Other than rad/bink there are no DS video formats that have been reverse engineered as far as making players for them. Mods (one of the vx and actimagine family, which Nintendo bought out at one stage) being one of the bigger formats here.
Some people found out the basics of the format but again no standalone player.
If you just want to rip them then either find a game (preferably from around the same time as the format did shift a bit over the years) or use the game they came from and rename files within it -- overwrite the game intro video with the final boss death scene video and hopefully said final boss death scene plays where the intro would. You can then rip it with the video options of the emulator or something.