PHP分析.wav文件并绘制png格式的波形图

1 2 [align=left]3 function wav_graph($file, $f=0, $w=0)[/align][align=left]4 {[/align][align=left]5 global $DATA_DIR;[/align][align=left]6[/align][align=left]7 if(!is_file($file)) return 0;[/align][align=left]8 $fp = fopen($DATA_DIR.$file, 'r');[/align][align=left]9 $raw = fread($fp, 36);[/align][align=left]10 $str = '';[/align][align=left]11 $header = unpack('A4Riff/VSize/A4Wav/A4Head/VHeadSize/vPCM/vChannels/VSampleRate/[/align][align=left]VByteRate/vBlockAlign/vSampleBits', $raw);[/align][align=left]12 foreach($header as $k=>$v)[/align][align=left]13 $str .= $k.': '. $v.' ';[/align][align=left]14 fseek($fp, 36 + $header['HeadSize'] - 16);[/align][align=left]15 $raw = fread($fp, 8);[/align][align=left]16 $data = unpack('A4Data/VDataSize', $raw);[/align][align=left]17 foreach($data as $k=>$v)[/align][align=left]18 $str .= $k.': '. $v.' ';[/align][align=left]19[/align][align=left]20 $b = $header['SampleBits'];[/align][align=left]21 $c = $header['Channels'];[/align][align=left]22 $l = $b * $c / 8; // sample frame length in bytes[/align][align=left]23 $s = $data['DataSize'] / $l; // total number of samples[/align][align=left]24 $r = $header['SampleRate'];[/align][align=left]25 if($f) $h = pow(2, $b) / $f;[/align][align=left]26 else { $h = 200; $f = pow(2, $b - 1) / $h; }[/align][align=left]27 if($w == 0) $w = round($r / 1000); // default to show 1k sample frames per minute[/align][align=left]28[/align][align=left]29 header("Content-type: image/png");[/align][align=left]30 $im = imagecreate($s / $w, $h * $c * 2);[/align][align=left]31 imagecolorallocate($im, 0xff, 0xff, 0xff); // white bg[/align][align=left]32 $color = imagecolorallocate($im, 0, 0, 255); // black[/align][align=left]33 //imagestring($im, 5, 5, 5, $str, $color);[/align][align=left]34[/align][align=left]35 $x=0; $y = array(); $yn = array();[/align][align=left]36 for($i = 0; $i < $c; $i++) $y[$i] = $h * $i + $h;[/align][align=left]37 $n = $l * $w;[/align][align=left]38 while(1)[/align][align=left]39 {[/align][align=left]40 if($s == 0) break;[/align][align=left]41 if($s < $n) $n = $s;[/align][align=left]42 $samples = fread($fp, 1000 * $n);[/align][align=left]43 if($samples === FALSE) break;[/align][align=left]44 $packed = unpack("s*", $samples);[/align][align=left]45 foreach($packed as $k=>$v)[/align][align=left]46 {[/align][align=left]47 $cnt = ($k-1) % ($w * $l) ;[/align][align=left]48 if( $cnt > $c - 1) continue;[/align][align=left]49 $yn[$cnt] = $h * $cnt + $h - $v / $f;[/align][align=left]50 imageline($im, $x, $y[$cnt], $x+1, $yn[$cnt], $color);[/align][align=left]51 $y[$cnt] = $yn[$cnt];[/align][align=left]52 $x++;[/align][align=left]53 }[/align][align=left]54 $s -= $n;[/align][align=left]55 }[/align][align=left]56[/align][align=left]57 imagepng($im);[/align][align=left]58 imagedestroy($im);[/align][align=left]59 }[/align][align=left]60[/align][align=left]61 //wav_graph('audio2.wav');[/align][align=left]62 ?>[/align]