我在这里有一个AVAssetReader的问题,从iPod库中获取样本并通过音频队列进行流式传输。我一直无法找到任何这样的例子,所以我尝试实现我自己的,但似乎不知何故AssetReader是“搞砸了”音频队列的回调函数。具体来说,它在执行copyNextSampleBuffer时会失败,即它在尚未完成时返回null。我已经确定指针存在,所以如果有人可以帮助,这将是很好的。AVAssetReader和音频队列流式传输问题
下面是我用过的回调函数代码。这个回调函数在AudioQueue回调没有调用的时候“有效”。
static void HandleOutputBuffer (
void *playerStateH,
AudioQueueRef inAQ,
AudioQueueBufferRef inBuffer
) {
AQPlayerState *pplayerState = (AQPlayerState *) playerStateH;
//if (pplayerState->mIsRunning == 0) return;
UInt32 bytesToRead = pplayerState->bufferByteSize;
[[NSNotificationCenter defaultCenter] postNotificationName:NOTIF_callsample object:nil];
float * inData =(float *) inBuffer->mAudioData;
int offsetSample = 0;
//Loop until finish reading from the music data
while (bytesToRead) {
/*THIS IS THE PROBLEMATIC LINE*/
CMSampleBufferRef sampBuffer = [pplayerState->assetWrapper getNextSampleBuffer]; //the assetreader getting nextsample with copyNextSampleBuffer
if (sampBuffer == nil) {
NSLog(@"No more data to read from");
// NSLog(@"aro status after null %d",[pplayerState->ar status]);
AudioQueueStop (
pplayerState->mQueue,
false
);
pplayerState->mIsRunning = NO;
return;
}
AudioBufferList audioBufferList;
CMBlockBufferRef blockBuffer;
CMSampleBufferGetAudioBufferListWithRetainedBlockBuffer(sampBuffer, NULL, &audioBufferList, sizeof(audioBufferList), NULL, NULL, 0, &blockBuffer);
AudioBuffer audioBuffer = audioBufferList.mBuffers[0];
memcpy(inData + (2*offsetSample),audioBuffer.mData,audioBuffer.mDataByteSize);
bytesToRead = bytesToRead - audioBuffer.mDataByteSize;
offsetSample = offsetSample + audioBuffer.mDataByteSize/8;
}
inBuffer->mAudioDataByteSize = offsetSample*8;
AudioQueueEnqueueBuffer (
pplayerState->mQueue,
inBuffer,
0,
0
);
}