HEV1

hev1 is a four-character code used in the ISO Base Media File Format (ISOBMF) and MP4 containers to identify a video track encoded with the High Efficiency Video Coding (HEVC, also known as H.265) standard. In MP4, video tracks are described by a VisualSampleEntry whose codec type can be 'avc1' for H.264, or 'hev1' / 'hvc1' for HEVC. The codes 'hev1' and 'hvc1' serve as compatible labels rather than distinct codecs, reflecting different branding conventions used by various tools and devices.

HEVC is defined by ITU-T H.265 / ISO/IEC 23008-2, with profile, level, and other constraints conveyed either in the sample entry or in the bitstream. For HEVC in MP4, the decoder configuration is typically stored in an HEVC-specific box (often referred to as hvcC), which contains parameter sets such as VPS, SPS, and PPS needed to initialize decoders. The presence of the hev1 or hvc1 label indicates that the accompanying data should be interpreted as HEVC-encoded video.

In practice, hev1 and hvc1 are commonly used interchangeably to label HEVC video in MP4 files; some workflows or devices may prefer one form over the other for compatibility reasons. Most modern media players and devices with HEVC support can handle either code, though exact compatibility can vary by platform.

Overall, hev1 represents part of the standardized method for packaging HEVC video within MP4, enabling efficient distribution of high-quality video in widely used container formats.