What is keyframe?
A fully-encoded frame in a compressed video, placed periodically so playback and editing can jump to that point without decoding everything before it.
Most frames in a compressed video only store the difference from the frame before them, which is efficient but means they can't be decoded on their own. A keyframe is a complete image, inserted every second or so, that playback and editing tools can seek to directly.
Trimming a video at a non-keyframe point sometimes forces a re-encode of the surrounding section rather than a fast cut, which is part of why some trims are instant and others take longer - it depends on where the nearest keyframe happens to fall.
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