Well, OK, not actual LDs as the size is the problem here :-)
What I am thinking is -- there were CD Video discs, which are essentially Audio CD with an LD track. But there were some of these discs without the Audio part.
So in theory it would be possible to:
- Get a CD burner unit from an old PC (plenty of those everywhere these days)
- Remove the original electronics
- Use an ATMEGA (probably too slow), STM32 or ESP32 and/or a BLDC driver to spin the disc into CAV mode (CAV is the easiest to do just as a proof of concept) -- essentially set a constant speed on the disc, sync to it and per every revolution move the record head 1 step to the outer radius
- Use some other CPU or analog processing circuitry to modulate the incoming composite video/audio signal, and a simple opamp/transistor-based amplifier to drive the burner LED
- Connect a video source, get a good CD-R (probably a Verbatim or a TDK at least), put it on the spindle,
The questions so far are --
a. How is the signal exactly modulated?
This page on the LaserdiscArchive explains it a little but without going into much detail. If there is some patent, or at least a function diagram, that would be a lot more helpful!
b. What is the distance between tracks, that "1 step" that the record head has to move per every revolution of the disc?
c. How is the digital data modulated into the frames, so the player knows the frame number, disc type and so on?
d. Figuring out the pinout of the laser head to control the focus feedback loop, though this is a bit less LD-related.
e. Probably, using some low-level programming under Linux or something, it may be possible to do that without modifying the burner, and just burn a video file right away, using sophisticated enough software? I think I've seen some programs that draw pictures in data patterns on DVD's, though that might be hard to do due to the PCM nature of the CD/DVD vs PWM on the LD. Oh, and I have a "Disc T@Too" DVD burner which can draw text and pictures on the bottom side of DVDs, so maybe it is possible to use one of those?
Update:1.
https://kompendium.infotip.de/laserdisc.html specifies that the distance between tracks is about 1.6um on an LD
2.
This page at domesday86 has some really decent info about how LD data is encoded in terms of frequencies used and so on. They are doing a really interesting project of digitizing LDs as an RF signal rather than a video capture, so check them out!