This is documented as: > you can query how many buffers are queued by reading the > #gstqueue:current-level-buffers property. you can track changes > by connecting to the notify::current-level-buffers signal (which > like all signals will be emitted from the streaming thread). the same > applies to the #gstqueue:current-level-time and > #gstqueue:current-level-bytes properties. ... but was not implemented. This also respects the `notify::silent` property for the notify signals to be less intrusive. Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/7486>