Uncompressed, YUV, DV, h.264 in the form of MP4 and AVCHD, MPEG2 of various possible bitrates and color sampling. Vegas also includes the ability to read MJPEG files, Windows Media. Why do you ask?
I am capturing old VHS tapes, and would like to adjust settings on the card and/or capture program such that Vegas will properly import the video and audio. Right now I am generating avi files that Windows Media Player and Premiere Pro can work with, but not Vegas 8.
AVI can be type 1 or type 2. Most editors seem to prefer type 2. Perhaps you are capturing type 1. If you cannot choose type at capture you will need a utility to change the type. Also AVI is only the wrapper. Is the underlying codec DV?
I am using VirtualDub to capture the video and audio. I am new to this program, and evidently this saves the file as an uncompressed AVI file (very big) that Wmp9 and Premiere Pro CS3 can work with, but not Vegas. I found that if I run the captured file though VirtualDub and save using the Intel YUV2 codec, Vegas is happy. I apparently can not tell VirtualDub to capture and save the file as a compressed file at the same time, but for the time being, this is good enough.
VCR = JVC SR-V101US, video -> capture card via S-video, capture card = Osprey 210, very happy with hardware, just got to the the software all working together.
I use uncompressed avi files exported from my slideshow software (Photodex Producer) all the time in Vegas with no issues (other than they are BIG). You might see what the GSpot utility (free) says is being used and other handy information about the files you are capturing.
I use a Canopus (now Grass Valley ) ADVC 100 for capture from my VHS stuff that works very well (output is DV format - about 13 gigs/hour). Vegas takes those files too with no problem.
For years I have been capturing VHS stuff through my AV<>DV conversion through to VEgas Video Capture Program. I take off the DV Scene detect and DV Control and it is quite faultless. Any reason why you aren't capturing this way too?
Find an old miniDV camcorder that has a feature called pass-through.
The camcorder doesn't have to have a working tape transport.
As long as the electronics are in working order, all you use it for is feeding the signal from your VHS deck (composite or S-video) into it and then firewire out into your computer.
File size will be much more manageable this way.
So get a capture device that easily and reliably translates analogue to 1394 with zero extra effort, such as ADS Pyro AV or a zillion others. Didn't you know that ;-)