* run node 12, 14, and 16 (next to be supported) on CI. This will catch
node version-specific problems like that solved in dad9bdc.
* mention 12 and 14 in build instructions and link to instructions for
installing that version.
* follow this in Dockerfile, installing version 14. This addresses
a "Cannot find module 'worker_threads'" error introduced in
39a63e0, which (inadvisedly) upgraded gzipper 4->5 in addition to
the material-ui upgrade.
* use utf-8 encoding rather than ascii in live part parser. Those
builds apparently don't support ascii. iThey must use "small-icu" or
have ICU disabled, as described here:
https://nodejs.org/api/util.html#util_encodings_supported_when_node_js_is_built_with_the_small_icu_option
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
