H.265, also called HEVC, is a video compression standard designed for efficient representation of video across a range of uses. Practical playback requires a decoder compatible with the stream's profile, level and other properties. Hardware support varies between devices, and software decoding can place substantial demand on a processor when compatible hardware is unavailable.
A practical example
A newer player box may decode an HEVC programme smoothly while an older television struggles with the same media. That difference can arise from decoding capability rather than the household's internet speed or the programme's subscription status.
A common misunderstanding
Do not interpret HEVC as a guarantee of 4K, HDR or superior quality. Resolution, dynamic range and encoding quality are separate properties of the actual stream.
Related terms
Further reading
Stable technical definition. Editorial approach