physecfed wrote:
On one hand, it would be quite interesting if someone could figure out an image processing/DSP-ish "hack" to generate correctly the static and artifacts that appear on the old CRT screens when fast-forwarding/reversing a tape. That being said, that's an aesthetic quirk and not necessarily a required feature.
That, I believe, is caused by the interaction between the refresh frequency of the display and the speed at which the tape is moving. One would have to convert the video stream to a model of the data on a VHS tape, simulate how that data would be processed by the VHS unit and CRT display, and render the output frame-by-frame. It's no small task as it would require simulation (read: real-time mathematical modelling) of multiple fairly (but not overly) complex interacting systems and the signals within those systems, but nevertheless it would be possible and it might be an interesting project (not something I'm going to try myself
). (A similar approach could be applied to playback of the "tape" as well, since we'd already have a fairly complete model of the tape and CRT systems and all the associated signal processing, and this might lead to a realistic (albeit potentially frustrating...) experience when watching video (it could simulate things such as tape flutter and stretching and the effects that these cause on the video signal). Finally, a VHS tape to play around with that can support widescreen HD movies! (Actually I wonder how the change in aspect ratio would affect the signal timings and resulting artefacts... I guess that would be handled by the CRT simulation, in whatever part is responsible for the vertical timing of the simulated electron beam.))