RaahUPSC · Video Tools
MP4 to WebM
Produce a royalty-free WebM version of an MP4 for an HTML5 video tag, a wiki or an open-source project. Encoding uses VP8's fastest realtime mode so it finishes quickly in the browser.
✓ No upload · ✓ No sign-up · ✓ No watermark
How to use MP4 to WebM
- Choose one or more .mp4 files.
- Press Convert to WEBM; the encoder settings are fixed.
- Wait for the progress bar. VP8 in realtime mode is usually faster than H.264 re-encoding here.
- Download the .webm file or a ZIP of all outputs.
What the WebM encoder is set to
The video is encoded with libvpx as VP8 at a target of 1 Mbps, using the realtime deadline and cpu-used 8, the fastest speed level. Audio is encoded with libvorbis. These choices favour speed over squeezing every last bit of quality, which is sensible for a tool running in a single browser thread.
One megabit per second looks good at 480p and acceptable at 720p for talks or slides, and works out to roughly 7–8 MB per minute for the video. WebM is a good fit for web pages where you want an open-format source alongside MP4, or for platforms that prefer free codecs.
Limitations
- The bitrate is fixed at about 1 Mbps, so 1080p or fast-moving footage will look soft or blocky.
- Output is VP8, not the newer VP9 or AV1, so files are larger than a slow VP9 encode would give.
- Many phone galleries, messaging apps and editors do not accept WebM; keep the MP4 for those.
Frequently asked questions
Is WebM smaller than MP4?
Not necessarily. At this fixed 1 Mbps target, a low-bitrate MP4 can be smaller. WebM is chosen for openness and browser support, not guaranteed savings.
Can I choose VP9 or a higher bitrate?
Not in this tool; the VP8 1 Mbps profile is built in.
Which browsers play the result?
Chrome, Edge, Firefox and Opera play VP8 WebM, and recent Safari versions also handle WebM.
Do I have to upload the MP4?
No. The VP8 encoder runs locally inside the page.