WebM → MP4
Transcodes WebM to MP4 (H.264 + faststart) for compatibility with Safari, iOS and players without VP9 support.
Drag files here or click to upload (multiple files supported)
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How to convert WebM to MP4
- 1Upload your WebM file by dragging, clicking, or pasting.
- 2Adjust quality settings if needed.
- 3Click 'Convert Now' and wait for the conversion to complete.
- 4Download your converted MP4 file.
About WebM to MP4 conversion
WebM is an open container promoted by Google that encapsulates VP8/VP9/AV1 video, and is royalty-free. Safari versions older than 14.1 do not support VP9 encoding. MP4 is a general-purpose container compatible with all platforms and all browsers, and supports faststart configuration for progressive playback. Conversion to MP4 meets the requirement of cross-compatibility.
This conversion is based on FFmpeg. The output encapsulates H.264 video and AAC audio, uses the CRF constant quality mode to control picture quality, retains the original audio track and original resolution, keeps the original frame rate unchanged, and the output file size falls within a normal range.
The converted output can be played on older versions of Safari, is compatible with iOS devices, older Windows systems and native players, and supports embedding in web pages for mainstream browsers. The single file size must not exceed 50MB, and the duration of the input WebM video must not exceed 10 minutes.
WebM vs MP4: technical comparison
| Feature | WebM | MP4 |
|---|---|---|
| Released | 2010 | 2001 |
| Developer | MPEG |
FAQ about WebM → MP4
Will picture quality decrease after conversion
Conversion quality is controlled by the CRF parameter. Reasonable parameter settings can maintain the original visual effect. Since transcoding requires re-encoding the video, a certain degree of quality loss is present.
Does conversion preserve the original audio track
All valid audio tracks in the input file are preserved by default. If the audio track format does not conform to the MP4 specification, it will be re-encoded to AAC format for output.
What is the single file size limit
For this conversion service on this site, the maximum single file size is 50MB, and only one file can be converted at a time. Requests that exceed the limit cannot be submitted for processing.
Will my files be stored
Files are uploaded to the server via HTTPS for conversion, and both the source file and output file are deleted immediately from the server after conversion completes. No files are stored.