Convert MP4 to FLAC — The Most Faithful Audio You Can Get from a Video

No, and this is an important distinction. FLAC is a lossless container, meaning it preserves whatever audio you put into it without any further loss. But if the audio inside your MP4 was already compressed with a lossy codec like AAC — which is the case for most MP4 files — then that lossy audio is what gets preserved. You get a perfect FLAC copy of the AAC audio, not a restoration of the original uncompressed recording. Think of it this way: FLAC guarantees no additional quality loss during the mp4 to flac conversion, but it cannot undo quality loss that already happened when the video was recorded or encoded. The result is still the best possible extraction from that MP4.

Both are lossless, so the audio quality is identical. The difference is file size and features. FLAC compresses the audio by 30-50% compared to WAV while remaining fully lossless — you can decode a FLAC file back to a bit-identical WAV at any time. FLAC also supports metadata tags (title, artist, date) and even cover art, while WAV has very limited metadata support. For archiving, FLAC is the better choice: same quality, smaller files, better organization. Convert MP4 to FLAC rather than WAV unless you specifically need raw uncompressed PCM for a tool that does not read FLAC.

It depends on the MP4's video resolution and the audio's characteristics. The video track makes up the vast majority of an MP4's file size, so the FLAC audio-only file will be dramatically smaller than the original video. As a rough guide: one minute of stereo FLAC audio at CD quality (16-bit, 44.1 kHz) is about 20-30 MB. A 1 GB MP4 video that is 10 minutes long might produce a FLAC file around 200-300 MB. That is still much larger than an MP3 of the same audio (which would be about 15-25 MB), but you get perfect lossless quality in exchange for the extra space.

Yes, both major platforms support FLAC. Android has played FLAC files natively since Android 3.1 — just open the file in any music player app. On iPhone, iOS has supported FLAC playback since iOS 11 through the Files app and third-party players like VLC. Apple Music on iPhone can also import and play FLAC files. So after you convert MP4 to FLAC, the resulting file will play on any modern smartphone without installing special apps, though a third-party player may give you a better experience with metadata display and library management.

Both are lossless — the decoded audio quality is mathematically identical. The practical differences are about ecosystem and flexibility. ALAC is Apple's lossless codec and works seamlessly in Apple Music, iTunes, and across Apple devices. FLAC has broader cross-platform support: it works on Windows, Linux, Android, and every major audio editor without any issues. FLAC files are also slightly smaller than ALAC at the same content in most cases. If you use exclusively Apple devices, ALAC integrates a bit more smoothly. For everything else — archiving, editing, cross-platform playback — FLAC is the more universal choice. You can always convert between FLAC and ALAC with zero quality loss since both are lossless.

Yes to all three. Audacity has supported FLAC import and export for years — just open the file directly. Logic Pro on macOS reads FLAC natively as of recent versions. Pro Tools can import FLAC files (some older versions may require a conversion to WAV first, but current versions handle FLAC directly). Ableton Live, Reaper, and Adobe Audition also import FLAC without issues. When you convert MP4 to FLAC, the resulting file is immediately usable in any modern DAW or audio editor.

FLAC will capture every bit of the audio that is in the MP4, regardless of the video quality. However, the video resolution (4K, 1080p, etc.) does not affect the audio quality — those are separate tracks. What matters is how the audio was recorded: the sample rate, bit depth, and the codec used. Many 4K cameras record audio at 48 kHz, 16-bit AAC, which is good but not audiophile-grade. Some professional cameras record at 24-bit, 48 kHz or 96 kHz PCM. When you extract FLAC from MP4, you get whatever audio quality was actually captured. FLAC supports up to 24-bit depth and 655 kHz sample rates, so it can handle anything your camera recorded.

FLAC, by a significant margin. FLAC typically compresses audio to 50-70% of the equivalent WAV file size while remaining perfectly lossless. For a 3-hour interview recording, the difference could be several hundred megabytes. Over an archive of dozens or hundreds of recordings, FLAC saves gigabytes of storage compared to WAV. And since FLAC is lossless, you lose nothing — you can always decode it back to an identical WAV file if you ever need one. For long-term storage, mp4 to flac conversion gives you the most practical lossless format.

Yes. There is no duration limit. A 3-hour MP4 will produce a FLAC file that faithfully preserves every moment of the interview audio. The FLAC file for a 3-hour stereo recording at CD quality will be roughly 3-5 GB, depending on the audio content (speech compresses better than music in FLAC because it has more silence and predictable patterns). The conversion takes longer for such a large file since it runs in your browser, but it will complete successfully. For very long recordings, just leave the tab open and let it finish.

Yes. FLAC supports bit depths up to 24-bit and sample rates up to 655.35 kHz, which covers every practical recording format in existence. If your MP4 contains high-resolution audio — for example, 24-bit/48 kHz from a professional camera or 24-bit/96 kHz from a studio recording — the FLAC extraction will preserve that full resolution. The mp4 to flac converter does not downsample or reduce bit depth. Whatever audio resolution is in your MP4 is what you get in the FLAC output. For archival purposes, this means you are keeping the full quality of the original capture.