iOS wav转mp3以及意见简单音频录制格式

简介

    基于wav音频文件太大,因项目上传作业录音,可能一次上传几十上百个wav 文件,就产生了将wav格式的录音转换成wav转换成轻量级的mp3上传的需求.

 实现

     实现是基于lame库的. 至于lame库的下载导入自己Google吧.

-(NSString *)changeWavToMp3WithOriginalPath:(NSString*)originalPath{

             NSString * mp3Path = [[originalPath stringByDeletingLastPathComponent]stringByAppendingPathComponent:@"sentenceRecoder.mp3"];

          @try {

              int read, write;

              FILE *pcm = fopen([originalPath 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([mp3Path 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);

             lame_set_VBR(lame, vbr_default);

             lame_init_params(lame);

             lame_set_brate (lame, 128 );

             lame_set_quality(lame,2);

            do {

                   read = 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 {

        }

         [[NSFileManager defaultManager] removeItemAtPath:originalPath error:NULL];

          return mp3Path;

}

一些音频格式Mark

1.aac格式 标准配置

@{AVFormatIDKey: @(kAudioFormatMPEG4AAC),

AVEncoderAudioQualityKey:@(AVAudioQualityMax),

AVSampleRateKey: @11025.0f,

AVNumberOfChannelsKey: @2,

AVLinearPCMBitDepthKey: @16};

2. wav 格式 标准配置

@{AVFormatIDKey: @(kAudioFormatLinearPCM),

AVSampleRateKey: @8000.00f,

AVNumberOfChannelsKey: @1,

AVLinearPCMBitDepthKey: @16,

AVLinearPCMIsNonInterleaved: @NO,

AVLinearPCMIsFloatKey: @NO,

AVLinearPCMIsBigEndianKey: @NO};