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Get MP3 bit rate and sample rate in PHP
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| //returns an assoc array with bitRate (kbps) and sampleRate (hz) | |
| function getMP3BitRateSampleRate($filename) | |
| { | |
| if (!file_exists($filename)) { | |
| return false; | |
| } | |
| $bitRates = array( | |
| array(0,0,0,0,0), | |
| array(32,32,32,32,8), | |
| array(64,48,40,48,16), | |
| array(96,56,48,56,24), | |
| array(128,64,56,64,32), | |
| array(160,80,64,80,40), | |
| array(192,96,80,96,48), | |
| array(224,112,96,112,56), | |
| array(256,128,112,128,64), | |
| array(288,160,128,144,80), | |
| array(320,192,160,160,96), | |
| array(352,224,192,176,112), | |
| array(384,256,224,192,128), | |
| array(416,320,256,224,144), | |
| array(448,384,320,256,160), | |
| array(-1,-1,-1,-1,-1), | |
| ); | |
| $sampleRates = array( | |
| array(11025,12000,8000), //mpeg 2.5 | |
| array(0,0,0), | |
| array(22050,24000,16000), //mpeg 2 | |
| array(44100,48000,32000), //mpeg 1 | |
| ); | |
| $bToRead = 1024 * 6; | |
| $fileData = array('bitRate' => 0, 'sampleRate' => 0); | |
| $fp = fopen($filename, 'r'); | |
| if (!$fp) { | |
| return false; | |
| } | |
| //seek to 8kb before the end of the file | |
| fseek($fp, -1 * $bToRead, SEEK_END); | |
| $data = fread($fp, $bToRead); | |
| $bytes = unpack('C*', $data); | |
| $frames = array(); | |
| for ($o = 0; $o < count($bytes) - 4; $o++) { | |
| //header is AAAAAAAA AAABBCCD EEEEFFGH IIJJKLMM | |
| if (($bytes[$o] & 0xFF) == 0xFF && ($bytes[$o+1] & 0xE0) == 0xE0) { | |
| $frame = array(); | |
| $frame['version'] = ($bytes[$o+1] & 24) >> 3; //get BB (0 -> 3) | |
| $frame['layer'] = abs((($bytes[$o+1] & 6) >> 1) - 4); //get CC (1 -> 3), then invert | |
| $frame['srI'] = ($bytes[$o+2] & 12) >> 2; //get FF (0 -> 3) | |
| $frame['brR'] = ($bytes[$o+2] & 240) >> 4; //get EEEE (0 -> 15) | |
| if ($frame['version'] != 1 && $frame['layer'] > 0 && $frame['srI'] < 3 && $frame['brR'] != 15 && $frame['brR'] != 0) { | |
| //valid frame! | |
| $frames[] = array_slice($bytes, $o-1, 4); | |
| } | |
| } | |
| if (count($frames) <= 4) { //verify at least 4 frames to make sure its an mp3 | |
| $o += 3; | |
| continue; | |
| } | |
| //throw out the first result as it is usually wrong | |
| array_shift($frames); | |
| //loop through verified frames trying to get any information we can | |
| do { | |
| $header = array_shift($frames); | |
| $fileData['sampleRate'] = $sampleRates[$header['version']][$header['srI']]; | |
| if ($header['version'] & 1 == 1) { | |
| $fileData['bitRate'] = $bitRates[$header['brR']][$header['layer']-1]; //v1 and l1,l2,l3 | |
| } else { | |
| $fileData['bitRate'] = $bitRates[$header['brR']][($header['layer'] & 2 >> 1)+3]; //v2 and l1 or l2/l3 (3 is the offset in the arrays) | |
| } | |
| } while (count($frames) && (!$fileData['bitRate'] || !$fileData['sampleRate'])); | |
| break; | |
| } | |
| //if both are 0 then its not an mp3 | |
| return $fileData; | |
| } | |
| /* | |
| Example: | |
| if (!empty($_FILES['mp3'])) { | |
| $data = verifyMP3File($_FILES['mp3']['tmp_name']); | |
| } | |
| */ |
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