User testing pinned the bug precisely: our try/catch is airtight now,
and the diagnostics showed "new-sample signal fired 0 times" — the
appsink genuinely never receives a single sample inside gnome-shell's
process, while an equivalent pipeline (videoconvert ! videoscale !
RGBA caps ! appsink) played correctly standalone via gst-launch-1.0.
Replaces Gst.parse_bin_from_description()'s gst-launch mini-language
parsing (with its automatic unlinked-pad ghosting) with explicit
ElementFactory.make() + Bin.add() + element.link() + a manually
created GhostPad. This removes the string-parsing path as a variable
entirely and, importantly, surfaces any link() failure as a thrown
error instead of failing silently, which the old code path had no way
to report even if that patch were the whole cachet of the problem.
Also fixes a related warning ("Trying to dispose element ..., but it
is in PLAYING instead of the NULL state") from _stop() dropping the
playbin reference immediately after requesting the NULL state, before
the (async) transition actually completed — now waits briefly via
get_state() for it to settle first.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019RDqbdjsiisSU7CbQke4g8
Claude
5157f4a1c9