The name `gst_element_get_request_pad()` is confusing to people
learning GStreamer. `gst_element_request_pad_simple()` aims at
providing the exact same functionality, while making it more
explicit it is a simplified `gst_element_request_pad()`.
`gst_element_request_pad_simple()` is consistent with other
functions such as `gst_element_seek_simple`.
This commit deprecates `gst_element_get_request_pad()` so that a
compilation warning is emitted when used and incite developers
to use the more explicit `gst_element_request_pad_simple()`.
See also https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/merge_requests/743#note_886586
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/802>
To allow the refcounting tracer to work better. In childproxy/iterator
these might be plain GObjects but gst_object_unref() also works on them.
In other places where it is never GstObject, g_object_unref() is kept.
Demultiplex a stream to multiple source pads based on the stream ids from the
stream-start events. This basically reverses the behaviour of funnel.
https://bugzilla.gnome.org/show_bug.cgi?id=707605
