# What is Codec?

*Development · Last updated: November 7, 2026*

> Coder-Decoder

Software or hardware that compresses or decompresses audio or video data.

## Overview

A codec is a compression technology that shrinks large audio and video files for streaming or storage over the internet, and restores them when played back. Etymologically, it is a portmanteau of coder and decoder. By using lossless or lossy compression methods, it allows files to save storage space.

***Analogy:** It is like compressing a thick quilt into a vacuum bag to make it smaller, and opening the bag to restore its original fluffy state when you want to use it.*

## How it works

When you record a video, the camera produces it in a raw and very large format. The codec software compresses the file by discarding unnecessary details in this data that the human eye or ear cannot perceive. The player, using the same codec, instantly decodes the file and brings it to the screen.

## Where it is used

It runs continuously in the background in video conferencing applications, music streaming services, and video editing programs.

## Commonly confused with

It is often confused with media file formats; for example, MP4 is a container, while the technology that processes the data inside it is the codec.

## Questions and answers

**Why doesn't every video open in every player?**

Because the correct codec that decodes or opens that video may not be installed on your device.

**Does a lossy codec reduce quality?**

Yes, while the file size shrinks, minor data losses that human senses cannot perceive may occur.

## Related terms

- [Video Editor](https://trescout.com/en/dictionary/video-editor/)
- [Streaming Applications](https://trescout.com/en/dictionary/streaming-applications/)
- [Binary](https://trescout.com/en/dictionary/binary/)
- [Assets](https://trescout.com/en/dictionary/assets/)

## Related tools

- [MPV](https://trescout.com/en/discover/mpv/)

This explanation was written in plain language for TreScout with AI and **machine-translated** from the Turkish original · the Turkish version prevails. If something looks wrong or missing, write to [hello@trescout.com](mailto:hello@trescout.com). [Read in Turkish →](https://trescout.com/dictionary/codec/)

---
Source: TreScout Dictionary · https://trescout.com/en/dictionary/codec/