應用第三方 lame ,Mp3音頻編碼器.   
應用 AVAudioRecorder 進行音頻錄制之前,進行參數(shù)設置:


NSString *recordTemporaryPathString = [NSString stringWithFormat:@"%@/temporary",self.audioTemporarySavePath];
//LinearPCM 是iOS的一種無損編碼格式,然則體積較為宏大年夜
//灌音設置
NSMutableDictionary *recordSettings = [[NSMutableDictionary alloc] init];
//灌音格式 無法應用
[recordSettings setValue :[NSNumber numberWithInt:kAudioFormatLinearPCM] forKey: AVFormatIDKey];
//采樣率
[recordSettings setValue :[NSNumber numberWithFloat:11025.0] forKey: AVSampleRateKey];//44100.0
//通道數(shù)
[recordSettings setValue :[NSNumber numberWithInt:2] forKey: AVNumberOfChannelsKey];
//線性采樣位數(shù)
//[recordSettings setValue :[NSNumber numberWithInt:16] forKey: AVLinearPCMBitDepthKey];
//音頻質量,采樣質量
[recordSettings setValue:[NSNumber numberWithInt:AVAudioQualityMin] forKey:AVEncoderAudioQualityKey];


#include "lame.h"



- (void)audio_PCMtoMP3
{
    NSString *mp3FileName = [self.audioFileSavePath lastPathComponent];
    mp3FileName = [mp3FileName stringByAppendingString:@".mp3"];
    NSString *mp3FilePath = [self.audioTemporarySavePath stringByAppendingPathComponent:mp3FileName];
    
    @try {
        int read, write;
        
        FILE *pcm = fopen([self.audioFileSavePath cStringUsingEncoding:1], "rb");  //source 被轉換的音頻文件地位
        fseek(pcm, 4*1024, SEEK_CUR);                                   //skip file header
        FILE *mp3 = fopen([mp3FilePath cStringUsingEncoding:1], "wb");  //output 輸出身成的Mp3文件地位
        
        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, 11025.0);
        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 {
        self.audioFileSavePath = mp3FilePath;
        NSLog(@"MP3生成成功: %@",self.audioFileSavePath);
    }
}

更多iOS猖狂詳解:http://blog.csdn.net/wanglongblog