Is there an advantage to having YCbCr inside the FPGA?
The FPGA verilog code I have played with so far all use an RGB color space, so it is super easy to manipulate each channel, then go out to DVI (like this PMOD). Would also be easy to use an triple DAC (like this adv7123 )then feed an encoder IC like the AD723.
I had initially thought about using the above for output and something like three of these AD9283 high speed ADCs for input.
The scheme for sync extraction and genlock shown above looks doable. A few multipliers and a few digital filters, -not- trivial but definitely doable.
I kind of like the idea of rolling our own instead of using an encoder to allow for non-standard video signals (@andrei_jay was bringing up the ability to tailor it to handle high frequency modulation and corrupted/circuit bent video feeds).
My experience with most chips that offer some sort of parallel bus output (or simple high speed serial interface like I2S or SPI) for FPGA interface is that they have the I2C interface for configuration but it is optional to use it. I’ve set up several different audio ADCs and DACs with the ICE40 and ECP5 this way so far.
There appears to be a an open source MIPI CSI-2 VHDL core. SO it may be possible to use that.