php获取flv视频时间方法

<?php  
function BigEndian2Int($byte_word, $signed = false) {  
$int_value = 0;  

$byte_wordlen = strlen($byte_word);  

for ($i = 0; $i < $byte_wordlen; $i++)  
{  

$int_value += ord($byte_word{$i}) * pow(256, ($byte_wordlen - 1 - $i));  

}  
if ($signed)  
{  

$sign_mask_bit = 0x80 << (8 * ($byte_wordlen - 1));  

if ($int_value & $sign_mask_bit)  
{  

$int_value = 0 - ($int_value & ($sign_mask_bit - 1));  

}  

}  

return $int_value;  

}  

function getTime($name){  

if(!file_exists($name)){  

return;  

}  

$flv_data_length=filesize($name);  

$fp = @fopen($name, 'rb');  

$flv_header = fread($fp, 5);  

fseek($fp, 5, SEEK_SET);  

$frame_size_data_length =BigEndian2Int(fread($fp, 4));  

$flv_header_frame_length = 9;  

if ($frame_size_data_length > $flv_header_frame_length) {  

fseek($fp, $frame_size_data_length - $flv_header_frame_length, SEEK_CUR);  

}  

$duration = 0;  

while ((ftell($fp) + 1) < $flv_data_length) {  

$this_tag_header = fread($fp, 16);  

$data_length = BigEndian2Int(substr($this_tag_header, 5, 3));  

$timestamp = BigEndian2Int(substr($this_tag_header, 8, 3));  

$next_offset = ftell($fp) - 1 + $data_length;  

if ($timestamp > $duration) {  

$duration = $timestamp;  

}  

fseek($fp, $next_offset, SEEK_SET);  

}  

fclose($fp);  

return $duration;  

}  

function fn($time){  

$num = $time;  

$sec = intval($num / 1000);  

$h = intval($sec / 3600);  

$m = intval(($sec % 3600) / 60);  

$s = intval(($sec % 60 ));  

$tm = $h . ':' . $m . ':' . $s ;  

return $tm;  

}  

echo getTime("27729.flv");//显示数字时间如236722  

echo fn(236722); //显示时间格式0:03:56  

?>