MP4 to FLAC Converter
Extract the audio from your MP4 video as a FLAC file for lossless compatibility. While the quality is limited by the video's original audio encoding, FLAC format ensures compatibility with audiophile players and lossless audio workflows.
The FLAC output stores the decoded audio from the video's audio track. Quality is limited by the original encoding in the MP4 (typically AAC).
How to Convert MP4 to FLAC
- 1
Upload your MP4 video.
- 2
Select FLAC as the output.
- 3
Click Convert and download the FLAC audio.
MP4 vs FLAC — Format Comparison
| Feature | MP4 | FLAC |
|---|---|---|
| Full Name | MPEG-4 Part 14 | Free Lossless Audio Codec |
| Type | Video | Audio |
| Codec | H.264 / H.265 / AV1 | FLAC |
| Lossless | No | Yes |
| Extension | .mp4 | .flac |
| Best For | Online video streaming | Audiophile music collections |
MP4 Strengths
- Universal device and browser support
- Excellent compression-to-quality ratio
- Supports subtitles, chapters, and metadata
FLAC Strengths
- 100% lossless — bit-for-bit identical to original
- Open source and royalty-free
- 50-60% smaller than uncompressed WAV
Frequently Asked Questions
When to Convert MP4 to FLAC
- Extracting audio in lossless format for editing
- FLAC compatibility with specific audio systems
- Creating lossless working copies from video audio
Related Conversions
About Our MP4 to FLAC Converter
This converter uses FFmpeg compiled to WebAssembly (WASM) to transform your MP4 files into FLAC format entirely inside your web browser. When you select a file for conversion, the processing happens locally on your device. Your file is never uploaded to any server, never transmitted over the internet, and never stored anywhere outside your own computer. This privacy-first architecture makes our tool safe for confidential and sensitive content — including legal recordings, medical files, financial presentations, personal media, and any other material you would not want on a third-party server.
The conversion process works by decoding the MP4 input using FFmpeg's highly optimized decoders, then encoding the output in FLAC format with carefully tuned settings that balance quality and file size. When possible, the tool uses stream copy mode to remux (rewrap) compatible streams without re-encoding, which preserves the original quality with zero generational loss. When re-encoding is necessary due to codec differences between the two formats, the converter uses high-quality encoding settings to minimize any visible or audible quality reduction.
Supported input formats include MP4, MOV, AVI, MKV, and WebM for video, with automatic detection of the codecs and parameters inside your source file. The output is optimized for maximum compatibility with modern devices and platforms including Windows, macOS, Linux, iOS, Android, smart TVs, and all major web browsers.
Why browser-based conversion is safer: traditional online converters require you to upload your file to a remote server, where it is processed by third-party infrastructure and then made available for download. This workflow exposes your data to interception during upload, unauthorized access on the server, unclear data retention policies, and potential data breaches. Professionals in regulated industries such as healthcare (HIPAA), legal (attorney-client privilege), and finance (SOX, GDPR) often cannot use server-based converters without violating compliance requirements. Our WebAssembly-powered approach eliminates all of these risks by ensuring your data never leaves the browser sandbox on your own device.
The tool handles files up to 500 MB on desktop browsers and 200 MB on mobile devices. No account registration, no software installation, and no recurring subscription is required. Conversion typically completes in seconds for small files and a few minutes for larger ones, depending on your device's processing capabilities. Once the conversion is finished, you can download the result immediately and the source data is discarded from browser memory.