ios录音wav格式转mp3

1：语音转换，需要关注录音的参数配置，如果你的转化有问题，就直接把如下代码粘贴使用。
录音代码：

AVAudioSession *session = [AVAudioSession sharedInstance];
    NSError *error = nil;
    [session setCategory:AVAudioSessionCategoryPlayAndRecord error:&error];
    [session setActive:YES error:&error];
    
    //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: 2], AVNumberOfChannelsKey,
                                   //录音质量
                                   [NSNumber numberWithInt:AVAudioQualityHigh],AVEncoderAudioQualityKey,
                                   nil];
    //wav
    NSString *path = [TUIKit_Voice_Path stringByAppendingString:[THelper genVoiceName:nil withExtension:@"wav"]];
    NSURL *url = [NSURL fileURLWithPath:path];
    _recorder = [[AVAudioRecorder alloc] initWithURL:url settings:recordSetting error:nil];
    _recorder.meteringEnabled = YES;
    [_recorder prepareToRecord];
    [_recorder record];
    [_recorder updateMeters];

转为mp3格式(使用lame)

- (BOOL) convertMp3from:(NSString *)wavpath topath:(NSString *)mp3path
{
    NSString *filePath =wavpath ;
    
    NSString *mp3FilePath = mp3path;
    
    BOOL isSuccess = NO;
    if (filePath == nil  || mp3FilePath == nil){
        return isSuccess;
    }
    
    NSFileManager* fileManager=[NSFileManager defaultManager];
    if([fileManager removeItemAtPath:mp3FilePath error:nil])
    {
        NSLog(@"删除");
    }
    
    @try {
        int read, write;
        
        FILE *pcm = fopen([filePath cStringUsingEncoding:1], "rb");  //source 被转换的音频文件位置
        if (pcm) {
            fseek(pcm, 4*1024, SEEK_CUR);
            FILE *mp3 = fopen([mp3FilePath 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, 8000.0);
            lame_set_num_channels(lame, 2);//通道
            lame_set_quality(lame, 1);//质量
            //lame_set_VBR(lame, vbr_default);
            lame_set_brate(lame, 16);
            lame_set_mode(lame, 3);
            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);
            isSuccess = YES;
        }
        //skip file header
    }
    @catch (NSException *exception) {
        NSLog(@"error");
    }
    @finally {
        if ([[NSFileManager defaultManager] fileExistsAtPath:filePath]) {
            [[NSFileManager defaultManager] removeItemAtPath:filePath error:nil];
        }
        return isSuccess;
    }
    
}

注意：在转换格式的时候，转化格式的参数，一定要和录制时的匹配【通道，采样率等】，才不会出现声音变短，变声等情况的发生。