Technical FLV question

Alright so i have a bit of a puzzle here i cant seem to solve
All the FLV files i have seem to be off a bit in size (x:y size)

for instance Dilbert animated comic i have one on my computer that plays just fine in FLV form, with x:y being 400:300 HOWEVER Gspot reads the file and says the video is 400:304, and i want to demux the video stream from this file, with the appropriate x:y (400:300 not 400:304)

i have tried FLVExtract and it adds 304 not 300. The extra 4 is simple a copy of the line above. I want to extract the stream correctly. This happends with most other FLV files i am finding as well

i want to do a direct stream copy becuase i dont like encoding.

Is is possible to hexedit out the 4? ive been doing research on file headers but im still not sure. Would that simply squash the image, or would it just not “display” the extra 4, or is it even possible

is there anyone else who has had this problem? or any insight into it mabye?

PS on Hulu videos its a difference of 8 not four, the videos are supposed to be either 480x360 or 640x360, instead they demux as 480x368 and 640x368