Reference

What is a Format?

Container formats are often confused with codecs. Understanding the difference makes everything else about media much clearer.

Reference-style page migrated from the original Codecs for Dummies archive and prepared for the Codec Help structure.

Simple explanation

Video stream

Encoded with H.264 or AV1

Audio stream

Encoded with AAC or Opus

Subtitles & metadata

Text tracks, chapters, timing

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Container (MP4 / MKV / WebM)

All elements combined into one file