Add a host-global quality knob (Discord-style) so the sharer can trade
resolution + bitrate for upload bandwidth. Quality is host-global by
design: one encode pipeline fans out to every viewer, so per-viewer
quality is out of scope (it would kill the broadcast fanout).
- New `--quality source|high|medium|low|auto` (ValueEnum) bundling a
(max-height, bitrate, fps) tuple per preset; `auto` derives the preset
from the saved bandwidth pre-flight (safe_mbps / viewer cap), falling
back to `medium` when unmeasured. Default is auto; the interactive
Host branch shows a picker when --quality is omitted (mirrors pick_app).
- `--max-height N` raw override; `--bitrate`/`--framerate` changed to
Option so an explicit flag overrides just that field of the preset
(precedence rule), leaving the rest of the preset intact.
- host/quality.rs: Preset table + resolve(); pure resolve_auto() split
from the config read for testability. 5 unit tests lock preset
pass-through, the Auto ladder, the unmeasured fallback, and override
precedence.
- pipeline::build_args inserts `videoscale ! video/x-raw,height=N,
pixel-aspect-ratio=1/1,width=[2,8192,2]` only for non-Source presets.
PAR 1/1 forces a proportional downscale (without it videoscale keeps
full width and squashes PAR — no bandwidth win); the even-stepped width
range + even-rounded height satisfy H.264 4:2:0. EffectiveQuality is
threaded capture -> wayland/x11 -> pipeline; max_viewers is now sized
against the effective (post-preset) bitrate.
- Banner gains a quality line (preset label + ≤Np/kbps/fps + provenance).
- deps.rs checks `videoscale`; smoke-pipeline.sh adds a 1080->480
downscale check asserting an even width below source.
- README: --quality preset table, Auto behavior, host-global note,
--max-height/--bitrate/--framerate override precedence.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
mollusk
7483b9aae8