What is container format?
A file format like MP4, MOV or WebM that wraps a video stream, an audio stream and metadata together - it's the packaging, not the compression.
Confusing a container with a codec is the most common source of "why won't this file play" problems. An MP4 is just a box; what's inside it (H.264? HEVC?) is what actually decides whether a given device can decode it. Two MP4 files can behave completely differently depending on their codec.
Converting between containers that hold the same codec - MOV to MP4 is the common case - is often close to instant and lossless, because the video and audio data is simply repackaged rather than re-compressed.
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