What happens when you convert OPUS to FLAC
- The audio is decoded and written as FLAC at compression level 5.
- FLAC is lossless, but it cannot restore what the OPUS encoder already discarded. The FLAC will sound identical to the OPUS and be several times larger.
How to convert OPUS to FLAC online
- Press "Choose OPUS files" and select one or more files, or drag them onto the box. You can add files of any size your device can hold in memory.
- Adjust the settings if you need to: the bitrate controls quality and size. The defaults suit most people.
- Press "Convert to FLAC". The first audio or video conversion downloads the converter engine, about 32 MB, which your browser then keeps for next time.
- Save each FLAC with its download button. Close the tab and every trace of the files is gone from memory.
Why convert OPUS to FLAC?
OPUS files usually come from WhatsApp and Telegram voice notes, Discord and video calls. People convert them to FLAC because FLAC keeps every detail of the original while cutting the size roughly in half compared with WAV.
In short, OPUS is good at what it was made for, and FLAC is the more practical choice when the file has to play on another device or app. OPUS plays in current browsers; many car stereos and older players cannot, while FLAC plays in current browsers and most Android devices; iPhones play it in the Files app.
How to convert OPUS to FLAC on Windows, Mac, iPhone and Android
On Windows
Open this page in Chrome, Edge or Firefox, drag your OPUS files in from File Explorer, and press Convert. Each FLAC is saved to your Downloads folder. If you prefer a desktop program, VLC can also convert OPUS to FLAC: choose Media, then Convert / Save.
On a Mac
Safari, Chrome and Firefox all work. Drag the OPUS files from Finder onto the drop zone and the FLAC files land in Downloads.
On iPhone and iPad
Open the page in Safari and tap Choose OPUS files. You can pick from Photos or from the Files app. The converted FLAC appears in Files, in the Downloads folder.
On Android
Open the page in Chrome, tap Choose OPUS files and pick them from Files or your gallery. The FLAC is saved to the Download folder, where any file manager can find it. Keep the screen on while a long video converts, because Android may pause a tab in the background.
Best settings for OPUS to FLAC
FLAC is lossless, so there is no quality setting: every sample of the decoded OPUS is kept. What changes is size. CD-quality stereo, 44.1 kHz at 16 bits, takes about 10 MB per minute as uncompressed PCM, and roughly half to two thirds of that once compressed losslessly.
Since the OPUS was lossy, the FLAC will sound identical to it, not better. Convert to FLAC when a program requires it, not to improve quality.
OPUS vs FLAC: the differences
| OPUS | FLAC | |
|---|---|---|
| Full name | Opus audio | Free Lossless Audio Codec |
| Type | audio | audio |
| Created by | the Internet Engineering Task Force | Josh Coalson and the Xiph.Org Foundation |
| First released | 2012 | 2001 |
| Compression | Lossy | Lossless |
| Usually contains | Opus in an Ogg container | FLAC lossless audio, up to 32-bit and 655 kHz |
| In a browser | plays in current browsers; many car stereos and older players cannot | plays in current browsers and most Android devices; iPhones play it in the Files app |
| Common uses | WhatsApp and Telegram voice notes, Discord and video calls | CD rips, hi-res music stores and audio archives |
| MIME type | audio/ogg | audio/flac |
About OPUS and FLAC files
What is an OPUS file?
Opus was built for speech and music over the internet, and it holds up at bitrates as low as 16 kbps. Voice messages from WhatsApp and Telegram usually arrive as Opus files.
What is a FLAC file?
FLAC shrinks audio to about half to two thirds of WAV size without losing a single sample, so it can be decoded back to a bit-identical copy of the original.
OPUS to FLAC not working? Common problems
- The conversion is slow. Audio and container changes take seconds, but re-encoding video runs on your own processor. Lower the resolution to 720p, close other tabs, and keep the device plugged in.
- The tab stops or reloads on a very large file. Browsers limit how much memory one tab can use, around 2 GB and less on phones. Split long recordings or convert them on a computer.
- Song titles are missing. Tags such as title and artist are copied when FLAC can store them, but cover art is not carried over.
Convert OPUS to FLAC with ffmpeg
This converter runs ffmpeg inside your browser. If you would rather use the ffmpeg command line on your own computer, this command produces an equivalent FLAC with the same kind of settings:
ffmpeg -i input.opus -vn -c:a flac output.flacReplace input.opus with the name of your file. For a whole folder of OPUS files, run the command in a loop, or drop them all on the converter above, which processes them one after another.
OPUS to FLAC converter FAQ
Will I lose quality converting OPUS to FLAC?
No further quality is lost, because FLAC is written losslessly. Detail the OPUS compression already removed does not come back.
Why is the FLAC a different size from the OPUS?
The FLAC is usually larger, because it stores every sample without compression losses, while the OPUS was compressed lossily.
Are my OPUS files uploaded anywhere?
No. The conversion runs inside this browser tab using ffmpeg compiled to WebAssembly, so your files stay on your device. You can disconnect from the internet after the page and converter engine have loaded and it still works.
Can I convert several OPUS files to FLAC at once?
Yes. Select or drop as many files as you like; they are converted one after another and each gets its own download button.
How do I open a FLAC file?
FLAC plays in current browsers and most Android devices; iPhones play it in the Files app. FLAC is common for CD rips, hi-res music stores and audio archives.
Is this OPUS to FLAC converter free?
Yes. There is no sign-up, no watermark and no limit on how many files you convert. The site is paid for by advertising, and because conversions run on your device there is no server cost per file.
Can I convert OPUS to FLAC on my phone?
Yes. The converter works in Safari on iPhone and iPad and in Chrome on Android. Converted files are saved to the Downloads folder.