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由于我是PortAudio的新手,我尝试了一个来自Internet的示例程序。该程序能够通过回调函数记录麦克风的输入。PortAudio通过音频数据迭代
我想获得表示为数字值(例如浮子)所记录的音频的每一个样品。我无法确定麦克风录制数据的存储位置。
这是回调函数:
static int recordCallback(const void *inputBuffer, void *outputBuffer,
unsigned long framesPerBuffer,
const PaStreamCallbackTimeInfo* timeInfo,
PaStreamCallbackFlags statusFlags,
void *userData)
{
paTestData *data = (paTestData*)userData;
const SAMPLE *rptr = (const SAMPLE*)inputBuffer;
SAMPLE *wptr = &data->recordedSamples[data->frameIndex * NUM_CHANNELS];
long framesToCalc;
long i;
int finished;
unsigned long framesLeft = data->maxFrameIndex - data->frameIndex;
(void)outputBuffer; /* Prevent unused variable warnings. */
(void)timeInfo;
(void)statusFlags;
(void)userData;
if (framesLeft < framesPerBuffer)
{
framesToCalc = framesLeft;
finished = paComplete;
}
else
{
framesToCalc = framesPerBuffer;
finished = paContinue;
}
if (inputBuffer == NULL)
{
for (i = 0; i<framesToCalc; i++)
{
*wptr++ = SAMPLE_SILENCE; /* left */
if (NUM_CHANNELS == 2) *wptr++ = SAMPLE_SILENCE; /* right */
}
}
else
{
cout << endl << "SAMPLE" << endl;
for (i = 0; i<framesToCalc; i++)
{
*wptr++ = *rptr++; /* left */
//cout << rptr<<endl;
if (NUM_CHANNELS == 2) *wptr++ = *rptr++; /* right */
}
}
data->frameIndex += framesToCalc;
return finished;
}
音频输入流在这里初始化:
err = Pa_OpenStream(
&stream,
&inputParameters,
NULL, /* &outputParameters, */
SAMPLE_RATE,
FRAMES_PER_BUFFER,
paClipOff, /* we won't output out of range samples so don't bother clipping them */
recordCallback,
&data);
你能告诉我在初始化(第二代码剪切)的哪个参数是inputBuffer?我现在明白了它在回调中的位置。 – bingoStack
@bingoStack初始化时没有输入缓冲区。它将通过回调函数传递给您。您可以通过inputParameters结构来调整,以告知您需要多少个通道以及示例格式,请参阅http://portaudio.com/docs/v19-doxydocs/structPaStreamParameters.html – Archie
谢谢!虽然,我无法读取数据。我刚刚添加了'cout << *(float *)(inputBuffer)<< endl';在回调中返回完成之前,我得到0或+/- 3.0517e-005。哪里不对? – bingoStack