Compress WEBA

How to Compress WEBA Audio Online

1. Upload Your WEBA File: Drag and drop your .weba file or click "Add Files" to select. Batch compression is supported, so you can queue several recordings or extracted audio tracks at once.
2. Pick a Compression Method: The default is "File Size Percentage" at 80%. Switch to "Specific file size" to target an exact output (default 8 MB), "Custom Bitrate" to enter any value in bps/Kbps/Mbps (default 64 Kbps), "Constant Bitrate" for fixed presets, or "Variable Bitrate" for Opus VBR ranges from 6k–24k (narrowband speech) up to 320k–510k (transparent fullband).
3. Set Audio Channel and Sample Rate (Optional): Keep original or force Mono / Stereo. Sample rate accepts the five Opus-native rates — 8000, 12000, 16000, 24000, 48000 Hz — plus 44100 Hz (resampled). Lowering channels and sample rate is the fastest way to shrink voice memos further.
4. Trim and Compress: Optionally set a Start time and Duration in seconds or HH:MM:SS.sss, then click "Compress". Files process in your browser session — no sign-up, no watermark.

Why Compress WEBA Files?

A .weba file is the audio-only variant of Google's WebM container, almost always carrying an Opus stream (sometimes Vorbis). Most users encounter .weba after capturing audio with the browser's MediaRecorder API or after extracting audio from a WebM video. The file is already efficient, but recordings made at the browser's default bitrate are often larger than they need to be — especially monologues, voice memos, podcast drafts, and lecture captures.

• Trim browser recordings before sharing — JavaScript apps using MediaRecorder with audio/webm; codecs=opus typically write at 96–128 kbps stereo. A 30-minute mono lecture at that rate is 21–28 MB; recompressing to a 32 kbps mono Opus stream drops it under 8 MB without audible loss for speech.
• Fit messaging caps — Discord's free tier caps uploads at 10 MB (raised to 50 MB on Nitro Basic, 500 MB on Nitro), and Gmail attaches up to 25 MB inline. Targeting an exact output size avoids the upload-rejected loop.
• Re-encode a downloaded yt-dlp audio track — yt-dlp and other downloaders save YouTube's audio/webm streams as .weba at whatever bitrate the source serves (often 160 kbps Opus). Down-encoding to 64–96 kbps recovers significant space for podcast-style content.
• Prepare assets for the open web — Opus is mandatory in WebRTC and is supported by Chrome, Firefox, Edge, and Safari 14.1+ (macOS) / iOS 15+, with caveats on early Safari versions. Lower-bitrate Opus loads faster on mobile.
• Archive voice memos in mono — A 16 kHz / 24 kbps mono Opus file holds intelligible speech at roughly 180 KB per minute, an order of magnitude smaller than uncompressed WAV.
• Match a strict bitrate budget — VoIP testbeds, embedded players, and some CMS uploaders enforce specific bitrates; the Custom Bitrate field accepts any value the encoder allows.

WEBA vs MP3 vs M4A — Format Comparison

Opus Bitrate Cheat Sheet (RFC 6716 sweet spots)

Frequently Asked Questions

Why does my browser save audio as .weba instead of .mp3?

The Web MediaRecorder API in Chrome, Edge, and Firefox produces audio/webm; codecs=opus by default — a WebM container with an Opus stream. When the developer (or a "save as" dialog) writes that blob to disk, the .weba extension distinguishes it from video-bearing .webm. MP3 isn't an option from MediaRecorder because the LAME encoder isn't built into the browser. If you need MP3, convert WEBA to MP3 after the recording finishes.

What bitrate should I target to keep speech intelligible?

For mono speech, Opus is intelligible at 16–20 kbps (wideband) and sounds natural at 32–40 kbps (fullband). RFC 6716's sweet-spot table lists 16–20 kbps for WB speech and 28–40 kbps for FB speech at a 20 ms frame size. For a podcast guest track you'll edit later, leave headroom and aim for 48–64 kbps.

Will lowering bitrate damage music more than speech?

Yes. Speech is concentrated in narrow frequency bands and tolerates aggressive compression; music has wide spectral content and stereo imaging that low bitrates flatten. Opus remains transparent for most listeners on stereo music around 96–128 kbps, while it's fine for speech at 32 kbps. The Opus bitrate cheat sheet above maps each use case to a safe range.

Can Safari play the compressed WEBA file?

Safari added WebM audio (Vorbis and Opus) starting in Safari 14.1 on macOS Big Sur 11.3 and iOS 15. Earlier Safari versions cannot play it natively, and even some Safari 15.x builds had reliability bugs with WebM Opus from blob URLs (WebKit bug 245428). For maximum compatibility across older iPhones and iPads, convert WEBA to M4A (AAC in MP4) instead — every Apple device since 2003 plays AAC.

How does Opus compare to MP3 at the same bitrate?

At 64 kbps stereo, blind listening tests consistently rank Opus above MP3 and HE-AAC. Opus was designed in 2010–2012 with twenty years of psychoacoustic research that MP3 (finalized in 1993) does not benefit from. The practical takeaway: a 64 kbps Opus file usually sounds as good as a 128 kbps MP3, so you can roughly halve bitrate when migrating from MP3 to Opus without quality loss.

Does compression re-encode the file, or just trim header metadata?

It re-encodes. Lowering bitrate, changing sample rate, switching channels, or trimming all require decoding the source Opus/Vorbis stream and re-encoding to a new Opus stream — there is no lossless way to reduce bitrate. Each compression generation introduces a small amount of additional loss, so keep the original if you may need to re-edit later.

What's the difference between Variable Bitrate and Constant Bitrate for WEBA?

Constant Bitrate (CBR) holds the bitrate steady regardless of content complexity, which produces predictable file sizes — useful for streaming with a fixed bandwidth budget. Variable Bitrate (VBR) lets the encoder spend more bits on complex passages and fewer on silence or simple tones, giving better quality per byte. For local files and most uploads, VBR is the better default; CBR is mainly for live streaming pipelines.

Can I compress a WEBA file straight to MP3 in one step?

Yes — pick "Compress" if you only want a smaller .weba, or use WEBA to MP3 to change container and codec at the same time. Going to MP3 raises bitrate-for-bitrate quality cost but maximizes compatibility (every device made since 1998 plays MP3). For the reverse direction, see WebM to WEBA if you need to extract audio from a video first.

How small can a one-hour podcast realistically get?

A one-hour mono podcast at 32 kbps Opus (a comfortable speech bitrate) is roughly 14 MB — well under Discord's 10 MB free cap if you split into two halves, or under Gmail's 25 MB attachment limit as one file. Drop to 24 kbps mono and you're at ~11 MB per hour. Below 16 kbps you start sacrificing intelligibility on consonants.