VLC is a multimedia player so versatile that it can virtually open any multimedia file available … but, as you may guess, that “virtually” actually imply that there IS a limit.
That obviously means that VLC doesn’t have the right codec to play H265/HEVC videos.
A little bit of knowledge
VLC is a popular, portable, free and open-source, cross-platform media player and streaming media server developed by the VideoLAN project that, as main strength, includes a large number of free decoding and encoding libraries to avoid (except in this case) the need to install and configure them manually.
HEVC stands for “High Efficiency Video Coding“ and it is a video compression standard developed by the Joint Collaborative Team on Video Coding; it offers about double the data compression ratio at the same level of video quality (or substantially improved video quality at the same bit rate) of the widely used AVC (H.264 or MPEG-4 Part 10). It also supports resolutions up to 8192×4320, including 8K UHD.
How to add HEVC support to VLC
In order to play videos encoded in H265/HEVC with VLC on Ubuntu, you need to install vlc-plugin-libde265 and it is easily done with the following commands from a terminal:
sudo apt-add-repository ppa:strukturag/libde265
sudo apt-get update
sudo apt-get install vlc-plugin-libde265
Once vlc-plugin-libde265 is installed, restart VLC and reopen the file. You should now be able to play any file encoded in HEVC with VLC.