The blur is universal, so it would swallow the logo along with everything else. The compositor
now defers every visible brand logo: skipped in both element loops, blitted immediately AFTER
the blur group, before the flash/social/ticker overlays. One logo per scene, so it is cheap.
Preview mirrors it: the staged scene's brand logo is drawn above the blur host (StagedBrandLogo),
so what you see in the editor is what the encoder gets.
Test: a blur covering the logo's area leaves the logo's pixels exactly white while the coloured
background beneath it blends.
The creator found the use case that reframes the feature: a moment of privacy while the webcam is
on. A blur that can only cover the desktop cannot do that.
- SceneCompositor applies the blur group AFTER every element is composited (still before the
flash / social bar / ticker / zoom overlays), so it covers webcam, chat, alerts — anything. Its
position in the layer list no longer affects the output, so it is added at the top and the
reorder clamp is gone.
- Supersedes the earlier "blur sits below the brand" rule: a universal blur does obscure the logo
when it covers it. Called out in frame-pipeline.md so it is not re-litigated.
- Preview mirrors it exactly: the blur host moved OUT of CanvasGrid to a sibling above it, so the
VisualBrush samples every layer (and cannot sample itself). It used to sample only the backdrop,
which is why a circle over the webcam would have shown sharp pixels in the editor and blurred
ones in the stream.
Creator request 2026-11-01: a layer that hides part of the desktop from viewers. Box or circle,
drag/resize like any layer, one strength slider, several allowed.
**Z-order is policy, not preference.** `AddSource` inserts a blur directly above the background
and therefore below the brand logo, and `OnSceneElementsReordered` pushes any blur that ends up
above the brand back down. Nothing else in the app can move it into the brand's way.
**Overlap = the strongest single blur, never a stack.** `SceneCompositor.ApplyBlurLayers` collects
every visible blur the first time one is reached in the z-order, sorts them strongest-first, and
shares one coverage map: a pixel already covered by a stronger blur is skipped. Blurring
back-to-front would have produced something stronger than any slider setting allows, which is
exactly what was ruled out.
**One blur curve, shared with the webcam.** `RegionBlur` carries the constants the webcam blur
already used — downscale 4, radius 1–6 downscaled px, `RadiusFor(strength)` — and
`BackgroundEffectProcessor` now delegates to it instead of holding its own copy. The layer's
slider is the same 0–1 scale with the same 0.5 default, so "half strength" means the same blur in
both features. Cost is proportional to the blur's own rect, not the frame.
**Live scene only**, enforced in `AddSource` as well as the (+) menu (`CanAddBlur`), so a stale
menu item or a scripted call cannot plant one on BRB. `ElementKind.Dynamic`, so it is never baked
into the static base and every render path gets it — pump, preview, thumbnails, scene dump.
Persistence: `Source.BlurAmount` column + migration; shape rides the existing `ClipShape`.
Properties panel: Box | Circle plus the strength slider, gated on `IsBlurSelected`.
4 tests: outside the mask is byte-identical, inside loses its hard edges, a circle leaves its
box corners alone, and two identical stacked blurs equal one (the coverage map). Release builds
at 0 warnings.
Creator's defaults: white text, Background ON (black, 20%), speed capped at 200 px/s, text size shown
in real pixels, and "plate" dropped from the label.
The important find is underneath those: `ScoreboardStyle` is a record STRUCT, and `new
ScoreboardStyle()` zero-initialises — it does NOT run the constructor's parameter defaults. So the
shipped strip had null text colour, NO background and zero opacity, whatever the source said. That is
why the Background checkbox and the opacity slider looked like they had no code behind them: the
renderer was faithfully drawing the zeros it was handed.
An explicit parameterless constructor now carries the real defaults, and the renderer test asserts
them (white / on / black / 0.20 / max speed 200) so this class of silent-zero cannot return.
Readouts fixed too: the opacity and text-size setters never raised their own property, so the numbers
never moved while the render did. Text size now reads "24 px" instead of a bare slider value, and
snaps to whole pixels.
The marquee now has the dial it needs. `ScoreboardPresenter.PixelsPerSecond` is the single owner of
the range (20-400, default 120), the layer's properties expose it with a live px/s readout, and the
value is persisted as Scoreboard.ScrollSpeed because it is a READABILITY choice — re-dialling it
every launch would be a tax on the creator who needs the strip to be readable.
Advance() still takes an optional override so tests can drive exact distances.
Guard: the presenter test proves speed is real (same elapsed time, twice the speed, different
window) — not a value that is stored and ignored — and the panel test pins the control, its range
and the persistence key.
Creator, plainly: "the entire point of a ticker is to tick… so, tick." The static strip was my
reading of an earlier exchange; it is gone.
How it ticks without becoming the compositor's most expensive layer:
- `ScoreboardRenderer.RenderRun` rasterises the run ONCE per value change at its natural width plus
a gap.
- `ScoreboardPresenter` crops a 1920-wide window at a moving offset each tick — a row-wise byte
copy, no text layout, no re-raster.
- `TickScoreboard` runs on the existing 30 Hz meter clock and only while the strip is shown, so a
hidden or disabled scoreboard costs nothing.
The dev simulation uses the same path, so what is previewed is what ships.
Test updated to the real contract: no tick → identical pixels; a tick → different pixels; a value
change → re-rasterised run. (The old test asserted frame-instance identity, which a cropped window
can never satisfy.)
ScoreboardTiles decides which of the eight facts appear and shapes their text (money uses the
session's dominant currency and flags a second one rather than converting; watch hours carry
'as of {date}' because Analytics is a daily aggregate). Tiles are OPT-IN, so 'None' really means the
layer draws nothing, and 'Default' is the six session facts.
ScoreboardPresenter owns the raster cache: ScoreboardRecorder.Changed fires only on a visible change,
so the strip rebuilds only then — a per-tick raster would be the compositor's most expensive layer
for identical pixels.
Guard: ScoreboardPresenterTests asserts the cache identity (same instance when nothing moved, a new
frame when a value moved, reuse when a recipient-side gift event arrives) and that an empty selection
returns no frame at all.
Rasterises enabled tiles into one straight-alpha BGRA frame: measured widths -> FitLine (shrink,
then wrap, never scroll) -> centred lines with dim separators, over an optional rounded plate whose
colour and opacity are the creator's knobs. Uses OutputPalette.Sans (bundled Inter) because on-stream
text wears the app's typefaces.
Static by design: it takes plain strings, so the caller caches the frame and only re-rasterises when
a value changes — a strip that re-rendered every tick would be the compositor's most expensive layer
for no benefit.
Guard: ScoreboardRendererTests paints real frames and inspects pixels — plate colour AND opacity,
text colour reaching glyphs, plate-off leaves the area transparent, and an empty tile set returns no
frame at all.
The broadcast picture is part of the app, so it stops carrying its own colours. Alert cards, the
ticker and the branding flash now paint from OutputPalette, which Mirrors DESIGN.md for the brand
tokens and owns the alert box's six-event accent language (gold/violet/pink — content, not
chrome; the standard has no purple and should not grow one, but they live in ONE file instead of
57 scattered literals).
It is a separate type because the renderers run on the frame-pump thread and must not touch
application resources. The duplication is made safe by OutputPaletteTests: it parses
Themes/Tokens.xaml and fails if any mirrored token drifts, and fails if a renderer reintroduces a
colour literal or "Segoe UI".
Ticker and flash glyphs now use the bundled Inter instead of Segoe UI. Neon red is the standard
live red — one red in the product, including the credit.
Fixed on the way: the palette's font fields were static pack-URI initialisers, which throw
TypeInitializationException in any host without a WPF Application (the test process caught it);
they are lazy now with a name fallback.
In the Socials drawer, under the show/hide switch: text colour, an optional background plate
with its own colour and opacity, and a text drop shadow. The bar had been hard-wired
white-on-transparent since it shipped.
- `SocialsConfig` gains five additive properties (BarTextColor, BarBackgroundEnabled,
BarBackgroundColor, BarBackgroundOpacity, BarTextShadow).
- Persistence: five new Socials columns, added by the per-column idempotent migration pattern
(a half-migrated DB heals instead of failing), written in Save and read back in Load with
defaults for pre-existing rows.
- `SocialBarRenderer.Render(entries, SocialBarStyle?)` — the look is a separate value type so the
renderer stays a pure "entries + look" function and the preview can never read a half-applied
config mid-edit. A malformed hex falls back to white/black instead of throwing inside a render
tick.
- The plate hugs the entries (rounded 20px, padding) so it reads as a caption bar, not a band
across the frame. Off by default, because transparent is what creators have today.
- The colour pickers reuse `BorderColorPalette` — one catalogue of the app's colours, per the
TASK 60/63 rule.
Guard: SocialBarAppearanceTests paints the real strip and inspects pixels — default is white with
no plate, a red text colour reaches the glyphs, a 55% blue plate yields half-transparent blue
pixels, and the shadow adds dark pixels that were not there before.
The cadence work ended with a question the log could not answer: the compositor
manages 6.8 composites/s at ~141ms while the 10:03 take did 29-34ms on the "same
scene shape" (full-render split=0 elements=6 dynamic=5). Nothing in the stats line
said WHICH of the six elements cost what, and nothing recorded the scene itself, so
the two takes could only be compared by eye. This closes that gap and nothing else:
no fix is attempted until a real take names the culprit.
- Services/Compositor/CompositeTimings.cs (new): per-window collector.
Add(stage, ticks) accumulates; Describe(renders, minMs = 0.1) prints the averaged
breakdown slowest-first, dropping sub-0.1ms noise.
- SceneCompositor.Render / CompositeLayers / BakeStaticBase / BlitBakedElement /
BlitCachedLayer + SceneGraph.GetBakedBase: trailing optional CompositeTimings?
Every stage is timed (backdrop, base, flash, social, ticker, zoom, scale, overlay,
bake backdrop, bake overlays) and EVERY element gets its own entry keyed by
z-index + name ("#2 Webcam"), with the nested "raster" sub-stage recording the
paste-cache rasterize miss - the split between "re-samples every tick" and "slow
paste" without a second session. Bake-pass elements are prefixed "bake #..." so a
one-off rebake cannot masquerade as a per-composite cost. Callers that pass
nothing (thumbnails, existing tests) are unaffected and pay nothing.
- FramePump: owns the collector, threads it through RenderScene/RenderFull/
GetBakedBase/CompositeLayers, and logs "FramePump parts (N renders/5s): ..." once
per 5s window beside the stats line (averaged per render, so it compares directly
with "avg render"), then resets it. Also dumps the scene - "FramePump scene dump:"
header plus one line per element (z-index, name, kind, source type, visibility,
rect, opacity, clip) - at pump start and on every scene change.
- One Good Dog integration test (ytLive.Tests/CompositeTimingTests.cs): a real
composite of a full-canvas element plus a 64x64 one through the real collector
must rank the full-canvas element first, carry the raster sub-stage and the fixed
stages, and the dump must name both elements with z-index/type/rect and echo the
split point.
Derivative work (AGENTS.md): OBS's answer to "which source is slow" is the Source
Profiler - average execution time of each source's tick and render functions
(https://docs.obsproject.com/reference-libobs-util-source-profiler, util/profiler.h).
Same shape here: one timer per element per composite, reported as an average, plus
the stage split this case needs.
Docs in the same commit: ai.md (new subsection "Per-element composite timing + scene
dump", the closed gap corrected in "Frame cadence"), Services/index.md (new file row
+ FramePump/SceneCompositor rows), TASKS.md (unit marked shipped, next = creator
take), HANDOFF.md (rewritten: unpushed commit, next step, verify.sh whitelist hole).
Also recorded this session (from the creator): the launch command is
`dotnet run -c Release` - Release is the DEFAULT, Debug only when explicitly named,
and perf takes must read Release. ai.md -> Run updated.
Full suite 428 tests, 0 warnings; the only failures are the known audio env flakes
(both pass in isolation). Scope check passed.
Creator corrected the "loupe" zoom on 2026-10-08: the click anchors a fixed
capture region (box/2 centred on the click) and the box is a live 2x view of
that region — dragging the box never changes its content; it magnifies the
fully-composited frame (every layer, incl. webcam) and draws LAST (n+1).
Rectangle shape is 4:3 ("more of a 640x480 aspect").
- MainViewModel.Zoom.cs rewritten: ActivateZoom anchors CaptureX/CaptureY
(independently clamped); UpdateZoomMove relocates the box only; the per-frame
BuildZoomFrame/ZoomFrameBuilder path is gone.
- SceneCompositor: skips the active ZoomSceneElement in every layer loop and
BlitZooms it last via the new pure ZoomMagnifier (2x bilinear, temp snapshot
via ArrayPool, round clip).
- Preview: ZoomBox hoisted above CanvasGrid as a sibling; its brush samples the
whole composed preview at the fixed capture (2x).
- Tests: ZoomMagnifierTests (box-over-blue shows green capture at 2x incl. an
extra red "layer" — the loupe/backdrop-only regressions both fail it) +
round-clip; ZoomBoxInteractionTests rewritten (anchored capture, move-doesn't-
change-capture, 4:3/9:16/square). 404 pass, 2 known environment flakes.
A composite splits into four horizontal row strips across four DEDICATED
background threads; the calling thread takes a strip too (so four workers
never mean five-way oversubscription), and anything under 64 rows runs
inline. BlitContentRaw, BlitBakedElement and BlitOverlay now fan out.
Output is byte-identical — strips already partitioned by row.
The demotion deliberately does NOT come from Parallel.For. The pool is
shared, so Thread.CurrentThread.Priority = BelowNormal inside it leaks
into every unrelated work item that thread later runs — a full test run
after trying it broke AudioPipelineTests.Mix_HonorsProviderGains_AndGameMute_
KillsTheLoopback. Established guidance agrees: use your own producer/consumer
queue with your own Threads and set their priority yourself
(https://stackoverflow.com/questions/524483/net-backgroundworker-objects-thread-priority,
https://stackoverflow.com/questions/1578599/c-sharp-lower-thread-priority-in-thread-pool).
Helpers/StripPool.cs is that queue. Four threads is the measured sweet
spot: fewer leaves render over budget, more steals cycles from the game
and the encoder and made render worse.
The scaled blit's column LUT moves from a shared static buffer to
ArrayPool<float>.Shared with a finally — a single static buffer is a data
race the moment strips run in parallel.
Gate: SceneCompositorTests.StripParallel_RepeatedRenders_AreByteIdentical —
8 renders of a scaled round webcam + mirrored image + master-sized flash over
a short backdrop must be byte-for-byte identical, and must differ from a
backdrop-only render so it cannot pass vacuously. It caught a loop-variable
capture (new Thread(() => Worker(i)) saw i == Workers) that crashed the test
host on the first run.
Handle the case where an opaque source exactly covers the destination
canvas with 1:1 dimensions (even if offsets differ in calculation). This
avoids per-pixel alpha branching and mirrors the existing memcpy fast
path. Byte-identical for opaque sources.
Creator 2026-09-26: "the ticker should appear over the stream alerts video, not over
the entire preview window". It was a GLOBAL 1920x48 bar blitted last at a hardcoded
(0, 0) -- it covered the whole preview width, not the alert video.
The strip is now rendered at the alert box's own size and the box's origin travels on
the frame in a new VideoFrame.Placement ((int X, int Y)?). OriginX/OriginY default to
0 when Placement is null, so every full-canvas overlay (the branding flash) is
unaffected. Every ticker blit site now reads tickerFrame.OriginX/OriginY instead of a
literal 0, 0 -- SceneCompositor x2 and FramePump's static-bake Overlay path -- and
PreviewPane.xaml's AlertTickerElement binds the same rect (AlertTickerLeft/Top/
Width/Height), so the preview cannot drift from the recording the creator is judging.
Why the position rides on the frame rather than in a full-canvas frame: a 1920x1080
overlay is 8.3MB of large-object-heap garbage per tick, ~2.5GB churned over one 10s
alert at 30fps. A box-sized strip is ~370KB. The branding flash does render
full-canvas but RECYCLES one 8MB buffer and bumps Epoch, so it never allocates per
frame; the ticker allocates per call, so it has to stay small.
Also fixed: CopyStrip now clips ROWS to the target height. The pill rasterises at its
natural 48px, so an alert box shorter than that would have written past the end of the
target buffer once the strip became box-sized.
No alert box in the scene now means no ticker at all -- there is no global position
left for it, and this is the guard against the old bar quietly coming back.
Tests (3 new facts, 27 in the file):
ComposedOutput_PutsTheTickerInsideTheAlertBox_NotAtTheTopEdge -- renders through
the real SceneCompositor and asserts the pixels land at (620, 430) and NOT at the
top-left corner. The creator is judging compositing from local recordings, so the
OUTPUT side is the side that needed proving.
ASceneWithNoAlertBox_PublishesNoTicker
ABoxShorterThanTheStrip_ClipsRowsInsteadOfOverrunning
Updated AlertLayer_PublishesARealTickerFrameToThePreviewSink, which asserted the old
1920 width from a box with no geometry (defaulted to 1px); it now uses the product's
own default box (680x200 at 620,430, MainViewModel.Sources.cs:54-57) and pins the
frame size and origin.
Full suite 367/367.
Creator 2026-09-26: "the made with llamacasty flash should appear in all scenes,
not just live" and "should also appear in recordings". The presenter was
Start()/Stop()-ed from UpdateLiveVisuals()'s IsLive branch, so a recording made
WITHOUT ever going live carried no credit at all -- the exact case the creator hit
while judging compositing from local recordings.
It is now Start()ed once in the MainViewModel ctor and never stopped on live-state
churn. One start covers every scene, the preview, the stream and the recording,
because go-live and local recording are the SAME FramePump: both
Streaming.Operations.cs:68 and :199 call StartAsync with the same brandFlash:
delegate. Verified by reading both call sites, not assumed -- there is no second
encoder path that needed a "redirect". The licence gate needs no live branch at
all: IsPremium's setter already pushes BrandFlashPresenter.Enabled from anywhere.
Fixed a trap that app-lifetime exposed: Enabled = false stops the presenter's
DispatcherTimer to cut the advertisement mid-credit. When Start() was per-go-live
the next go-live restarted it; with a single app-lifetime Start() nothing would,
so a key entered mid-session would leave the credit dead until the process was
restarted. The setter now restarts the timer when re-enabling while _running.
Tests (12 facts in BrandFlashOutputTests, +2):
Credit_IsComposited_WithNoLiveSession_AndSoARecordingCarriesIt -- drives a real
never-live VM past the 5s first-flash delay and asks the frame the pump would
composite. Uses a new internal AdvanceBrandFlash seam; because Advance only
advances the cadence while the presenter is running, a credit coming out
proves Start() happened at construction.
ADowngradeMidSession_RestartsTheCadenceTimer -- asserts the premium/downgrade
edge decision directly (IsCadenceTimerEnabled) instead of sleeping through a
30-60s interval, which a synchronous test body cannot observe.
Full suite 364/364.
The credit existed only as a WPF BrandFlashLayer TextBlock in the preview at
25% opacity on a 300s timer. A viewer of the stream or the recording never saw
it, so "free tier shows branding" was not actually being delivered. The frame
pump has carried an unused per-frame flashFrame slot for exactly this.
Reverses the documented "Pre-GA posture" (ai.md Monetization), which kept the
flash preview-only so test VODs stayed clean. Creator ruling 2026-09-26: the
free tier has to be honest advertising, so it now reaches the broadcast.
One rendered VideoFrame feeds BOTH the frame pump and the preview, so the
creator's view cannot drift from what viewers get. Spec: 500ms in / 1000ms hold
/ 500ms out, first credit ~5s after go-live then every rand(30s)+30s, single
unwrapped line at a random spot inside the frame every time, neon white core
with a feathered red/blue halo.
Neon recipe is derivative work, per AGENTS.md: bright core + feathered
multi-radius halo with R and B split in opposite directions, from
https://nudaui.dev/components/neon-glow (layered text-shadow falloff),
https://help.maxon.net/rg/en-us/Content/html/Blurs-and-Glows-chromatic-glow.html
("with no displacement, the green channel is all but invisible behind your
white text" once R and B are split) and the OBS obs-stroke-glow-shadow
"feathered stroke with user-defined size and intensity". Neon blue is #4d8bff
rather than the theme's #0f3460, which renders near-black as a halo.
Also fixes a PRE-EXISTING bug found on the way: FramePump's fully-static
shortcut stretched the cached bake and returned it, silently discarding every
per-frame overlay - the social bar and the alert ticker were already lost
there. SceneCompositor.Overlay is now internal (it copies before blitting, so
the bake is never mutated) and the shortcut composites overlays first.
The credit is deliberately NOT folded into SceneGraph.GetBakedBase:
SceneRegion.Matches compares element ids only, so a credit in the cached bake
would freeze there and never expire. Per-frame only, and Epoch is stamped
every read because the 8MB master buffer is recycled - without that the
paste cache would freeze a stale credit.
BrandFlashEnabled is now derived !IsPremium and non-assignable, and the
presenter re-checks the licence on every read, so a key entered mid-credit
cuts the advertisement on the next tick instead of letting it finish.
Tests: 10 new facts. 357 total, 356 pass; the one failure is the known
environment-flaky RealMouseDrag layer test (needs an uncovered desktop
session). Adds RealAppHost.RunAsync - a frame-pump test must await inside the
collection's shared STA thread or the whole suite deadlocks silently.
NOTE: scope-check.sh flags Helpers/InstanceProfile.cs, AppLog.cs,
TokenStore.cs, WebView2Manager.cs and InstanceIsolationTests.cs as outside
this commit. That is a false positive: it uses `git diff HEAD`, which cannot
distinguish a planned second commit in the same session from an unrelated
edit. Those files are the dev multi-instance unit, committed immediately
after this one - as is the InstanceProfile paragraph in ai.md, which shares a
file with the Monetization section corrected here.
The creator confirmed the clip fix ("the video plays now"), then asked where the
scrolling text was — it was invisible, for a structural reason. AlertTickerFrame
existed only as a frame-pump callback blitted into the OUTPUT; PreviewPane.xaml had
no element for it, because the strip is master-width and global, not a Source, so it
cannot ride a per-element Image. Nothing was wrong in the renderer: there was no
consumer in the preview. Same class of defect as the missing IsAlertBox trigger, one
layer up (MyMistakes RULE 5/6).
- tickerPreviewSink on AlertOverlayLayer, published from RefreshAlertPreviews() so it
is always the UI thread; MainViewModel.AlertTicker writes it into one reused
WriteableBitmap bound to a new global AlertTickerElement, mirroring SocialBarElement.
- Source.AlertDisplayMethod + panel "Display" selector: TickerScroll / Flash / Solid.
Flash pulses 0.5s on / 0.5s off for the whole alert; Solid is centred and still.
- The marquee was also unreadable: a fixed 140px/s took ~17s per pass, so a 10s alert
showed the text once, entering from the right and never crossing. Paced in reads per
alert instead (TickerReadsPerAlert = 3 inside the alert's own length, speed derived
from it) — never px/s. Research (websearch: how do OBS/Streamlabs/StreamElements
alert boxes present announcement timing?) settled the unit: Streamlabs exposes "Alert
Duration: choose how long your alert stays on your stream" and "Text Delay", never a
scroll-speed slider (https://support.streamlabs.com/hc/en-us/articles/52499995174299-Setting-up-Your-Streamlabs-Alerts).
Run is phase-started half a frame in so the first frame isn't blank.
- Persistence: AlertDisplayMethod INTEGER NOT NULL DEFAULT 0 via the idempotent
table_info migration, appended LAST in the SELECT because the Source reader is
positional (GetInt32(32..34)) — a mid-list insert would silently shift a neighbour.
Tests: 15 new facts (suite 339/339). RealApp STA host: the pane draws the strip and
collapses at alert end; the layer publishes a real 1920x48 frame for all three methods
and nothing when the ticker is off; three passes counted in 10s by the pill's leading
edge resetting (a seamless marquee never blanks, so an empty frame cannot count a pass);
Solid byte-identical at every moment; Flash on for half of each second; the panel shows
and writes back the choice; the DB round-trips all three alert fields together.
Incidental finding: a bound ItemsSource ComboBox in LeftPanel.xaml broke
LayerReorderPersistenceTests.RealMouseDrag (that test injects PHYSICAL mouse input, so a
load-time re-measure moves the rows out from under the cursor). Rewritten as inline
ComboBoxItems, the shape the chat Font selector already uses in that panel. Recorded as
MyMistakes RULE (8).
TASK 43's alert box grows a real video celebration. Per-alert IAlertClipDecoder
(ffmpeg bgra + f32le pipes, real-time paced, disposed at drain) plays the shipped
Assets/alert-default.mp4 (stamped into the Asset table at startup) unless the
creator picks their own file — path reference only, never stored in the DB; the
six AlertRenderer animations stay the fallback. ~0.3s fade rides the alpha
envelope on straight-source copies (EOF freeze-frames then fades out); audio
forwards to a new AudioMixer alert ring (8s, 48k stereo) drained at unity — no
duck, creator ruling — scaled by volume × fade. An auto-composed marquee ticker
('Funder — Super Chat · $10.00', 140px/s) scrolls top-of-frame via a
FramePump._alertTicker seam through Render/CompositeLayers, mixed into the cache
signature (dynamic overlay, never baked). New Stream Alerts section in LeftPanel.
Derivative-work references (how OBS/Streamlabs alert boxes do per-alert video):
- https://support.streamlabs.com/hc/en-us/articles/217741147-Setting-Up-Your-Streamlabs-Alerts (custom image/video per alert type + variations)
- https://obsproject.com/kb/stream-tutorial-2-alerts (alert overlay as an on-screen zone)
- https://streamlabs.com/content-hub/widgets/alert-box (per-event alert playback)
Good Dog: AlertLayerVideoTests drives a fake IAlertClipDecoder through the whole
lifecycle in one pass (custom path wins, decoder spawns/disposes, fade envelope
0→127→255, audio volume×fade, ticker scrolls, EOF fade-drain to idle). It caught
the clip branch of Advance not clearing _current before AdvanceToNext — the layer
stayed IsPlaying after drain (MyMistakes post-mortem).
Full vstest 319/319; clean build 0 warnings; scope check green.
- AudioSyncDelay.Configure reallocated/zeroed its buffer every ~10ms tick
(AudioMixer re-reads the UI setting each mix), so any non-zero sync offset
erased the just-written audio -> total silence. Now early-returns when the
delay samples are unchanged. Regression test proven both ways.
- SceneCompositor.BlitContentRaw defaulted cbW/cbH=0 when CropBounds is null
(regression from ed9d7c1) -> webcam blit to an empty rect = gray block.
Default to src.Width/Height. Regression test proven both ways.
- Truncated recordings: rawvideo mux stamps frames at declared 60fps by
arrival; a scene whose first layer is dynamic (hidden elements still count)
kills the bake cache -> full render ~35ms -> ~27fps submitted -> halved
file length. Static scenes bake once (246ms cold, then <1ms) -> 60fps,
full-length (probe + 13:53 take, 301/300 per 5s, 12.46s file from 12.3s
wall). FramePump.ProbeRender names the hot render path on slow frames.
The element-space raster builds on a TRANSPARENT base but BlitContentRaw's
partial-alpha branch applied the opaque-dst source-over blend: color premultiplied
by the sampled alpha, then alpha forced to 255. Pasting that raster saw a==255 and
straight-copied darkened ink over the scene — a recording box that the raw-bitmap
preview (correct alpha) never showed. Transparent margins and opaque content were
unaffected, which is why every take looped on the page/CSS while the capture was
transparent all along (15:51 dumps: alpha max 255, mean ~19, zero 57%).
BlitContentRaw now takes transparentDst; the raster call passes true and writes
straight color + straight alpha so the paste rows (BlendRowOpaque/Weighted) do the
real source-over onto the opaque master. Master paths byte-identical.
ONE integration test PasteCache_SemiTransparentLayer_RevealsBackdrop_NotOpaqueInk:
50%-blue over red reads (127,0,128) fixed vs (0,0,128) buggy — proven both ways
(verified by stashing the fix: fails before, passes after). Clean build, 0 warnings;
22/23 compositor-class tests pass, the sole failure the documented pre-existing
Composite_FullScene_MasterPixels pixel (1380,700).
Alpha-compositing model: standard source-over with producer-cached surfaces, the
OBS/libyuv paste model already cited in ai.md/MyMistakes (rawvideo recipe, row-blit
BLEND_NONE / straight-alpha branches); full story in MyMistakes (RESOLVED entry).
Per the good-dog rule: one integration test, memory updates (MyMistakes/ai.md/
HANDOFF) in the same commit.
Slice 10 from today-slices (d1126dd): the paste cache minted a fresh raster
array per new source frame (webcam ~30 keys/s ≈ 18MB/s LOH churn →
gen2 pauses that ate camera frames). Fix: _elementRasters — re-rasterize
INTO the element's existing array when geometry holds, so steady-state
allocation ≈ 0. The paste cache keys on (array+epoch) still protect correctness;
_elementRasters[element] tracks the element's current raster so stale keys can
never paste a mid-update array. MaxPasteEntries 48→256 (was a leak guard,
not an allocation stream). Regression test:
PasteCache_RingRecycledSources_ReRasterInPlace_WithoutAllocationChurn.
Build 0 warnings, 289 tests.
Take 11 (c10ce06c) validated the off-UI architecture: typical frames land
work ~10ms + wait ~6.8ms = 16.7 exactly on the deadline; 212/300 best yet.
The ENTIRE remaining gap is periodic 35-65ms render spikes that WORSENED
across the take (189 -> 147) — the signature of gen2 GC pauses. Biggest
churner is structural: the screen capture minted a fresh ~8.3MB byte[] per
DWM frame (~500MB/s of LOH), a producer OBS never does (it owns fixed
surface pools).
- ScreenCaptureFrameSource: 4-deep buffer ring with size-matched slots (a
<=17ms consumer cannot be lapped at 60Hz) + reused downscale row scratch.
- VideoFrame.Epoch: monotonic per producer frame. The paste cache keys on
array IDENTITY, so recycled arrays MUST be distinguished — epoch joins the
PasteKey. Producers handing fresh arrays leave it 0 (key unchanged effect).
- Stats print 'gen2 +N' per 5s window: next take acquits or convicts GC
without another guess (rule: prove the stage).
- Test (the ONE): PasteCache_RecycledArrayWithNewEpoch_ReRasterizes_NotStaleHits
— same array, new content, bumped epoch; fails on the old key by
construction. 37/37 compositor/pump, clean build.
- Next suspect if gen2 stays hot: the 10Hz WebView2 capture (full-canvas PNG
decode + fresh arrays on the UI thread) — recorded, untouched.
Creator audio ask queued in the same working session (+40% post-mix master
gain before the -1dBFS limiter) lands as its own commit next.
Take 10 (59a02a5b, slice 6) finally produced a self-contradicting stat: render
22.4ms + submit 2.5 against a 16.7ms deadline, yet avg wait 10ms — a rebasing
pacer CANNOT sleep after a blown deadline. The wait was queue time: StartAsync
fires from a UI command handler, and async continuations re-capture the current
SynchronizationContext — the 'WPF-free, hermetic' frame pump had been rendering
ON THE DISPATCHER behind the live preview the entire starvation saga. OBS keeps
obs_graphics_thread/video_thread off-UI for exactly this reason (dedicated
threads; see docs.obsproject.com/backend-design 'Libobs Threads').
- FramePump: _pumpTask = Task.Run(() => PumpAsync(...)) — null context inside,
every continuation stays on the pool.
- Audited, not ignored, what that exposes: StaticPixelCache.Get now locks (pool
miss-decodes raced UI callers); ChatOverlayLayer.RenderFrame checks its cache
off-thread but marshals the rare raster MISS to the dispatcher (DrawingVisual
+ RenderTargetBitmap are UI-thread objects) and re-validates there; pump
events already marshal in the VM.
- GCLatencyMode.SustainedLowLatency for the pump's life (restored in finally).
- Stats gained 'worst render Xms' — bimodal averages hid per-tick spikes.
- Webcam routes through the paste cache (the IsOpaque bypass re-sampled ~156k
px every tick even between identical device frames).
ONE integration test: Pump_Produces_OffTheStartingContext — an inline-pumping
SynchronizationContext makes the old construction run the resolver on the
starting thread by capture; the loop must never. 70/70 per-class green, clean
build 0 warnings. Docs same commit (ai.md slice 7, TASKS take-11 gate,
MyMistakes #6, HANDOFF). take 11: ~300/300 + honest wait -> saga closed,
Unit B (two-line top bar spec, fully captured) starts.
Take 9's numbers were decisive: paste cache moved work to ~25ms/frame but the
period stayed ~37ms. The missing ~12ms per tick is Task.Delay rounding every
sub-tick request up to the Windows system-clock tick (~15.6ms default —
documented: learn.microsoft.com/en-us/dotnet/api/system.threading.tasks.task.delay).
A frame finishing 3ms early requested 3ms and slept 15.6. Producer capped at
~27fps no matter how fast the compositor got — which is why two real render
fixes read as 'zero change' in playback. Game-loop/OBS canon for this
(stackoverflow.com/questions/5441464; learn.microsoft.com/en-us/windows/win32/
api/timeapi/nf-timeapi-timebeginperiod): raise the timer resolution for the
session, sleep only the bulk of the remainder, and SPIN the last ~2ms across
the deadline.
- FramePump: timeBeginPeriod(1) on entering the pump loop, timeEndPeriod(1) in
the finally; pacing = bulk _pacingDelay(ahead - 2ms) + bounded Thread.SpinWait
tail; blown deadlines rebase unchanged (never burst).
- Stats now report avg wait: render+submit+wait must equal the period — the
accounting is closed, no stage can hide in an unmeasured gap again.
- Webcam dropped its IsOpaque paste-cache bypass: it re-sampled ~156k px every
tick even between identical device frames; cached paste beats the sampler on
hits, costs the same on misses.
52/52 per-class green (pacing + pixel suites unchanged — output byte-stable),
clean build 0 warnings. Docs same commit (ai.md slice 6, TASKS.md take-10
gate, MyMistakes #3 + renumber, HANDOFF). User's top-bar spec remains next in
queue (Unit B) — re-sent many times, captured, no open questions.
The stamped build settled what slices 3-4 could not: chat cache works (resolve
~0.0ms) but render stayed 26-27ms -> 124-135/300. The cost was the compositor
re-rasterizing EVERY layer every tick: this Live scene re-samples chat (159k) +
web widget (271k) + image (95k) + cam (156k) ~ 680k px @ ~38ns — for layers
whose pixels do not change between chat/web/cam updates.
OBS shape: cache the surface, paste per tick. BlitCachedLayer rasterizes a
non-opaque layer ONCE into an element-space, transparent-based frame keyed by
(source-array identity, src W/H, ceil'd dst rect, round, mirror), then pastes:
integer position, row alpha-blend, opacity applied at paste. Producers hand out
fresh immutable arrays -> array-identity keys cannot serve stale content; dict
bounded (48, clears whole). Drag/opacity live in paste params, not keys, so
editing stops triggering resamples too. Opaque backdrop keeps the memcpy path;
the webcam keeps the direct path via its IsOpaque flag (revisit if take 9 is
borderline).
ONE integration test: PasteCache_RepeatRender_IsByteIdentical_And_ContentChange-
Propagates (byte-exact raster-vs-paste incl. round-clip margins, new-array
propagation); existing pixel suite guards sampler semantics. 85/85 across
compositor/pump/chat/capture/session classes, clean build 0 warnings. Also:
BuildStampTests.cs was written last commit but never staged — its own scope-check
slip, added here (the run had used the on-disk file; tracked now).
Docs same commit: ai.md slice 5 + stale 'general path only 130k' claim corrected,
TASKS.md take-9 gate, MyMistakes recipe (prove the stage; a fix that doesn't move
the stat wasn't the bottleneck), HANDOFF. take 9 expectation: 300/300, render
<= ~8ms -> saga closes, Unit B starts.
Two defects made the producer 17x slow (37s record -> 2.1s/127-frame file,
rawvideo stamps by arrival): FramePump slept the FULL interval after each
render (period = render+submit+interval) and SceneCompositor did per-pixel
float sampling + Math.Round blends over all 2.07M master pixels, scanning the
whole destination per overlay (258ms avg render vs 1.5ms submit).
Both solutions are established, not invented — researched before coding per
the derivative-work rule:
- deadline pacing: OBS libobs/media-io/video-io.c video_thread (nextTick +=
intervalTicks, sleep only the remainder, rebase on overrun, never burst)
- row blits: libyuv pattern (BSD-3, chromium.googlesource.com/libyuv/libyuv)
— 1:1 aligned identity fast path, per-pixel alpha branch, integer
fixed-point blend, overlay clipped to the intersection rect, skip the dead
black pre-fill when the backdrop covers
ONE integration test: Pump_Paces_To_The_Deadline_Compensating_Render_Cost
(lands after a fake-seam lesson: pacing fakes must await, not complete
synchronously, or the pump loop runs inline on StartAsync and hangs vstest).
Clean build 0 warnings; FramePumpTests 10/10, SceneCompositor/SceneGraph/
SocialBar/StretchMath 20/20. Docs same commit: ai.md pipeline section,
TASKS.md TASK 18 (webcam-in-output + rename modal verified from take 3),
MyMistakes recipe, HANDOFF rewritten. Take 4 pending on the user's machine.
- Add ElementKind (Static/Dynamic) to SceneElement base; Source/WebcamSceneConfig classify
- Services/SceneGraph.cs: owns the Scenes collection (ViewModel's Scenes delegates to it),
the element mutation surface (Add/Insert/Remove/Move, each invalidating the bake), and the
queries that were scattered LINQ (GetBackground/GetWebcam/GetChatBoxes/GetSplitPoint/IsStatic)
- SceneCompositor: split-aware BakeStaticBase + CompositeLayers + Render(.., staticBase, split);
builds/caches the static base below the split point in source-rect space
- FramePump: optional SceneGraph -> optimized bake+composite path; falls back to full render
- MainViewModel: routes element mutations through the graph; invalidates the bake on static
layout/opacity/visibility/useDefaultBackground changes and after background heal/Ensure
- Integration test SceneGraphTests.BakedStaticBase_WithDynamicLayer_CompositesCorrectly
Derivative survey (mandated): tried before writing — OBS does per-source opacity/visibility
caching and static-scene baking; this mirrors OBS's 'cached static source' optimization.
3 documented defensive deviations from the spec (ChatOverlayLayer stays decoupled;
background helpers stay VM-static for direct testability; full facade peel deferred post-1.0)
in TASKS.md + ai.md. Scope check passed; clean build 0 warnings.
- TRAX: LocalGain now applies 0.2× factor so music is quieter relative to desktop audio slider
- TRAX tooltip: switched to ToolTipService with Placement=Top to fix z-order in Viewbox overlay
- Mic meter: MeterLevel multiplied by 1.2× before clamping for ~20% higher visual readout
- Volume sliders: click anywhere on track to jump thumb to that position before dragging
- Backdrop: Image Visibility now binds to BackdropVisible; compositor checks IsVisible before blit
- Renamed 'Backdrop' to 'Game Capture' in EnsureBackdrop + test assertions
Software compositor that renders a scene into the encoder's master VideoFrame,
mirroring the XAML preview minus editing chrome: backdrop -> background ->
elements (UniformToFill cover-crop, round clip, mirror, opacity, border) ->
branding flash.
NOTE FOR USERS: this change shows NO difference in the app's UI — it is pure
backend scaffolding laying the groundwork for live video capture/streaming.
The preview you see is unchanged.
- Services/Compositor/: SceneCompositor (Render(scene, frameFor resolver,
flashFrame, CompositorOptions)), CompositorOptions (source rect + output
size; 16:9 full master, vertical 607x1080 -> 1080x1920), StretchMath (pure
UniformToFill + bilinear), StaticPixelCache (asset bytes -> BGRA8 frame)
- Frame sources injected via Func<SceneElement, VideoFrame?> resolver, so the
compositor is pure, WPF-free, and hermetic to test (D3D11 upgrade behind the
same seam later)
- SceneElement.TryGetBorderColor public (shared hex parse), stale
MainViewModel comment fixed, pre-existing CS1998 in YouTubeAuthServiceTests
cleaned up
- Tests: SceneCompositorTests integration (full scene + vertical tier + flash)
+ StretchMath units, docs updated (72 tests passing, 0 warnings)
gramps
