By default,
VirtualDub uses the uncompressed RGB/YUV codec, which uses about 75GB/hour. Your camera, on the other hand, uses DV25 compression, at about 13GB/hour.
You can easily change the codec in
VirtualDub, both in editor mode and capture mode, by going to VIDEO > COMPRESSION. ("Video" is one of the menus. File, Edit, etc.)
vdub-compressions.jpg
The codecs you have available depends entirely on what you have installed.
The codec you choose depends entirely on what your goals are. For example, I would capture uncompressed if the video is heavily damaged, which will netx be restored. For most footage,
HuffYUV is a good choice, and you can use this in an editor. If this simply needs to be archived, I might consider Matrox MPEG (broadcast standard, not DVD-Video standard).
Side note about "capturing"...
You're also not really "capturing" video from the camera, but rather transferring raw DV data from a tape to a container file on the computer -- the reason your DV video is in an AVI in Windows, or in a MOV file on a Mac.
The analog-in computer capture card, on the other hand, is actually creating a new digital version from the analog data it's being given.
If you're using an HD PVR type capture card, it will often "capture" the HD TV streams and store them in files unchanged, similar to how DV is "captured" from a tape -- new video encodes are not created, but video is simply re-stored in a new container file, from raw (or "rawer") type video feed sources. The analog portion of the card reacts like any other analog-in/analog-only card.