初学者数字合成器

Question

我正在研究用Java编写音频同步器,并且想知道是否有人有任何建议或良好的资源来编写这样的程序.我正在寻找有关生成原始声波的信息,如何将它们输出为可用的形式(在扬声器上播放),以及关于该主题的一般理论.多谢你们.

Answer 1

1. 这个问题基本上是将函数映射到数字数组.支持一流功能的语言在这里非常方便.

2. 有关Java相关信息,请访问 http://www.harmony-central.com/Computer/Programming和 http://www.developer.com/java/other/article.php/3071021.

3. 如果您不了解编码声音数据的基本概念,请阅读http://en.wikipedia.org/wiki/Sampling_rate

4. 规范的WAVE格式非常简单,请访问http://www.lightlink.com/tjweber/StripWav/Canon.html.标题(前44个字节)+波数据.您不需要任何库来实现它.

在C/C++中,相应的数据结构如下所示:

typedef struct _WAVstruct
{
    char headertag[4];
    unsigned int remnantlength;
    char fileid[4];

    char fmtchunktag[4];
    unsigned int fmtlength;
    unsigned short fmttag;
    unsigned short channels;
    unsigned int samplerate;
    unsigned int bypse;
    unsigned short ba;
    unsigned short bipsa;

    char datatag[4];
    unsigned int datalength;

    void* data; //<--- that's where the raw sound-data goes
}* WAVstruct;

我不确定Java.我想你必须将"struct"替换为"class"和"void*data"替换为"char [] data"或"short [] data"或"int [] data",对应于每位数样本,如字段bipsa中所定义.

要用数据填充它,你可以在C/C++中使用类似的东西:

int data2WAVstruct(unsigned short channels, unsigned short bipsa, unsigned int samplerate, unsigned int datalength, void* data, WAVstruct result)
{
    result->headertag[0] = 'R';
    result->headertag[1] = 'I';
    result->headertag[2] = 'F';
    result->headertag[3] = 'F';
    result->remnantlength = 44 + datalength - 8;
    result->fileid[0] = 'W';
    result->fileid[1] = 'A';
    result->fileid[2] = 'V';
    result->fileid[3] = 'E';

    result->fmtchunktag[0] = 'f';
    result->fmtchunktag[1] = 'm'; 
    result->fmtchunktag[2] = 't';
    result->fmtchunktag[3] = ' ';
    result->fmtlength = 0x00000010;
    result->fmttag = 1;
    result->channels = channels;
    result->samplerate = samplerate;
    result->bipsa = bipsa;
    result->ba = channels*bipsa / 8;
    result->bypse = samplerate*result->ba;

    result->datatag[0] = 'd';
    result->datatag[1] = 'a';
    result->datatag[2] = 't';
    result->datatag[3] = 'a';
    result->datalength = datalength;

    result->data = data; // <--- that's were the data comes in

    return 0; // an error code, not implemented, yet ...; in Java: return result
}

同样,我不确定Java,但如果将void-pointer转换为与bitrate对应的数组,则转换应该是直截了当的.

然后简单地将整个结构写入文件以获得可播放的波形文件.