C-使用portaudio和回调函数同时进行音频输入和输出

如何解决C-使用portaudio和回调函数同时进行音频输入和输出

我正在尝试制作一个全双工音频程序，该程序可以检测来自麦克风的音频输入，并使用portaudio库和回调函数将其实时定向到扬声器，但是我一直遇到错误。我试图打开一个完整的输入输出流，然后从麦克风开始读取并将捕获的数据发送到回调函数，该函数将开始将音频流传输到扬声器 谁能帮我这个 ？？ 错误如下：

ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear
ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe
ALSA lib pcm.c:2495:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side
ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map
ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map
ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map
ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map
Output device # 14.
Output LL: 0.00870748 s
Output HL: 0.0348299 s
Now recording!!
An error occured while using the portaudio stream
Error number: -9988
Error message: Invalid stream pointer
An error occured while using the portaudio stream
Error number: -9988
Error message: Invalid stream pointer
An error occured while using the portaudio stream
Error number: -9977
Error message: Can't read from a callback stream

这是我的代码：

#include "diffusion.c"
#include "confusion.c"
#include "portaudio.h"
#include "wave_file.c"

/* #define SAMPLE_RATE  (17932) // Test failure to open with this value. */
#define SAMPLE_RATE  (44100)
#define FRAMES_PER_BUFFER (0)
#define NUM_SECONDS     (2)
#define NUM_CHANNELS    (2)
/* #define DITHER_FLAG     (paDitherOff)  */
#define DITHER_FLAG     (0) /**/

#define WRITE_TO_WAVE_FILE  (1)

/* define sample format. */

#define PA_SAMPLE_TYPE  paInt16
typedef short SAMPLE;
#define SAMPLE_SILENCE  (0)
#define PRINTF_S_FORMAT "%d"


PaStreamParameters inputParameters,outputParameters;
    PaStream *stream;
    PaError err;
    SAMPLE *recordedSamples,*recordedSamples2;
    int i;
    int totalFrames;
    int numSamples;
    int numBytes;

static int playCallback (const void *input,void *output,unsigned long frameCount,const PaStreamCallbackTimeInfo* timeInfo,PaStreamCallbackFlags statusFlags,void *userData
 ) 
{


    err = Pa_StartStream( stream );
    if( err != paNoError ) goto error;
    printf("Now recording!!\n"); fflush(stdout);

    err = Pa_WriteStream( stream,userData,totalFrames );
    if( err != paNoError ) goto error;
    
    err = Pa_CloseStream( stream );
    if( err != paNoError ) goto error;
    free( userData );
    return paContinue;

error:
    fprintf( stderr,"An error occured while using the portaudio stream\n" );
    fprintf( stderr,"Error number: %d\n",err );
    fprintf( stderr,"Error message: %s\n",Pa_GetErrorText( err ) );
    return paContinue;
}





int main(void);
int main(void)
{
    PaStreamParameters inputParameters,*recordedSamples2;
    int i;
    int totalFrames;
    int numSamples;
    int numBytes;
    
    printf("patest_read_record.c\n"); fflush(stdout);
    totalFrames = NUM_SECONDS * SAMPLE_RATE; /* Record for a few seconds. */
    numSamples = totalFrames * NUM_CHANNELS;

    numBytes = numSamples * sizeof(SAMPLE);
    recordedSamples = (SAMPLE *) malloc( numBytes );
    if( recordedSamples == NULL )
    {
        printf("Could not allocate record array.\n");
        exit(1);
    }
    for( i=0; i<numSamples; i++ ) recordedSamples[i] = 0;

    err = Pa_Initialize();
    if( err != paNoError ) goto error;

    inputParameters.device = Pa_GetDefaultInputDevice(); /* default input device */
    if (inputParameters.device == paNoDevice) {
      fprintf(stderr,"Error: No default input device.\n");
      goto error;
    }
    inputParameters.channelCount = NUM_CHANNELS;
    inputParameters.sampleFormat = PA_SAMPLE_TYPE;
    inputParameters.suggestedLatency = Pa_GetDeviceInfo( inputParameters.device )->defaultLowInputLatency;
    inputParameters.hostApiSpecificStreamInfo = NULL;

    outputParameters.device = Pa_GetDefaultOutputDevice(); /* default output device */
    printf( "Output device # %d.\n",outputParameters.device );
    printf( "Output LL: %g s\n",Pa_GetDeviceInfo( outputParameters.device )->defaultLowOutputLatency );
    printf( "Output HL: %g s\n",Pa_GetDeviceInfo( outputParameters.device )->defaultHighOutputLatency );
    outputParameters.channelCount = NUM_CHANNELS;
    outputParameters.sampleFormat = PA_SAMPLE_TYPE;
    outputParameters.suggestedLatency = Pa_GetDeviceInfo( outputParameters.device )->defaultHighOutputLatency;
    outputParameters.hostApiSpecificStreamInfo = NULL;

    /* Record some audio. -------------------------------------------- */
    err = Pa_OpenStream(
              &stream,&inputParameters,&outputParameters,/* &outputParameters,*/
              SAMPLE_RATE,paFramesPerBufferUnspecified,paClipOff,/* we won't output out of range samples so don't bother clipping them */
              playCallback,/* no callback,use blocking API */
              recordedSamples ); /* no callback,so no callback userData */
    if( err != paNoError ) goto error;

    err = Pa_StartStream( stream );
    if( err != paNoError ) goto error;
    printf("Now recording!!\n"); fflush(stdout);

    err = Pa_ReadStream( stream,recordedSamples,totalFrames );
    if( err != paNoError ) goto error;
    
    err = Pa_CloseStream( stream );
    if( err != paNoError ) goto error;
     /* save the recorded data in a wave file " recording.wav ".  -------------------------- */
    saveInWaveFile(recordedSamples,totalFrames,"recording.wav");
    for (int i =0; i< numSamples ; i++){
        recordedSamples2[i] = recordedSamples[i];
    }

    free( recordedSamples );
    Pa_Terminate();
    return 0;

error:
    Pa_Terminate();
    fprintf( stderr,Pa_GetErrorText( err ) );
    return -1;
}

解决方法

首先请确保默认输入和输出设备正确。为此，您可以先运行examples文件夹中的pa_devs.c示例，以打印已连接到计算机的已启用音频设备的列表。确定正确的设备后，将这些行替换为设备号，例如

inputParameters.device = Pa_GetDefaultInputDevice();

为

inputParameters.device = <device number (e.g. 11)>;

和

outputParameters.device = Pa_GetDefaultOutputDevice();

为

outputParameters.device = <device number (e.g. 11)>;

您可以尝试的另一种方式是称为paex_read_write_wire.c的示例。这样可以实现与您所讨论的功能相同的功能，但是使用阻塞方法，而不是您在代码中使用的回调函数。

,

我现在无法测试它，但它应该播放（监视）输入缓冲区（麦克风）：

table.column(colID).search('Tokyo').draw();