H.264 is the most widely used codec, with significant penetration in optical disc, broadcast, and streaming video markets.
H.264 is a video compression technology. As a video codec, H.264 can be incorporated into multiple container formats and is frequently produced in the MPEG-4 container format, which uses the .MP4 extension, as well as QuickTime (.MOV), Flash (.F4V), 3GP for mobile phones (.3GP), and the MPEG transport stream (.ts). Most of the time, but not all the time, H.264 video is encoded with audio compressed with the AAC (Advanced Audio Coding) codec, which is an ISO/IEC standard (MPEG4 Part 3).
Most Reolink Cameras support H.264, but if you are using 8MP camera and the image quantity is set to Clear (main stream), then the video compression format is H.264+. Currently, Reolink cameras only support H.264 and H.264+ video compression formats.