The "263" in the filename points to the H.263 standard , a video coding format originally designed by the ITU-T for low-bitrate communication.
: The codec often uses a single initial I-frame followed by a sequence of P-frames to compress data as much as possible for real-time delivery. The Role of MP4 and Live Streaming LIVE263.mp4
While H.263 is traditionally found in files, it is also supported within the .mp4 (MPEG-4 Part 14) container. The "263" in the filename points to the H
263 codec or the of live video streaming? LIVE263.mp4
: H.263 was revolutionary for enabling video playback over dial-up modems and early mobile networks (3G) where bandwidth was extremely limited.