PHP MP3 ID3

function shift7_8($num) {
$num_1 = bindec(str_pad(substr($num, 0, 4), 8, "0", STR_PAD_LEFT));
$num_2 = bindec(substr($num, 4, 8));
$num_3 = bindec(substr($num, 12, 8));
$num_4 = bindec(substr($num, 20, 8));
$num = $num_1 . $num_2 . $num_3 . $num_4;
unset($num_1, $num_2, $num_3, $num_4);
return $num;
}

function id3_read($file) {
// BEGIN ID3 READ

// OPEN MP3 FILE
$mp3 = fopen($file, "r");

// ID3 HEADER READ

// READ THE "ALWAYS PRESENT "ID3"
$id3['base'] = fread($mp3, 3);
// GET THE HEX ID3 VERSION AND CONVERT IT
$id3['version'] = "";
for ($x = 0; $x < 2; $x++) {
$id3['version'] .= str_pad(dechex(ord(fread($mp3, 1))), 2, "0", STR_PAD_LEFT);
}
$id3['version'] = str_split($id3['version']);
if ($id3['version'][0] == "0") { $id3['version'][0] = ""; }
if ($id3['version'][2] == "0") { $id3['version'][2] = ""; }
$id3['version'] = "2." . $id3['version'][0] . $id3['version'][1] . "." . $id3['version'][2] . $id3['version'][3];
// GET THE ID3 BINARY FLAGS - STANDARDS STORED IN FIRST 4 BITES
for ($x = 0; $x < 1; $x++) {
$id3['flags'] = str_pad(decbin(ord(fread($mp3, 1))), 8, "0", STR_PAD_LEFT);
}
$id3['flags'] = str_split($id3['flags']);
// GET THE 4 ID3 SIZE BYTES AND CONVERT THEM TO 8 BIT NUMBERS.
$id3['size'] = "";
for ($x = 0; $x < 4; $x++) {
$id3['size'] .= str_pad(decbin(ord(fread($mp3, 1))), 8, "0", STR_PAD_LEFT);
}
$id3['size'] = shift7_8($id3['size']);

// IF THERE IS AN EXTENDED HEADER, SKIP IT
if ($id3_['flags'][1] == 1) {
// GET THE 4 ID3 EXT HEADER SIZE BYTES AND CONVERT THEM TO 8 BIT NUMBERS.
$id3_exthead_size = "";
for ($x = 0; $x < 4; $x++) {
$id3_exthead_size .= str_pad(decbin(ord(fread($mp3, 1))), 7, "0", STR_PAD_LEFT);
}
$id3_exthead_size = shift7_8($id3_exthead_size);
// SKIP THE EXT HEADER
$tmp = fread($mp3, ($id3_exthead_size - 4));
unset($tmp, $id3_exthead_size);
}

// READ FRAME HEADERS AND LOAD FRAMES INTO ARRAY
$v = 0;
$r = 0;
while ($v < $id3['size']) {
// GET FRAME ID
$id3['frames'][$r]['id'] = "";
for ($x = 0; $x < 4; $x++) {
$id3['frames'][$r]['id'] .= chr(hexdec(str_pad(dechex(ord(fread($mp3, 1))), 2, "0", STR_PAD_LEFT)));
}
if (!preg_match('/[A-Z0-9][A-Z0-9][A-Z0-9][A-Z0-9]/', $id3['frames'][$r]['id']) || $id3['frames'][$r]['id'] == "") {
unset ($id3['frames'][$r]);
break;
break;
}
// GET THE 4 FRAME SIZE BYTES AND CONVERT THEM TO 8 BIT NUMBERS.
$id3['frames'][$r]['size'] = "";
for ($x = 0; $x < 4; $x++) {
$id3['frames'][$r]['size'] .= str_pad(decbin(ord(fread($mp3, 1))), 7, "0", STR_PAD_LEFT);
}
$id3['frames'][$r]['size'] = shift7_8($id3['frames'][$r]['size']);
echo $id3['frames'][$r]['size'];
// GET THE 2 FRAME FLAG BYTES
$id3['frames'][$r]['flags'] = "";
for ($x = 0; $x < 2; $x++) {
$id3['frames'][$r]['flags'] .= str_pad(dechex(ord(fread($mp3, 1))), 2, "0", STR_PAD_LEFT);
}
// SKIP A BYTE - (TEXT ENCODING)...
$temp = fread($mp3, 1);
unset($temp);
// IF NOT APIC, THEN GET THE FRAME CONTENT
if ($id3['frames'][$r]['id'] != "APIC") {
$id3['frames'][$r]['content'] = fread($mp3, ($id3['frames'][$r]['size'] - 1));
} else {
$tmp = fread($mp3, 1);
while (str_pad(dechex(ord($tmp)), 2, "0", STR_PAD_LEFT) != "00") {
$id3['frames'][$r]['mime'] .= $tmp;
$id3['frames'][$r]['size'] = $id3['frames'][$r]['size'] - 1;
$tmp = fread($mp3, 1);
}
echo $id3['frames'][$r]['size'];
$id3['frames'][$r]['picture_type'] = fread($mp3, 1);
$id3['frames'][$r]['size'] = $id3['frames'][$r]['size'] - 2;
$tmp = fread($mp3, 1);
while (str_pad(dechex(ord($tmp)), 2, "0", STR_PAD_LEFT) != "00") {
$id3['frames'][$r]['description'] .= $tmp;
$id3['frames'][$r]['size'] = $id3['frames'][$r]['size'] - 1;
$tmp = fread($mp3, 1);
}
unset ($tmp);
$id3['frames'][$r]['size'] = $id3['frames'][$r]['size'] - 1;
$id3['frames'][$r]['content'] = fread($mp3, ($id3['frames'][$r]['size']));
}
// INCREMENT FRAME NUMBER AND START OVER
$v = $v + 10 + $id3['frames'][$r]['size'];
$r++;
}
// END ID3 READ

// CLOSE MP3 FILE & RETURN VALUES
fclose($mp3);
return $id3;
}