Hi @aripod,
Using structs and arrays is discouraged in Vitis HLS to works with streams, and (I believe) it should not work. In addition to that, you are not generating the user signal, which indicates start of frame.
I would suggest you look at the PYNQ HLS IP and use hls::stream for streams PYNQ/boards/ip/hls/pixel_unpack at master · Xilinx/PYNQ · GitHub
Mario