How to convert MP4 to FLAC
- Drop your MP4 file.
- Adjust quality, resolution or bitrate if you want (defaults are optimized).
- Optionally set a start time and duration to trim.
- Click Convert, watch the progress and download your FLAC file.
Why convert MP4 to FLAC?
MP4 is excellent for sharing, uploading and playing video anywhere, but it has some limitations:
- Lossy compression
- Re-encoding reduces quality slightly
Converting to FLAC gives you:
- Lossless quality
- Smaller than WAV
- Open and free
MP4 vs FLAC: side-by-side comparison
| Feature | MP4 | FLAC |
|---|---|---|
| Full name | MPEG-4 Part 14 | Free Lossless Audio Codec |
| File extension | .mp4 | .flac |
| Type | Video | Audio |
| Compression | Lossy (H.264/H.265) | Lossless |
| Transparency | No | No |
| Animation / multi-frame | Yes | No |
| Introduced | 2001 | 2001 |
| Developed by | MPEG (ISO) | Xiph.Org Foundation |
| MIME type | video/mp4 | audio/flac |
| Best for | sharing, uploading and playing video anywhere | archiving music at full quality |
What are MP4 and FLAC files?
MP4 (.mp4)
MP4 is the most compatible video format today. Phones, YouTube, Facebook, WhatsApp and smart TVs all play MP4, usually with H.264 video and AAC audio.
FLAC (.flac)
FLAC is a lossless audio format that keeps CD quality while cutting file size roughly in half compared with WAV. Audiophiles use it to archive music.
Tips for the best FLAC results
- For phones and social media, MP4 (H.264 + AAC) is the safest choice for video and MP3 for audio.
- Very large files (over 1 GB) may exceed browser memory on phones; trim them or use a computer.
- 128 kbps is ideal for speech (lectures, waz, voice notes) and 192–320 kbps for music.
- Bookmark this page or install the app to convert MP4 files offline next time.
Private by design: how this converter works
Unlike typical online converters that upload your file to a remote server, this MP4 to FLAC converter processes everything on your own device using FFmpeg compiled to WebAssembly — the same engine used by professional video tools. Your file is read into browser memory, converted, and offered back as a download — it is never sent to us.
- No upload wait — conversion starts instantly, even on slow mobile data.
- Private — safe for NID copies, certificates, bank statements and personal photos.
- No limits — no daily quota, no queue and no watermark.
- Offline-ready — once loaded, many tools keep working without internet.
Frequently asked questions
Is this MP4 to FLAC converter free?
Yes — free, unlimited and without watermarks or sign-up.
Are my MP4 files uploaded to a server?
No. Conversion happens inside your browser on your own device, so your files stay private.
Will I lose quality converting MP4 to FLAC?
FLAC preserves the quality of your source file exactly — though it cannot restore detail already lost in the original MP4.
Can I convert several files at once?
Yes. Drop multiple files and download them individually or together as a ZIP.
Does it work on iPhone and Android?
Yes. It works in Chrome, Safari, Edge and Firefox on phones, tablets and computers. You can also install the site as an app.
What is the difference between MP4 and FLAC?
MP4 (MPEG-4 Part 14) is lossy (h.264/h.265) and best for sharing, uploading and playing video anywhere, while FLAC (Free Lossless Audio Codec) is lossless and best for archiving music at full quality.
Why does the first conversion take longer?
The FFmpeg WebAssembly engine (about 30 MB) is downloaded once and cached. Later conversions start immediately.