http://www.jackxiang.com/index.php zh-cn http://www.jackxiang.com/post// jack <xdy108@126.com> Fri, 20 May 2011 08:01:57 +0000 http://www.jackxiang.com/post// 这里有wave file format 和 MicroSoft wave soundfile format可以参考。这里是一个实际的例子(下载放大看)

以下是引用片段：
<?Php unction wav_graph($file, $f=0, $w=0) lobal $DATA_DIR; f(!is_file($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('audio2.wav'); ?> ]]> http://www.jackxiang.com/post//#blogcomment <user@domain.com> Thu, 01 Jan 1970 00:00:00 +0000 http://www.jackxiang.com/post//#blogcomment