iOS 录音文件格式转换 lame库

心已赠人 2022-06-08 02:55 340阅读 0赞

1.  导入 lame 库文件 ，引入lame.h 头文件

下面方法 实现了 格式转换 并删除原文件

*  (NSString\*)audio\_PCM\_to\_MP3:(NSString \*)recordFilePath changeName:(BOOL)isChange audioTime:(NSInteger)audioTime\{
    
    NSString \*wavFileName = \[recordFilePath lastPathComponent\];
    
    if (isChange) \{  
    wavFileName = \[wavFileName stringByReplacingOccurrencesOfString:\[NSString stringWithFormat:@”%d”,PerRecordFileLimitCount - 1\] withString:\[NSString stringWithFormat:@”%ld”,audioTime\]\];
    
    \}
    
    NSString \*wavFilePath = \[recordFilePath stringByDeletingLastPathComponent\];
    
    NSString \*mp3FilePath = \[wavFilePath stringByAppendingPathComponent:\[NSString stringWithFormat:@”%@.mp3”,\[wavFileName componentsSeparatedByString:@”.”\].firstObject\]\];
    
    @try \{
    
        int read, write;
        
        
        
        FILE *pcm = fopen([recordFilePath cStringUsingEncoding:1], "rb");  //source 被转换的音频文件位置
        if (!pcm)return nil;
        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, 11025);
        
        lame_set_VBR(lame, vbr_default);
        
        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);
    
    \}
    
    @catch (NSException \*exception) \{
    
        NSLog(@"%@",[exception description]);
    
    \}
    
    @finally \{
    
        if ([[NSFileManager defaultManager]fileExistsAtPath:recordFilePath]) {
            [[NSFileManager defaultManager] removeItemAtURL:[NSURL fileURLWithPath:recordFilePath] error:nil]; // 生成文件移除原文件
            NSLog(@"MP3生成成功: %@",mp3FilePath);
            return mp3FilePath;
        }
        return nil;
    
    \}  
    \}