The browser runs the encoder directly, so there is no upload to a server.
Drop video files here or click to browse
Files queue into the current batch until you convert · MP4, MOV, MKV, WebM, M4V
"Browser-based" used to mean "uploads to a server, server does the work, sends the result back." That is not what is happening here. This converter uses the WebCodecs API, a relatively new browser interface that lets the page run video encoding and decoding directly in the browser, on your device.
The practical effect: encoding can be quick on supported codec paths because the browser drives the encoder directly rather than uploading to a server. Performance depends on your browser, OS, and hardware.
Browser support is codec-specific. A browser can expose WebCodecs yet lack the H.264, AAC, VP9, or Opus path needed for a selected output. Recent desktop Chrome or Edge, or Safari 26+, provide the widest support; WebM may work where AAC-based output does not.
WebCodecs is a low-level browser API for encoding and decoding video frames. It lets the page run the encoder in the browser directly, which is why browser conversion can be quick for common codecs.
Sources: MDN: WebCodecs API · W3C: WebCodecs specification · Reviewed 2026-10-12
When the browser exposes a hardware encoder for the selected codec, encoding can be substantially faster. Without it, the browser may use a software encoder, but that fallback is codec- and platform-dependent rather than guaranteed.
Sources: W3C: WebCodecs specification · Reviewed 2026-10-12
WebCodecs video APIs are available in current desktop browsers, but codec support is not uniform. Firefox and desktop Linux browsers lack native AAC encoding. Safari 16.4 added video WebCodecs and Safari 26 added audio encoding and decoding. Mobile support remains device-dependent.
Sources: MDN: WebCodecs API · MDN: WebCodecs codec selection · WebKit: WebCodecs video support in Safari 16.4 · WebKit: WebCodecs audio support in Safari 26 · Mediabunny: supported formats and codecs · Reviewed 2026-10-12
Whether the browser uses a hardware encoder depends on your OS, GPU, browser, and codec. A software path may exist for some codecs, but it is not guaranteed; unsupported configurations fail instead of automatically falling back.
Sources: W3C: WebCodecs specification · MDN: checking decoder support · Reviewed 2026-10-12
Mobile browser WebCodecs support is improving but lags desktop. For one-off conversions on a phone, recent Chrome and Safari work in many cases; for serious batch work, use desktop.
HEVC (H.265) decoding varies by browser, operating system, device, profile, and bit depth. WebCodecs does not require browsers to ship HEVC, and this app does not bundle a browser-independent HEVC software decoder.
Sources: W3C: WebCodecs specification · MDN: checking decoder support · Reviewed 2026-10-12
Encode your videos using the browser's built-in WebCodecs API rather than a server.
Drag and drop your video files into the converter, or click to pick them.
Pick the output format, quality, optional width, and whether to remove audio.
Click Convert files. Each file is processed locally on your device.
Download files individually, or grab the whole batch as a ZIP.
No. Encoding runs in your browser via WebCodecs and the file stays on your device.
It can run on all four, but output support varies. Desktop Linux browsers lack native AAC encoding, so WebM output or removing audio may work where MP4, MOV, or MKV with audio does not.
Sources: MDN: WebCodecs API · MDN: WebCodecs codec selection · WebKit: WebCodecs video support in Safari 16.4 · WebKit: WebCodecs audio support in Safari 26 · Mediabunny: supported formats and codecs · Reviewed 2026-10-12
WebCodecs lets the page use codecs exposed by the browser instead of round-tripping the file to a server. Hardware acceleration can improve speed when the browser and device expose it for the selected codec; a software fallback is not guaranteed.
Sources: MDN: WebCodecs API · W3C: WebCodecs specification · Reviewed 2026-10-12
Partially. Mobile support depends on the browser, operating system, hardware codecs, source profile, and selected output. Test a representative file first; desktop remains the recommended path for batches.
Sources: MDN: WebCodecs API · MDN: WebCodecs codec selection · WebKit: WebCodecs video support in Safari 16.4 · WebKit: WebCodecs audio support in Safari 26 · Mediabunny: supported formats and codecs · Reviewed 2026-10-12
The encoder is already in your browser. The page just provides the UI and tells WebCodecs what to do with each file.
Conversion requires WebCodecs video encoding and decoding, but each browser and device supports a different codec subset. MP4, MOV, and MKV output use H.264 video with AAC audio; Firefox and desktop Linux browsers do not natively encode AAC. Safari 16.4 added video WebCodecs, while Safari 26 added audio encoding and decoding. WebM output uses VP9 with Opus and may work where AAC output does not. For the widest support, use a recent desktop Chrome or Edge release, or Safari 26+. The converter still validates the actual source and output codec configuration when a job starts.
Sources: MDN: WebCodecs API · MDN: WebCodecs codec selection · WebKit: WebCodecs video support in Safari 16.4 · WebKit: WebCodecs audio support in Safari 26 · Mediabunny: supported formats and codecs · Reviewed 2026-10-12
Conversion runs in your browser. Files stay on your device.
For multi-GB clips, slow connections, metered networks, and offline work. Skip the upload step entirely.
For when the right answer to 'how do I convert ten MOVs to MP4' is not 'memorize a shell loop'.
Drop in a folder of mixed-format videos. Pick one destination format. Download the whole batch.