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MP4 to AC3 converter

Convert MP4 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
Advanced 4
sec

Leave both at 0 for the whole file.

sec
Channels

Bytes of your files sent anywhere: 0 B

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Other ways to convert MP4

Convert other formats to AC3

Read more about the MP4 format and the AC3 format, or see every video tool and all video conversions.

Should you convert MP4 to AC3?

Yes, when you only need the sound: a song from a music video, the audio of a lecture, or a voice recording to transcribe. The picture is left out and the soundtrack is saved as AC3.

MP4 is the video container that plays on everything, usually holding H.264 video and AAC audio; AC3 is Dolby Digital surround sound from DVDs and TV. Use AC3 for soundtracks going to DVD authoring or a home cinema system.

MP4 and AC3 compared
Property MP4 AC3
What it is The video container that plays on everything, usually holding H.264 video and AAC audio Dolby Digital surround sound from DVDs and TV
Audio inside H.264 or HEVC video with AAC audio 192–640 kbps, up to 5.1
Plays on Every phone, browser, TV, editor, chat app and upload form Home cinema receivers, TVs, VLC and video editors; phones and browsers often can’t
Best for Sharing video anywhere 5.1 surround soundtracks for DVDs and TVs

How to convert MP4 to AC3

  1. 01

    Add your MP4

    Drop your MP4 video 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 MP4 becomes AC3

From AAC to AC-3

MP4 soundtracks are usually AAC, so saving AC3 is one more lossy step. 192 kbps suits music, 128 kbps is plenty for speech, and going above the original bitrate only makes the file bigger.

Surround sound

AC3 can hold 5.1 surround, so a surround soundtrack keeps its channels. Stereo soundtracks stay stereo.

Video files without sound

Screen recordings and some exported clips have no audio track at all. The file is checked as soon as you add it, and you’ll be told before converting if there’s nothing to extract.

This page is put together from our notes on each format, choosing only what is true of MP4 and AC3, so every pairing states the same facts the same way. How these pages are made.

Why it doesn’t upload

Uploading a whole video to keep only its sound wastes time and data, and hands over the footage too. The audio track is read and saved right here, and the file never leaves your device.

How to check for yourself

Worth knowing

  • About the MP4. An MP4 that won’t play is rarely broken; it usually holds a newer codec such as HEVC or AV1 that the player doesn’t support.
  • 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.
  • AVI, WMV, FLV and other older formats use the FFmpeg engine, a one-time 31 MB download.

Questions

Does extracting AC3 from an MP4 lose quality?

The soundtrack is compressed again as AC3. At 192 kbps the difference from the original is inaudible for nearly everyone.

Can I get the audio from only part of the video?

Yes. Set a start and end time before converting, and only that section is saved as AC3.

Read more about this

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