There are several options for H.265 encoding in MFormats SDK and MPlatform SDK - both CPU-based and GPU-powered.
If your hardware supports one of the options, it is listed among available video codecs supported by the specified container.
NVIDIA NVEnc H.265 (HEVC) Encoder
Configuration Parameter: 'n265'
There is a hardware limitation for a number of encoding processes running at the same time. This is made by NVIDIA.
To get information about card supported formats, please refer to this table:
https://developer.nvidia.com/video-encode-decode-gpu-support-matrix#Encoder
Additional attributes - https://support.medialooks.com/hc/en-us/articles/20251506839698-Audio-and-video-codecs#NVIDIA%20NVEnc%20H.265%20(HEVC)%20Encoder
Intel QuickSync HEVC Encoder
Configuration Parameter: 'q265hw' and 'hevc_qsv'
Additional attributes - https://support.medialooks.com/hc/en-us/articles/20251506839698-Audio-and-video-codecs#Intel%20QuickSync%20HEVC%20Encoder
AMD AMF H.265 (HEVC) Encoder
Configuration Parameter: 'hevc_amf'
Additional attributes - https://support.medialooks.com/hc/en-us/articles/20251506839698-Audio-and-video-codecs#AMD%20AMF%20H.265%20(HEVC)%20Encoder
x265 H.265/HEVC
The only CPU-based HEVC encoder. Available only with the GPL build of FFmpeg, so you should license the codec before using it.
Configuration Parameter: 'libx265'
Additional attributes - https://support.medialooks.com/hc/en-us/articles/20251506839698-Audio-and-video-codecs#x265%20H.265/HEVC