About MP4 to M4A
M4A keeps the AAC audio from an MP4 in a small audio-only file that Apple devices and most players understand.
When the MP4 audio is already AAC it is copied without re-encoding, so the conversion is fast and lossless.
The FFmpeg engine (about 31 MB) downloads the first time you convert and is then cached by your browser. Files up to about 100 MB are supported because everything runs in browser memory.
MP4 vs M4A
| MP4 | M4A | |
|---|---|---|
| What it is | MPEG-4 Part 14 container | AAC audio in an MP4 container |
| Typical codecs | H.264 or HEVC video, AAC audio | AAC |
| Common use | Plays almost everywhere | Apple devices, voice memos, iTunes |
How to do it
- 1
Drop a MP4 file into the converter above (already set to M4A).
- 2
Pick a bitrate if you want something other than 192 kbps.
- 3
Tap Convert, keep the tab open until it finishes, then download the M4A.