PHP MP3提取音量峰值
假设你有一个mp3文件 是否可以使用PHP提取mp3文件中每个字节的音量级别(设置在0和100之间) 这是我已经有的,它可能会帮助你PHP MP3提取音量峰值,php,mp3,Php,Mp3,假设你有一个mp3文件 是否可以使用PHP提取mp3文件中每个字节的音量级别(设置在0和100之间) 这是我已经有的,它可能会帮助你 function peaks($filename) { if (!file_exists($filename)) { return false; } $bitRates = array( array(0,0,0,0,0), array(
function peaks($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 * 12;
$fileData = array('bitRate' => 0, 'sampleRate' => 0, 'bits' => 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();
$lastFrameVerify = null;
for ($o = 1; $o < count($bytes) - 4; $o++) {
//http://mpgedit.org/mpgedit/mpeg_format/MP3Format.html
//header is AAAAAAAA AAABBCCD EEEEFFGH IIJJKLMM
if (($bytes[$o] & 255) == 255 && ($bytes[$o+1] & 224) == 224) {
$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
$srIndex = ($bytes[$o+2] & 12) >> 2; //get FF (0 -> 3)
$brRow = ($bytes[$o+2] & 240) >> 4; //get EEEE (0 -> 15)
$frame['padding'] = ($bytes[$o+2] & 2) >> 1; //get G
if ($frame['version'] != 1 && $frame['layer'] > 0 && $srIndex < 3 && $brRow != 15 && $brRow != 0 &&
(!$lastFrameVerify || $lastFrameVerify === $bytes[$o+1])) {
//valid frame header
//calculate how much to skip to get to the next header
$frame['sampleRate'] = $sampleRates[$frame['version']][$srIndex];
if ($frame['version'] & 1 == 1) {
$frame['bitRate'] = $bitRates[$brRow][$frame['layer']-1]; //v1 and l1,l2,l3
} else {
$frame['bitRate'] = $bitRates[$brRow][($frame['layer'] & 2 >> 1)+3]; //v2 and l1 or l2/l3 (3 is the offset in the arrays)
}
if ($frame['layer'] == 1) {
$frame['frameLength'] = (12 * $frame['bitRate'] * 1000 / $frame['sampleRate'] + $frame['padding']) * 4;
} else {
$frame['frameLength'] = 144 * $frame['bitRate'] * 1000 / $frame['sampleRate'] + $frame['padding'];
}
$frames[] = $frame;
$lastFrameVerify = $bytes[$o+1];
$o += floor($frame['frameLength'] - 1);
} else {
$frames = array();
$lastFrameVerify = null;
}
}
if (count($frames) < 3) { //verify at least 3 frames to make sure its an mp3
continue;
}
$header = array_pop($frames);
$fileData['sampleRate'] = $header['sampleRate'];
$fileData['bitRate'] = $header['bitRate'];
$fileData['bits'] = $bytes;
break;
}
return $fileData;
}
函数峰值($filename)
{
如果(!file_存在($filename)){
返回false;
}
$bitRates=数组(
数组(0,0,0,0,0),
数组(32,32,32,32,8),
阵列(64,48,40,48,16),
阵列(96,56,48,56,24),
阵列(128,64,56,64,32),
阵列(160,80,64,80,40),
阵列(192,96,80,96,48),
阵列(224112,96112,56),
阵列(256128112128,64),
阵列(288160128144,80),
阵列(320192160160,96),
阵列(352224192176112),
阵列(384256224192128),
阵列(416320256224144),
阵列(448384320256160),
数组(-1,-1,-1,-1,-1),
);
$sampleRates=数组(
阵列(11025120008000),//mpeg 2.5
数组(0,0,0),
阵列(22050240016000),//mpeg 2
阵列(44100480003200),//mpeg 1
);
$bToRead=1024*12;
$fileData=array('bitRate'=>0,'sampleRate'=>0,'bits'=>0);
$fp=fopen($filename,'r');
如果(!$fp){
返回false;
}
//在文件结尾之前查找8kb
fseek($fp,-1*$b向前,搜索结束);
$data=fread($fp,$bToRead);
$bytes=unpack('C*',$data);
$frames=array();
$lastFrameVerify=null;
对于($o=1;$o>3;//获取BB(0->3)
$frame['layer']=abs(($bytes[$o+1]&6)>>1)-4;//获取CC(1->3),然后反转
$srIndex=($bytes[$o+2]&12)>>2;//获取FF(0->3)
$brRow=($bytes[$o+2]&240)>>4;//获取EEEE(0->15)
$frame['padding']=($bytes[$o+2]&2)>>1;//获取G
如果($frame['version'!=1&&$frame['layer']>0&&$srIndex<3&&$brRow!=15&&$brRow!=0&&
(!$lastFrameVerify | |$lastFrameVerify===$bytes[$o+1])){
//有效帧头
//计算跳转到下一个标题的次数
$frame['sampleRate']=$sampleRates[$frame['version']][$srIndex];
if($frame['version']&1==1){
$frame['bitRate']=$bitRates[$brRow][$frame['layer']-1];//v1和l1、l2、l3
}否则{
$frame['bitRate']=$bitRates[$brRow][($frame['layer']&2>>1)+3];//v2和l1或l2/l3(3是数组中的偏移量)
}
如果($frame['layer']==1){
$frame['frameLength']=(12*$frame['bitRate']*1000/$frame['sampleRate']+$frame['padding'])*4;
}否则{
$frame['frameLength']=144*$frame['bitRate']*1000/$frame['sampleRate']+$frame['padding'];
}
$frames[]=$frames;
$lastFrameVerify=$bytes[$o+1];
$o+=地板($frame['frameLength']-1);
}否则{
$frames=array();
$lastFrameVerify=null;
}
}
如果(计数($frames)<3){//请验证至少3帧,以确保它是mp3
继续;
}
$header=array\u pop($frames);
$fileData['sampleRate']=$header['sampleRate'];
$fileData['bitRate']=$header['bitRate'];
$fileData['bits']=$bytes;
打破
}
返回$fileData;
}
如果这样做有效,它将用于从mp3文件生成波形。这个类也可以是一个很好的起点: 此处的用例:
您有什么解决方案吗