If you're looking for a computerless capture option like the Pinnacle Video Transfer, the HD PVR Rocket is a more modern and easy to find option that I've used and works great. Haven't used the PVT so I can't truly say which is better for Melee, but it can output excellent looking 480p60 video from 480i, and I've heard the PVT has audio sync issues on long recordings that I haven't encountered with the Rocket.
You can connect composite to the blue (Pb) plug on the component breakout cable that comes with it, or optionally get a cable with s-video input from the Hauppauge site (there's also a composite breakout cable I believe but it accomplishes the same thing as connecting to the blue component anyway, just more obvious to hook up by connecting yellow->yellow plug rather than yellow->blue). I think there was also another standalone capture device I was looking at that I forget that supposedly works with 480i by similarly connecting composite to the green (Y) component plug, so that's probably another device option besides the PVT and Rocket.
It also needs a USB adapter like a phone charger to plug it into an outlet if you're using a GC, as it's powered by USB cable. With a Wii, I can say that it does work by using the 2nd USB port while USB loading with Nintendont. Dunno about if SD loading, and I don't use DIOS-MIOS as installing it causes crashes when loading some melee stages running on disc despite claims it doesn't mess with disc play on newer versions, and can't use my USB gecko debugger with it either. I doubt you can power it with the Wii's USB while running off disc as iirc the ports don't have power in GC mode.
You'll want to update the firmware and configure the capture settings with the Hauppauge Capture software (they'll save to the device for when recording PC-less), as the default bitrate is way too high for 480 video (default is 20mbps I believe. went with 3mbps iirc for 480p60). Deinterlaces the 480i signal to 480p 60fps by default with updated firmware and looks really nice (the deinterlace interpolation is good. though sometimes on stuff like when you flicker from electric attacks you can notice some interlacing artifacts on the character if you look closely. dunno if it's due to dot crawl from the composite when being deinterlaced that'd be fixed by using s-video, or if it's from the interpolation of the deinterlacing method itself).
If you run into an issue where it just loses the ability to pick up a 480i signal at all like I did when messing with the firmware and software to configure the capture settings, try reinstalling the firmware or to an older version of the firmware to get it working again then update the firmware again. Running Hauppauge Capture software more than once since last installing the firmware seemed to cause that issue (maybe the saved settings get messed up and nonfunctional somehow when loaded by the software the second time), though could just be my really outdated OS not working well with the drivers and software. Was a bit of a hassle to get configured the way I wanted without breaking 480i compatibility, but once done I don't need to bother with it again.
Also I've tried using the AV OUT on one of my CRT's and that doesn't actually work as intended either. Perhaps I need to connect splitters into the capture device aswell I'm not sure?
