Lossless baseline for further work.
ALAC preserves every detail of the source WEBM, which prevents additional quality loss during subsequent edits or re-encoding. The original WEBM compression cannot be undone, but no new artifacts will be introduced.
WHY CONVERT
01
ALAC preserves every detail of the source WEBM, which prevents additional quality loss during subsequent edits or re-encoding. The original WEBM compression cannot be undone, but no new artifacts will be introduced.
02
ALAC is the format most receiving systems expect for this kind of content. Converting upstream avoids the rejection and silent re-encoding that often happen when WEBM reaches an unprepared pipeline.
03
ALAC files are typically smaller than their WEBM counterparts, which reduces hosting, transfer, and storage costs at scale. The savings compound when serving the same content to many recipients.
Visit this page on any modern browser — no install, no signup, no plugin.
Drag your WEBM into the drop area, or click to pick one from your device.
Conversion runs entirely in your browser. When it's done, your ALAC file downloads to your device.
QUALITY & FIDELITY
FORMAT SPECS
| WEBM | ALAC | |
|---|---|---|
| Extensions | .webm | .m4a .caf |
| MIME types | video/webm | audio/alac |
| Introduced | 2010 | 2004 |
| Maintainer | Google / WebM Project | Apple |
| Magic # | 1A 45 DF A3 | — |
| Spec | View spec ↗ | View spec ↗ |
COMPATIBILITY
| Platform | Windows | macOS | iOS | Android | Chrome | Firefox | Safari | Edge |
|---|---|---|---|---|---|---|---|---|
| WEBM | App | App | App | Native | Native | Native | Native | Native |
Why LocalConvert
| Category | LocalConvert | Cloud converters |
|---|---|---|
| PRIVACY | Files never leave your device. The whole pipeline runs in your browser via WebAssembly. | Files travel to a remote server, sit in queue storage, and may be retained for analytics or moderation. |
| COST | Free, no signup, no daily quotas. | Often free for small files; paid tiers for batch / large / commercial use. |
| LIMITS | Limited only by your device's memory and CPU. Multi-GB raw footage OK on desktop. | Typical 100 MB to 1 GB per-file caps, plus rate limits. |
An open, royalty-free video container designed for the web. Often paired with VP9 or AV1 codecs.
Typical uses
Web video, screen recordings, HTML5 playback.
Apple's lossless audio format inside an M4A container.
Typical uses
Apple Music lossless, iTunes lossless libraries.
Yes. LocalConvert is completely free, with no signup and no per-file or per-day limits.
No. WEBM to ALAC conversion happens entirely inside your browser using WebAssembly — your file never leaves your device.
There's no fixed cap — the practical limit is your device's available memory. Very large files may take longer or fail on low-RAM devices.
Yes — once the page has loaded, WEBM to ALAC conversion works without an internet connection. Re-open the page once to cache it.
LocalConvert uses the industry-standard tools (FFmpeg, ImageMagick, Pandoc) — quality matches what professionals use on the command line. Lossy formats will still lose some quality on each re-encode.
Last verified:
WEBM to ALAC is processed in your browser with WebAssembly. No upload, no tracking, no limits. Your file never leaves your device.