Add your OPUS file
Drop one or more .opus files onto the converter above, or browse for them. They load into browser memory only. Nothing is uploaded, so there is no size-based pricing and no server queue.
Re-encoding .opus audio as .ogg changes how the sound is compressed and which players will accept it. Free, private, and validated: the file never leaves your browser.
Batch files can each use a different output. Nothing uploads for local conversions.
Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.Re-encoding .opus audio as .ogg changes how the sound is compressed and which players will accept it. An .opus file contains audio compressed with the Opus codec, stored in an Ogg container. Opus represents the current state of the art in lossy audio, beating MP3, AAC, and Vorbis in listening tests at nearly every bitrate from whisper-thin speech settings up to transparent music encoding.
An .ogg file almost always means Vorbis-compressed audio in the Ogg container, the free-software world's answer to MP3. The .ogg extension originally covered any Xiph media; audio kept the name when video moved to .ogv, and game developers and Wikipedia still lean on it heavily. For this route the practical draw is patent-free from its first release and strong quality at mid-range bitrates, balanced against apple's Music app and iOS offer no native playback, which is worth knowing before you commit a large batch.
The practical trigger for this conversion is usually a mismatch: with .opus, older car stereos, AV receivers, and MP3 players have never heard of it. Switching to .ogg buys you patent-free from its first release, which is why it is the better fit for shipping game audio assets without codec royalties. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
| Aspect | Opus audio (.opus) | Ogg audio (.ogg) |
|---|---|---|
| Format type | Lossy: discards detail it judges invisible to shrink files | Lossy: discards detail it judges invisible to shrink files |
| How it stores data | the hybrid SILK/CELT design switches coding modes automatically based on content | vorbis is an MDCT-based lossy codec tuned through a quality scale (-q) rather than fixed bitrates |
| Strongest at | compressing podcast and voice-chat audio to tiny files | shipping game audio assets without codec royalties |
| Weak spot | older car stereos, AV receivers, and MP3 players have never heard of it | apple's Music app and iOS offer no native playback |
| Metadata | vorbis comments in the OpusTags header, including cover art via METADATA_BLOCK_PICTURE, plus an output-gain field used for loudness normalization. A file written here carries no comments and no cover art, because metadata mapping is disabled on every conversion, and no output gain is calculated or set | vorbis comments, the flexible key=value system shared with FLAC and Opus, plus METADATA_BLOCK_PICTURE for embedded cover art. Neither reaches an output written here: metadata mapping is disabled on every conversion, so comments and embedded artwork are dropped in both directions |
Drop one or more .opus files onto the converter above, or browse for them. They load into browser memory only. Nothing is uploaded, so there is no size-based pricing and no server queue.
Select .ogg in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if OGG is selectable, the route is real and validated.
Press Convert. The transcode runs on an FFmpeg engine compiled to WebAssembly, so the audio never leaves your device.
Each result is checked before the download unlocks: where OGG has a signature or a structure this converter can read back, the file is re-opened and parsed, and where it has neither, the check is that a non-empty file of the declared type came back. A result that fails is reported as an error instead of being offered for download, and outputs keep the original filename with the .ogg extension.
A second lossy step always costs a little, because opus is lossy-oriented and ogg is lossy-oriented and each encoder discards detail differently (generation loss). At the default quality the difference is rarely visible; avoid repeated round-trips between .opus and .ogg.
Yes. The .opus file is processed inside your browser tab and never uploaded. The transcode runs on an FFmpeg engine compiled to WebAssembly, so the audio never leaves your device. Close the tab and the file is gone from memory.
Chrome, Firefox, and Edge have decoded Ogg Vorbis for many years, and Android plays it natively, while Safari and iOS remained the notable holdouts until only recently. Dedicated players such as VLC and foobar2000 cover the desktop everywhere. Novus Convert writes .ogg with libvorbis in variable-bitrate mode, mapping the quality slider onto the encoder's 0-to-8 quality scale, and the .ogg it produces is always Vorbis: an Ogg container holding Opus or FLAC is not something this target can make, and the separate .opus and .flac targets exist for those. Reading .ogg requires the OggS capture pattern at the head of the file, and input is capped at 500 MB.
It depends on the content: vorbis is an MDCT-based lossy codec tuned through a quality scale (-q) rather than fixed bitrates. Convert one representative file first and compare before batch-processing a large set.
This converter strips container metadata deliberately (the FFmpeg command runs with metadata mapping disabled) so exported files do not leak recording details. In the source, vorbis comments in the OpusTags header, including cover art via METADATA_BLOCK_PICTURE, plus an output-gain field used for loudness normalization. A file written here carries no comments and no cover art, because metadata mapping is disabled on every conversion, and no output gain is calculated or set; none of it is transmitted anywhere because the file never leaves your browser.
Yes. The reverse route exists as a separate tool. Bear in mind that round-tripping .opus → .ogg → .opus is not a perfect undo when any lossy step is involved; keep your original if fidelity matters.