音频压缩转码文件 ： lame
使用方法
- (void)conventToMp3 {
NSString *cafFilePath = [NSTemporaryDirectory() stringByAppendingString:@"VoiceInputFile"];
_mp3FileName = [[NSUUID UUID] UUIDString];
self.mp3FileName = [self.mp3FileName stringByAppendingString:@".mp3"];
NSString *mp3FilePath = [[NSHomeDirectory() stringByAppendingFormat:@"/Documents/"] stringByAppendingPathComponent:self.mp3FileName];
@try {
int read, write;
FILE *pcm = fopen([cafFilePath cStringUsingEncoding:NSASCIIStringEncoding], "rb");
FILE *mp3 = fopen([mp3FilePath cStringUsingEncoding:NSASCIIStringEncoding], "wb");
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, self.sampleRate);
lame_set_VBR(lame, vbr_default);
lame_init_params(lame);
long curpos;
BOOL isSkipPCMHeader = NO;
do {
curpos = ftell(pcm);
long startPos = ftell(pcm);
fseek(pcm, 0, SEEK_END);
long endPos = ftell(pcm);
long length = endPos - startPos;
fseek(pcm, curpos, SEEK_SET);
if (length > PCM_SIZE * 2 * sizeof(short int)) {
if (!isSkipPCMHeader) {
//Uump audio file header, If you do not skip file header
//you will heard some noise at the beginning!!!
fseek(pcm, 4 * 1024, SEEK_SET);
isSkipPCMHeader = YES;
NSLog(@"skip pcm file header !!!!!!!!!!");
}
read = (int)fread(pcm_buffer, 2 * sizeof(short int), PCM_SIZE, pcm);
write = lame_encode_buffer_interleaved(lame, pcm_buffer, read, mp3_buffer, MP3_SIZE);
fwrite(mp3_buffer, write, 1, mp3);
NSLog(@"read %d bytes", write);
}
else {
[NSThread sleepForTimeInterval:0.05];
NSLog(@"sleep");
}
} while (!self.isStopRecorde);
read = (int)fread(pcm_buffer, 2 * sizeof(short int), PCM_SIZE, pcm);
write = lame_encode_flush(lame, mp3_buffer, MP3_SIZE);
DWDLog(@"read %d bytes and flush to mp3 file", write);
lame_close(lame);
fclose(mp3);
fclose(pcm);
self.isFinishConvert = YES;
}
@catch (NSException *exception) {
DWDLog(@"%@", [exception description]);
}
@finally {
NSLog(@"convert mp3 finish!!!");
}
}