why is my file so big?

[So12]

i was using Virtual DUB to record a some tv, to see if it worked. i noticed that that 1 min of video took up almost a gig, and i want to know what im doing wrong.
It's set to full NTSC (640x480) and on cd quality sound and at 29.97 fps, Followed the Doom9 Guide, but says nothing about size

Is it because of the resolution, or is it the resolution too big

[trevlac]

You need a capture codec to compress the video. Uncompressed video is real big. Go to the "The Capture Codec settings" section in the guide. :)