[FFmpeg-user] problem converting and combining these FLV files

[phil curb]

I have this file, i'm trying to combine it with a copy of itself. 
http://www.sendspace.com/file/dkg3rz

But the result while being twice as big, is the same duration.

C:\blah>dir 
Karateka.flv        (399,375)

I want to create one big file that is 2 of them combined.

So I convert the flv to mpg which one can combine with copy /B

ffmpeg -i Karateka.flv -sameq Karateka.mpg

this has created

Karateka.mpg  753,664 

I create 2 copies of this. So now 3 in total

 753,664 Karateka.mpg
 753,664 Karateka2.mpg
 753,664 Karateka3.mpg

Now I do  Copy /B Karateka.mpg+Karateka2.mpg
 1,507,328 Karateka.mpg
   753,664 Karateka2.mpg
   753,664 Karateka3.mpg

The problem here is that the mpg that is twice the size, is exactly the same duration as the original.  It hasn't combined.