While making the movie player, I had realised one problem and that was that the frames could not decode fast enough. So I decided that multithreading was needed so it could continue to decode frames in the background while occasionally waking up to update the screen.
Of course, Ndless provides no such features. You have to write it yourself! So, without further ado, I present to you a proof-of-concept of multithreading on the Nspire calculator. After I refine it a bit, I'll integrate it into the movie player.
It's BSD licenced so feel free to take it, hack it, modify it, improve it, use it in your own projects or rip it to shreds.Source code