What is h.264 (avc)?
The most widely supported video codec, decoded natively by essentially every phone, browser and TV made in the last fifteen years.
H.264 is the default codec inside most MP4 and MOV files, and the safest choice for anything that needs to play everywhere without a compatibility question. It's less space-efficient than newer codecs like HEVC or AV1, but the universal hardware decoding support is usually worth more than the extra megabytes.
Every platform in this site's specs re-encodes uploaded video to H.264 (or its own internal codec) regardless of what you upload, which is part of why uploading an ultra-high-bitrate source rarely changes what viewers actually see.
Koldflux picks the right codec, container and bitrate for every platform automatically - this glossary exists because our own team had to get it right first.
Automate this in Koldflux