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M4A to AC3 converter

Convert M4A to AC3 in your browser. No upload and no account: the file never leaves your device, so the only size limit is your device’s memory.

I want AC3
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Related conversions

Need it the other way round? Convert AC3 to M4A

Other ways to convert M4A

Convert other formats to AC3

Read more about the M4A format and the AC3 format, or see every audio tool and all audio conversions.

Should you convert M4A to AC3?

Fine when a player or app needs AC3. Converting between two lossy formats compresses the sound a second time, so match or exceed the original bitrate to keep the loss inaudible.

M4A is AAC audio in an MP4 container, Apple’s everyday audio format; AC3 is Dolby Digital surround sound from DVDs and TV. Use AC3 for soundtracks going to DVD authoring or a home cinema system.

M4A and AC3 compared
Property M4A AC3
Compression Lossy Lossy
Typical quality 128–256 kbps AAC 192–640 kbps, up to 5.1
Support Opens almost everywhere Has patchy support
Best for Good-sounding audio at small sizes 5.1 surround soundtracks for DVDs and TVs
Introduced 2003 1991

How to convert M4A to AC3

  1. 01

    Add your M4A

    Drop your M4A file onto the box, or click to choose it. It is read from your disk and stays there.

  2. 02

    Check the settings

    The output is already set to AC3. Change the bitrate if you want to; the defaults suit most files.

  3. 03

    Save the AC3

    Press convert and save the AC3. Several files come back together as a ZIP.

What changes when M4A becomes AC3

Two rounds of compression

Each lossy encode throws away a little more. A M4A at 128 kbps converted to AC3 at 192 kbps sounds like the original; converted at 96 kbps it can turn swirly and dull.

Surround channels

AC3 keeps up to 5.1 channels, so surround sources stay surround. Stereo sources are written as stereo.

Expect a larger file

AC3 generally takes more room than M4A. If the file has to fit an upload limit, check the size once it’s converted. M4A: About 1 MB a minute at 128 kbps. AC3: About 3.4 MB a minute at 448 kbps.

This page is put together from our notes on each format, choosing only what is true of M4A and AC3, so every pairing states the same facts the same way. How these pages are made.

Why it doesn’t upload

Recordings are often private: interviews, voice notes, unreleased music. Your browser can decode and encode audio itself, so there is no reason to send it anywhere.

How to check for yourself

Worth knowing

  • About the M4A. An .m4a can also hold lossless ALAC audio, several times larger; the extension alone doesn’t tell you which.
  • About the AC3. Converting a 5.1 AC3 to a stereo format mixes it down; dialogue that lived in the center channel can end up quieter.
  • MP3, WAV, M4A, OGG, Opus and FLAC are converted by your browser directly. WMA, AMR, APE, AC3 and the other specialist formats use the FFmpeg engine, a one-time 31 MB download.

Questions

Does converting M4A to AC3 lose quality?

AC3 is lossy, so a little is discarded, but at the default bitrate the difference is inaudible for nearly everyone.

Will an AC3 play in my car or on my phone?

AC3 has patchy support: home cinema receivers, TVs, VLC and video editors; phones and browsers often can’t.

Read more about this

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