Audio Tools — Convert Audio to Royalty-Free OGG/Opus
Audio to OGG / Opus Converter
OGG Opus Converter - Convert Audio to Royalty-Free OGG or Opus Online — Turn any common audio file (MP3, WAV, FLAC, M4A, AAC, WMA, AIFF and more) into OGG (Vorbis) or Opus. Both are open, royalty-free formats - great for the web, games and podcasts. For OGG you choose a quality level, for Opus a bitrate. A metadata tag editor is built in: existing tags (title, artist, album, album artist, genre, year, track, comment) are read from the source file automatically, can be edited, and are written into the output as Vorbis Comments while encoding. Everything is processed locally in your browser, with files never uploaded to a server.
Supported input: MP3, WAV, FLAC, OGG, Opus, M4A, AAC, WMA, AIFF and other common audio formats. Everything is converted locally in your browser; files are never uploaded to a server.
First use loads an ~30MB audio processing engine into the current browser. It is cached and reused afterwards, so please be patient.
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Click to select or drag and drop an audio file
Any common audio format; under 500MB recommended
Quality:
Bitrate:
Ogg Vorbis: Ogg Vorbis quality scale 0-10; higher values give better sound and larger files. Vorbis is an open, royalty-free codec.
Opus: Opus is an IETF open standard with permanently royalty-free licensing. At 128 kbps it is transparent for most music. Note: encoding happens in the browser with a 32 MB wasm heap, so files over ~90 seconds may fail with "memory access out of bounds". If that happens, split the file with Audio Split, convert each part, then merge with Audio Merge. Files up to ~90 seconds are usually fine.
Audio Tags
Fill in any fields below to write metadata tags into the output file (fields left empty are omitted). Existing tags in the input file are read automatically and filled in here after you select a file.
What are OGG and Opus?
Ogg and Opus are frequently confused because they sit next to each other in file extensions. The short version: Ogg is a container, Vorbis and Opus are codecs. An .ogg file is a wrapper that holds packets of encoded audio (or video); the two codecs this page writes are Vorbis, the open-source codec from 2002 built to compete with MP3, and Opus, the 2012 IETF standard (RFC 6716) that now outperforms every other lossy codec at most bitrates. Both are permanently royalty-free — no patents, no licensing fees, which is why the web, games and nearly every messenger app standardized on them.
Five facts to anchor the rest of the page:
• Ogg = container format; Vorbis and Opus = the codecs inside it (files here are .ogg or .opus)
• both are lossy, like MP3 — quality is chosen per encode and discarded data cannot be recovered
• Vorbis quality scale runs 0–10; quality 5 stereo works out to roughly 160 kbps
• Opus scales from 6 to 510 kbps and is transparent for most music at 128 kbps
• metadata in both is Vorbis Comments — the open tag system, not ID3
Container vs codec: what an .ogg file actually is
The Ogg container (by the Xiph.Org Foundation) does for its family what MP4 does for AAC: it frames compressed packets, adds timestamps so a player knows when to decode each one, and checksums every page so damaged files degrade instead of dying. One container can hold different codecs — Vorbis audio, Opus audio, FLAC-in-Ogg, even Theora video — which is why a file's extension alone doesn't tell you which codec is inside. That is also why some older players open an .ogg file and play silence: they understand the container but not the codec inside it. Modern browsers, VLC and Foobar2000 handle both codecs on any platform.
Vorbis and Opus: two open codecs, two eras
Vorbis (2002) was created because MP3 was patent-encumbered. It beat MP3 sound-per-bit decisively — a quality-5 Vorbis file sounds like a ~192 kbps MP3 at ~160 kbps — and became the codec of Wikipedia, Spotify's early streaming and most PC games of the 2000s.
Opus (2012, RFC 6716) is the successor, and its design explains the features list. It merges two codecs: SILK, Skype's speech codec, excellent for voice, and CELT, Xiph's music codec, excellent for full-bandwidth sound — and switches between them (or blends them) every frame. Practical consequences: it works from telephone-speech quality at 6 kbps up to studio full-band at 510 kbps; it runs at very low latency (frames as short as 5 ms, default 26.5 ms — MP3 needs ~100 ms+) which matters for calls; and it is mandatory in WebRTC, so it carries voice in Chrome, Firefox, WhatsApp, Discord and Zoom calls today.
Quality settings and Vorbis Comments
The two format panels above expose the native control of each codec. Vorbis is quality-driven: you pick a target quality (0–10) and the encoder finds whatever bitrate that quality needs for each moment of the music — quiet passages get fewer bits, dense choruses get more. Opus is bitrate-driven: you set the average bitrate and the encoder manages quality within it, with 128 kbps already transparent for most listeners.
Tags in both formats use Vorbis Comments: simple FIELD=value pairs (artist, title, album, and freeform custom fields of any length). The tag editor above writes these while encoding. Vorbis Comments are the same system FLAC uses — one more thing the open-format family shares.
Common misconceptions
OGG sounds worse than MP3. No. Controlled listening tests consistently rank Vorbis above MP3 at equal bitrates, and Opus above both. The perception dates from early 2000s players that decoded Vorbis badly, not from the format.
Opus is only for voice calls. No. The speech lineage (SILK) is half its engine; the other half (CELT) is built for full-bandwidth music. Opus is transparent at 128 kbps for most music and is YouTube's current audio codec.
Ogg files use ID3 tags. No. Ogg audio uses Vorbis Comments. Tools that force ID3 chunks into an Ogg file produce files some players reject — one more reason to let the converter above write tags natively.
