MP4 → WebM
Transcodes MP4 to WebM (VP9 with constant-quality CRF) as a royalty-free, smaller alternative source for web video.
Drag files here or click to upload (multiple files supported)
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How to convert MP4 to WebM
- 1Upload your MP4 file by dragging, clicking, or pasting.
- 2Adjust quality settings if needed.
- 3Click 'Convert Now' and wait for the conversion to complete.
- 4Download your converted WebM file.
About MP4 to WebM conversion
MP4 is a general container defined in MPEG-4 Part 14, commonly used to encapsulate H.264/H.265 video and AAC audio, and is compatible with all platforms. WebM is an open, royalty-free container promoted by Google, designed for web video, and encapsulates VP8/VP9/AV1 video and Vorbis/Opus audio. Converting to WebM meets the requirement of royalty-free licensing for web usage.
The conversion uses the CRF constant quality mode to control output quality, and can produce VP8/VP9/AV1 encoded videos that conform to the WebM specification. The original video resolution is retained, and the original audio is transcoded to the corresponding format. At the same visual quality, the output file size is usually smaller than that of a MP4 of the same quality.
VP9-encoded WebM output requires Safari 14.1 or newer to play normally. This conversion is suitable for open source web video deployment and royalty-free video storage scenarios. The duration of the source MP4 file must not exceed 10 minutes.
MP4 vs WebM: technical comparison
| Feature | MP4 | WebM |
|---|---|---|
| Released | 2001 | 2010 |
| Developer | MPEG |
FAQ about MP4 → WebM
Will quality decrease after conversion
Output quality is controlled by the CRF parameter. You can adjust the parameter to balance output quality and file size. Following the basic rules of encoding conversion, there is no unnecessary additional quality loss.
Will the original audio track be preserved
The original audio track is preserved by default. During conversion, the AAC audio from the source MP4 is transcoded and stored in Vorbis or Opus format, which is natively supported by the WebM standard. The audio track will not be discarded.
What is the maximum single file size limit
The maximum single file size processed by this service is 50MB, and only one file can be converted at a time. If the source file exceeds the size limit, the system will reject the conversion request.
Will my files be stored
Conversion is completed server-side. Files are uploaded to the server via HTTPS, and both the source file and output file are deleted immediately from the server after conversion completes. No files are stored.