MP4 vs WebM — which should you pick?
If you're unsure, pick MP4. The rest of this explains the narrow set of cases where WebM is the better answer.
- MP4 plays on essentially every device made in the last fifteen years
- WebM is roughly 20–30% smaller at equivalent quality
- Editors and TVs are where WebM tends to fail
What they have in common
Both are containers — boxes that hold a video track and an audio track. The compression is done by the codec inside, usually H.264 in an MP4 and VP9 in a WebM. Neither container makes a video look better or worse on its own.
Why MP4 is the safe default
H.264 has hardware decoding on virtually every phone, laptop, TV and set-top box. That means smooth playback and less battery drain, and it means the file will still open in five years.
When WebM wins
VP9 delivers the same visual quality in a meaningfully smaller file. If you're archiving hundreds of videos or working with limited storage, that adds up quickly — provided everything you'll play them on supports it.
The trap
Converting a WebM to MP4 afterwards re-encodes it, which loses quality and takes time. Choose the container you need at download time instead.