Container versus codec
A container is the box; codecs are how the video and the audio are compressed inside it. Saying a file is “MP4” does not say how it is encoded, which is why two MP4 files can behave differently on the same device.
MP4 with H.264 and AAC
This is the most widely supported combination: phones, TVs, editors, social platforms and most browsers play it. It is the safest choice when you are not sure where the file will end up.
WebM with VP9 and Opus
WebM was designed for the web. VP9 and Opus are open formats, and compress efficiently, but support is narrower than MP4 outside browsers: some editors, TVs and phone apps do not accept WebM.
Which one should you pick?
- Sharing, uploading to a platform or sending to someone: MP4.
- Playing on your own web page: WebM can be a good fit, with MP4 as a fallback.
- Unsure: MP4.
Converting between them
Clipvexa can export either format when your browser can encode it, and it shows what your browser supports on the home page. Re-encoding a file always applies the quality setting, so avoid converting back and forth repeatedly.
Frequently asked questions
Is WebM better quality than MP4?
Not by itself. Quality depends on the codec, the bitrate and the source. VP9 can be efficient, but that does not make a WebM automatically better.
Do all browsers play WebM?
Current major browsers do play common WebM files, but codec support still varies by browser and system.