The Apple TV 4K supports HEVC video when the codec identifier is hvc1, but not hev1. From the last sentence, it appears that hev1 is supported for HTTP Live Streaming.
hev1 and hvc1 were both used as identifiers for HEVC before Apple included HEVC decoding in its OSes.
You can change hev1 ro hvc1 using an HEX editor such as Hex Fiend (on the Mac) and the file will play with Quicktime Player and on the Apple TV 4K’s native media player.
Or you can have an app such as iFlicks 3 (currently in beta here: http://iflicksapp.com/beta ) do it for you.
Would you please have the link to your post with the 24fps demo video and the description of te issue?
I have checked the link to the video, it’s still alive. Just play it, you’ll see yourself. Funny enough it plays perfectly on my MBP 13" with High Sierra. And thanks for the explanation!
PS: I have tried to use iFlick but it basically converts everything. It has also got stuck with the video in this thread. So I have downloaded Hex Fiend as well. I don’t find any “hev1” or “HEV1” string in the text view…
PPS: Ok, I have found hev1 in the "24 fps " video above, changed it to hvc1 but I get the same identical issues. Actually it still vibrates with the video converted from iFlicks. I am not pleased with this answer from Apple!!
Specifically for those two files these are the commands (do I really have to add the HTML tags manually??):
ffmpeg -i 01.\ FPS_UHD_HDR10_23.976.mp4 -c:v copy -tag:v hvc1 -c:a copy 01.\ FPS_UHD_HDR10_23.976.m4v