A monitor with Capturing=Ondemand and LinkedMonitors never recorded a linked
alarm unless someone happened to be watching it. Links are evaluated in
Analyse(), per captured packet, and zmc pauses an on-demand camera, stopping
its analysis thread, 10 s after the last viewer. While paused nothing looked
at the links, so every alarm on the linked monitor was missed. This is the
low-bandwidth setup of a substream that analyses and a main stream that
records on demand.
zmc's on-demand decision moves into Monitor::CheckOndemand(), around a
DecideOndemand() table that can be tested:
- While paused, the links are checked on every pass. The analysis thread is
stopped then, so the capture thread reads them without racing it. An alarm
reopens the camera.
- An unwatched monitor keeps capturing while it is alarmed or in its
post-event frames, instead of pausing in the middle of the event.
- A link only reports an alarm while it lasts, and reopening the camera can
take longer than that (2.5 s against a local camera). So the wake is
remembered for up to 30 s, and the first packet Analyse() scores counts it
as a linked alarm, then clears it.
Tested live on 1.38 with a paused on-demand passthrough monitor linked to an
analysing one. Before: an 8 s forced alarm on the source recorded nothing.
After: the monitor woke within 0.1 s, alarmed 2.5 s later and recorded the
event. A 1 s alarm, over before the camera reopened, was also recorded.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
