The keyframe backstop added for the black LG TV only arms while AUs are
actually going into the decoder (`fed > fed_at_output`) — deliberately, so
an idle stream never asks for anything. That leaves its mirror image
uncovered: a session that receives NOTHING. A decoder cannot be starved of
output when it was handed no input, so no signal in either loop fires, and
the session sits connected — audio, input and the control plane all alive —
behind a black surface.
That state is what a user just reported as "the stats are all basically 0":
fps and Mb/s are counted at AU receipt (`note_received`), so all-zero stats
with a drawn overlay means the decode thread started and received nothing.
Same bug as the black screen, seen from the HUD.
Both loops now watch for it: nothing received 1.5 s into a session ⇒ request
a keyframe and log it, re-asking every 2 s while it lasts. Where it can help
it does — the host encoding fine while every picture references an IDR this
client never saw is precisely a keyframe request away. Where it can't, the
log line is the point: "no video received N ms into the session" separates
"the host never sent a picture" from "we received AUs and lost them", which
no previous black-screen report could distinguish.
Not a root cause. The remaining occurrences are still unattributed — this
makes the next report diagnosable and recovers the case that is ours to
recover.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>