Recently I'm toying a little in Nintendo DS Roms.

It has become very easy to hack anything in DS, due to programs like DSLazy or Taxahan.

With those programs, I'm able to extract/insert files in DS Roms. like graphics files, font files, files with script of the Rom & its pointers, audio and video files, etc.

analysing files in a Rom, I've extracted video files. they are in .VX extension, and it seems that this extension is used not only in video, but in audio files too.

I plan to add hardsubbed subtitles in those videos and reinsert it. But I didn't found any existent tool to do it.

My question is: anyone know about existence of some tool/program/codec able to decode/encode video & audio files used in DS games?