MPEG1,2 - reading info from MPG

pape

Hi all,
I need to find the *.MPG file, MPEG-1/2 information on the duration and number of frames by reading the file bytes.

My way is now:
Duration_mS = lastGOPTime_mS - firstGOPTime_mS + (I_FramesCnt/Framerate)
Frames = Duration_mS / 1000 * FrameRate
where:
GOP = 0xB8010000 packet.
I_FramesCnt is 0x00010000 packets.

This method is quite satisfactory, but probably not very accurate.
I can use MCI-commands (on MS-Windows), but not want.

Any idea, principe ? May be in VB or C.

Thanks everyone.