我发现(自定义我找到的方法)一种方法来转换MpMediaItem并获取mp3文件。可能这不是最好的方式,但它的工作。objective c - 将mpmediaitem转换为ogg vorbis
有没有办法获得* .ogg文件而不是* .mp3?什么是正确的方法?
这是我使用来获取* .MP3文件的方法:
-(void)exportMP3:(NSURL*)url toFileUrl:(NSString*)fileURL
{
AVURLAsset *asset=[[AVURLAsset alloc] initWithURL:url options:nil];
AVAssetReader *reader=[[AVAssetReader alloc] initWithAsset:asset error:nil];
NSMutableArray *myOutputs =[[NSMutableArray alloc] init];
for(id track in [asset tracks])
{
AVAssetReaderTrackOutput *output=[AVAssetReaderTrackOutput assetReaderTrackOutputWithTrack:track outputSettings:nil];
[myOutputs addObject:output];
[reader addOutput:output];
}
[reader startReading];
NSFileHandle *fileHandle ;
NSFileManager *fm=[NSFileManager defaultManager];
if(![fm fileExistsAtPath:fileURL])
{
[fm createFileAtPath:fileURL contents:[[NSData alloc] init] attributes:nil];
}else{
NSURL *url = [NSURL URLWithString:fileURL];
[fm removeItemAtURL:url error:nil];
[fm createFileAtPath:fileURL contents:[[NSData alloc] init] attributes:nil];
}
fileHandle=[NSFileHandle fileHandleForWritingAtPath:fileURL];
[fileHandle seekToEndOfFile];
AVAssetReaderOutput *output=[myOutputs objectAtIndex:0];
int totalBuff=0;
int test = 1;
while(test == 1)
{
CMSampleBufferRef ref=[output copyNextSampleBuffer];
if(ref==NULL)
test = 0;
if(ref==NULL)
break;
//copy data to file
//read next one
AudioBufferList audioBufferList;
NSMutableData *data;
CMBlockBufferRef blockBuffer;
CMSampleBufferGetAudioBufferListWithRetainedBlockBuffer(ref, NULL, &audioBufferList, sizeof(audioBufferList), NULL, NULL, 0, &blockBuffer);
for(int y=0; y<audioBufferList.mNumberBuffers; y++)
{
AudioBuffer audioBuffer = audioBufferList.mBuffers[y];
void *frame = audioBuffer.mData;
data = [[NSMutableData alloc] initWithBytes:frame length:audioBuffer.mDataByteSize];
}
totalBuff++;
NSLog(@"\n%d\n",totalBuff);
int time = [self.mediaPlayer durationOfCurrentItem];
if (totalBuff * 2 <= time + 1)
[fileHandle writeData:data];
}
[fileHandle closeFile];
}
如果你的编码MP3编码正常工作,这将是一个重大突破,因为它是一个普遍接受的事实,没有像[跛脚](http://lame.sourceforge.net/)第三方库,它是不可能在ios中将音频编码成MP3格式。你确定这是有效的,而不是简单地播放,因为一个音频播放器,它接受一个MP3文件内的其他格式的善意? –