H.264 — also called AVC — is the most widely deployed video codec in history. Standardised in 2003 by ITU and ISO, it powers virtually every YouTube video below 4K, every video on social media, every Zoom call's fallback layer, every recording from a phone, every Blu-ray disc. If you've watched video on a screen any time in the last 20 years, you've watched H.264.
Its dominance comes from two things. First, it was a massive leap when it landed — about 50 % more efficient than MPEG-2, the codec it replaced. Second, hardware encoders and decoders for it are universal: every phone, TV, browser, IoT camera, set-top box, gaming console made in the last 15 years has H.264 silicon. That makes H.264 the safe default for anything that has to "just play" everywhere.
The cost is twofold. By 2026 standards, H.264 is the least efficient of the mainstream codecs — HEVC saves ~50 %, AV1 saves ~70 % on the same content. And in 2026, Via LA (the patent pool) raised streaming licensing fees from a flat $100,000/year cap to up to $4.5 million/year for the largest platforms (existing licensees keep old terms; only new entrants pay the higher rates). The combination is pushing every serious streaming service to layer AV1 on top of H.264 — ship the efficient codec to devices that can decode it, keep H.264 as the universal safety net for everything else.
