{ "_": [ "The 3x3 VIDEO WALL: nine 1920x1080 screens driven as one 5760x3240 output.", "", "Cells are named row-then-column, as the operator names them: 11 12 13 across the top, 21 22 23,", "31 32 33 along the bottom. Each is 1920x1080, so cell RC sits at x=(C-1)*1920, y=(R-1)*1080.", "", " +----------------+----------------+----------------+", " | 11 | 12 | 13 Boat cam A |", " + Race view, 2x2 projection +----------------+", " | 21 | 22 | 23 Boat cam B |", " +----------------+----------------+----------------+", " | 31 results|rost| 32 Boat cam D | 33 Boat cam C |", " +----------------+----------------+----------------+", "", "THIS FILE OWNS BOTH LEVERS, because they are different things and each one alone is a trap.", "The CANVAS belongs to an OBS PROFILE, so the wall names its own (`Video wall`, 5760x3240) and", "leaves the 1080p profile's stream key and output settings untouched. The SCENES belong to a", "COLLECTION, and collections are shared across profiles — so a 1080p scene laid out at 1920x1080", "still exists, with those same absolute transforms, when the operator switches to this profile,", "where it fills the top-left NINTH and black fills the rest. Naming a collection too is what stops", "the wall's scenes and the streaming scenes from ever being shown against each other's canvas.", "", "The wall owns its four cameras (`wall:cam:A..D`) rather than borrowing the streaming collection's,", "because each sits in its own CELL rather than in a grid. Each asks for a SLOT, not a hull, so they", "follow the racing fleet with nothing running — see `vars._slots`.", "", "Cell 31 is split in two because Burgee serves recent results and the entry list as two pages;", "there is no combined one.", "", " python -m v3.broadcast.live.obs_scenes apply v3/broadcast/live/obs/video_wall.json \\", " --var producer=http://localhost:8766 --var burgee=http://127.0.0.1:8090", " ...or the same file against gcloud by changing only --var producer=https://" ], "profile": "Video wall", "canvas": [ 5760, 3240 ], "vars": { "producer": "http://localhost:8766", "burgee": "http://127.0.0.1:8090", "event": "trwc-2026", "_mediabase": "Clips are fetched from a SECOND ORIGIN, and that is load-bearing. Every page on this wall holds a permanent SSE connection to the feed; a browser allows about six connections per origin and OBS shares one network stack across all its browser sources, so a wall of cameras plus the programme page exhausts the origin and every clip fetch queues behind them for ever - readyState 0, no error, no fallback card: a black tile under a live overlay. 127.0.0.1 and localhost are DIFFERENT ORIGINS to Chromium, so this is the very same server with its own pool of connections.", "mediabase": "http://127.0.0.1:8766/demo/data/media/", "readbase": "http://127.0.0.1:8766", "_slots": "Each camera cell asks for a POSITION — `boatcam.html?slot=A..D` — and the race plane answers with `meta.cameraSlots` in the feed header. The cells used to be PINNED to four hulls by `--var camA=…` at apply time, which is right for the race it was applied for and black for every race after it: the pinned hulls become spectators, no clips exist for them, and nothing says so. Keeping them honest then needed a second process rewriting four URLs on every heat. A slot URL is permanent, so a rotation re-points nothing and there is nothing left to run." }, "program": "Video wall", "scenes": [ { "name": "Video wall", "items": [ { "source": "wall:race", "kind": "browser_source", "enabled": true, "_cell": "11 12 21 22 — the race, at native 3840x2160 rather than a 1080p page stretched 2x", "settings": { "url": "${producer}/core/web/index.html?feed=live&res=1&adaptive=guard&resmin=1&fpsmin=24&trustedAutoplayAudio=1&mediaBase=${mediabase}", "width": 3840, "height": 2160, "shutdown": false, "restart_when_active": false, "reroute_audio": true }, "transform": { "positionX": 0, "positionY": 0, "alignment": 5, "boundsType": "OBS_BOUNDS_SCALE_INNER", "boundsAlignment": 5, "boundsWidth": 3840, "boundsHeight": 2160 } }, { "source": "wall:cam:A", "kind": "browser_source", "enabled": true, "_cell": "13 — Boat cam A", "settings": { "url": "${producer}/core/web/boatcam.html?slot=A&feed=live&hls=1&readBase=${readbase}", "width": 1920, "height": 1080, "shutdown": false, "restart_when_active": false, "reroute_audio": false }, "transform": { "positionX": 3840, "positionY": 0, "alignment": 5, "boundsType": "OBS_BOUNDS_SCALE_INNER", "boundsAlignment": 5, "boundsWidth": 1920, "boundsHeight": 1080 } }, { "source": "wall:cam:B", "kind": "browser_source", "enabled": true, "_cell": "23 — Boat cam B", "settings": { "url": "${producer}/core/web/boatcam.html?slot=B&feed=live&hls=1&readBase=${readbase}", "width": 1920, "height": 1080, "shutdown": false, "restart_when_active": false, "reroute_audio": false }, "transform": { "positionX": 3840, "positionY": 1080, "alignment": 5, "boundsType": "OBS_BOUNDS_SCALE_INNER", "boundsAlignment": 5, "boundsWidth": 1920, "boundsHeight": 1080 } }, { "source": "wall:cam:C", "kind": "browser_source", "enabled": true, "_cell": "33 — Boat cam C", "settings": { "url": "${producer}/core/web/boatcam.html?slot=C&feed=live&hls=1&readBase=${readbase}", "width": 1920, "height": 1080, "shutdown": false, "restart_when_active": false, "reroute_audio": false }, "transform": { "positionX": 3840, "positionY": 2160, "alignment": 5, "boundsType": "OBS_BOUNDS_SCALE_INNER", "boundsAlignment": 5, "boundsWidth": 1920, "boundsHeight": 1080 } }, { "source": "wall:cam:D", "kind": "browser_source", "enabled": true, "_cell": "32 — Boat cam D", "settings": { "url": "${producer}/core/web/boatcam.html?slot=D&feed=live&hls=1&readBase=${readbase}", "width": 1920, "height": 1080, "shutdown": false, "restart_when_active": false, "reroute_audio": false }, "transform": { "positionX": 1920, "positionY": 2160, "alignment": 5, "boundsType": "OBS_BOUNDS_SCALE_INNER", "boundsAlignment": 5, "boundsWidth": 1920, "boundsHeight": 1080 } }, { "source": "wall:results", "kind": "browser_source", "enabled": true, "_cell": "31 left half — recent results, beside the roster rather than above it: both are tall lists, so splitting the cell down the middle gives each its full height instead of halving it", "_legibility": "Rendered at HALF the half-cell and scaled 2x by the bounds below. These are ordinary desktop pages; at native width the type lands at desk-reading size, which is unreadable across a room from a video wall.", "settings": { "url": "${burgee}/e/${event}/results", "width": 480, "height": 540, "shutdown": false, "restart_when_active": false, "reroute_audio": false }, "transform": { "positionX": 0, "positionY": 2160, "alignment": 5, "boundsType": "OBS_BOUNDS_SCALE_INNER", "boundsAlignment": 5, "boundsWidth": 960, "boundsHeight": 1080 } }, { "source": "wall:roster", "kind": "browser_source", "enabled": true, "_cell": "31 right half — the entry list", "_legibility": "Half-size render, scaled 2x — see the results cell beside it.", "settings": { "url": "${burgee}/e/${event}/entries", "width": 480, "height": 540, "shutdown": false, "restart_when_active": false, "reroute_audio": false }, "transform": { "positionX": 960, "positionY": 2160, "alignment": 5, "boundsType": "OBS_BOUNDS_SCALE_INNER", "boundsAlignment": 5, "boundsWidth": 960, "boundsHeight": 1080 } } ] } ], "collection": "Video wall" }