I see you didn't
get response, so I'll see if I can be helpful here as a non-expert who's gotten some good results.
Ideally, you'll want to end up with a .mp4 file. Anything and everything can play mp4's, including pretty much every new smart TV. If your files are properly captured to interlaced .avi files, AND if you're perfectly happy with the image quality in terms of luminance (no crushed blacks or blown out whites) and chroma (colors aren't washed out or overly saturated) and noise, you can convert them directly to mp4 with something fairly simple like Handbrake. Most captured videos can be improved with corrections to luminance and chroma values, and you may want to edit out some bits (family appreciates this LOL), so for that you could use a more sophisticated non-linear editor like Adobe Premiere, or any number of cheaper programs. Whether in Handbrake or a NLE like Premiere, you want to export to a 60 frame per second file (technically 59.94 fps), same resolution as your original file (probably 720x480), where each field of your interlaced video is converted to its own frame. In Handbrake you set the frame rate to a fixed 59.94 and use the deinterlacing plugin set to "Bob". In Premiere, you can just put the file into a 59.94fps timeline for editing/color fixing/etc, and export to 59.94, and it'll convert each field to a frame. This 60fps rate will avoid smushing fields together and causing blurred motion, and preserve the smooth motion of television we all know and love. So you'll end up with an mp4 at 720x480 and 59.94 fps, and that should be ideal for viewing on computers or TVs.
BUT... If you ever do want to upload said videos to YouTube or Facebook, etc., there are other considerations. YouTube doesn't allow the 60fps frame rate unless your video is at least 720p, and they use awful bitrates for 480p videos. So for YouTube, I upscale the video in a 1920x1080p 60fps timeline, and even zoom in just enough to crop off the head switching noise at the bottom, and export to 1920x1080p60 with about a 20 Mbps bitrate, and just leaving the black bars on the sides. You could export to 1440x1080p60 or 960x720p60 for a 4x3 image, but I feel like it looks better at a 16x9 aspect ratio with the black bars on the side, mostly because YouTube allocates more bitrate for higher resolution files. Obviously you can't create detail out of thin air by upscaling, but you can perserve what's there better.
For Facebook, you have to deinterlace to 30fps, and for that I just do a basic field blend and let the motion be blurry because who cares, Facebook video is atrocious.
But again, for your scenario where nothing is going online, 720x480p60 mp4 is fine, with a bitrate around 5-10 Mbps. I've never used
avidemux, but I'm sure there's a way. But I can only tolerate so much user UNfriendly software. :-)
