About a year ago I talked to your support about an issue with video transcoding. If I upload 2mb Mp4 for a background video, webflow will create a webm version (a format that is intended to make mp4 videos smaller in filesize) around 1mb, increasing the filesize by 100%.
You can try different encoding methods / settings on your end to see if you get different (better) results. If you can’t and size is important to you, upload your encoded files to a CDN or webhost and include them using custom code. Webflow’s background video component has no settings to effect quality.
Why not reveal video quality settings for the WebM conversion so they can be configured in Webflow? In terminal, it’s simple to customize these settings - takes minutes. There would be high value to this improvement now that Google ranks sites inclusive of LCP (largest contentful paint, or the time it takes for the largest above-fold image to load).
I totally agree that Webflow should offer at least a basic control on the transcoded files in background videos, but I noticed that normally only the mp4 version is used and the webm is not downloaded (tested in Chrome Linux).
If a browser supports mp4 it will use that and most modern browsers do. Some browsers (older) don’t and will fall back to something they do like webm. So having multiple versions is important for backwards compatibility with much older browsers.
I get your point but support for webm is more recent than support for mp4 (take a look at caniuse.com), so I really don’t know which browsers would you the webmversion.