What is an AAC file?
AAC sounds better than MP3 at the same file size, noticeably so in smaller files. It is what Apple Music, YouTube and most video soundtracks use, and it plays on essentially every modern device. You can convert AAC files here, both into the format and out of it.
Specification
| Full name | Advanced Audio Coding |
|---|---|
| Extensions | .aac |
| Media type | audio/aac |
| Compression | Lossy |
| Transparency | — |
| Animation | — |
| Multiple pages | — |
| Colour depth | — |
| Size limits | — |
| Introduced | 1997 |
| Developed by | ISO/IEC MPEG |
| Standard | Open |
| Browser support | Every browser, including older ones |
What AAC is used for
- Audio tracks inside MP4 video
- Streaming services and broadcast delivery
- Apple ecosystem music and podcasts
- Mobile audio where bandwidth is limited
Strengths and limitations
What AAC does well
- Better quality than MP3 at any comparable file size
- Plays everywhere without draining the battery
- Supports multichannel audio up to 48 channels
Where AAC falls short
- Patent licensing applies to encoders in commercial products
- A bare .aac file cannot hold artwork and track details the way M4A can
- Opus sounds better in very small files
Convert AAC to
Every target this format can be written out as, each on its own page.
Convert to AAC
Everything that can be turned into a AAC file.
Tools that accept AAC
Questions about AAC
What is a .aac file?
AAC sounds better than MP3 at the same file size, noticeably so in smaller files. The extension .aac identifies it, and its media type is audio/aac.
How do I open an AAC file?
Any current browser will open it directly, so dragging the file into a tab is usually enough. Most operating systems also preview it without extra software.
Is AAC lossy or lossless?
Lossy. That means detail is discarded during encoding and each re-save compounds the loss, so keep an untouched master where quality matters.
What is AAC good for?
Better quality than MP3 at any comparable file size. Plays everywhere without draining the battery. Supports multichannel audio up to 48 channels. In practice that makes it a good fit for audio tracks inside MP4 video, and Streaming services and broadcast delivery.
What are the drawbacks of AAC?
Patent licensing applies to encoders in commercial products. A bare .aac file cannot hold artwork and track details the way M4A can. Opus sounds better in very small files.