H.264, also called AVC (Advanced Video Coding), is the video compression standard that has carried most of the world's surveillance video for over a decade. Standardised jointly by ITU-T and ISO/IEC, it shrinks raw camera frames enough to stream and store at practical bitrates while keeping wide hardware support: virtually every camera, VMS, browser, and phone can decode it, which is exactly why it became the safe default.
It works by sending occasional full "keyframes" (I-frames) and, in between, much smaller frames that describe only what changed — so a static corridor compresses far harder than a busy street. For surveillance this matters because the bitrate, and therefore the storage bill, depends heavily on scene motion, resolution, and frame rate. A 1080p camera on H.264 commonly lands around 4–8 Mbps.
The trade-off against its successor H.265 is efficiency. H.265 delivers similar quality at roughly half the bitrate, which is decisive at 4K or across hundreds of cameras, but H.264 still wins on universal compatibility and licence simplicity. The pitfall is defaulting to H.264 on a large 4K deployment out of habit: the extra storage and bandwidth can dwarf the convenience. For the codec choice in depth, this is owned by the Video Encoding section, not the VMS layer.
The handbook · 7 volumes
Fora Soft Video Engineering Handbook
H.264 is the safe default in surveillance because every camera, VMS and browser supports it, but it costs more bitrate than H.265. We wrote seven volumes covering the full video stack, and for H.264 start with Volume 1: H.264 internals, profiles, rate control and encoder settings. Volume 6 shows how decoded frames feed analytics. Written by Nikolay Sapunov, CEO at Fora Soft.
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