From: Steinar H. Gunderson Date: Wed, 7 Mar 2018 20:26:34 +0000 (+0100) Subject: Add some documentation about tally display. X-Git-Url: https://git.sesse.net/?p=nageru-docs;a=commitdiff_plain;h=152df450d9b0b5bb36474b4a111a109514706121 Add some documentation about tally display. --- diff --git a/monitoring.rst b/monitoring.rst index 8e64307..204c37a 100644 --- a/monitoring.rst +++ b/monitoring.rst @@ -31,3 +31,31 @@ backward compatibility in metrics, so if Nageru internals change significantly, some graphs could stop working. Of course, you can change the dashboard as you see fit; if you don't use e.g. HDMI/SDI output, you will probably want to remove the panels related to it. + + +Tally display +------------- + +Not related to Prometheus per se, but yet an important part of monitoring is the +*tally light*, or just tally for short. The tally is a talkback signal from the +mixer to the camera, showing the cameraperson that they are indeed on air (or are +about to get to). Professional studio cameras will often not only have a tally +light for the operator, but also for the subject (to know which camera to look +into). However, most cheaper cameras will have none at all. + +Nageru does not have functionality to talk to tally lights directly (there are too +many kinds of interfaces and standards), but it does have functionality to expose +tally _data_. Using this, you can build your own tally light, be in through injecting +the right bits on an SDI cable, having a single-board computer set some GPIO pins +for a LED, or simply show a red or green dot on a mobile phone with a web browser. + +Nageru's tally data is automatically exposed over HTTP, just as any other monitoring. +You can get one JSON file with a list of all channels (at “http://yourserver.example.org:9095/channels”), +or you can ask for a specific channel and get just its color in plain text +(at “http://yourserver.example.org:9095/channels/2”, where 2 is the lowest +channel ID, since live and preview don't have tally). The tally color values +are taken automatically from the theme's *channel_color* function, so that they +match the borders around the input in the producer's mixer display—typically +green for on preview and red for live. This also means they can be CSS textual +colors (like “red”), although you can of course make the theme return only +“#ff0000” or similar if this makes your tally application simpler.