如何将CMSampleBufferRef转换为NSData

Question

如何将CMSampleBufferRef转换为NSData？

我已经设法MPMediaItem通过跟踪Erik Aigner在这个线程上的答案来获取数据,但数据是类型的CMSampleBufferRef.

我知道CMSampleBufferRef是一个结构,在iOS Dev Library 的CMSampleBuffer Reference中定义,但我不认为我完全理解它是什么.CMSampleBuffer函数似乎都不是一个明显的解决方案.

Answer 1

在这里,您可以使用音频样本缓冲区,这是您正在查看的内容,如果您想查看整个过程(将所有音频数据从MPMediaItem获取到文件中,请查看此问题

CMSampleBufferRef ref=[output copyNextSampleBuffer];
        // NSLog(@"%@",ref);
        if(ref==NULL)
            break;
        //copy data to file
        //read next one
        AudioBufferList audioBufferList;
        NSMutableData *data=[[NSMutableData alloc] init];
        CMBlockBufferRef blockBuffer;
        CMSampleBufferGetAudioBufferListWithRetainedBlockBuffer(ref, NULL, &audioBufferList, sizeof(audioBufferList), NULL, NULL, 0, &blockBuffer);
        // NSLog(@"%@",blockBuffer);



        for( int y=0; y<audioBufferList.mNumberBuffers; y++ )
        {
            AudioBuffer audioBuffer = audioBufferList.mBuffers[y];
            Float32 *frame = (Float32*)audioBuffer.mData;


            [data appendBytes:frame length:audioBuffer.mDataByteSize];



        }


        CFRelease(blockBuffer);
        CFRelease(ref);
        ref=NULL;
        blockBuffer=NULL;
        [data release];