Format guide

Slow Down OGG Online

Slow down OGG Vorbis and Opus files in your browser with speed, reverb and bass controls. Game audio, Bandcamp and Linux sources, browser support, MP3 export.

Open the free editor: upload MP3, WAV, AAC, OGG or FLAC, adjust speed, reverb, bass, tone, width and space, then export MP3 or a ZIP of many tracks. Everything runs in your browser.

OGG is the format you end up with from places that avoid patents and licensing: game asset folders, Bandcamp's download menu, Linux music libraries, and open-source tools. The editor above decodes .ogg files in browsers that support them, slows the audio from 0.50x to 1.50x with or without a pitch drop, adds reverb, bass, tone and stereo width, and encodes an MP3 on your device. Nothing is uploaded.

This page is about what is particular to OGG as a source: the two very different codecs that share the extension, where these files come from, how browsers handle them, and the quality chain through to the MP3 export. For the general controls and presets, see the slowed reverb maker. If you have a choice of formats from a store, the FLAC page explains why lossless is better for slowing, and the MP3 page covers the other common lossy format.

OGG is a container, not a codec

The .ogg extension names the container, the wrapper around the audio data. What is inside can differ, and the two you will meet are:

• Vorbis. The older codec, used for most .ogg music files, most game audio, and Bandcamp's "Ogg Vorbis" download option. Lossy, roughly comparable to MP3 at the same bitrate, somewhat better at low bitrates.
• Opus. The newer codec, often in a .opus file but also sometimes inside .ogg or .oga. Lossy, very efficient, common in voice chat recordings, Discord and Telegram voice notes, some podcast feeds and some newer game engines.

Both are lossy, so the same logic as MP3 applies: the bitrate of the source caps the quality of the slowed result, and slowing stretches encoder artifacts into audibility. Vorbis at its common quality settings, around q5 to q6 or roughly 160 to 192 kbps, is a decent slowed source. Opus at voice bitrates, 24 to 64 kbps, is not, although it is fine for the speech it was meant for.

Less commonly, an .ogg or .oga file can carry FLAC, which is lossless. Those behave like the FLAC page describes.

Browser decode support

Decoding depends on the browser, so treat this table as a starting point and confirm by loading a file.

If a file fails to load, the editor reports the decode error rather than producing silence. On Safari the practical answer is to convert the file on a computer, or to try the same file in Chrome or Firefox. For a conversion, go to WAV if you have disk space (lossless, so nothing further is lost) or to a high-bitrate AAC. The AAC page describes what Safari decodes reliably.

Where OGG files come from

Game audio. Many game engines ship music and sound as Ogg Vorbis because it is free to use and loops cleanly. If you are slowing a game soundtrack you own, the files are often in the game's asset folders, sometimes with no extension or a custom one. Rename to .ogg and try. Loop-point metadata is ignored; the editor plays and exports the file start to finish.

Bandcamp. The download dialog offers Ogg Vorbis alongside MP3, FLAC and others. If you are downloading to slow the track, pick FLAC instead; it is lossless and decodes in more browsers. Choose Vorbis only if space is tight.

Linux workflows. Rips made with default settings in many Linux tools come out as Vorbis. Audacity's default export on some systems is also Vorbis. These are fine sources at q5 and above.

Voice notes and chat recordings. Telegram, WhatsApp exports and Discord recordings are often Opus at low bitrates. They slow down fine for speech, and Preserve pitch keeps the voice natural, but they are not good music sources because of the bitrate.

Vorbis quality levels and what they mean slowed

Vorbis is usually encoded by quality level rather than fixed bitrate. Rough correspondences and how they hold up at 0.80x:

Game audio is often q4 to q6, which is workable. If a soundtrack sounds swirly when slowed, pull Tone down to -5 or -6 dB and keep speed at 0.85x or above. The muddy edit guide has more on hiding source artifacts without burying the mix.

Settings for OGG sources

For the voice rows, Preserve pitch is the whole point. Speech sped up without it sounds cartoonish; with it, the pace changes and the voice stays recognisable. Preserve pitch changes the live preview only; exported files keep the speed-linked pitch.

The export, and the chain

Whatever goes in, what comes out is MP3 at 96 kbps, 32 kHz, encoded in a web worker in your browser. There is no OGG, Opus, WAV or FLAC output, and no higher MP3 bitrate.

Converting Vorbis to MP3 is a lossy-to-lossy step, and so is the source's original encode. That is two lossy stages before the video platform adds a third. In practice a q6 Vorbis source through this chain sounds fine on YouTube, TikTok and Shorts. A q2 source sounds like a q2 source, slower. The one link under your control is the source; get the best version you can.

If you need a lossless or OGG output, this is not the tool for the final file. Find your settings here, then reproduce them in a DAW or in Audacity, which exports Ogg Vorbis natively.

Batch and memory notes

OGG files are compact on disk, but decode to the same uncompressed audio as everything else, so memory use in the tab depends on duration, not file size. A folder of short game loops loads trivially. A set of long ambient stems takes more. On a phone, process a few tracks at a time; on a laptop, an album is fine. The bulk converter page describes the group workflow.