (int)fread(pcm_buffer, 2*sizeof(short int), PCM_SIZE, pcm);      if (read == 0)        write = lame_encode_flush(lame, mp3_buffer, MP3_SIZE);      else        write = lame_encode_buffer_interleaved(lame, pcm_buffer, read, mp3_buffer, MP3_SIZE);            fwrite(mp3_buffer, write, 1, mp3);          } while (read != 0);        lame_close(lame);    fclose(mp3);    fclose(pcm);  }  @catch (NSException *exception) {    NSLog(@"%@",[exception description]);  }  @finally {    NSLog(@"MP3生成成功");    base64Str = [self mp3ToBASE64];  }}

 - (NSString *)mp3ToBASE64{   NSData *mp3Data = [NSData dataWithContentsOfFile:[NSTemporaryDirectory() stringByAppendingString:@"myselfRecord.mp3"]];   NSString *_encodedImageStr = [mp3Data base64Encoding];   NSLog(@"===Encoded image:/n%@", _encodedImageStr);   return _encodedImageStr; }