很早之前在网上看到一个获取 MP3 音频信息的 php 类。如：播放时长、文件大小、文件编码等等
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<?php class mp3file { protected $block; protected $blockpos; protected $blockmax; protected $blocksize; protected $fd; protected $bitpos; protected $mp3data; public function __construct($filename) { $this->powarr = array(0=>1,1=>2,2=>4,3=>8,4=>16,5=>32,6=>64,7=>128); $this->blockmax= 1024; $this->mp3data = array(); $this->mp3data['Filesize'] = filesize($filename); $this->fd = fopen($filename,'rb'); $this->prefetchblock(); $this->readmp3frame(); } public function __destruct() { fclose($this->fd); } //------------------- public function get_metadata() { return $this->mp3data; } protected function readmp3frame() { $iscbrmp3=true; if ($this->startswithid3()) $this->skipid3tag(); else if ($this->containsvbrxing()) { $this->mp3data['Encoding'] = 'VBR'; $iscbrmp3=false; } else if ($this->startswithpk()) { $this->mp3data['Encoding'] = 'Unknown'; $iscbrmp3=false; } if ($iscbrmp3) { $i = 0; $max=5000; //look in 5000 bytes... //the largest framesize is 4609bytes(256kbps@8000Hz mp3) for($i=0; $i<$max; $i++) { //looking for 1111 1111 111 (frame synchronization bits) if ($this->getnextbyte()==0xFF) if ($this->getnextbit() && $this->getnextbit() && $this->getnextbit()) break; } if ($i==$max) $iscbrmp3=false; } if ($iscbrmp3) { $this->mp3data['Encoding' ] = 'CBR'; $this->mp3data['MPEG version' ] = $this->getnextbits(2); $this->mp3data['Layer Description'] = $this->getnextbits(2); $this->mp3data['Protection Bit' ] = $this->getnextbits(1); $this->mp3data['Bitrate Index' ] = $this->getnextbits(4); $this->mp3data['Sampling Freq Idx'] = $this->getnextbits(2); $this->mp3data['Padding Bit' ] = $this->getnextbits(1); $this->mp3data['Private Bit' ] = $this->getnextbits(1); $this->mp3data['Channel Mode' ] = $this->getnextbits(2); $this->mp3data['Mode Extension' ] = $this->getnextbits(2); $this->mp3data['Copyright' ] = $this->getnextbits(1); $this->mp3data['Original Media' ] = $this->getnextbits(1); $this->mp3data['Emphasis' ] = $this->getnextbits(1); $this->mp3data['Bitrate' ] = mp3file::bitratelookup($this->mp3data); $this->mp3data['Sampling Rate' ] = mp3file::samplelookup($this->mp3data); $this->mp3data['Frame Size' ] = mp3file::getframesize($this->mp3data); $this->mp3data['Length' ] = mp3file::getduration($this->mp3data,$this->tell2()); $this->mp3data['Length mm:ss' ] = mp3file::seconds_to_mmss($this->mp3data['Length']); if ($this->mp3data['Bitrate' ]=='bad' || $this->mp3data['Bitrate' ]=='free' || $this->mp3data['Sampling Rate']=='unknown' || $this->mp3data['Frame Size' ]=='unknown' || $this->mp3data['Length' ]=='unknown') $this->mp3data = array('Filesize'=>$this->mp3data['Filesize'], 'Encoding'=>'Unknown'); } else { if(!isset($this->mp3data['Encoding'])) $this->mp3data['Encoding'] = 'Unknown'; } } protected function tell() { return ftell($this->fd); } protected function tell2() { return ftell($this->fd)-$this->blockmax +$this->blockpos-1; } protected function startswithid3() { return ($this->block[1]==73 && //I $this->block[2]==68 && //D $this->block[3]==51); //3 } protected function startswithpk() { return ($this->block[1]==80 && //P $this->block[2]==75); //K } protected function containsvbrxing() { //echo "<!--".$this->block[37]." ".$this->block[38]."-->"; //echo "<!--".$this->block[39]." ".$this->block[40]."-->"; return( ($this->block[37]==88 && //X 0x58 $this->block[38]==105 && //i 0x69 $this->block[39]==110 && //n 0x6E $this->block[40]==103) //g 0x67 /* || ($this->block[21]==88 && //X 0x58 $this->block[22]==105 && //i 0x69 $this->block[23]==110 && //n 0x6E $this->block[24]==103) //g 0x67*/ ); } protected function debugbytes() { for($j=0; $j<10; $j++) { for($i=0; $i<8; $i++) { if ($i==4) echo " "; echo $this->getnextbit(); } echo "<BR>"; } } protected function prefetchblock() { $block = fread($this->fd, $this->blockmax); $this->blocksize = strlen($block); $this->block = unpack("C*", $block); $this->blockpos=0; } protected function skipid3tag() { $bits=$this->getnextbits(24);//ID3 $bits.=$this->getnextbits(24);//v.v flags //3 bytes 1 version byte 2 byte flags $arr = array(); $arr['ID3v2 Major version'] = bindec(substr($bits,24,8)); $arr['ID3v2 Minor version'] = bindec(substr($bits,32,8)); $arr['ID3v2 flags' ] = bindec(substr($bits,40,8)); if (substr($bits,40,1)) $arr['Unsynchronisation']=true; if (substr($bits,41,1)) $arr['Extended header']=true; if (substr($bits,42,1)) $arr['Experimental indicator']=true; if (substr($bits,43,1)) $arr['Footer present']=true; $size = ""; for($i=0; $i<4; $i++) { $this->getnextbit();//skip this bit, should be 0 $size.= $this->getnextbits(7); } $arr['ID3v2 Tags Size']=bindec($size);//now the size is in bytes; if ($arr['ID3v2 Tags Size'] - $this->blockmax>0) { fseek($this->fd, $arr['ID3v2 Tags Size']+10 ); $this->prefetchblock(); if (isset($arr['Footer present']) && $arr['Footer present']) { for($i=0; $i<10; $i++) $this->getnextbyte();//10 footer bytes } } else { for($i=0; $i<$arr['ID3v2 Tags Size']; $i++) $this->getnextbyte(); } } protected function getnextbit() { if ($this->bitpos==8) return false; $b=0; $whichbit = 7-$this->bitpos; $mult = $this->powarr[$whichbit]; //$mult = pow(2,7-$this->pos); $b = $this->block[$this->blockpos+1] & $mult; $b = $b >> $whichbit; $this->bitpos++; if ($this->bitpos==8) { $this->blockpos++; if ($this->blockpos==$this->blockmax) //end of block reached { $this->prefetchblock(); } else if ($this->blockpos==$this->blocksize) {//end of short block reached (shorter than blockmax) return;//eof } $this->bitpos=0; } return $b; } protected function getnextbits($n=1) { $b=""; for($i=0; $i<$n; $i++) $b.=$this->getnextbit(); return $b; } protected function getnextbyte() { if ($this->blockpos>=$this->blocksize) return; $this->bitpos=0; $b=$this->block[$this->blockpos+1]; $this->blockpos++; return $b; } //----------------------------------------------------------------------------- public static function is_layer1(&$mp3) { return ($mp3['Layer Description']=='11'); } public static function is_layer2(&$mp3) { return ($mp3['Layer Description']=='10'); } public static function is_layer3(&$mp3) { return ($mp3['Layer Description']=='01'); } public static function is_mpeg10(&$mp3) { return ($mp3['MPEG version']=='11'); } public static function is_mpeg20(&$mp3) { return ($mp3['MPEG version']=='10'); } public static function is_mpeg25(&$mp3) { return ($mp3['MPEG version']=='00'); } public static function is_mpeg20or25(&$mp3) { return ($mp3['MPEG version']{1}=='0'); } //----------------------------------------------------------------------------- public static function bitratelookup(&$mp3) { //bits V1,L1 V1,L2 V1,L3 V2,L1 V2,L2&L3 $array = array(); $array['0000']=array('free','free','free','free','free'); $array['0001']=array( '32', '32', '32', '32', '8'); $array['0010']=array( '64', '48', '40', '48', '16'); $array['0011']=array( '96', '56', '48', '56', '24'); $array['0100']=array( '128', '64', '56', '64', '32'); $array['0101']=array( '160', '80', '64', '80', '40'); $array['0110']=array( '192', '96', '80', '96', '48'); $array['0111']=array( '224', '112', '96', '112', '56'); $array['1000']=array( '256', '128', '112', '128', '64'); $array['1001']=array( '288', '160', '128', '144', '80'); $array['1010']=array( '320', '192', '160', '160', '96'); $array['1011']=array( '352', '224', '192', '176', '112'); $array['1100']=array( '384', '256', '224', '192', '128'); $array['1101']=array( '416', '320', '256', '224', '144'); $array['1110']=array( '448', '384', '320', '256', '160'); $array['1111']=array( 'bad', 'bad', 'bad', 'bad', 'bad'); $whichcolumn=-1; if (mp3file::is_mpeg10($mp3) && mp3file::is_layer1($mp3) )//V1,L1 $whichcolumn=0; else if (mp3file::is_mpeg10($mp3) && mp3file::is_layer2($mp3) )//V1,L2 $whichcolumn=1; else if (mp3file::is_mpeg10($mp3) && mp3file::is_layer3($mp3) )//V1,L3 $whichcolumn=2; else if (mp3file::is_mpeg20or25($mp3) && mp3file::is_layer1($mp3) )//V2,L1 $whichcolumn=3; else if (mp3file::is_mpeg20or25($mp3) && (mp3file::is_layer2($mp3) || mp3file::is_layer3($mp3)) ) $whichcolumn=4;//V2, L2||L3 if (isset($array[$mp3['Bitrate Index']][$whichcolumn])) return $array[$mp3['Bitrate Index']][$whichcolumn]; else return "bad"; } //----------------------------------------------------------------------------- public static function samplelookup(&$mp3) { //bits MPEG1 MPEG2 MPEG2.5 $array = array(); $array['00'] =array('44100','22050','11025'); $array['01'] =array('48000','24000','12000'); $array['10'] =array('32000','16000','8000'); $array['11'] =array('res','res','res'); $whichcolumn=-1; if (mp3file::is_mpeg10($mp3)) $whichcolumn=0; else if (mp3file::is_mpeg20($mp3)) $whichcolumn=1; else if (mp3file::is_mpeg25($mp3)) $whichcolumn=2; if (isset($array[$mp3['Sampling Freq Idx']][$whichcolumn])) return $array[$mp3['Sampling Freq Idx']][$whichcolumn]; else return 'unknown'; } //----------------------------------------------------------------------------- public static function getframesize(&$mp3) { if ($mp3['Sampling Rate']>0) { return ceil((144 * $mp3['Bitrate']*1000)/$mp3['Sampling Rate']) + $mp3['Padding Bit']; } return 'unknown'; } //----------------------------------------------------------------------------- public static function getduration(&$mp3,$startat) { if ($mp3['Bitrate']>0) { $KBps = ($mp3['Bitrate']*1000)/8; $datasize = ($mp3['Filesize'] - ($startat/8)); $length = $datasize / $KBps; return sprintf("%d", $length); } return "unknown"; } //----------------------------------------------------------------------------- public static function seconds_to_mmss($duration) { return sprintf("%d:%02d", ($duration /60), $duration %60 ); } } |
调用
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<?php include_once 'mp3file.class.php'; function mp3Time($file) { $m = new mp3file($file); $a = $m->get_metadata(); return $a['Length mm:ss'] ? $a['Length mm:ss'] : 0; } function mp3Info($file) { $m = new mp3file($file); return $m->get_metadata(); } $_time = mp3Time('Beyond-情人.mp3'); echo "歌曲时间长：{$_time}\n"; $_info = mp3Info('Beyond-情人.mp3'); print_r($_info); |
输出信息
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→ php mp3.php 歌曲时间长：5:15 Array ( [Filesize] => 7576152 [Encoding] => CBR [MPEG version] => 11 [Layer Description] => 01 [Protection Bit] => 1 [Bitrate Index] => 1011 [Sampling Freq Idx] => 00 [Padding Bit] => 0 [Private Bit] => 0 [Channel Mode] => 00 [Mode Extension] => 00 [Copyright] => 0 [Original Media] => 1 [Emphasis] => 0 [Bitrate] => 192 [Sampling Rate] => 44100 [Frame Size] => 627 [Length] => 315 [Length mm:ss] => 5:15 ) |
