mp3ファイルを波形画像に変換するWebスクリプトを作成する必要があり、このWebサイトに出くわしました。
PHPファイル.dllと.exeファイルをLAMBから自分のWebサイト（ホストモンスターによってホストされている）にアップロードしました。
しかし、MP3ファイルをWebサイトにアップロードしようとすると、波形画像ではなく黒い画像が生成されます。
私はPHPの知識がほとんどないので、何が悪いのか正確にはわかりませんが、プログラムのアップロード部分に関係していると思います。
誰かが私に何が悪いのか、そしてどうすればそれを乗り越えることができるのか教えてもらえますか？
以下は、そのままのphpコードです（GitHubのこのリポジトリでも入手できます）。
<?php
ini_set("max_execution_time", "30000");
// how much detail we want. Larger number means less detail
// (basically, how many bytes/frames to skip processing)
// the lower the number means longer processing time
define("DETAIL", 5);
define("DEFAULT_WIDTH", 500);
define("DEFAULT_HEIGHT", 100);
define("DEFAULT_FOREGROUND", "#FF0000");
define("DEFAULT_BACKGROUND", "#FFFFFF");
/**
* GENERAL FUNCTIONS
*/
function findValues($byte1, $byte2){
$byte1 = hexdec(bin2hex($byte1));
$byte2 = hexdec(bin2hex($byte2));
return ($byte1 + ($byte2*256));
}
/**
* Great function slightly modified as posted by Minux at
* http://forums.clantemplates.com/showthread.php?t=133805
*/
function html2rgb($input) {
$input=($input[0]=="#")?substr($input, 1,6):substr($input, 0,6);
return array(
hexdec(substr($input, 0, 2)),
hexdec(substr($input, 2, 2)),
hexdec(substr($input, 4, 2))
);
}
if (isset($_FILES["mp3"])) {
/**
* PROCESS THE FILE
*/
// temporary file name
$tmpname = substr(md5(time()), 0, 10);
// copy from temp upload directory to current
copy($_FILES["mp3"]["tmp_name"], "{$tmpname}_o.mp3");
// support for stereo waveform?
$stereo = isset($_POST["stereo"]) && $_POST["stereo"] == "on" ? true : false;
// array of wavs that need to be processed
$wavs_to_process = array();
/**
* convert mp3 to wav using lame decoder
* First, resample the original mp3 using as mono (-m m), 16 bit (-b 16), and 8 KHz (--resample 8)
* Secondly, convert that resampled mp3 into a wav
* We don't necessarily need high quality audio to produce a waveform, doing this process reduces the WAV
* to it's simplest form and makes processing significantly faster
*/
if ($stereo) {
// scale right channel down (a scale of 0 does not work)
exec("lame {$tmpname}_o.mp3 --scale-r 0.1 -m m -S -f -b 16 --resample 8 {$tmpname}.mp3 && lame -S --decode {$tmpname}.mp3 {$tmpname}_l.wav");
// same as above, left channel
exec("lame {$tmpname}_o.mp3 --scale-l 0.1 -m m -S -f -b 16 --resample 8 {$tmpname}.mp3 && lame -S --decode {$tmpname}.mp3 {$tmpname}_r.wav");
$wavs_to_process[] = "{$tmpname}_l.wav";
$wavs_to_process[] = "{$tmpname}_r.wav";
} else {
exec("lame {$tmpname}_o.mp3 -m m -S -f -b 16 --resample 8 {$tmpname}.mp3 && lame -S --decode {$tmpname}.mp3 {$tmpname}.wav");
$wavs_to_process[] = "{$tmpname}.wav";
}
// delete temporary files
unlink("{$tmpname}_o.mp3");
unlink("{$tmpname}.mp3");
// get user vars from form
$width = isset($_POST["width"]) ? (int) $_POST["width"] : DEFAULT_WIDTH;
$height = isset($_POST["height"]) ? (int) $_POST["height"] : DEFAULT_HEIGHT;
$foreground = isset($_POST["foreground"]) ? $_POST["foreground"] : DEFAULT_FOREGROUND;
$background = isset($_POST["background"]) ? $_POST["background"] : DEFAULT_BACKGROUND;
$draw_flat = isset($_POST["flat"]) && $_POST["flat"] == "on" ? true : false;
$img = false;
// generate foreground color
list($r, $g, $b) = html2rgb($foreground);
// process each wav individually
for($wav = 1; $wav <= sizeof($wavs_to_process); $wav++) {
$filename = $wavs_to_process[$wav - 1];
/**
* Below as posted by "zvoneM" on
* http://forums.devshed.com/php-development-5/reading-16-bit-wav-file-318740.html
* as findValues() defined above
* Translated from Croation to English - July 11, 2011
*/
$handle = fopen($filename, "r");
// wav file header retrieval
$heading[] = fread($handle, 4);
$heading[] = bin2hex(fread($handle, 4));
$heading[] = fread($handle, 4);
$heading[] = fread($handle, 4);
$heading[] = bin2hex(fread($handle, 4));
$heading[] = bin2hex(fread($handle, 2));
$heading[] = bin2hex(fread($handle, 2));
$heading[] = bin2hex(fread($handle, 4));
$heading[] = bin2hex(fread($handle, 4));
$heading[] = bin2hex(fread($handle, 2));
$heading[] = bin2hex(fread($handle, 2));
$heading[] = fread($handle, 4);
$heading[] = bin2hex(fread($handle, 4));
// wav bitrate
$peek = hexdec(substr($heading[10], 0, 2));
$byte = $peek / 8;
// checking whether a mono or stereo wav
$channel = hexdec(substr($heading[6], 0, 2));
$ratio = ($channel == 2 ? 40 : 80);
// start putting together the initial canvas
// $data_size = (size_of_file - header_bytes_read) / skipped_bytes + 1
$data_size = floor((filesize($filename) - 44) / ($ratio + $byte) + 1);
$data_point = 0;
// now that we have the data_size for a single channel (they both will be the same)
// we can initialize our image canvas
if (!$img) {
// create original image width based on amount of detail
// each waveform to be processed with be $height high, but will be condensed
// and resized later (if specified)
$img = imagecreatetruecolor($data_size / DETAIL, $height * sizeof($wavs_to_process));
// fill background of image
if ($background == "") {
// transparent background specified
imagesavealpha($img, true);
$transparentColor = imagecolorallocatealpha($img, 0, 0, 0, 127);
imagefill($img, 0, 0, $transparentColor);
} else {
list($br, $bg, $bb) = html2rgb($background);
imagefilledrectangle($img, 0, 0, (int) ($data_size / DETAIL), $height * sizeof($wavs_to_process), imagecolorallocate($img, $br, $bg, $bb));
}
}
while(!feof($handle) && $data_point < $data_size){
if ($data_point++ % DETAIL == 0) {
$bytes = array();
// get number of bytes depending on bitrate
for ($i = 0; $i < $byte; $i++)
$bytes[$i] = fgetc($handle);
switch($byte){
// get value for 8-bit wav
case 1:
$data = findValues($bytes[0], $bytes[1]);
break;
// get value for 16-bit wav
case 2:
if(ord($bytes[1]) & 128)
$temp = 0;
else
$temp = 128;
$temp = chr((ord($bytes[1]) & 127) + $temp);
$data = floor(findValues($bytes[0], $temp) / 256);
break;
}
// skip bytes for memory optimization
fseek($handle, $ratio, SEEK_CUR);
// draw this data point
// relative value based on height of image being generated
// data values can range between 0 and 255
$v = (int) ($data / 255 * $height);
// don't print flat values on the canvas if not necessary
if (!($v / $height == 0.5 && !$draw_flat))
// draw the line on the image using the $v value and centering it vertically on the canvas
imageline(
$img,
// x1
(int) ($data_point / DETAIL),
// y1: height of the image minus $v as a percentage of the height for the wave amplitude
$height * $wav - $v,
// x2
(int) ($data_point / DETAIL),
// y2: same as y1, but from the bottom of the image
$height * $wav - ($height - $v),
imagecolorallocate($img, $r, $g, $b)
);
} else {
// skip this one due to lack of detail
fseek($handle, $ratio + $byte, SEEK_CUR);
}
}
// close and cleanup
fclose($handle);
// delete the processed wav file
unlink($filename);
}
header("Content-Type: image/png");
// want it resized?
if ($width) {
// resample the image to the proportions defined in the form
$rimg = imagecreatetruecolor($width, $height);
// save alpha from original image
imagesavealpha($rimg, true);
imagealphablending($rimg, false);
// copy to resized
imagecopyresampled($rimg, $img, 0, 0, 0, 0, $width, $height, imagesx($img), imagesy($img));
imagepng($rimg);
imagedestroy($rimg);
} else {
imagepng($img);
}
imagedestroy($img);
} else {
?>
<form method="post" action="<?php print $_SERVER["REQUEST_URI"]; ?>" enctype="multipart/form-data">
<p>MP3 File:<br />
<input type="file" name="mp3" /></p>
<p>Image Width:<br />
<input type="text" name="width" value="<?php print DEFAULT_WIDTH; ?>" /></p>
<p>Image Height:<br />
<input type="text" name="height" value="<?php print DEFAULT_HEIGHT; ?>" /></p>
<p>Foreground Color: <small>(HEX/HTML color code)</small><br />
<input type="text" name="foreground" value="<?php print DEFAULT_FOREGROUND; ?>" /></p>
<p>Background Color: (Leave blank for transparent background) <small>(HEX/HTML color code)</small><br />
<input type="text" name="background" value="<?php print DEFAULT_BACKGROUND; ?>" /></p>
<p>Draw flat-line? <input type="checkbox" name="flat" /></p>
<p>Stereo waveform? <input type="checkbox" name="stereo" /></p>
<p><input type="submit" value="Generate Waveform" /></p>
</form>
<?php
}