MP3 → OGG
MP3 to OGG converter
MP3 audio is decoded and re-encoded as Ogg Vorbis, a royalty-free lossy codec. Both formats are lossy, so the output is one generation further from the original.
…or drag files and folders here. Add as many as you like — everything is processed on this device.
.aac .aif .aifc .aiff .flac .m4a .mp3 .wav .wave
In one paragraph
Vorbis is the format open platforms ask for. Godot imports it natively, Unity and Unreal handle it well, Wikimedia Commons requires patent-free codecs, and a lot of Linux and homebrew software prefers it. It also seeks more cleanly than MP3, which matters for looping game music.
Sonic Batch encodes with libvorbis and exposes the codec’s real VBR quality scale rather than hiding it behind vague labels. Quality 5 is the classic default and lands around 160 kbps for typical music.
Does this change the audio quality?
Both sides of this conversion are lossy, so the encoder is working from audio that has already been through a codec. The result is one generation further from the original recording.
- Vorbis at the same bitrate is slightly more efficient than MP3, so matching the source bitrate roughly preserves what is left.
- ID3 tags are mapped to Vorbis comments where an equivalent exists. Embedded cover art is not carried into Ogg here.
- Ogg needs a decoder. Safari and iOS have none, and neither do most car stereos — check your target platform before converting away from MP3.
A worked example
Preparing background music for a Godot project
- Drop the MP3 tracks into the queue.
- Switch rate control to Quality and set 5 — the standard Vorbis default, around 160 kbps.
- Leave the sample rate alone so loop points stay sample-accurate relative to the source.
- Convert all and download the ZIP, then import the .ogg files into the project’s music folder.
Use the quality scale, not a fixed bitrate
Vorbis was designed around VBR. Quality 3 is roughly 112 kbps and fine for looping ambience; quality 5 is roughly 160 kbps and the sensible default for music; quality 7 is roughly 224 kbps and worth it only if the MP3 source was 256 kbps or better. Setting a fixed bitrate makes the encoder spend bits on passages that do not need them.
Supported formats, limits and browser notes
Sonic Batch decodes with the browser when it can (faster, no engine download) and falls back to the self-hosted WebAssembly engine when it cannot. Every combination below works in every listed browser; the column only tells you which decoder does the work.
| Input | What it is | Chrome | Firefox | Safari | iOS |
|---|---|---|---|---|---|
| MP3 | The universal lossy format. Plays on essentially every device made since 1998. | Native | Native | Native | Native |
| WAV | Raw PCM samples with a small header. Perfect fidelity, roughly 10 MB per stereo minute. | Native | Native | Native | Native |
| FLAC | Lossless compression, typically 50–60% of WAV size, bit-identical when decoded. | Native | Native | Native | Native |
| M4A | Apple’s default AAC container. Better quality than MP3 at the same bitrate. | Native | Native | Native | Native |
| AAC | Bare AAC frames with no MP4 wrapper — used by broadcast streams and some hardware. | Native | Partial | Native | Native |
| AIFF | Apple’s uncompressed PCM format — the WAV equivalent for Logic and Pro Tools. | Partial | Partial | Native | Native |
| Output | Encoder | Bitrates / depth | Sample rates | Tags |
|---|---|---|---|---|
| OGG | libvorbis | 32–320 kbps | 8–96 kHz | Yes |
- Max per file
- 400.0 MB
- Max per queue
- 4.00 GB
- Max duration
- 4:00:00
- Max archive
- 1.50 GB
These are enforced ceilings, checked before any decoding starts, not measured maximums — a file over the limit is rejected rather than allowed to exhaust the tab’s memory. Real-world capacity is lower on older phones, which is why the scheduler runs one file at a time on iOS and Safari.
Where your audio goes
Nowhere. Your file is read from disk into this browser tab with the File API, decoded and encoded by code running in that same tab, and handed back to you as a download. It is never transmitted.
That is a structural property of the application, not a policy promise: there are no API routes, no server actions and no third-party processing services in this project, so there is nothing capable of receiving a file. The page’s Content-Security-Policy also restricts connections to this origin, and the automated test suite includes a browser test that fails if any network request during import, preview, conversion or download carries media bytes.
The trade-off, stated plainly:results live in your tab’s memory until you download them. Closing or reloading the page discards them. There is nothing on a server to recover, because nothing was ever put there.
Troubleshooting
The Ogg will not play in Safari.
Safari has no Vorbis decoder — that is a browser limitation, not a bad file. If you need Safari playback, MP3 or AAC is the right target.
The file is bigger than the MP3.
You have probably set a quality level above what the source bitrate justifies. Check the source bitrate in the file panel and pick a quality level that lands near it.
My cover art disappeared.
Cover art in Ogg uses a base64-encoded METADATA_BLOCK_PICTURE comment that support for is patchy. Sonic Batch does not write it, and says so rather than producing a file some players choke on.
Frequently asked questions
Is Ogg Vorbis better than MP3?
At the same bitrate, usually yes, and especially below 128 kbps. Its disadvantage is hardware support. This conversion makes sense for platform requirements, not for a quality gain.
Will converting MP3 to OGG make the file smaller?
At a similar perceived quality, slightly — Vorbis is a bit more efficient. If you set a higher quality than the source justifies, it will be larger for no benefit.
Should I use Opus instead?
If your platform supports Opus, yes: it beats Vorbis at nearly every bitrate. Vorbis is the safer choice for older game engines and tooling.
Does this run in the browser?
Yes. libvorbis is compiled into the WebAssembly engine served from this site. No file is uploaded.