在AudioQueueOutputCallback中接收“静音”（零）

Question

语言目标C ++。

我已经使用AudioQueueNewInput设置了一个音频队列，排队了5个缓冲区，每个缓冲区的大小为44100 * 3 * 2（对于3秒钟的音频，在单个通道上具有16位数据）。在回调中，我似乎在传递给AudioQueueInputCallback的缓冲区中收到零。

从我的ViewController.mm文件中：

static void audioQueueInputCallback(void* data,
                                    AudioQueueRef queue,
                                    AudioQueueBufferRef buffer,
                                    const AudioTimeStamp* timpestamp,
                                    uint32 numberOfPacketDescriptions,
                                    const AudioStreamPacketDescription* packetDescriptions){
    void* const bytes = buffer->mAudioData;
    uint32 size = buffer->mAudioDataByteSize;

    uint32 count = 0;
    const short* dataBytes = (const short*)bytes;
    for(int i = 0; i< size/(sizeof(short));++i){
        if(dataBytes[i]!= 0){
            ++count;
        }
    }

    NSLog(@"---------Non-zero bytes:%u of %u(%lu)(%lu)",count,(unsigned int)size,size/(sizeof(short)),numberOfPacketDescriptions);

   AudioQueueLevelMeterState meters[1];
    UInt32 dlen = sizeof(meters);
    OSStatus Status = AudioQueueGetProperty(queue,kAudioQueueProperty_CurrentLevelMeterDB,meters,&dlen);

    NSLog(@"METER STATE. Average power:%f. Peak power:%f.",meters[0].mAveragePower,meters[0].mPeakPower);


    AudioQueueEnqueueBuffer(queue, buffer, 0, NULL);
}

事件处理程序：

- (IBAction)startRecording:(id)sender{

    OSStatus status;

    self.state->recording = YES;

    status = AudioQueueNewInput(&(self.state->format), audioQueueInputCallback, (__bridge void*)self, NULL, kCFRunLoopCommonModes, 0, &(self.state->queue));

    NSLog(@"AudioQueueNewInput:%d",status);

    bufferLength = 3; /* seconds */
    int bytes = (int)ceil(bufferLength * self.state->format.mSampleRate) * self.state->format.mBytesPerFrame;

    for (int i = 0; i < NUM_BUFFERS; i++) {
        AudioQueueAllocateBuffer(self.state->queue, bytes, &(self.state->buffers[i]));
        AudioQueueEnqueueBuffer(self.state->queue, self.state->buffers[i], 0, NULL);
    }

    status = AudioQueueStart(self.state->queue, NULL);
    NSLog(@"AudioQueueStart:%d",status);
}

- (IBAction)stopRecording:(id)sender{
    AudioFileClose(self.state->outputFile);

    self.state->recording = NO;

    AudioQueueStop(self.state->queue,false);
    AudioQueueDispose(self.state->queue, true);
}