Status for the two changes just landed, plus the consequence AR-004's
fix has for the scene join.
The annotator's old comment said blocking there was safe because the
branches are independent. That stopped being true when the fanout became
lossless: it now stops popping once one branch stops taking, so a
starved detector and a waiting annotator would wedge. What actually
makes it safe is join depth -- the fanout can run the dense branch ahead
by the whole of the sampled branch's buffering, which at kSceneJoinDepth
256 and sample_fps 5 against a 25 fps source is ~1200 dense frames
against TransNetV2's 100-frame window. Cutting kSceneJoinDepth below the
window would reintroduce the wedge, so it is now a correctness
precondition rather than a tuning knob.
TRACES: AR-004, AR-010, AR-028, AR-029 | VR-015 | SR-002