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AC3 to FLAC converter

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

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Related conversions

Need it the other way round? Convert FLAC to AC3

Other ways to convert AC3

Convert other formats to FLAC

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

Should you convert AC3 to FLAC?

Only when software insists on FLAC. It stores the decoded AC3 perfectly, but the detail the AC3 discarded is already gone, so the FLAC is bigger without sounding better.

FLAC also plays in more places: most modern players, Android and recent iPhones; some car stereos and older apps don’t.

AC3 is Dolby Digital surround sound from DVDs and TV; FLAC is lossless audio at roughly half the size of WAV. Use FLAC to archive music and recordings you may want to convert again later.

AC3 and FLAC compared
Property AC3 FLAC
Compression Lossy Lossless
Typical quality 192–640 kbps, up to 5.1 lossless, 16 or 24-bit
Support Has patchy support Opens almost everywhere
Best for 5.1 surround soundtracks for DVDs and TVs Archiving music and recordings without losing anything
Introduced 1991 2001

How to convert AC3 to FLAC

  1. 01

    Add your AC3

    Drop your AC3 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 FLAC. Change the bitrate if you want to; the defaults suit most files.

  3. 03

    Save the FLAC

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

What changes when AC3 becomes FLAC

Bigger, not better

FLAC can’t restore what AC3 compression removed. It does make editing easier and stops further loss, which is why editors and some broadcast systems ask for it.

Surround channels

AC3 is often 5.1 surround. Converting to FLAC mixes it down to stereo when FLAC can’t hold six channels, and dialogue may end up quieter than effects.

A one-time engine download

AC3 is decoded by FFmpeg compiled to WebAssembly, a 31 MB download the first time. After that it is cached, and the conversion never leaves your device.

Expect a much larger file

FLAC is far bigger for the same content. Choose it because something needs FLAC, not to send or store the file. AC3: About 3.4 MB a minute at 448 kbps. FLAC: About 5–7 MB a minute for music.

This page is put together from our notes on each format, choosing only what is true of AC3 and FLAC, 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 AC3. Converting a 5.1 AC3 to a stereo format mixes it down; dialogue that lived in the center channel can end up quieter.
  • About the FLAC. FLAC made from an MP3 is lossless only in name: it perfectly preserves an already lossy recording, at five times the size.
  • 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 AC3 to FLAC lose quality?

No quality is lost converting to FLAC, though it can’t restore what the AC3 already discarded.

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

FLAC opens almost everywhere: most modern players, Android and recent iPhones; some car stereos and older apps don’t.

Read more about this

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