When dealing with Ultra HD, sooner or later you will find this abbreviation and I’m sure you want to know what does it mean. HEVC means High Efficiency Video Coding and it is new video compression standard. You maybe know H.264 (MPEG-4 AVC) and HEVC is direct successor to this as it is also called H.265.
HEVC improves quality of video, doubles the data compression (compared with MPEG-4 AVC) and what is most important to us, it supports Ultra HD resolution up to 8K (8192×4320).
HEVC was created mostly to considerably improve efficiency of coding, that means to reduce bitrate requirements while the quality of the image will not be damaged. Simply, HEVC makes it easier to work with Ultra HD video because it can trade off computational complexity, compression rate, robustness to errors, and encoding delay time.
The key parts where HEVC (H.265) is better than H.264(MPEG-4 AVC) are better parallel processing methods and already mentioned support for video in Ultra HD.
If you are looking for more info about HEVC, then check out wikipedia.