note 90970 modified in function.swfmovie.streammp3 by danbrown
| From: | danbrown@php.net | Date: | Tue, 19 May 2009 11:48:18 +0000 |
| Subject: | note 90970 modified in function.swfmovie.streammp3 by danbrown | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-155721@lists.php.net to get a copy of this message | ||
Hey all,
For those using Ming 0.3 (like me), there is a way to calculate the length of the MP3 you are using.
It might be a bit iffy for VBR files, but it seems to work well for the files I've tested thus
far. The process of calculating the frame length (and size) is detailed at http://www.mpgedit.org/mpgedit/mpeg_format/mpeghdr.htm
<?php
function get_mp3_len ($file) {
$rate1=array(0, 32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384, 416, 448,
"bad");
$rate2=array(0, 32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384,
"bad");
$rate3=array(0, 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320,
"bad");
$rate4=array(0, 32, 48, 56, 64, 80, 96, 112, 128, 144, 160, 176, 192, 224, 256,
"bad");
$rate5=array(0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160, "bad");
$bitrate=array(
'1' => $rate5,
'2' => $rate5,
'3' => $rate4,
'9' => $rate5,
'10' => $rate5,
'11' => $rate4,
'13' => $rate3,
'14' => $rate2,
'15' => $rate1
);
$sample=array(
'0' => 11025,
'1' => 12000,
'2' => 8000,
'8' => 22050,
'9' => 24000,
'10' => 16000,
'12' => 44100,
'13' => 48000,
'14' => 32000
);
$fd=fopen($file, 'rb');
$header=fgets($fd, 5);
fclose($fd);
$bits="";
while (strlen($header) > 0) {
//var_dump($header);
$bits.=str_pad(base_convert(ord($header{0}), 10, 2), 8, '0',
STR_PAD_LEFT);
$header=substr($header, 1);
}
$bits=substr($bits, 11); // lets strip the frame sync bits first.
$version=substr($bits, 0, 2); // this gives us the version
$layer=base_convert(substr($bits, 2, 2), 2, 10); // this gives us the layer
$verlay=base_convert(substr($bits, 0, 4), 2, 10); // this gives us both
$rateidx=base_convert(substr($bits, 5, 4), 2, 10); // this gives us the bitrate index
$sampidx=base_convert($version.substr($bits, 9, 2), 2, 10); // this gives the sample index
$padding=substr($bits, 11, 1); // are we padding frames?
$rate=$bitrate[$verlay][$rateidx];
$samp=$sample[$sampidx];
$framelen=0;
$framesize=384; // Size of the frame in samples
if ($layer == 3) { // layer 1?
$framelen=(12 * ($rate * 1000) / $samp + $padding) * 4;
} else { // Layer 2 and 3
$framelen=144 * ($rate * 1000) / $samp + $padding;
$framesize=1152;
}
$headerlen=4 + ($bits{4} == 0 ? '2' : '0');
return (filesize($file) - $headerlen) / $framelen / ($samp / $framesize);
}
?>
--was--
Hey all,
For those using Ming 0.3 (like me), there is a way to calculate the length of the MP3 you are using.
It might be a bit iffy for VBR files, but it seems to work well for the files I've tested thus
far.
<?php
function get_mp3_len ($file) {
$rate1=array(0, 32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384, 416, 448,
"bad");
$rate2=array(0, 32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384,
"bad");
$rate3=array(0, 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320,
"bad");
$rate4=array(0, 32, 48, 56, 64, 80, 96, 112, 128, 144, 160, 176, 192, 224, 256,
"bad");
$rate5=array(0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160, "bad");
$bitrate=array(
'1' => $rate5,
'2' => $rate5,
'3' => $rate4,
'9' => $rate5,
'10' => $rate5,
'11' => $rate4,
'13' => $rate3,
'14' => $rate2,
'15' => $rate1
);
$sample=array(
'0' => 11025,
'1' => 12000,
'2' => 8000,
'8' => 22050,
'9' => 24000,
'10' => 16000,
'12' => 44100,
'13' => 48000,
'14' => 32000
);
$fd=fopen($file, 'rb');
$header=fgets($fd, 5);
fclose($fd);
$bits="";
while (strlen($header) > 0) {
//var_dump($header);
$bits.=str_pad(base_convert(ord($header{0}), 10, 2), 8, '0',
STR_PAD_LEFT);
$header=substr($header, 1);
}
$bits=substr($bits, 11); // lets strip the frame sync bits first.
$version=substr($bits, 0, 2); // this gives us the version
$layer=base_convert(substr($bits, 2, 2), 2, 10); // this gives us the layer
$verlay=base_convert(substr($bits, 0, 4), 2, 10); // this gives us both
$rateidx=base_convert(substr($bits, 5, 4), 2, 10); // this gives us the bitrate index
$sampidx=base_convert($version.substr($bits, 9, 2), 2, 10); // this gives the sample index
$padding=substr($bits, 11, 1); // are we padding frames?
$rate=$bitrate[$verlay][$rateidx];
$samp=$sample[$sampidx];
$framelen=0;
$framesize=384; // Size of the frame in samples
if ($layer == 3) { // layer 1?
$framelen=(12 * ($rate * 1000) / $samp + $padding) * 4;
} else { // Layer 2 and 3
$framelen=144 * ($rate * 1000) / $samp + $padding;
$framesize=1152;
}
$headerlen=4 + ($bits{4} == 0 ? '2' : '0');
return (filesize($file) - $headerlen) / $framelen / ($samp / $framesize);
}
?>
http://php.net/manual/en/function.swfmovie.streammp3.php