一个解析mp3 ID3 tag和MPEG信息的类

<?php
    /*
     * MP3 class
     *
     * rel. 0.1
     *
     * Copyright (c) 2000 Sumatra Solutions srl    http://www.sumatrasolutions.com
     *                    Ludovico Magnocavallo    ludo@sumatrasolutions.com
     *
     * License type: GNU GPL http://www.gnu.org/copyleft/gpl.html
     *
     *    Heavily inspired by
     *                    Perl Apache::MP3 module (L. Stein) -- great module to create an apache-based mp3 server
     *                    Perl MP3::Info (C. Nandor) -- very complicated, hard stuff but useful
     *                    Java class de.vdheide.mp3 (J. Vonderheide) -- great stuff, easy to read, had to debug synchronize() method
     *
     * ID3v2 tags support not completed
     *
     * MP3 header reference at http://www.mp3-tech.org/
     *
     * // quick start:
     * $mp3 = new MP3($myfilepath);
     * $mp3->get_info();                    // file info in $mp3->info array
     * $mp3->get_id3();                    // id3 info in $mp3->id3 array
     * $mp3->send_pls($HTTP_HOST)        // uses physical path to file in playlist url
     * $mp3->stream()                        // streams file to browser
     *
     * $Id: mp3.php,v 1.10 2000/07/18 11:05:16 ludo Exp $
     *
     */  
    class MP3 {
        var $id3_genres_array = array(
            'Blues', 'Classic Rock', 'Country', 'Dance', 'Disco', 'Funk', 'Grunge', 'Hip-Hop', 'Jazz', 'Metal', 'New Age', 'Oldies', 'Other', 'Pop', 'R&B', 'Rap', 'Reggae', 'Rock', 'Techno', 'Industrial',
            'Alternative', 'Ska', 'Death Metal', 'Pranks', 'Soundtrack', 'Euro-Techno', 'Ambient', 'Trip-Hop', 'Vocal', 'Jazz+Funk', 'Fusion', 'Trance', 'Classical', 'Instrumental', 'Acid', 'House',
            'Game', 'Sound Clip', 'Gospel', 'Noise', 'AlternRock', 'Bass', 'Soul', 'Punk', 'Space', 'Meditative', 'Instrumental Pop', 'Instrumental Rock', 'Ethnic', 'Gothic', 'Darkwave',
            'Techno-Industrial', 'Electronic', 'Pop-Folk', 'Eurodance', 'Dream', 'Southern Rock', 'Comedy', 'Cult', 'Gangsta', 'Top 40', 'Christian Rap', 'Pop/Funk', 'Jungle', 'Native American', 'Cabaret',
            'New Wave', 'Psychadelic', 'Rave', 'Showtunes', 'Trailer', 'Lo-Fi', 'Tribal', 'Acid Punk', 'Acid Jazz', 'Polka', 'Retro', 'Musical', 'Rock & Roll', 'Hard Rock', 'Folk', 'Folk/Rock', 'National Folk',
            'Swing', 'Fast Fusion', 'Bebob', 'Latin', 'Revival', 'Celtic', 'Bluegrass', 'Avantgarde', 'Gothic Rock', 'Progressive Rock', 'Psychedelic Rock', 'Symphonic Rock', 'Slow Rock', 'Big Band',
            'Chorus', 'Easy Listening', 'Acoustic', 'Humour', 'Speech', 'Chanson', 'Opera', 'Chamber Music', 'Sonata', 'Symphony', 'Booty Bass', 'Primus', 'Porn Groove', 'Satire', 'Slow Jam', 'Club', 'Tango', 'Samba',
            'Folklore', 'Ballad', 'Power Ballad', 'Rhythmic Soul', 'Freestyle', 'Duet', 'Punk Rock', 'Drum Solo', 'Acapella', 'Euro-house', 'Dance Hall'
        );
        var $info_bitrates = array(
            1    =>    array(
                1    =>    array( 0 => 0, 16 => 32, 32 => 64, 48 => 96, 64 => 128, 80 => 160, 96 => 192, 112 => 224, 128 => 256, 144 => 288, 160 => 320, 176 => 352, 192 => 384, 208 => 416, 224 => 448, 240 => false),
                2    =>    array( 0 => 0, 16 => 32, 32 => 48, 48 => 56, 64 =>  64, 80 =>  80, 96 =>  96, 112 => 112, 128 => 128, 144 => 160, 160 => 192, 176 => 224, 192 => 256, 208 => 320, 224 => 384, 240 => false),
                3    =>    array( 0 => 0, 16 => 32, 32 => 40, 48 => 48, 64 =>  56, 80 =>  64, 96 =>  80, 112 =>  96, 128 => 112, 144 => 128, 160 => 160, 176 => 192, 192 => 224, 208 => 256, 224 => 320, 240 => false)
            ),
            2    =>    array(
                1    =>    array( 0 => 0, 16 => 32, 32 => 48, 48 => 56, 64 =>  64, 80 => 80, 96 => 96, 112 => 112, 128 => 128, 144 => 144, 160 => 160, 176 => 176, 192 => 192, 208 => 224, 224 => 256, 240 => false),
                2    =>    array( 0 => 0, 16 =>  8, 32 => 16, 48 => 24, 64 =>  32, 80 => 40, 96 => 48, 112 =>  56, 128 =>  64, 144 =>  80, 160 =>  96, 176 => 112, 192 => 128, 208 => 144, 224 => 160, 240 => false),
                3    =>    array( 0 => 0, 16 =>  8, 32 => 16, 48 => 24, 64 =>  32, 80 => 40, 96 => 48, 112 =>  56, 128 =>  64, 144 =>  80, 160 =>  96, 176 => 112, 192 => 128, 208 => 144, 224 => 160, 240 => false)
            ),
        );
        var $info_versions = array(0 => "reserved", 1 => "MPEG Version 1", 2 => "MPEG Version 2", 2.5 => "MPEG Version 2.5");
        var $info_layers = array("reserved", "Layer I", "Layer II", "Layer III");
        var $info_sampling_rates = array(
            0        =>    array(0 => false, 4 => false, 8 => false, 12 => false),
            1        =>    array(0 => "44100 Hz", 4 => "48000 Hz", 8 => "32000 Hz", 12 => false),
            2        =>    array(0 => "22050 Hz", 4 => "24000 Hz", 8 => "16000 Hz", 12 => false),
            2.5    =>    array(0 => "11025 Hz", 4 => "12000 Hz", 8 => "8000 Hz", 12 => false),
        );
        var $info_channel_modes = array(0 => "stereo", 64 => "joint stereo", 128 => "dual channel", 192 => "single channel");
        var $file = "";
        var $fh = false;
        var $error = false;
        var $id3_parsed = false;
        var $id3 = array(
/*            "tag"            =>    "",
            "title"        =>    "unknown",
            "author"        =>    "unknown",
            "album"        =>    "unknown",
            "year"        =>    "unknown",
            "comment"    =>    "unknown",
            "genre_id"    =>    0,
            "genre"        =>    "unknown"
*/        );
        var $url = "";
        var $info = array();
         
        function mp3($file, $exitonerror=true) {
            if (file_exists($file)) {
                $this->file = $file;
                $this->fh = fopen($this->file,"r");
                global $HTTP_HOST, $PHP_SELF;
                $this->url = "http://$HTTP_HOST/$PHP_SELF";
            } else {
                $this->error = "No such file";
                if ($exitonerror) $this->exitonerror();
            }
        }
        function exitonerror() {
            echo($this->error);
            exit;
        }
        function set_id3($title = "", $author = "", $album = "", $year = "", $comment = "", $genre_id = 0) {
            $this->error = false;
            $this->wfh = fopen($this->file,"a");
            fseek($this->wfh, -128, SEEK_END);
            fwrite($this->wfh, pack("a3a30a30a30a4a30C1", "TAG", $title, $author, $album, $year, $comment, $genre_id), 128);
            fclose($this->wfh);
        }
        function get_id3() {
            $this->id3_parsed = true;
            fseek($this->fh, -128, SEEK_END);
            $line = fread($this->fh, 10000);
            if (preg_match("/^TAG/", $line)) {
                $this->id3 = unpack("a3tag/a30title/a30author/a30album/a4year/a30comment/C1genre_id", $line);
                $this->id3["genre"] = $this->id3_genres_array[$this->id3]["genre_id"]];
                return(true);
            } else {
                $this->error = "no idv3 tag found";
                return(false);
            }
        }
        // get_info() helper methods
        function calculate_length($id3v2_tagsize = 0) {
          $length = floor(($this->info["filesize"] - $id3v2_tagsize) / $this->info["bitrate"] * 0.008);
            $min = floor($length / 60);
            $min = strlen($min) == 1 ? "0$min" : $min;
            $sec = $length % 60;
            $sec = strlen($sec) == 1 ? "0$sec" : $sec;
            return("$min:$sec");
        }
        function get_info() {
//            $this->get_id3v2header();
            $second = $this->synchronize();
//            echo("2nd byte = $second <b>" . decbin($second) . "</b><br>");
            $third = ord(fread($this->fh, 1));
            $fourth = ord(fread($this->fh, 1));
            $this->info["version_id"] = ($second & 16) > 0 ? ( ($second & 8) > 0 ? 1 : 2 ) : ( ($second & 8) > 0 ? 0 : 2.5 );
            $this->info["version"] = $this->info_versions[ $this->info]["version_id"] ];
            $this->info["layer_id"] = ($second & 4) > 0 ? ( ($second & 2) > 0 ? 1 : 2 ) : ( ($second & 2) > 0 ? 3 : 0 );     ;
            $this->info["layer"] = $this->info_layers[ $this->info]["layer_id"] ];
            $this->info["protection"] = ($second & 1) > 0 ? "no CRC" : "CRC";
            $this->info["bitrate"] = $this->info_bitrates[ $this->info]["version_id"] ][ $this->info]["layer_id"] ][ ($third & 240) ];
            $this->info["sampling_rate"] = $this->info_sampling_rates[ $this->info]["version_id"] ][ ($third & 12)];
            $this->info["padding"] = ($third & 2) > 0 ? "on" : "off";
            $this->info["private"] = ($third & 1) > 0 ? "on" : "off";
            $this->info["channel_mode"] = $this->info_channel_modes[$fourth & 192];
            $this->info["copyright"] = ($fourth & 8) > 0 ? "on" : "off";
            $this->info["original"] = ($fourth & 4) > 0 ? "on" : "off";
            $this->info["filesize"] = filesize($this->file);
            $this->info["length"] = $this->calculate_length();
        }
        function synchronize() {
            $finished = false;
            rewind($this->fh);
            while (!$finished) {
                $skip = ord(fread($this->fh, 1));
//                echo("inside synchronize() skip = $skip <b>" . decbin($skip) . "</b><br>");
                while ($skip != 255 && !feof($this->fh)) {
                    $skip = ord(fread($this->fh, 1));
//                    echo("inside synchronize() skip = $skip <b>" . decbin($skip) . "</b><br>");
                }
                if (feof($this->fh)) {
                    $this->error("no info header found");
                    if ($exitonerror) $this->exitonerror();
                }
                $store = ord(fread($this->fh, 1));
//                echo("inside synchronize() store = $store <b>" . decbin($store) . "</b><br>");
                if ($store >= 225) {
                    $finished = true;
                } else if (feof($this->fh)) {
                    $this->error("no info header found");
                    if ($exitonerror) $this->exitonerror();
                }
            }
            return($store);
        }
        function get_id3v2header() {
            $bytes = fread($this->fh, 3);
            if ($bytes != "ID3") {
                echo("no ID3 tag");
                return(false);
            }
            // get major and minor versions
            $major = fread($this->fh, 1);
            $minor = fread($this->fh, 1);
            echo("ID3v$major.$minor");
        }
        function stream() {
            if (!$this->id3_parsed) {
                $this->get_id3();
            }
            header("ICY 200 OK\r\n");
            header("icy-notice1:This stream requires a shoutcast/icecast compatible player.<br>\r\n");
            header("icy-notice2:php MP3 class<br>\r\n");
            header("icy-name:" . (count($this->id3) > 0 ? $this->id3["title"] . " - " . $this->id3["author"] . " - " . $this->id3["album"] . " - " . $this->id3["year"] : $this->file) . "\r\n");
            header("icy-genre:" . (count($this->id3) > 0 ? $this->id3["genre"] : "unspecified") . "\r\n");
            header("icy-url:bbb\r\n");
            header("icy-pub:1\r\n");
            header("icy-br:320\r\n");
            rewind($this->fh);
            fpassthru($this->fh);
        }
        function send_playlist_header($numentries = 1) {
            header("Content-Type: audio/mpegurl;");
            echo("[playlist]\r\n\r\n");
            echo("NumberOfEntries=$numentries\r\n");
        }
        function send_pls($server) {
            $this->send_playlist_header();
            $path = "/";
            $path_array = explode("/", dirname($this->file));
            while(list($key,$val) = each($path_array)) {
                $path .= empty($val) ? "" : rawurlencode($val);
            }
            $path .= "/";
            $file = rawurlencode(preg_replace("/\.mp3$/", "", basename($this->file)));
            echo("File1=http://$server$path$file.mps\r\n");
        }
        function close() {
            @fclose($this->fh);
        }
    }

?>

原文转自：http://www.ltesting.net