Three changes to make the stream survive constrained links:
Adaptive quality: the sender pipeline now tracks the PLI rate from
the receiver. Every 5 seconds it evaluates: >0.5 PLI/s means the
link is saturated (the receiver is dropping frames), so the CRF
increases by 2 (lower quality, fewer bits) and the encoder restarts
with a keyframe. <0.1 PLI/s means the link is stable, so the CRF
decreases by 1 (better quality) and the encoder probes upward.
Clamped to [user CRF, user CRF + 10] so quality never degrades
below what the link can handle, and never exceeds what the user
asked for. The adaptation is logged to stderr for visibility.
Frame rate capping (--fps N): throttles the capture loop to N
frames per second (0 = no cap; monitor rate). At 15fps instead of
60fps, the bandwidth requirement drops 4x at the same quality
level. Desktop content is still smooth at 15-20fps.
Tighter VBV: one frame period of buffer instead of two. A two-frame
buffer lets a keyframe spike to twice the target rate in one burst,
which overflows any constrained hop (Wi-Fi hotspot, slow switch)
and cascades into PLI storms. One frame period keeps bursts
within what the link can absorb in real time.
fegger
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