Why three separate 80MHz 16bit video DACs? SC11487 https://datasheetspdf.com/pdf-file/502918/Sierra/SC11487/1
pdl-644kip is a glass ultrasonic delay line 63.943us, PAL comb filter
saa1101 philips sync generator
sony video encoder
4x NEC uPD42102 dedicated PAL Line Buffer ram https://pdf1.alldatasheet.com/datasheet-pdf/v … C/UPD42102.html
all magic in Lattice CPLD and surrounding GALs
TDA8444P 8 slow 6-Bit DACs - video signal black level control?
I dont see any ADCs, that Philips chip under the delay line? something like TDA8708?

This is a weird boy.

All the circuitry seems to be for TV out capability, not for any recording functions. Really interesting hardware ~

So is it just a TV-Out or maybe it can also decode video? Why there are two black round connectors on the back? Usually TV-Out has only two connectors (RCA and this black one) and here are 3 of them. Here is another picture:

There aren't any ADCs etc. for any actual recording capability, only DACs and most chips have to do with outputting. But the PAL delay line is certainly for decoding composhit signal and there are few support parts that show that there is a video input (the upper connector) but nothing to suggest it can digitize video as it is, just decode it into RGB. There's also a chance that any recording capability is with another daughterboard attaching to those pin headers in top.
Documentation would help a lot but I cannot see any identifying info that yields anything online and I have doubts it will fully work without its software side of things...
I also see few deep scratches at the back that look like they've broken some traces and they should be fixed before powering up the card.

Bend back black plastic box in upper right corner, the one with white sticker saying "pdl-644kip". Everything will be clear after we markings of the chip hiding under that.

Definitely no video decode 😀 It could maybe do genclocking/time base correction and frame grabbing if that hiding chip is video ADC.

Decode as in PAL > RGB (by the chip under delayline), as encode is RGB to PAL (which is done by that Sony chip). The chip under the delayline is likely some late 80s/early 90s color TV video processor where all the bandpass filters and whatnot were all external as the support circuitry seems to show and of course the 2x PAL color frequency crystal (2 * 4.433619MHz) . I'm definitiely curious about that chip.

EDIT: I have a thought what it may be, it could be one of those titling things, which explains video input but no actual digitizing of it. It can insert new video into a stream that is fed into it and output it on the next connector. So input is decoded from PAL to RGB (to avoid rainbow artifacts on forceful entry on new video), digitally generated RGB video is mixed into it and then encoded back to PAL for output into whatever is down the line (video recording device perhaps).

Unfortunately this black plastic box is soldered at 90 degrees and if I will bend it it will break. Right now I don't have capability to desolder it and put it back again.