AAC Audio — Advanced Audio Coding lossy format, common in MP4.
Quick facts
What is .aac
A .aac file is a AAC Audio — Advanced Audio Coding lossy format, common in MP4.
In the mime-db registry it maps to audio/aac. When serving .aac over HTTP, set the Content-Type header as shown in Developer info below.
Related entities: it maps to audio/aac — and is delivered over HTTP via the Content-Type header.
How to open .aac files
Developer info
When served over HTTP, responses should set the following header:
Content-Type: audio/aac
Common software that reads/writes .aac:
Relation chain
Related extensions
Related MIME types
Common uses
How to edit .aac files
How to create .aac files
Frequently asked questions
Common options include VLC, iTunes, QuickTime. You can also open many of these files with built-in viewers or a browser.
Create a new file in any text editor or the app that owns the format and save it with the .aac extension.
audio/aac is the media type identifier used for .aac files during network transfer (for example in the HTTP Content-Type header).
Sources & standards
Updated 2026-08-18
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