【iOS 录音转码MP3及转码BASE64上传】

iOS 录音转码MP3及转码BASE64上传

一，开始录音

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:] forKey:AVNumberOfChannelsKey];
     //线性采样位数  8、16、24、32
     [recordSetting setValue:[NSNumber numberWithInt:] 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];
     }
 }

二，停止录音

[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
 }

三，转码成MP3

 - (void)transformCAFToMP3 {
     mp3FilePath = [NSURL URLWithString:[NSTemporaryDirectory() stringByAppendingString:@"myselfRecord.mp3"]];

     @try {
         int read, write;

         FILE *pcm = fopen([[recordUrl absoluteString] cStringUsingEncoding:], "rb");   //source 被转换的音频文件位置
         fseek(pcm, *, SEEK_CUR);                                                   //skip file header
         FILE *mp3 = fopen([[mp3FilePath absoluteString] cStringUsingEncoding:], "wb"); //output 输出生成的Mp3文件位置

         const int PCM_SIZE = ;
         const int MP3_SIZE = ;
         short int pcm_buffer[PCM_SIZE*];
         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, *sizeof(short int), PCM_SIZE, pcm);
             if (read == )
                 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, , mp3);

         } while (read != );

         lame_close(lame);
         fclose(mp3);
         fclose(pcm);
     }
     @catch (NSException *exception) {
         NSLog(@"%@",[exception description]);
     }
     @finally {
         NSLog(@"MP3生成成功");
        base64Str = [self mp3ToBASE64];
     }
 }

四，上传需要转码BASE64

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

备注：其中可以直接生成的.caf  .wav    有压缩的MP3需要转格式，不能直接录音生成