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
?>