# Audio extension (/en/realtime-media/marketplace/build/build-your-own-extension/audio-filter/macos)

> For AI agents: see the complete documentation index at [llms.txt](/llms.txt).

The audio filters you create are easily integrated into apps to supply voice effects and noise cancellation.

      
  
      
  
      
## Understand the tech

An audio filter accesses voice data when it is captured from the user's local device, modifies it, then plays the updated data to local and remote video channels.

![Audio extension pipeline](https://assets-docs.agora.io/images/video-sdk/extension-audio-filter.png)

A typical transmission pipeline consists of a chain of procedures, including capture, pre-processing, encoding, transmitting, decoding, post-processing, and playback. To modify the voice or video data in the transmission pipeline, audio extensions are inserted into either the pre-processing or post-processing stage.

## Prerequisites

* Xcode 12.0 or higher.
* A device running macOS 10.11 or higher.
* An Apple developer account.
* A project to develop in.

## Project setup

* Follow the macOS SDK setup flow in [Quickstart - integrate an extension](../../quickstart-integrate.mdx).
* Prepare the framework packaging, code signing, and runtime loading flow for your extension.

## Create an audio extension

Implement the extension and package it as a macOS framework or xcframework for testing and Marketplace submission.

## Reference

* [Quickstart - integrate an extension](../../quickstart-integrate.mdx)