MP4 to FLAC converter
Pull the sound out of your MP4 and keep it as a FLAC, leaving the picture behind. MP4 is the video file that plays everywhere: phones, TVs, browsers, editors and every social platform. Expect the FLAC to be a good deal bigger, which is what keeping every detail costs. Your file never leaves your computer.
How to convert MP4 to FLAC
- 1 Drop your MP4 .mp4 file onto the page, or click to browse for it.
- 2 Choose the sound quality, or lift the existing track out untouched where that is possible.
- 3 Convert. The work happens on your own machine, so how long it takes depends on your computer and the file.
- 4 Download the FLAC, or add more files and do the whole set in one go.
Why convert MP4 to FLAC
- You only want the sound: a lecture, an interview, a podcast that was filmed, or a track to listen to with the screen off.
- You want a copy that will not get any worse each time you edit and save it, and FLAC gives you that.
- Identical to the recording at roughly half the size of a WAV.
- Fast decoding and good tagging with embedded artwork.
- Archiving CD rips without losing anything.
MP4 compared with FLAC
How the two formats differ on the things that decide whether a conversion is worth making.
| Property | MP4 | FLAC |
|---|---|---|
| File extension | .mp4 | .flac |
| Compression | Lossy | Lossless |
| Typical file size | Smaller | Larger |
| Browser support | Every browser | All current browsers |
| Developed by | ISO/IEC MPEG | Xiph.Org Foundation |
Quality and what changes
Whether anything is lost depends on the codec. If the track already matches the target, it can be copied out untouched and the audio is bit for bit what was in the MP4. Choosing a different codec means decoding and re-encoding, which is a second generation of lossy compression on top of whatever the video already applied. Encoding at 192 kbps or above keeps that second generation inaudible for most material.
- One FLAC limitation to keep in mind: wasted on speech and on recordings that were never good to begin with.
Questions about MP4 to FLAC
Does converting MP4 to FLAC improve the quality?
No. FLAC preserves what it is given perfectly, including the compression artefacts already present in the MP4. It stops further loss from happening, which is worth doing before editing, but it cannot recover detail that was discarded.
Why is my FLAC bigger than the MP4?
Because MP4 was discarding data and FLAC is not. A lossless format has to write out every pixel it is handed, artefacts included, so growing several times over is normal and does not mean anything went wrong.
Does extracting the audio re-encode it?
Only when the target codec differs from the one in the MP4. Where they match, the track is copied and the result is identical to the audio inside the video. Converting to a different codec means one extra generation of lossy compression.
Is my MP4 file uploaded anywhere?
No. The whole thing runs inside the browser tab you already have open. Your MP4 is read straight from your own disk, converted on your machine and handed back as a FLAC. Nothing is sent anywhere, nothing is stored and there is no account.
Is there a file size limit?
There is no server-side limit because no server sees the file. The real ceiling is your device memory, since the input and the output both have to fit in the tab. A few hundred megabytes is usually fine on a desktop machine and considerably less on a phone.
Can I convert several MP4 files at once?
Yes. Add as many as you like and they are processed one after another, then offered as separate FLAC downloads or as a single ZIP. Speed depends on your own processor rather than on a queue.
Does the converter work offline?
Yes, after the page has loaded once. The engine is cached by the browser, so you can disconnect, reload and keep converting. That falls out of doing the work locally rather than being a separate mode you switch on.