php实现将wav文件转换成图像文件并在页面中显示的方法

本文实例讲述了php实现将wav文件转换成图像文件并在页面中显示的方法。分享给大家供大家参考。具体分析如下：

需求：将wav文件转换成png文件并且显示出来。

Wav_To_Png.php：

    <?php
     function wav_graph($file, $f=0, $w=0)
     {
      global $DATA_DIR;
      if(!is_file($file))
       return 0;
      $fp = fopen($DATA_DIR.$file, 'r');
      $raw = fread($fp, 36);
      $str = '';
      $header = unpack('A4Riff/VSize/A4Wav/A4Head/VHeadSize/vPCM/vChannels/VSampleRate/VByteRate/vBlockAlign/vSampleBits', $raw);
      foreach($header as $k=>$v)
       $str .= $k.': '. $v.' ';
      fseek($fp, 36 + $header['HeadSize'] - 16);
      $raw = fread($fp, 8);
      $data = unpack('A4Data/VDataSize', $raw);
      foreach($data as $k=>$v)
       $str .= $k.': '. $v.' ';
      $b = $header['SampleBits'];
      $c = $header['Channels'];
      $l = $b * $c / 8; // sample frame length in bytes
      $s = $data['DataSize'] / $l; // total number of samples
      $r = $header['SampleRate'];
      if($f)
       $h = pow(2, $b) / $f;
      else
       { $h = 200; $f = pow(2, $b - 1) / $h; }
      if($w == 0)
       $w = round($r / 1000); // default to show 1k sample frames per minute
      header("Content-type: image/png");
      $im = imagecreate($s / $w, $h * $c * 2);
      imagecolorallocate($im, 0xff, 0xff, 0xff); // white bg
      $color = imagecolorallocate($im, 0, 0, 255); // black
      imagestring($im, 5, 5, 5, $str, $color);
      $x=0; $y = array(); $yn = array();
      for($i = 0; $i < $c; $i++) $y[$i] = $h * $i + $h;
      $n = $l * $w;
      while(1)
      {
       if($s == 0) 
        break;
       if($s < $n) 
        $n = $s;
       $samples = fread($fp, 1000 * $n);
       if($samples === FALSE)
        break;
       $packed = unpack("s*", $samples);
       foreach($packed as $k=>$v)
       {
        $cnt = ($k-1) % ($w * $l) ;
        if( $cnt > $c - 1) 
         continue;
        $yn[$cnt] = $h * $cnt + $h - $v / $f;
        imageline($im, $x, $y[$cnt], $x+1, $yn[$cnt], $color);
        $y[$cnt] = $yn[$cnt];
        $x++;
       }
       $s -= $n;
      }
      imagepng($im);
      imagedestroy($im);
     }
     wav_graph('GetWave.wav');
    ?>

效果图如下：

希望本文所述对大家的php程序设计有所帮助。