Features
Video format comparison
Encode the same video as WebM VP9, WebM VP8, and MP4 H.264 side-by-side. Pick the right format for size and quality.
What it does
Drop one video file and the tool re-encodes it in all three of the formats the web actually uses:
- WebM (VP9): modern open codec. Best size/quality ratio.
- WebM (VP8): older fallback, still widely compatible.
- MP4 (H.264): universal compatibility, slightly larger files.
The result is three downloadable files plus a side-by-side comparison showing the file size of each. You can preview each result inline before downloading.
When you'd use this
- Picking the right format for a self-hosted
<video>tag: providing multiple<source>children with different formats means each visitor's browser picks the one it can play, and you want to know which to ship. - Verifying VP9 is actually smaller than H.264 on your specific content. The savings vary by content type; for animation it's often huge, for grainy/noisy footage it's smaller.
- Comparing the visual quality of the three codecs at matched bitrate.
How it sets a fair comparison
All three encoders are configured for the same target perceptual quality (effective bitrate around 3 Mbps at 1080p). The actual output file size is the metric the comparison surfaces.
For comparison at a different quality target, the slider scales all three encoders together.
Sequential encoding caveat
Encoding three videos serially takes ~3× the encode time of one. On a 60-second 1080p source this is typically 2–3 minutes total on a modern desktop, longer on phones.
The encodes run sequentially (not in parallel) so the browser doesn't get squeezed for GPU resources, running three WebCodecs encoders in parallel on the same device fails on most hardware.
Privacy
All encoding happens in your browser. No file is uploaded.
Related
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