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Supports: OPUS
Opus is a lossy streaming codec built for voice and music at low bitrates; FLAC is a lossless archival codec that stores audio bit-for-bit. This converter rewraps your Opus audio into a FLAC file — useful when an editor, player, or hardware device only accepts lossless input. One thing to be clear about up front: converting Opus to FLAC does not restore quality. The detail Opus discarded during its original lossy encode is gone, and FLAC can only losslessly preserve whatever the Opus file already contains. You get a larger file that sounds identical to the source, not a better one.
| Property | Value |
|---|---|
| Standard | IETF RFC 6716 (Opus Audio Codec) |
| Released | September 2012 |
| Compression | Lossy (SILK linear prediction + CELT/MDCT) |
| Container | Usually Ogg (.opus); also Matroska, WebM |
| Sample rate | 8 kHz (narrowband) to 48 kHz (fullband) |
| Bitrate | 6 to 510 kbit/s, variable or constant |
| Best for | Streaming, VoIP, podcasts, low-bitrate music |
| Maintained by | Xiph.Org / IETF (royalty-free) |
| Property | Value |
|---|---|
| Standard | IETF RFC 9639 (published December 2024) |
| Released | 2001 (reference encoder by Josh Coalson) |
| Compression | Lossless — decoded audio is bit-for-bit identical |
| Container | Native FLAC stream (.flac) |
| Bit depth | 4 to 32 bits per sample |
| Sample rate | 1 Hz up to 1,048,575 Hz |
| Channels | 1 to 8 |
| Metadata | VORBIS_COMMENT tags + embedded PICTURE (album art) blocks |
| Maintained by | Xiph.Org Foundation (non-proprietary, patent-unencumbered) |
Because Opus already throws data away and FLAC keeps everything, a FLAC made from Opus is typically several times larger than the Opus source while carrying no extra audible information. FLAC's advantage shows up only when your source is already lossless — it is the wrong tool for "upgrading" a lossy file, and the right tool for storing a master without further loss.
.opus file onto the page or click "+ Add Files" to browse. You can queue several files to convert in one batch.Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours after conversion — never shared, never made public. Need the opposite direction to shrink a file back down for sharing? Use FLAC to Opus.
No. Opus is a lossy codec, so some audio information was permanently discarded when the file was first encoded. FLAC is lossless, which means it can store exactly what is in the Opus file — no more, no less. The FLAC output will sound the same as the Opus source, just in a larger, lossless container. To get genuinely higher quality you would need to start from a lossless or uncompressed master.
Opus achieves small sizes by discarding inaudible (and some audible) data; a typical music Opus stream runs roughly 96-160 kbit/s. FLAC stores audio losslessly, so it encodes far more bits per second even when the underlying audio came from a lossy source. A multiple-times-larger output is expected and normal for this conversion — it reflects FLAC's lossless storage, not added quality.
No. FLAC is lossless at every compression level, so levels 1 through 12 all decode to bit-for-bit identical audio. The only difference is the tradeoff between output file size and encoding time: higher levels search harder for redundancy and produce a smaller file but take longer to encode. In our testing, raising the level on an already-lossy Opus source shaves only a little off the size, because lossy audio has less exploitable redundancy than a true lossless master.
FLAC supports rich metadata through VORBIS_COMMENT blocks for text tags (title, artist, album) and PICTURE blocks for embedded album art, mirroring the Vorbis Comment system Opus uses in its Ogg container. Common fields carry over during conversion. If a niche or non-standard tag matters to you, verify it in your tag editor after converting, since field mapping between containers is not always one-to-one.
Yes. FLAC has a long-stable bitstream and is developed by the Xiph.Org Foundation. In December 2024 the format was formally standardized as IETF RFC 9639, giving it a vendor-neutral written specification. It remains non-proprietary and unencumbered by patents, which is a large part of why it is the default lossless format for archival and audiophile use.
Choose FLAC when a workflow, audio editor, or hardware player specifically requires a lossless input, or when you want a single archival copy that will not lose further quality if re-encoded later. If your goal is broad device compatibility or a smaller shareable file, Opus to MP3 is usually the better fit, since FLAC made from a lossy source is large without sounding better. WAV is worth picking only when an application demands uncompressed PCM specifically.