I used to have a youtube channel with a couple mario kart ds speedruns about a year ago but I took them down a while ago and I no longer have the files. I also recorded it by holding up a phone to the ds so the capture was bad. If anyone could tell me about a good way to capture that kind of stuff? Maybe emulator, though not sure if emulators are looked down on in the community so might just keep using my phone. I also have a discord if anyone wants to reach me there

Hello and welcome! I don't know for Mario Kart DS, but I know that emulators are common in certain games, such as older Pokémon games. But be careful to use the approved emulators with the correct settings for your runs to be accepted! If emulators are not accepted, capture cards are often used to record gameplay. I hoped this helped at least a bit!