VHS-Decode today makes FM RF archive decoding look like childs play, I guess this was a CX Card capture with CXADC ay? (be intresting to see it re-decoded today)

This is awesome. It's just really awesome.... software RF decoding. I happen to know he can do color too!

@Zcooger

Жыл бұрын

VHS-Decode does color RF decoding

holy damn this is so rad

owwwwww yeeaaaaaaa

Andrew, I don't understand what you've done. VCRs have composite, s-video or RGB video outputs only. What do you mean by "RF capture"? Are you tinkering with the hardware opening the cover and touching or tampering with any of the electronics inside the VCR???

@andrewmjenner

Жыл бұрын

Yes, that's exactly what I did. The encoding of the images on the tape is described as RF (presumably because the frequencies involved are high enough to be described as Radio Frequency). VCRs have test points that can be tapped to monitor this signal encoded for tape, and I tapped them.

source code

So this is basically an emulated VCR running on a computer, or is it something else? If it's the former, congratulations!

@andrewmjenner

5 жыл бұрын

Parts of the VCR are emulated, parts are real. The tape and heads are real, but the process for decoding the data coming from the heads and turning it into a visible image is done in software. It is not a huge step to go from there to a completely emulated VCR - I just haven't implemented it yet. It's something that I'd like to do at some point, though.

@eribetra

5 жыл бұрын

@@andrewmjenner I bet you'd be able to digitize the magnetic signals from the tape and emulate the heads, and then try to run it through the decoder.

@andrewmjenner

5 жыл бұрын

@@eribetra Well, to digitize the magnetic signals from the tape you need some heads to get the signal off the tape and into an electrical signal that can be sampled. Which is what I am doing in this video - the source digitized signal is the one coming right off the tape heads (after they are combined into a single signal). It's possible to emulate the tape and heads as a system but not really just one or the other as emulated heads can't read physical tape and physical heads can't read emulated tape.

@eribetra

5 жыл бұрын

@@andrewmjenner So then you emulate the tape & heads, alongside everything you've already done, and then it's basically a completely emulated VCR?

@andrewmjenner

5 жыл бұрын

Almost. The other part is that this is only a decoder so far - an encoder would be needed as well but that's just a matter of reversing the steps of the decoder. An interesting thing to do would be to add various real-world imperfections to the emulation, like dropouts, tape stretching, and the heads being misaligned with the data on the tape (and emulating the servo mechanism to get it back in synchronisation).