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iOS – 录音文件lame转换MP3相关配置

文件下载整个功能完成了,那么对应的文件上传也跑不了。So~ Look here~


业务需求是录制音频然后上传到七牛并且Android可以读。

与安卓沟通了一下统一了mp3格式,大小质量都不错。由于AVAudioRecorder录音的格式为.caf或者.wav而且很大需要进行转换压缩为MP3格式。这里需要用到三方库 lame

使用lame转换后音频的质量和

 _recorder = [[AVAudioRecorder alloc] initWithURL:_recordFilePath settings:setting error:NULL];

里的 setting 息息相关。 所以整理了两个配置。

我把这两种的配置写在了工具类所以直接贴代码了~要用的话直接CV大法就可以。

lame三方库的资源


  • 获取转换文件所在文件夹
+ (NSString *)getRecPathUrl{     NSString *str = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];      NSString *recordDir = [str stringByAppendingPathComponent:@"RecordCourse"];      return recordDir; }
  • 获取时间戳用于文件的命名
+ (NSString *)getTimestamp{     NSDate *nowDate = [NSDate date];     double timestamp = (double)[nowDate timeIntervalSince1970]*1000;     long nowTimestamp = [[NSNumber numberWithDouble:timestamp] longValue];     NSString *timestampStr = [NSString stringWithFormat:@"%ld",nowTimestamp];     return timestampStr; }
  • PCM转换MP3配置
+ (NSDictionary *)getAudioSettingWithPCM {     NSMutableDictionary *dic = [NSMutableDictionary dictionary];     //设置录音格式     [dic setObject:@(kAudioFormatLinearPCM) forKey:AVFormatIDKey];     //设置录音采样率,8000是电话采样率,对于一般录音已经够了     [dic setObject:@(44100.0) forKey:AVSampleRateKey];     //设置通道,这里采用双声道     [dic setObject:@(1) forKey:AVNumberOfChannelsKey];     //每个采样点位数,分为8、16、24、32     [dic setObject:@(16) forKey:AVLinearPCMBitDepthKey];     //是否使用浮点数采样     [dic setObject:@(YES) forKey:AVLinearPCMIsFloatKey];     //....其他设置等     return dic; }
  • CAF转换MP3配置
+ (NSDictionary *)getAudioSettingWithCAF {     NSDictionary *setting = [NSDictionary dictionaryWithObjectsAndKeys:                              [NSNumber numberWithInt:AVAudioQualityMin],                              AVEncoderAudioQualityKey,                              [NSNumber numberWithInt:16],                              AVEncoderBitRateKey,                              [NSNumber numberWithInt:2],                              AVNumberOfChannelsKey,                              [NSNumber numberWithFloat:44100.0],                              AVSampleRateKey,                              nil];      return setting; }
  • PCM转换MP3的lame方法
+ (NSString *)audioPCMtoMP3:(NSString *)wavPath {     NSString *cafFilePath = wavPath;      NSString *mp3FilePath = [NSString stringWithFormat:@"%@.mp3",[NSString stringWithFormat:@"%@%@",[cafFilePath substringToIndex:cafFilePath.length - 4],[self getTimestamp]]];      NSFileManager* fileManager = [NSFileManager defaultManager];     if([fileManager removeItemAtPath:mp3FilePath error:nil]){         NSLog(@"删除原MP3文件");     }     @try {         int read, write;         FILE *pcm = fopen([cafFilePath 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 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, 22050.0);         lame_set_VBR(lame, vbr_default);         lame_init_params(lame);          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 {         return mp3FilePath;     } }
  • CAF转换MP3的lame方法
+ (NSString *)audioCAFtoMP3:(NSString *)wavPath {      NSString *cafFilePath = wavPath;      NSString *mp3FilePath = [NSString stringWithFormat:@"%@.mp3",[NSString stringWithFormat:@"%@%@",[cafFilePath substringToIndex:cafFilePath.length - 4],[self getTimestamp]]];      @try {         int read, write;          FILE *pcm = fopen([cafFilePath 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 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_num_channels(lame,1);//设置1为单通道,默认为2双通道         lame_set_in_samplerate(lame, 44100.0);         lame_set_VBR(lame, vbr_default);          lame_set_brate(lame,8);          lame_set_mode(lame,3);          lame_set_quality(lame,2);          lame_init_params(lame);          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 {         return mp3FilePath;     } }

两种质量大小不错都可以使用😁😁

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