Save as MP3 when the file has to open anywhere, WAV when it goes into an editor, and WebM or OGG when you want the smallest file at good voice quality. In Audio Recorder – Voice Recorder all four come from the same take, so you can export one recording in several formats without recording it again.
The format choice lives under Settings → Save as. WebM is the default. The setting only affects the file you get when you press Download or Share; the copy inside the popup's library stays the same no matter what you pick.
What each format actually is
People often treat these as four "qualities". They are really two codecs in three containers, plus one uncompressed option.
| Save as | Codec inside | Compression | Bitrate follows Quality? | Typical use |
|---|---|---|---|---|
| WebM | Opus | Lossy | Yes | Browser playback, web uploads, smallest files |
| OGG | Opus | Lossy | Yes | Same audio as WebM in a container some players prefer |
| MP3 | MP3 (LAME encoder, bundled) | Lossy | Yes | Old car stereos, office software, anyone who asks for "an MP3" |
| WAV | 16-bit PCM | None | No | Desktop audio editors, transcription tools, archiving an edit master |
WebM and OGG carry identical Opus audio; only the wrapper differs. If a player refuses one, try the other before assuming the recording is broken.
How the export works behind the button
While you record, the extension writes Opus audio in a WebM container to local browser storage, one-second chunk at a time. That stored take is the source for every export:
- WebM, untrimmed — the original Opus packets are re-wrapped with a proper duration so players can seek. No re-encoding, so nothing is lost.
- WAV — the take is decoded to 16-bit PCM at 48 kHz and written as is. Lossless from this point on, but it cannot add back detail that the Opus recording never had.
- OGG, trimmed WebM — decoded and encoded to Opus again at the current Quality bitrate.
- MP3 — decoded and encoded with the bundled LAME encoder at the current Quality bitrate.
That last point matters: MP3 export is a second lossy pass. At High or Best you are unlikely to hear it on speech, but if a voice will be edited, compressed again by a video platform, and then played on a phone, every lossy step adds up. For that path, export WAV once and let the final tool do the only compression.
Picking by destination
Sending to a person
MP3. It is the format least likely to produce a "can't open this file" reply. A ten-minute voice note at High is about 9.6 MB (128 kbps ÷ 8 = 16 kB per second × 600 s), small enough for most email and chat apps.
Editing in desktop audio software
WAV. Editors handle PCM without any decoding step, and you avoid stacking an MP3 encode under whatever export the editor does later. Expect large files: 48 kHz, 16-bit mono WAV is 96 kB per second, about 346 MB per hour. The file size guide has the full table.
Uploading to a website or keeping an archive
WebM. It is the original take with no extra encoding, it plays in Chrome and other modern browsers, and at the default High setting an hour is roughly 58 MB. My own habit: keep WebM as the archive copy and make an MP3 only when someone asks for one.
A player that only accepts .ogg
OGG. Some media players, game engines, and Linux tools expect Opus in an Ogg container. The audio quality matches WebM at the same Quality setting.
Quality and bitrate interact with format
The Quality setting (Standard 64 kbps, High 128 kbps, Best 192 kbps) is used twice: when the take is recorded, and again when you export MP3, OGG, or trimmed WebM. The export uses whatever Quality is selected at the moment you press Download.
So exporting a Standard take as MP3 with Best selected gives you a bigger file, not a better one. The recording only ever had 64 kbps worth of detail. If you need Best, choose it before you press Record. The bitrate explainer goes into what each level sounds like for speech.
Honest limits
- OGG and trimmed WebM exports use Chrome's built-in audio encoder. If your browser cannot provide it, the popup says "Your browser can't create this format. Try WAV or WebM."
- WebM and OGG don't open everywhere. Some older devices and some built-in operating-system players ignore them. MP3 or WAV is the safe fallback.
- Long WAV and MP3 exports take a moment, because the whole take is decoded first. A one-hour WAV also needs several hundred megabytes of available disk space in your Downloads folder.
- Channels carry through to every format. A Mono take exports as mono WAV or MP3; see mono or stereo for voice for when Stereo is worth it.
If you only remember one rule: record with the Quality you actually want, keep WebM as the master, and export the other formats on demand. When you trim first, the export contains only the kept part — the trim guide shows the handles.