I was interested in finding the total duration of an mpeg video file
and other information,
I understand that this can be done by looking at the frame headers of
the file but I donot know how to go about looking/accessiing the frame
headers of the file.

P.S I have used mpeg parser and similar programs but need the source
code or how to do it

With an MPEG, you probably won't be able to extract length from a
header... the file format is designed so that groups of frames can be
extracted and played independently.  (See
http://www.dv.co.yu/mpgscript/mpeghdr.htm for a more in-depth
explanation)  What that means is that unless the file's author
voluntarily included some sort of meta-information, there's no
guarantee that length or other file attributes are included within the
file.  Other formats require the use of that type of header, but not
most versions of MPEG.

Maybe this will help:

http://www.wotsit.org/download.asp?f=mpeg

It is the file format for mpeg video files. It gives you every
information you need to calculate the duration.