After quick analysis, it seems discoverer_ is null when passed to gst_discoverer_discover_uri, and this is because it gets destroyed after all directories are scanned in FileSystemWalker::Private::NotifyFinished.
After quick analysis, it seems discoverer_ is null when passed to gst_discoverer_ discover_ uri, and this is because it gets destroyed after all directories are scanned in FileSystemWalke r::Private: :NotifyFinished .