php flv视频时间获取函数

<?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 

?>