Change the pad health calculation to consider a pad 'healthy'
if it has received data within the last 'timeout' window. Previously,
inactive pads were constantly flip-flopping between healthy and not
healthy depending on whether they were slightly ahead of or behind
the active pad running_time.
When the health status of a pad changes, make sure to always notify
the property, so that applications that are manually controlling
the active pad can make their switching decisions.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/merge_requests/1198>
The element has a small race condition where it might output two buffers
with the same running time during e.g. a manual switch. In practice this
is not a problem, so the test takes this race into account.
Fixes: https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/issues/195
fallbackswitch now supports multiple sink pads, and on a timeout of the
active pad, it will automatically switch to the next lowest priority pad
that has data available.
fallbackswitch sink pads follow the `sink_%u` template and have
`priority` as a pad property.
Co-authored-by: Vivia Nikolaidou <vivia.nikolaidou@ltnglobal.com>
