(not OP)
This nerdsniped me.
10 minutes later, and TIL: MPD is some sort of streamed-MP4 format; dash-mpd-cli is a xplatform Rust utility binary that can download this to an MP4, just given the MPD URL in dev tools.
However I keep getting 1.5 MB and 500 KB for the two videos, no matter window width. Chrome on macOS arm64, 16" MBP.
I'm curious what your environment is, if you don't mind sharing
(also, trivia for audience: last week I saw a tweet that palantir.com was doing over 100 MB worth of videos, and of course, A) they are B) they're poorly compressed, as much as 10x the bitrate they need to be.)
Frontend is full blazor w/hybrid WASM, almost zero JS, all C#. Browser DOM is controlled by the app service in realtime, I plan on using this as a basis for our subscribers to be able to do live traffic & link stats monitoring, among other things.
Similar specs here. Here's a full load in a Chrome guest window with resolution constrained to an iPhone SE: https://imgur.com/a/xRjKWNb
In the left panel, at the end of the video you'll see two important numbers: 28.5MB transferred, 40.7MB resources. "Transferred" is the (compressed) size of everything downloaded over the wire, 40.7MB is the ultimate (uncompressed) size of those.
I don't show it in that video but you can filter by "initiator" to see that the video files are the lion's share of this.