Convert Opus to FLAC online

Your Opus file is converted to FLAC right here in your browser, using FFmpeg compiled to WebAssembly. Nothing is uploaded to us, the audio never leaves your device. Quality is preserved and the download is ready in seconds.

What is an Opus file?

Opus is the newest major audio codec (standardised in 2012) and the best-in-class at speech and low bitrates. Which is exactly why WhatsApp voice notes are Opus files. It was designed for real-time internet audio and it is what Discord, WhatsApp and most VoIP apps use.

Every WhatsApp voice note you have ever received is an Opus file. Discord recordings, Telegram voice messages and browser-based calls use it too. So 'a.opus file I can't open' is one of the most common conversion needs in Nigeria.

Why FLAC?

FLAC (Free Lossless Audio Codec) compresses audio the way ZIP compresses files: the data gets smaller (typically 50 to 60% of WAV size) but decodes back to exactly the original samples. Nothing is lost, ever.

Convert to FLAC to archive: you keep bit-perfect quality at roughly half the size of WAV, with full metadata and checksum support built in. It is the right long-term home for irreplaceable recordings. Opus support outside chat apps is patchy: many car stereos, editors and upload forms don't accept it, which is why voice notes so often need converting to MP3 or WAV first.

Frequently asked questions

Will converting Opus to FLAC lose quality?

Honest answer: quality stays exactly where it is, no better, no worse. FLAC is lossless, but it cannot restore detail your Opus already discarded when it was first encoded. What you gain is safety: the FLAC copy can be edited and re-exported repeatedly without any further loss, which is exactly why editors ask for it.

Is it free?

Yes, completely, with no account and no watermark. The conversion runs on your own device, so it costs us nothing to let you use it. The only limit is file size: up to 50 MB, which is what a browser can hold in memory comfortably.

Do I need to install anything, or upload my file?

Neither. It runs entirely in your browser using FFmpeg compiled to WebAssembly. Your audio is never sent to us, which is also why it works on a slow connection, only the page downloads, not your file.

Need a transcript of the audio?

Autrans also transcribes audio in Nigerian English, Pidgin, Yoruba, Hausa, Igbo, French, and Spanish.