.aac MIME type
AAC audioaudio
audio/aacRaw AAC audio in an ADTS stream. Most AAC files you meet are in .m4a containers instead.
| MIME type | audio/aac |
|---|---|
| Extensions | .aac |
| Content-Type | audio/aac |
| Compress in transit? | No — already compressed |
Good to know
- For podcasts and downloads,
.m4a(audio/mp4) is better supported than raw.aac.
Serve .aac files with the right type
The response header to send:
Content-Type: audio/aac
Most servers pick the type from the file extension. If yours sends the wrong one, map it explicitly:
nginx (inside the types block in mime.types)
audio/aac aac;
Apache (.htaccess or server config)
AddType audio/aac .aac
Express
res.set("Content-Type", "audio/aac");Python
import mimetypes
mimetypes.add_type("audio/aac", ".aac")HTML file input
<input type="file" accept=".aac,audio/aac">
Check it
See what a server sends for a file, and what type a local file really is by its contents:
curl -sI https://example.com/file.aac | grep -i '^content-type:' file --mime-type file.aac
Frequently asked questions
What is the MIME type for .aac files?
audio/aac.
What Content-Type header should a .aac file be served with?
Content-Type: audio/aac. It's already compressed, so servers shouldn't gzip it.
Related types
Headers that go with it: Content-Type · Content-Disposition · X-Content-Type-Options