This signal is emitted from the streaming thread and only when the
"emit-signals" property is %TRUE.
The new preroll sample can be retrieved with the "pull-preroll" action
signal or gst_app_sink_pull_preroll() either from this signal callback
or from any other thread.
Note that this signal is only emitted when the "emit-signals" property is
set to %TRUE, which it is not by default for performance reasons.
Signal that a new preroll sample is available.
This signal is emitted from the streaming thread and only when the "emit-signals" property is %TRUE.
The new preroll sample can be retrieved with the "pull-preroll" action signal or gst_app_sink_pull_preroll() either from this signal callback or from any other thread.
Note that this signal is only emitted when the "emit-signals" property is set to %TRUE, which it is not by default for performance reasons.