This keeps a coarser-grained `toplevel` property rather than `user`
and `session`. It also synthesizes a `streams` field within it with ids.
This makes it easier to put the streams in the URL by id.
This requires a bunch of package name changes. See
[https://mui.com/blog/material-ui-is-now-mui/] for their rationale.
[https://mui.com/guides/migration-v4/] lists the changes:
```
@material-ui/core -> @mui/material
@material-ui/system -> @mui/system
@material-ui/unstyled -> @mui/core
@material-ui/styles -> @mui/styles
@material-ui/icons -> @mui/icons-material
@material-ui/lab -> @mui/lab
@material-ui/types -> @mui/types
@material-ui/styled-engine -> @mui/styled-engine
@material-ui/styled-engine-sc ->@mui/styled-engine-sc
@material-ui/private-theming -> @mui/private-theming
@material-ui/codemod -> @mui/codemod
@material-ui/docs -> @mui/docs
@material-ui/envinfo -> @mui/envinfo
```
We only use a few of these.
It's a start. It can display several streams at once, which is nice.
There are lots of opportunities for improvement:
* it doesn't keep the videos approximately in sync.
* it accumulates extra buffering, drifting behind live. This is
particularly noticeable when it's paused and played again; it can
be several seconds before it jumps to after the break.
* it always uses the sub stream rather main. I'd prefer it support
"auto" (use main if the viewport is larger than the sub stream and
there's sufficient bandwidth), "main", or "sub".
* it has a kludgy heuristic where it throws away everything buffered 5
seconds before the current timestamp. It should throw away
everything before the current GOP instead, but I need to alter the
API so it can easily know when that is.
* it can't tell you when a camera connection is down. This needs an
API change also.
* it'd be nice to quickly double-click on a stream to view only it,
then double-click again to go back to the multi-pane view.
* it doesn't allow you to zoom in on part of the video. This would be
nice particularly when viewing 4k video streams on small screens.
* it has only four preconfigured layouts that subdivide a 16x9
viewport. You have to choose every camera every time. It'd be nice
to both allow more flexibility and have more memory.
React prototype: #111
live stream: #59
Once I have more than one area of the UI (e.g., adding config, live
video, or a scrub bar prototype), I'll use this for a pull-down menu to
go between them, and maybe add a filter icon to do what this does. But
this works for now and most closely matches the old UI.
I tried to use a Collapse or Slide transition, but I had trouble getting
it to work on both desktop and mobile. In particular, the way I used the
flex wrap to display the selectors on the left/above doesn't seem
compatible with picking an orientation. If I pick the wrong orientation,
the list views won't fill the empty space.
