Gst.Pad.prototype.query_caps

function query_caps(filter:Gst.Caps):Gst.Caps {
    // Gjs wrapper for gst_pad_query_caps()
}

Gets the capabilities this pad can produce or consume. Note that this method doesn't necessarily return the caps set by sending a Gst.Event.new_caps - use Gst.Pad.prototype.get_current_caps for that instead. gst_pad_query_caps returns all possible caps a pad can operate with, using the pad's CAPS query function, If the query fails, this function will return filter, if not #NULL, otherwise ANY.

When called on sinkpads filter contains the caps that upstream could produce in the order preferred by upstream. When called on srcpads filter contains the caps accepted by downstream in the preffered order. filter might be null but if it is not null the returned caps will be a subset of filter.

Note that this function does not return writable Gst.Caps, use gst_caps_make_writable() before modifying the caps.