Make an H.264 MP4 from a supported WebM clip. Video and audio are converted on your device so you can check playback before downloading.
Drop a video here
WebM · Up to 2 GB on a computer
Converting video…
Runs on your device. Keep this tab open.
ChatCut opens in a new tab with your request. Add your file there.
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Why ChatCut
Get an MP4 copy for workflows that do not accept WebM.
Supported Opus or Vorbis audio is converted to AAC, rather than just changing the extension.
The picture is not cropped. Odd frame dimensions are rounded up to even dimensions for H.264 encoding.
Your recording stays on the device while the browser encodes the new file.
The MP4 produced here has no converter watermark or end card.
Keep the source WebM and download a new MP4 for sharing.
How it works
Pick a supported WebM file from your device. Keep it within 128 MB and 5 minutes.
Start the local conversion to MP4. Keep this tab open until the file is ready.
Check the result, save the converted copy, or restart with another video.
Learn
WebM is a media format designed for web use, with a container based on Matroska. Common tracks use VP8 or VP9 for video and Opus or Vorbis for sound. A clip can play in a web page yet be unsuitable for a destination that specifically asks for H.264 MP4. Confirm the receiving workflow first. Keeping the original WebM alongside a converted copy lets you retain the source without asking every recipient to use the same player.
The output uses H.264 video and AAC audio when a supported audio track exists. Typical WebM tracks use different codecs, so the browser decodes and re-encodes them. The engine targets 8 Mbps for newly encoded video and 192 kbps for newly encoded audio. It retains only the primary tracks. A source with no sound stays silent, while a present but unsupported audio track causes an error instead of being quietly dropped from the finished file.
H.264 encoding needs even frame dimensions in this workflow. If a source has an odd width or height, the output rounds that dimension up by one pixel and contains the full picture rather than cropping it. Re-encoding cannot restore detail already missing from the recording. It can also change fine text or gradients, so inspect those areas in screen recordings. This H.264 output does not preserve transparent backgrounds; retain the WebM if an alpha channel matters.
A new MP4 can be larger than the WebM even when it looks similar. The result depends on the source and the encoding settings, not just the filename extension. This page has no target-size control. Preview a section with movement and listen to the audio before downloading. If the goal is a smaller attachment after conversion, use a separate compression step and check the final result again in the application where it will be shared.
Use cases
Convert a short supported WebM recording for an MP4-only upload.
Prepare a clip for a workflow that expects H.264 video.
Check the converted sound and picture before sending a copy.
Keep editing
Add your downloaded file in ChatCut to trim it, add captions or make a vertical cut. Manual editing and export do not use credits; built-in Agent requests do.
Skills
100+ Skills. No experience needed. Start in one click.
FAQ
Usually yes. WebM commonly contains VP8 or VP9 video and Opus or Vorbis audio, while this tool produces H.264 and AAC.
No. Conversion cannot recover detail missing from the source. Re-encoding can change quality, so keep the original.
No. This H.264 MP4 output does not preserve an alpha channel. Keep the WebM when transparency is needed.
Different codecs and encoding settings produce different sizes. Conversion targets a usable MP4, not a specific size; use the compressor if needed.
Yes. A video-only WebM produces a video-only MP4. If audio exists but cannot be converted, the tool reports an error.
Yes. Conversion on this page is free, needs no sign-up and adds no watermark. Continuing in ChatCut is separate: built-in Agent messages use credits; manual editing and export do not.
No. The conversion engine reads and writes media inside your browser. If you choose to continue in ChatCut, add the downloaded file there yourself.
Use a recent browser with WebCodecs. Files are limited to 128 MB, 5 minutes and 4096 × 2160 pixels; AVI is limited to 60 seconds, and codec support varies by browser.
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