why do i have a smaller file?

[jeex]

i just got through encoding "clerks" to divx with vidomi.

it made 2 files

clerks.avi 736,282,624 bytes [702mb]
clerks1.avi 806,912 bytes [788k]

i then decided i didnt want 2 seperate files, so i decided to merge them through virtual dub.

i opened "clerks.avi", set "video" to "direct stream copy" the same for audio. i then "append avi segment" and added clerks1.avi. it merged them together, and the file plays just fine and dandy. the only thing is the merged file is;
734,732,288 bytes [700mb]

why is it when i merge the 2 files together, the end result file is smaller?

is it lowering the quality of the video or something?


thanks for any help

[jeex]

c'mon! i dont want to have to hurt avery lee. he's got a such a nice program.