Video File Formats

A video file format is the way the frames and sound of a moving image are stored in a file. Formats store or compress video in different ways, which affects file size, quality and whether a device can play the video.

Common video formats and compression standards include MP4, AVI, MOV, WMV, MPEG-2 and H.264.

MPEG-2 is an older compressed standard still used for some broadcast and disc video. H.264 is a compression method often used inside MP4 files.

Compressed or uncompressed?

Uncompressed video preserves all the original data and gives the highest quality, but the files are very large. A short clip can take up more storage than a whole folder of photos. Compressed video reduces the file size by storing less data. The more compression applied, the more likely you are to see digital artefacts — blocky, smeared or fuzzy patches, especially around fast movement or sharp edges.

For example, a youth theatre group recording its summer show might export an MP4 for its website so parents can watch on a phone without a long wait. It keeps an uncompressed copy until the final edit is agreed, so every cut is made from complete data.

Compatibility matters

A format is only useful if the audience's device can open it. Less common formats may have compatibility issues: a video saved in a rare format might not play on a phone, tablet or smart TV, so the audience sees nothing at all. Checking support before distributing a video avoids this problem.