yes a supported card will. gtx1050 will support 4k to 1080.
there is still no color conversion between HDR to SDR, so if you try to watch a 4k movie on a non-4k device, then it will probably have washed out colors.
see also @ Plex, 4k, transcoding, and you
if you are not worried about 4k, then you can even use an older card.
here @ Video Encode and Decode GPU Support Matrix | NVIDIA Developer is the official nvidia chart of what cards support what codecs for transcoding.
DECODING and ENCODING are 2 different things, so make sure that whatever card you choose supports the video codecs you intend to use.
