Convert MP4 to FLAC
Free online converter for MP4 files. Lossless compression with roughly half the size of WAV. Nothing to install, no watermark, and every file is deleted automatically.
Drag and drop your files
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Upload a MP4 file to convert it to FLAC. Up to 3 files at once, 100 MB each.
Free · up to 3 files · 100 MB each · files deleted automatically after 1 hour.
About MP4 and FLAC
MP4 .mp4
The universal video container, normally holding H.264 video and AAC audio. If a device plays video at all, it plays MP4.
Good for
- Plays on effectively every device, browser and editor
- Excellent compression at high quality
- Streams well, and seeks quickly
Trade-offs
- H.264 carries patent licensing obligations
- Lossy — quality drops each time it is re-encoded
- Less flexible than MKV for subtitles and multiple tracks
video/mp4
FLAC .flac
Lossless compression for audio. Roughly half the size of WAV, and it decodes back to the original samples exactly — nothing is approximated.
Good for
- Perfect reconstruction — identical to the source
- Around 50–60% of the size of WAV
- Full tagging, and an open royalty-free format
Trade-offs
- Still far larger than MP3 or AAC
- Not supported by every portable player or car stereo
audio/flac
MP4 and FLAC side by side
| MP4 | FLAC | |
|---|---|---|
| Compression | Lossy (usually H.264) | Lossless |
| Transparency | No | n/a |
| Typically used for | Everything — the safe default for video | Archiving, high-fidelity libraries |
What changes when you convert MP4 to FLAC
Only the sound is kept
This takes the audio track out of the MP4 and writes it as FLAC. The picture is discarded entirely, and no conversion back will return it — keep the MP4 if you still need the video.
This is a re-encode, not a repackage
Some tools can move a stream into a different container untouched when the codecs happen to line up. We do not — every job here is decoded and encoded again, so the conversion takes time in proportion to the length of the file and costs a small amount of quality even where a repackage would have been possible. In exchange the output is predictable: it plays everywhere, rather than inheriting whatever the source happened to contain.
What your FLAC will contain
The output is FLAC — which is lossless, so there is no bitrate to set — the size is decided entirely by how compressible your audio turns out to be, usually landing near half of the equivalent WAV while preserving every sample exactly.
Other MP4 conversions
Other ways to get FLAC
Worth reading next
MP4, MOV and MKV are not really video formats
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Bitrate is the single dial that decides how big an audio file is and how good it sounds. Here is what the numbers mean, why they are not comparable between codecs, and where the real thresholds sit.
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