php获取mp3音频信息实例教程

<?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 );
 }
}

<?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}
";
$_info = mp3Info('Beyond-情人.mp3');
print_r($_info);

→ 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
)