Actually looking into it, it might be a Cyclone 10 GX chip given their integrated 12.5Gb/s I/O transceiver (on the money for 4K60Hz output at 12.54Gb/s, though that's without HDR- I am not an FPGA dev so I don't know if 12.5Gb/s transceivers are necessary for HDMI's TMDS pairs, but typically you read it's difficult to hit such high pixel clocks with regular I/O pins at the very least). The cheapest of these (10CX085 line) is $130 in low quantities with that lovely 64 week lead time.
Digikey lists the 5CEFA5F23C8N the OSSC Pro was built around as Active, but with no ability to even place an order.
well, 130$ seems kinda reasonable as a price, but as many people expect... the rt4k will be very expensive device. someone spoke to its creator on twitter if it would be 500 or 400$ and he said it will be much more than that. most expectations are 800-1000$ which is why it won't replace the 5X since very very few people will be willing to pay such huge prices.
FPGAs are not optimized for anything, they are general chips. therefore you need a chip which is more powerful than the application you want to design. the market is very bad pricing and it does not seem to settle down or get better. availability is very bad too.
till now looks like rt4k does not have anything significant more than the 5x, besides outputting to 4k60 or so. i could be wrong here since i didn't follow all news.
Oh, duh, it would be pointless to convert an 8-bit color source to 10-bit, which is the part of HDR that requires higher bandwidth. So the Cyclone 10 GX is very likely what the Tink 4K is targeting.
hmmm there is SDR to HDR conversion which does enhance the colors and output, you can search on it and see results. it requires that the outputting source or scaler in this case to be the one doing it not the tv which needs the designer to make all that himself... unless fpga he is using have an IP for it.
doing the flagging to HDR thing will be kind of gimmicky feature more than anything.
I feel these new scalers are going to get delayed even more but nothing to do about it.