声波锯齿

Question

我正试图在c中产生锯齿波。我的工作快结束了，但我有一些问题必须解决。我把clode附在下面。

#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <tgmath.h>

/******************************
*  Magic file format strings. *
******************************/
const char fChunkID[]     = {'R', 'I', 'F', 'F'};
const char fFormat[]      = {'W', 'A', 'V', 'E'};
const char fSubchunk1ID[] = {'f', 'm', 't', ' '};
const char fSubchunk2ID[] = {'d', 'a', 't', 'a'};

/********************************
* WriteWavePCM() configuration: *
* - 2 channels,                 *
* - frequency 44100 Hz.         *
********************************/
const unsigned short N_CHANNELS = 2;
const unsigned int SAMPLE_RATE = 48000;
const unsigned short BITS_PER_BYTE = 8;

bool WriteWavePCM(short* sound, size_t pairAmount, char* fileName){
    const static unsigned int fSubchunk1Size = 16;
    const static unsigned short fAudioFormat = 1;
    const static unsigned short fBitsPerSample = 16;

    unsigned int fByteRate = SAMPLE_RATE * N_CHANNELS * fBitsPerSample / BITS_PER_BYTE;

    unsigned short fBlockAlign = N_CHANNELS * fBitsPerSample / BITS_PER_BYTE;
    unsigned int fSubchunk2Size;
    unsigned int fChunkSize;

    FILE* fout;
    size_t ws;

    if (!sound || !fileName || !(fout = fopen( fileName, "w" ))) return false;

    fSubchunk2Size = pairAmount * N_CHANNELS * fBitsPerSample / BITS_PER_BYTE;
    fChunkSize = 36 + fSubchunk2Size;

    // Writing the RIFF header:
    fwrite(&fChunkID, 1, sizeof(fChunkID),      fout);
    fwrite(&fChunkSize,  sizeof(fChunkSize), 1, fout);
    fwrite(&fFormat, 1,  sizeof(fFormat),       fout);

    // "fmt" chunk:
    fwrite(&fSubchunk1ID, 1, sizeof(fSubchunk1ID),      fout);
    fwrite(&fSubchunk1Size,  sizeof(fSubchunk1Size), 1, fout);
    fwrite(&fAudioFormat,    sizeof(fAudioFormat),   1, fout);
    fwrite(&N_CHANNELS,      sizeof(N_CHANNELS),     1, fout);
    fwrite(&SAMPLE_RATE,     sizeof(SAMPLE_RATE),    1, fout);
    fwrite(&fByteRate,       sizeof(fByteRate),      1, fout);
    fwrite(&fBlockAlign,     sizeof(fBlockAlign),    1, fout);
    fwrite(&fBitsPerSample,  sizeof(fBitsPerSample), 1, fout);

    /* "data" chunk: */
    fwrite(&fSubchunk2ID, 1, sizeof(fSubchunk2ID),      fout);
    fwrite(&fSubchunk2Size,  sizeof(fSubchunk2Size), 1, fout);

    /* sound data: */
    ws = fwrite(sound, sizeof(short), pairAmount * N_CHANNELS, fout);
    fclose(fout);
    return true;
}

////////////////////////////////////////////////

const unsigned int N_SAMPLE_PAIRS = 50000;

int main(int argc, char* argv[]){
    short* sound;
    int i;
    int j;
    bool status;
    char* file_name;
    int l; // dodane

    sound = (int*) malloc(sizeof(int) * N_SAMPLE_PAIRS * N_CHANNELS );

    if (!sound)
    {
        puts("Could not allocate space for the sound data.");
        return (EXIT_FAILURE);
    }

    int amplitude = 10000;
    int frequency = 80;
    short record = 0;
    short waveNumber = 1;
    int samplesPerWavelength = SAMPLE_RATE / (frequency/N_CHANNELS);
    int soundLen = 10 * samplesPerWavelength;
    int ampStep = (int)((amplitude*2)/(int)samplesPerWavelength);
    short step = 5*samplesPerWavelength;
    short muteRate = amplitude/(soundLen/samplesPerWavelength);
    int totalSamplesWritten = 0;
    int tempSample =0;

    for (i=0, j=0; i<N_SAMPLE_PAIRS*N_CHANNELS; i+=2, j++) {
        ampStep = (int)((amplitude*2)/(int)samplesPerWavelength);
        tempSample = (int)((totalSamplesWritten%samplesPerWavelength)*ampStep);
        sound[i] = tempSample;
        sound[i+1] = tempSample;
        totalSamplesWritten++;
    }


    file_name = argc > 1 ? argv[1] : "Default2.wav";
    status = WriteWavePCM(sound, N_SAMPLE_PAIRS, file_name);


    free(sound);

    if (status)
    {
        printf("Discotheque is ready in \"%s\"\n", file_name);
    }
    else
    {
        puts( "Something seems to have gone wrong." );
        return (EXIT_FAILURE);
    }

    return 0;
}

这是我的结果。有锯齿，但有奇怪的行为。我不知道为什么会有这个。我检查了我的样本，一切看起来都很好。

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有人能帮我吗？我被困住了我不知道该怎么办。我检查了两个不同的程序:听觉和波音频，在这两种情况下，这种行为存在。所以我的密码肯定有问题。请帮帮我。

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Answer 1

当我查看文件转储(MSVC编译)时，我注意到了一些0D 0A数据对。然后我改变了这个

fout = fopen( fileName, "w" )

来指定二进制文件。

fout = fopen( fileName, "wb" )

现在故障已经消失了。

请注意，

如果t或b没有在mode中提供，则由全局变量_fmode定义默认的转换模式。

因此，默认的翻译模式必须是“文本”。

Answer 2

下面是一些我得到的输出的屏幕截图。对我来说很好。

使用内置规格。COLLECT_LTO_WRAPPER=/usr/lib/gcc/i686-pc-cygwin/5.4.0/lto-wrapper.exe目标:i 686-pc-cygwin配置: /cygdrive/i/szsz/tmpp/gcc/gcc-5.4.0-1.i686/src/gcc-5.4.0/configure --srcdir=/cygdrive/i/szsz/tmpp/gcc/gcc-5.4.0-1.i686/src/ gcc-5.4.0 -前缀=/usr-exec-前缀=/usr --localstatedir=/var -sysconfdir=/etc-docdir=/usr/share/doc/gcc-htmldir=/usr/share/doc/gcc/h tml -C -build=i 686-pc-cygwin-host=i 686-pc-cygwin-目标=i686-pc-cygwin-目标=i686-pc-cygwin-不带-libiconv前缀-不带-libintl前缀-前缀-libexecdir= /usr/lib -启用-共享-启用共享-libgcc-启用-静态-允许-特定运行时-libintl-可引导-引导-启用-允许-共享-启用-libgcc-使能__cxa_ate xit --具有-侏儒-具有-arch=i 686-具有--xit=泛型-禁用-sjlj-异常-启用--语言=ada，c，c++，fortran，java，lto，objc，obj-c++ -启用-libssp-enable-libgomp enable-libcilkrts-启用-libgomp-启用-libgomp-启用-lib44-enab-libssp-支持-启用-libssp-启用-libada-启用-libjava-启用-libgcj-sublibs禁用-java awt-禁用-symvers-与-ecj-jar=/usr/share/java/ecj.-with-gnu-as-with-gnu-as-with-cloog g-包括/usr/usr/usr/cloog-isl-没有--libintl-前缀-前缀

无名-a Cygwin _NT-WOW DE-E 03895 2.8.0(0.309/5/3) 2017-04-01 20:42 i686 Cygwin

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这是你的输出中损坏的样本的屏幕截图；

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