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');

									?>