OSDev.org

This is especially for those who remember the VCR and videocassette tapes.

What if someone made an emulator for PC that emulated the entire operation of a VCR? Any idea of how this can be done?

Start tearing apart VCRs until you find one that has a well-documented microcontroller managing its operations, and dump its ROM. That's a good start.

In what way does software like NextPVR not satisfy your requirements?

I better learn about engineering

In what way is it "emulating the operation of a VCR"? The interface? The fuzzy picture? Playback of magnetic flux dumps from VCR tapes?

SeanMc wrote:What if someone made an emulator for PC that emulated the entire operation of a VCR?

An emulator provides the same result giving a certain input and (unlike a simulator) is allowed to "cheat" to do so.

A vcr emulator would be a visual interface that should allow for inserting a cassette(*) and interacting with the buttons on the emulated machine and the remote.

*) Loading a video file and using it as if it was a vhs tape.

And that is exactly what I had in mind.

Importantly, it should allow you to fast-forward through all those pointless copyright notices (which only serve to encourage people to make copies of everything just so that they can be rid of the infuriating copyright notices), and it should remember where you stopped the tape so that you can continue viewing from there the next time without having to hunt for that location from scratch as you would on a DVD player (and without having to see a copyright notice each time). It should do this even if the computer has been switched off and on again, and still be able to do it if the DVD (which is pretending to be a VHS tape [though optionally with higher resolution]) has been taken out, another one has been played, and then has been put back in again. If you can produce a program like that, maybe developers of modern media players would learn a few things from it and improve their awful software in order to provide the same essential services.

Take a regular DVD capable player like VLC, on stopping vid save a current scene/chapter/frame for a given Video/DVD, save that in the players user settings, check said file when loading new Videos. Any reason why it's not this simple? all the the commercial DVD players i have owned have this feature.

Nutterts wrote:

SeanMc wrote:What if someone made an emulator for PC that emulated the entire operation of a VCR?

An emulator provides the same result giving a certain input and (unlike a simulator) is allowed to "cheat" to do so.

A vcr emulator would be a visual interface that should allow for inserting a cassette(*) and interacting with the buttons on the emulated machine and the remote.

*) Loading a video file and using it as if it was a vhs tape.

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.

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.))