HEVC
/ˌeɪtʃiːviːˈsiː/ · noun · codec · High Efficiency Video Coding (H.265)
HEVC, or H.265, is a video codec that makes files about half the size of H.264. HEIC photos use it too.
In more detail
HEVC stands for High Efficiency Video Coding. It is also called H.265. It was designed to make files about half the size of H.264 video at the same quality. HEIC photos use it to store still images.
HEVC licensing is complicated. That is a big reason support lagged outside Apple devices, and why people still need to convert HEIC photos and HEVC videos.
How HEVC compresses video
HEVC splits each frame into blocks. It predicts what each block contains from nearby pixels or from other frames, then stores only the difference. Its blocks are larger and more flexible than in H.264. That helps most with high-resolution video.
The better compression costs more computing power. HEVC can take longer to encode, and smooth playback may need hardware decoding. A device can play normal video fine and still struggle with 4K HEVC in software.
HEVC vs H.264 compatibility
HEVC is used for 4K video, iPhone recordings, streaming, Blu-ray discs and HEIC photos. Support depends on the browser, operating system, hardware and installed codec licenses. So the same file may play on a phone and fail in a web page or a desktop editor.
Convert to H.264 when it matters more that the video plays everywhere than that it stays small. Expect the H.264 file to be larger at similar quality. Avoid converting back and forth between lossy codecs. For archives, keep the original HEVC file next to any compatible copy.
Key points
- HEVC and H.265 are two names for the same video codec.
- It compresses high-resolution video well but needs more power to encode and play.
- Whether it plays depends on the device, browser and codec licenses.