Links this to
dest using the given caps as filtercaps.
The link must be from source to destination; the other direction will not be tried. The function looks for existing pads that aren't linked yet. It will request new pads if necessary. If multiple links are possible, only one is established.
Make sure you have added your elements to a bin or pipeline with add before trying to link them.
a Element containing the source pad.
the Element containing the destination pad.
the Caps to filter the link, or