Hey man, do you mean some video capturing features directly into Renoise? Well, here I have to disagree, because there are millions of good screen capture tools available, for OSX and for Windows. I bet there are also open source tools available.
This feature would be too much unrelated to music production, in my opinion.
I understand the scopes and spectrums are quite pretty and would be neat to have in the video as the music, however, simply timestretch the stems/output wav then record it what your computer can handle without any hickups
I’d rather say: multichannel rendering + rendering master, and then use some real visualization software to make pixels out of it? What’s so pretty about pure diagnostic visualizations like the scopes or spectrum in renoise, now there’s really better ways to visualize waveforms. Only Extra I’ve brought here would be to render (selected) channels individually to make some pretty scopes dance by single instruments.