c – 使用PortAudio输入音频

除了之前提到的以外,您还有以下几个问题,我在下面的代码转储中已经解决了所有这些问题.

>次要：你不会一直使用你自己的cst_wave API.
>次要的：我喜欢把我的时间,如果块总是包含{}.这有一个防止神秘错误的习惯.
>最大帧被设置为零.这是因为在(cst_wave_num_samples(w)/ cst_wave_sample_rate(w))* cst_wave_num_channels(w)* sizeof(short)中,您除以采样率,大于您的采样数.假定整数除法是左关联的并截断,yadda yadda yadda为零.
>最大帧仍然是错误的,因为帧包括所有通道样本.因此,帧的数量对于信道的数量和样本本身的大小是不可知的.允许自己猜测,flite将样本误认为是帧,您的最大帧索引只是cst_wave_num_samples(w).否则它将是cst_wave_num_samples(w)/ cst_wave_num_channels(w).
> PortAudio的文档指出,在流变为无效后,您应该调用Pa_StopStream(流),无论您是否等待,直到它变得如此.
>我简化了回调,并对其进行了更正

>次要：一致使用您的API
> MAJOR：Ehm … cst_wave_set_frameIndex(data,framesPerBuffer);肯定是错的你固定在帧索引512而不是递增！这是因为您打开流时要求每个缓冲区512帧,而不是通过framePerBuffer递增帧索引,您将帧索引设置为framesPerBuffer.你没有这么做,因为你的maxFrameIndex是0,所以你退出.我修改它,以便帧索引增加 – 当然你的API.

这是代码,我采取了文件和清洁的自由,直到它接近我的优雅标准.请享用！

#include <stdio.h>
#include <string.h>

/**
 * Audio play callback.
 * 
 * Follows the PaStreamCallback signature,wherein:
 * 
 * @param input   and
 * @param output  are either arrays of interleaved samples or; if
 *                non-interleaved samples were requested using the
 *                paNonInterleaved sample format flag,an array of buffer
 *                pointers,one non-interleaved buffer for each channel.
 * @param frameCount    The number of sample frames to be processed by the
 *                      stream callback.
 * @param timeInfo      Timestamps indicating the ADC capture time of the first
 *                      sample in the input buffer,the DAC output time of the
 *                      first sample in the output buffer and the time the
 *                      callback was invoked. See PaStreamCallbackTimeInfo and
 *                      Pa_GetStreamTime()
 * @param statusFlags   Flags indicating whether input and/or output buffers
 *                      have been inserted or will be dropped to overcome
 *                      underflow or overflow conditions.
 * @param userData      The value of a user supplied pointer passed to
 *                      Pa_OpenStream() intended for storing synthesis data
 *                      etc.
 */

static int  playCallback(const void*                     inputBuffer,void*                           outputBuffer,unsigned long                   framesPerBuffer,PaStreamCallbackFlags           statusFlags,void*                           userData){
    (void) inputBuffer; /* Prevent unused variable warnings. */
    (void) timeInfo;
    (void) statusFlags;
    (void) userData;


    /**
     * Compute current processing state.
     */

    cst_wave*    data;
    short*       rptr;
    short*       wptr;
    unsigned int framesLeft,/* Number of frames of data remaining within the stream ***as a whole*** */
                 frames,/* Number of frames of data to be written for this buffer. */
                 framesPad,/* Number of frames of padding required within the final buffer. */
                 samples,/* Number of samples of data to be written for this buffer. */
                 samplesPad,/* Number of samples of padding required within the final buffer. */
                 numBytes,/* Number of bytes of data to be written for this buffer. */
                 numBytesPad;/* Number of bytes of padding required within the final buffer. */
    int          finalBuffer;/* Stores whether or not this is the final buffer. */


    data         = (cst_wave*)userData;
    rptr         = &data->samples[cst_wave_frameIndex  (data) *
                                  cst_wave_num_channels(data)];
    wptr         = (short*)outputBuffer;
    framesLeft   = cst_wave_maxFrameIndex(data) - cst_wave_frameIndex(data);
    finalBuffer  = framesLeft      <= framesPerBuffer;
    frames       = finalBuffer     ?  framesLeft     : framesPerBuffer;
    framesPad    = framesPerBuffer -  frames;
    samples      = frames     * cst_wave_num_channels(data);
    samplesPad   = framesPad  * cst_wave_num_channels(data);
    numBytes     = samples    * sizeof(short);
    numBytesPad  = samplesPad * sizeof(short);


    /**
     * Debug code. Comment out in production.
     */

    printf("framesLeft in callback: %u\n",framesLeft);
    printf("framesPerBuffer in callback: %lu\n",framesPerBuffer);
    printf("frames in callback: %u\n",frames);

    printf("frameIndex in callback: %d\n",cst_wave_sample_rate(data));


    /**
     * Output data. We handle the final buffer specially,padding it with zeros.
     */

    memcpy(wptr,rptr,numBytes);
    wptr += samples;
    rptr += samples;
    cst_wave_set_frameIndex(data,cst_wave_frameIndex(data) + frames);
    memset(wptr,numBytesPad);
    wptr += samplesPad;
    rptr += samplesPad;


    /**
     * Return a completion or continue code depending on whether this was the
     * final buffer or not respectively.
     */

    return finalBuffer ? paComplete : paContinue;
}

/**
 * Play wave function.
 * 
 * Plays the given cst_wave data as audio,blocking until this is done.
 */

int play_wave(cst_wave *w){
    PaStream*          stream;
    PaStreamParameters outputParameters;
    int                err;

    /**
     * Initialize custom fields in cst_wave struct.
     */

    cst_wave_set_frameIndex(w,(cst_wave_num_samples(w)));
    // / cst_wave_sample_rate(w)  * cst_wave_num_channels(w) * sizeof(short)


    /**
     * Initialize Port Audio device and stream parameters.
     */

    err = Pa_Initialize();
    outputParameters.device = Pa_GetDefaultOutputDevice();
    if (outputParameters.device == paNoDevice){
        fprintf(stderr,"Error: No default output device.\n");
        return -5;
    }

    printf("frameIndex: %d\n",cst_wave_sample_rate(w));

    outputParameters.channelCount = cst_wave_num_channels(w);
    outputParameters.sampleFormat = paInt16;
    outputParameters.suggestedLatency = Pa_GetDeviceInfo( outputParameters.device )->defaultLowOutputLatency;
    outputParameters.hostApiSpecificStreamInfo = NULL;


    /**
     * Open the stream for playback.
     */

    puts("=== Now playing back. ===");
    err = Pa_OpenStream(&stream,w);

    if(stream){
        /**
         * Start the stream.
         */

        err = Pa_StartStream(stream);
        if(err != paNoError){
            goto done;
        }

        /**
         * Block while it plays.
         */

        puts("Waiting for playback to finish.");
        while((err = Pa_IsstreamActive(stream)) == 1){
            Pa_Sleep(100);
        }
        if(err < 0){
            goto done;
        }


        /**
         * Stop and close the stream. Both are necessary.
         */

        Pa_StopStream(stream);
        err = Pa_CloseStream(stream);
        if(err != paNoError){
            goto done;
        }
        puts("Done.");
    }

    /**
     * Terminate and leave.
     */
done:
    Pa_Terminate();
    return 0;
}