FMV playback?

[GithubPrankster]

Games in the PS1 loved their full motion video.

It allowed them to display bombastic action, cinematic moments or even full-scale animations alongside the models (one famous example is some of the action moments in Final Fantasy VIII)

phoboslab's pl_mpeg.h is the best single header lib for this kind of application, MPEG-1 video being very close to what the Motion Decoder in the PS1 hardware decoded blocks of. A file can also include MP2 audio thus also providing pretty much everything else needed for FMVs. The creator even outlines how to create a suitable file using FFmpeg.

I'd only look into this after all the basic features of Polybox are done, specially if you look into doing the decoding in a thread (mimicking how it works in actual hardware)