I have two different computers, each with v1.2.2.649 of GoPro Player. On one of them I can export 360° HEVC video with a resolution of 5.6K without issue. On the other one I cannot - the max resolution I can encode to is 4K. If I try to select a higher resolution with HEVC it switches to CineForm.
Both computers support HVEC hardware acceleration.
The one that does encode 5.6K resolution has an Intel Iris Plus Graphics adapter (Intel Core i7-1065G7). The one that only encodes up to 4K has an Intel UHD Graphics 620 adapter (Intel Core i7-10610U).
So I guess in this case experimentation has revealed the max resolution I can encode HEVC videos at BUT if I were in the market for a new computer could I find out what the maximum resolution the computer supports for HEVC encoding is?
https://software.intel.com/content/www/us/en/develop/articles/encode-and-decode-capabilities-for-7th-generation-intel-core-processors-and-newer.html mentions which Intel cards support HEVC encoding but it doesn't mention the max resolution that they'll do that encoding at.