Is this MP4 to FLAC converter really free?

Yes. Up to 5 files at a time, no signup, no catch. The free tier adds a small watermark to image output — Pro ($9.99/mo or $49/yr) removes it, raises the file size limit to 500 MB, and unlocks unlimited batch conversion.

Are my files uploaded to a server?

No — and you can verify it yourself. Open DevTools → Network tab, then convert a file. You'll see zero upload requests. Everything runs right in your browser. We never see your files.

How long does conversion take?

Usually 1–3 seconds for a typical file. The very first conversion on a fresh page load may take 5–20 seconds while the converter engine loads — after that it's instant. Your CPU does all the work locally.

What is the file size limit?

Free: up to 10 MB per file, 5 files per batch. Pro: up to 500 MB per file, unlimited batch. If you're working with large videos or RAW photos, Pro is built for that.

Can I batch convert multiple MP4 files at once?

Yes — drop multiple files at once (or Ctrl/Cmd+click to select them) and they all convert in parallel. Free accounts handle up to 5 files per batch; Pro has no limit.

What bitrate will the converted audio use?

We default to 192 kbps for MP3, 128 kbps for OGG/Opus, and 320 kbps for M4A/AAC. These settings are perceptually transparent — most listeners can't tell the difference in a blind test.

Will my metadata (ID3 tags, album art) be preserved?

Yes, when both formats support it. Tags carry over on conversions like MP3→M4A or FLAC→MP3. WAV has limited tag support, so some metadata may not transfer.

Is the FLAC output truly lossless if the MP4 had AAC audio?

The FLAC stores the decoded AAC audio without further loss, but cannot undo the original AAC compression. If the MP4's audio track was high-bitrate AAC (256+ kbps), the FLAC output will sound excellent.

Will FLAC extracted from a high-quality MP4 work for a hi-fi system?

Yes — audiophile media players and network streamers (Roon, Naim, Bluesound) read FLAC natively. Extracting audio from a high-quality video recording as FLAC is a common way to archive live performance audio.

How private is this converter?

Completely private — by design, not policy. There is no upload endpoint. Files are processed right inside your browser tab and disappear the moment you close it. We collect only anonymous page-view counts; your file content is never seen or stored.

MP4 to FLAC Converter — Free, Online, No Upload

How to convert MP4 to FLAC online

1
Drop your MP4 file
Drag and drop your MPEG-4 Part 14 file onto the converter, or click to browse your files. You can select up to 5 at once. Nothing leaves your device — conversion happens right here in the browser.
2
Hit Convert — it happens locally
Click Convert and watch it go. There's no upload, no server queue, no waiting. The converter runs MPEG-4 Part 14 → Free Lossless Audio Codec entirely in your browser tab. Most files finish in 1–3 seconds.
3
Download your FLAC
Your Free Lossless Audio Codec file is ready. Click Download, or grab a ZIP if you converted a batch. Close the tab and everything disappears — no copies kept anywhere.

MP4 vs FLAC: format overview

MP4

MPEG-4 Part 14

Moving Picture Experts Group · 2001

Compression: lossy
Transparency: No

✓ Universal compatibility across all platforms
✓ Excellent compression with H.264/H.265
✗ H.264 has royalty implications

FLAC

Free Lossless Audio Codec

Josh Coalson / Xiph.Org · 2001

Compression: lossless
Transparency: No

✓ Lossless compression — identical to source
✓ 50–60% smaller than WAV with no quality loss

MP4 magic bytes: 00 00 00 xx 66 74 79 70

FLAC magic bytes: 66 4C 61 43

Why convert MP4 to FLAC?

You have a video recording of a concert, a studio session, or a live radio broadcast as an MP4. The performance is exactly what you want to preserve, but storing it as video is wasteful — you'll never watch it, only listen. More importantly, your audiophile media player (Roon, Plex, Naim, Bluesound) wants FLAC, not MP4, in its music library.

This converter extracts the audio track from your MP4 and outputs it as FLAC — the lossless archival audio format preferred by hi-fi systems, music servers, and audio archivists. One important caveat: FLAC is lossless from the point of extraction forward, but it cannot undo the original AAC compression that was already applied to the audio inside the MP4. If the MP4 was encoded at 256 kbps AAC — common for modern recordings — the FLAC output will sound excellent and contain every decoded sample. If the source was low-bitrate (96 kbps or less), the quality ceiling is set by that original encoding.

The FLAC file will be several times larger than the audio-only equivalent in AAC or MP3, but smaller than a WAV, because FLAC compresses losslessly. For archival and hi-fi playback, this is the right trade-off: every streaming player, NAS music server, and audiophile DAC that supports FLAC will import it directly.

Quality & file size: MP4 to FLAC

Typical file sizes: MP4 100–300 MB → FLAC 20–40 MB.

Converting from lossy MP4 to lossless FLAC will not recover detail the MP4 codec already discarded — but the output will not degrade any further. This is useful when you need a lossless format for editing or compatibility without additional compression artifacts.

Color depth: MP4 supports standard color, FLAC supports standard color.

Transparency: MP4 does not support transparency. FLAC does not support transparency — transparent areas become solid white.

Frequently asked questions

Privacy: how FormatDrop handles your files

Your MP4files are converted 100% inside your browser. They are never uploaded to our servers, never stored, and never seen by anyone other than you. This isn't a privacy policy claim — it's an architectural guarantee: our server has no endpoint that receives file bytes.