我正在尝试访问发送到Audio Queue回调的原始音频数据,但是在调用AudioFileReadPackets之后,我的字节数(numBytes)为0。
void AQRecorder::MyInputBufferHandler(void *inUserData, AudioQueueRef inAQ, AudioQueueBufferRef inBuffer, const AudioTimeStamp * inStartTime, UInt32 inNumPackets, const AudioStreamPacketDescription* inPacketDesc) {
AQRecorder *aqr = (AQRecorder *)inUserData;
try {
if (inNumPackets > 0) {
//read packets
UInt32 numBytes;
OSStatus result = AudioFileReadPackets(aqr->mRecordFile, // The audio file from which packets of audio data are to be read.
FALSE, // Set to true to cache the data. Otherwise, set to false.
&numBytes, // On output, a pointer to the number of bytes actually returned.
(__bridge AudioStreamPacketDescription*)inPacketDesc, // A pointer to an array of packet descriptions that have been allocated.
aqr->mRecordPacket, // The packet index of the first packet you want to be returned.
&inNumPackets, // On input, a pointer to the number of packets to read. On output, the number of packets actually read.
inBuffer->mAudioData); // A pointer to user-allocated memory.
inBuffer->mAudioDataByteSize = numBytes;
SInt16 *testBuffer = (SInt16*)inBuffer->mAudioData;
for (int i=0; i < numBytes; i++)
{
UInt16 currentData = testBuffer[i];
printf("Current data in testbuffer is %d", currentData);
}
// if we're not stopping, re-enqueue the buffe so that it gets filled again
if (aqr->IsRunning())
XThrowIfError(AudioQueueEnqueueBuffer(inAQ, inBuffer, 0, NULL), "AudioQueueEnqueueBuffer failed");
} catch (CAXException e) {
char buf[256];
fprintf(stderr, "Error: %s (%s)\n", e.mOperation, e.FormatError(buf));
}
}
当我仅打印出testBuffer的第一个索引时,我能够获得0到4294967296之间的值,因此它似乎不是空的。有什么想法为什么AudioFileReadPackets执行后numBytes为0?
最佳答案
我仍然不确定为什么numBytes为0,但是我从this问题中找到了一个可行的解决方案。
为了获得testBuffer的大小,我使用了以下代码:
int sampleCount = inBuffer->mAudioDataBytesCapacity / sizeof(SInt16);