MP4 to FLAC Converter – Free Online

Video & Audio Converter

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How to Convert MP4 to FLAC Online

Upload your MP4 file

Drag and drop your .mp4 file onto the page or click to browse. You can select several MP4 files at once to batch-convert them.

FLAC is preselected

The output format is already set to FLAC, so you can convert immediately. If you need to, adjust the audio codec, bitrate or sample rate in the settings panel first.

Convert and download

Click Convert. The FLAC file is processed on your own device; nothing is uploaded to a server. When it finishes, click Download to save it (or Download all to get a batch as a ZIP).

Why Convert MP4 to FLAC?

FLAC keeps every bit of the decoded audio yet compresses it to about half the size of WAV, which makes it the best archival format for the soundtrack of a concert recording, lecture or interview stored in MP4. Music servers such as Plex, Roon and foobar2000 handle FLAC natively.

Remember that the audio inside an MP4 is normally lossy AAC, so FLAC will faithfully preserve it but cannot add back detail that was never there. It does guarantee that no further quality is lost in future edits or conversions.

Private by design: your MP4 file is converted on your own device and never uploaded.
FLAC preselected: the output format is already chosen, so it is a one-click conversion.
Batch friendly: convert several MP4 files in one go and download them as a ZIP.
No limits, no watermark: free for files of any size, with nothing stamped on the output.

MP4 vs FLAC

MP4 (MPEG-4 Part 14): MP4 is the most widely supported video container in the world. It usually carries H.264 or H.265 video with AAC audio, plays on every phone, browser, TV and editing app, and is the safest choice for sharing. It is best for sharing, social media, web playback and mobile devices.

FLAC (Free Lossless Audio Codec): FLAC (Free Lossless Audio Codec) compresses audio to roughly half the size of WAV without discarding a single bit, so it decodes back to the identical original. It is best for lossless music libraries and audiophile listening.

In short: keep MP4 when the priority is sharing, social media, web playback and mobile devices, and switch to FLAC when the file is headed for lossless music libraries and audiophile listening. Need a different target? The full Video Converter supports every format listed below.

MP4 to FLAC FAQ

Is MP4 to FLAC really lossless?

The FLAC output is a perfect copy of the decoded MP4 audio. The original AAC track was lossy, so think of FLAC here as 'no further loss' rather than 'studio master'.

Why not just use WAV?

FLAC gives you the same audio as WAV in roughly half the space and supports tags such as title and artist. Choose WAV only if your editing software cannot open FLAC.

Is this MP4 to FLAC converter free?

Yes. Converting MP4 to FLAC on MediaConverter.io is completely free, with no watermark, no sign-up and no daily conversion limit.

Are my MP4 files uploaded to a server?

No. The converter runs inside your browser using WebAssembly and WebCodecs, so your .mp4 file is read and converted on your own device. Nothing is uploaded, which keeps private recordings private and means there is no waiting in an upload queue.

Is there a file size limit for MP4 to FLAC?

No fixed limit. Because processing happens locally, the practical limit is your computer's memory and patience; multi-gigabyte MP4 files convert fine on a desktop browser. Very large files take longer on phones.

Will converting MP4 to FLAC reduce quality?

FLAC is a lossless format, so it stores exactly the audio decoded from your MP4 file. No additional quality is lost during the conversion.

Which browsers support the MP4 to FLAC converter?

Current versions of Chrome, Edge, Firefox and Safari on desktop all work. Chrome and Edge are fastest because they expose hardware-accelerated WebCodecs decoders.