【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];

 

 1 - (void)startRecord
 2 {
 3     //删除上次生成的文件，保留最新文件
 4     NSFileManager *fileManager = [NSFileManager defaultManager];
 5     if ([NSTemporaryDirectory() stringByAppendingString:@"myselfRecord.mp3"]) {
 6         [fileManager removeItemAtPath:[NSTemporaryDirectory() stringByAppendingString:@"myselfRecord.mp3"] error:nil];
 7     }
 8     if ([NSTemporaryDirectory() stringByAppendingString:@"selfRecord.wav"]) {
 9         [fileManager removeItemAtPath:[NSTemporaryDirectory() stringByAppendingString:@"selfRecord.wav"] error:nil];
10     }
11    
12     //开始录音
13     //录音设置
14     NSMutableDictionary *recordSetting = [[NSMutableDictionary alloc] init];
15     //设置录音格式  AVFormatIDKey==kAudioFormatLinearPCM
16     [recordSetting setValue:[NSNumber numberWithInt:kAudioFormatLinearPCM] forKey:AVFormatIDKey];
17     //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
18     [recordSetting setValue:[NSNumber numberWithFloat:11025.0] forKey:AVSampleRateKey];
19     //录音通道数  1 或 2 ，要转换成mp3格式必须为双通道
20     [recordSetting setValue:[NSNumber numberWithInt:2] forKey:AVNumberOfChannelsKey];
21     //线性采样位数  8、16、24、32
22     [recordSetting setValue:[NSNumber numberWithInt:16] forKey:AVLinearPCMBitDepthKey];
23     //录音的质量
24     [recordSetting setValue:[NSNumber numberWithInt:AVAudioQualityHigh] forKey:AVEncoderAudioQualityKey];
25     
26     //存储录音文件
27     recordUrl = [NSURL URLWithString:[NSTemporaryDirectory() stringByAppendingString:@"selfRecord.wav"]];
28     
29     //初始化
30     audioRecorder = [[AVAudioRecorder alloc] initWithURL:recordUrl settings:recordSetting error:nil];
31     //开启音量检测
32     audioRecorder.meteringEnabled = YES;
33     audioSession = [AVAudioSession sharedInstance];//得到AVAudioSession单例对象
34 
35     if (![audioRecorder isRecording]) {
36         [audioSession setCategory:AVAudioSessionCategoryPlayAndRecord error:nil];//设置类别,表示该应用同时支持播放和录音
37         [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.
38         
39         [audioRecorder prepareToRecord];
40         [audioRecorder peakPowerForChannel:0.0];
41         [audioRecorder record];
42     }
43 }

 

二，停止录音

[self endRecord];

 

1 - (void)endRecord
2 {
3     [audioRecorder stop];                          //录音停止
4     [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
5 }

 

三，转码成MP3

 1 - (void)transformCAFToMP3 {
 2     mp3FilePath = [NSURL URLWithString:[NSTemporaryDirectory() stringByAppendingString:@"myselfRecord.mp3"]];
 3     
 4     @try {
 5         int read, write;
 6         
 7         FILE *pcm = fopen([[recordUrl absoluteString] cStringUsingEncoding:1], "rb");   //source 被转换的音频文件位置
 8         fseek(pcm, 4*1024, SEEK_CUR);                                                   //skip file header
 9         FILE *mp3 = fopen([[mp3FilePath absoluteString] cStringUsingEncoding:1], "wb"); //output 输出生成的Mp3文件位置
10         
11         const int PCM_SIZE = 8192;
12         const int MP3_SIZE = 8192;
13         short int pcm_buffer[PCM_SIZE*2];
14         unsigned char mp3_buffer[MP3_SIZE];
15         
16         lame_t lame = lame_init();
17         lame_set_in_samplerate(lame, 11025.0);
18         lame_set_VBR(lame, vbr_default);
19         lame_init_params(lame);
20         
21         do {
22             read = (int)fread(pcm_buffer, 2*sizeof(short int), PCM_SIZE, pcm);
23             if (read == 0)
24                 write = lame_encode_flush(lame, mp3_buffer, MP3_SIZE);
25             else
26                 write = lame_encode_buffer_interleaved(lame, pcm_buffer, read, mp3_buffer, MP3_SIZE);
27             
28             fwrite(mp3_buffer, write, 1, mp3);
29             
30         } while (read != 0);
31         
32         lame_close(lame);
33         fclose(mp3);
34         fclose(pcm);
35     }
36     @catch (NSException *exception) {
37         NSLog(@"%@",[exception description]);
38     }
39     @finally {
40         NSLog(@"MP3生成成功");
41        base64Str = [self mp3ToBASE64];
42     }
43 }

 

四，上传需要转码BASE64

1 - (NSString *)mp3ToBASE64{
2     NSData *mp3Data = [NSData dataWithContentsOfFile:[NSTemporaryDirectory() stringByAppendingString:@"myselfRecord.mp3"]];
3     NSString *_encodedImageStr = [mp3Data base64Encoding];
4     NSLog(@"===Encoded image:\n%@", _encodedImageStr);
5     return _encodedImageStr;
6 }

 

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