Hi RIPNHL2005
Welcome to apple discussions. If you find that the avi file/s will not work within iDvd directly (and some will not since avi is simply a container format) then the best way I find is to first convert them with an app like Mpeg streamclip. There are at least two web locations where you can download this freeware and they are shown below.
http://www.squared5.com/svideo/mpeg-streamclip-mac.html
http://www.apple.com/downloads/macosx/video/mpegstreamclip.html
Assuming your episodes do not exceed 120 mins. per single layer dvd (or about twice that for dual layer media) then you can use iDvd thereafter.
However I do have an alternate suggestion also. I use software from Elgato / EyeTV3 in combination with EyeTV products to capture directly to my Hdd and then I can use Toast to burn them to Dvd thereafter. Works rather well and especially if I need to exceed 120 mins per dvd. Toast offers a fit to dvd option that you can't find within iDvd.
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