Convert MP4 to M4A
An M4A is an MP4 that holds only sound, a name Apple's iTunes made common. Since most MP4s carry AAC sound, the M4A is made by copying that sound out as it is: seconds, at any length, with nothing lost.
Your file never leaves this device. Everything runs in your browser.
How it works
- Drop your video.
- Pick MP3, WAV or M4A. The tool says whether the sound is copied or re-encoded.
- Press Extract and download the sound file.
Questions
What's the difference between M4A and MP4?
The container is the same. The .m4a extension tells players and phones the file holds sound only, so they open it in a music app rather than a video player.
Is it really not re-encoded?
When the MP4's sound is AAC, as it is from phones, cameras and most editors, yes: the sound packets are copied as they are. Other sound, such as Opus or PCM, is re-encoded to AAC at 192 kbps, and the tool says which before you press Extract.
Which format should I pick?
MP3 plays on almost anything. WAV is uncompressed, the format editors and DAWs take without converting. M4A is AAC sound in an MP4 container: it's what most phones and cameras record, so it's usually copied rather than re-encoded.
Does extracting lose quality?
Not when the sound is copied into an M4A, and not in a WAV, which stores the decoded sound uncompressed. An MP3, or an M4A made from sound that isn't AAC, is re-encoded at 192 kbps, which keeps music and speech clear but, like any re-encode, isn't bit-for-bit the original.
Is there a length limit?
Files up to 2 GB, and no limit on length: sound is quick to encode. A WAV gets large, though: about 11.5 MB a minute for 48 kHz stereo.
Can I keep only part of the sound?
Trim the video first with Trim a video. Its fast mode cuts without re-encoding. Then drop the trimmed file here.
Does my video get uploaded?
No. The sound is read and written in your browser, on your device.
Which browsers does it work in?
Current Chrome, Edge, Safari and Firefox. Browsers have no MP3 encoder of their own, so the page loads LAME, the open-source MP3 encoder, compiled to WebAssembly (about 300 KB, from this site) the first time you make an MP3. If your browser can't read the sound in your file, the tool says so before it starts.