Definition
What is a video codec?
A codec is a system for encoding and decoding media data. Video codecs such as H.264, HEVC, ProRes, and AV1 reduce the data needed to store or transmit images; compatible software or hardware decodes that compressed data for playback or editing.
Codecs make trade-offs between image quality, file size, encoding time, playback compatibility, and editing performance. Long-GOP delivery codecs can make small files by predicting changes between frames, while intraframe editing codecs store each frame more independently and can be easier to seek and edit.
A codec is not the same thing as a file extension or container. An .mp4 file can carry H.264, HEVC, AV1, or other streams, subject to platform support. Editors therefore check both the codec and the container when preparing media for a workflow or delivery target.
Example in the edit
A camera records H.264 in an MP4 file for efficient storage. For a demanding multicamera edit, the team creates ProRes proxy files so the computer can play several angles more smoothly.
Why editors use it
Codec choices govern how media looks, moves through an edit, and plays for viewers. Selecting the wrong one can cause slow timelines, huge files, failed uploads, or incompatible playback.
Quick answers
Frequently asked questions about Codec
Is MP4 a codec?
Usually no. MP4 is a container format; it can hold media compressed with different codecs, such as H.264 or HEVC.
Which codec is best for editing?
It depends on the workflow, but intraframe production codecs and well-made proxies often edit more smoothly than heavily compressed delivery codecs.
Does a better codec always make a smaller file?
Codec efficiency matters, but size also depends on bitrate, resolution, frame rate, content complexity, and encoding settings.