new_preroll

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 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.