A brow at 320x200 is fourteen pixels wide and three tall. Its shape carries
almost nothing at that size; its height above the eye carries the expression,
and a brow raise is the most legible beat on a face. So the ring is traced and
the height is quantised - the split the eyes already got, where the lid is a
traced feature and the iris a quantised primitive.
The decomposition is the point. The traced ring already contains the real
height, so adding a quantised raise on top would move the brow twice. The
height is measured OUT of the ring, quantised, and put back, so the shape that
renders is his at a height that snaps between a few levels and holds.
Measured at both ends rather than as one number, because raise and tilt are
different expressions out of one mechanism: both ends up is surprise, inner up
alone is worry, inner down is anger. They share a dwell - the gaze quantiser,
renamed quantizeSnap now that it has two callers - so the brow hits its pose in
one frame instead of crawling into it with one end arriving before the other.
Measured against the eye's corner midpoint, never its lid. Same trap the gaze
origin has and worth avoiding twice: brows and lids move together constantly,
so a brow that jumped on every blink would read as a tic. Rest pose from the
take median rather than the neutral frame, for the reason gaze learned the hard
way - that frame is picked by minimum mouth aperture and says nothing about the
brows.
Two correspondences resolved from geometry, not declared: which ring is which
brow, and which end is the outer one. The second matters more - backwards, the
tilt mirrors and worry renders as its own opposite, which reads as a directed
performance choice rather than a bug and would never be questioned. Which EDGE
is upper is deliberately left unresolved: it traverses the same ring the other
way, an even-odd fill has no winding, and both ends still land on fixed slots.
Also fixes a bug from the exposure work: the live render applied exposure to
the plate and the mouth but not to the eyes, so on 2s the preview and the
export disagreed. A preview that disagrees with the export is the one bug this
tool cannot afford. perfIndex now exists as a named thing so the two paths
cannot drift apart again.
91 -> 105 assertions. Ground truth on all four synthetic brow poses, tilt
separating worry from anger by sign, a blink not faking a raise, and a shared
dwell never emitting a half-raised brow.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Three parts per eye, stacked the way the mouth is - dark lash ring, sclera
inside it, iris inside that, square pupil in the iris. A blink then costs
nothing: when the lid shuts the traced ring goes flat and the lash line
collapses to a lens, which is a closed eye, drawn correctly, for free.
Lids are a FEATURE, rotoscoped like the mouth: head-local, a key on every
frame, the same contour avg knob. The iris is a PRIMITIVE - a disc at a
quantised position - and that is where the stylisation lives.
Line of sight. Gaze is the iris centre relative to the midpoint of the eye's
two corners, in units of corner distance. Both corners are in RIGID, so the
origin and the scale are immune to the performance being measured; against the
lid ring's centroid instead, every blink would drag the origin down and fake a
glance at the floor on exactly the frames where the eye is most visible. Both
eyes share one gaze - at this size the difference between the two measurements
is noise, not vergence, and independent per-eye noise reads as wall-eyed
immediately. Openness stays per-eye so a wink survives.
Gaze is then quantised to a pixel grid with a dwell, which is not a
stylisation imposed on the truth: real eyes move in saccades, and the smooth
drift left in the measurement is tracker noise plus head-compensation error.
Snapping to a grid removes the noise and recovers the saccade in one operation.
The iris is placed in the frame of the already-smoothed, already-subsampled lid
ring - slots 0 and 8 of a 16-slot ring are the corners, and subsampling to any
even budget keeps them at 0 and n/2 - so it cannot drift relative to its own
eye. Size is authored from the take mean, never remeasured per frame: a radius
that breathes by a fraction of a pixel flickers a pixel on and off around the
whole silhouette. iris anchor toggles steady/free/locked, because how much the
eye wanders turns out to be an aesthetic choice and not only a correctness one.
Blinking gets hysteresis and a dwell like the teeth, plus one knob they do not
have: blink hold. A blink is one frame at 12fps and a single frame of closed
eye reads as a dropped frame, so once the eye shuts it stays shut long enough
to be legible. Detection accuracy is not the problem; legibility is.
The pupil is a square because at three pixels a circle is a plus sign with the
corners gnawed off, and it changes shape as it moves. Drawn from a rounded
centre shared with the iris so it is exactly its nominal size on every frame.
Iris/pupil clip by colour key against the indexed buffer, the way Animator Pro
would: the lid crops the iris at extreme gaze for free, so nothing has to clamp
the gaze, which would flatten the performance at the extremes that carry it.
Which iris block belongs to which eye is RESOLVED from geometry, not declared.
A swap looks almost right - each eye still has a disc roughly where it belongs
- so it survives an eyeball and then reads as a subtly wall-eyed character
forever. Voted across every frame; the test feeds a deliberately swapped track.
Also: exposure. Aesthetic sparseness was set by the extraction rate, which made
the timing a property of a directory of PNGs - auditioning 12 against 24 meant
re-ripping and re-detecting the whole clip. It is now a render-time grid, on
1s/2s/3s/4s, so the dense track keeps everything and the audio clock is
untouched. The take format already carried an exposure field; it was never
driven. Everything rides the same grid, because a head cutting on the odd
frames while the mouth cuts on the even ones reads as two performances laid
over each other.
41 -> 91 assertions. The load-bearing new ones: the iris pairing follows a
swapped track, a blink does not fake a change of gaze, a stencilled disc cannot
spill past its clip, a 3px pupil is 3x3 at every sub-pixel centre, and exposure
never reads a pose from the future.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
The test renderer turned out to be the product. Everything that decides how the
work looks - stabilisation, reduction, timing, frame removal, palette - already
happens here, and the flat indexed output already reads the way it should.
The reason to leave is in the original design's own rule: never make a timing
decision that requires a full render to evaluate. Honouring that moved every
judgement out of Animator Pro, which left the host doing nothing but writing a
file, in exchange for modal UI, minutes-long renders, one-level undo, FLX delta
invariants, a single tween state and a cel singleton.
What does NOT change is the constraint. 320x200, indexed palette, flat fills,
no antialiasing - inherited, but load-bearing rather than accidental. The
rasteriser writes palette indices and expands to RGBA only at the end precisely
so nothing can soften an edge. Modern conveniences belong in the workflow.
Adds docs/design.md: the principles, carried over without the Poco/FLX/cel
machinery, plus architecture and an honest list of what is missing - the
largest gap being that plates still have nowhere to be drawn.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
"It feels like it does nothing" is indistinguishable from "it does nothing",
and at 24fps a lead of 1 is 42ms - small enough to reasonably doubt. So the
shift is now provable and visible rather than taken on trust:
- shiftIndex is a pure exported function with assertions covering identity,
both directions, and clamping at each end
- the frame label always shows the mouth frame, not only when shifted, so the
number can be watched diverging from f; non-zero leads also report in ms
- the slider readout carries an explicit + sign
- the stabilised pane draws the unshifted contour as a dark-green ghost when a
lead is set, so the offset is something you can see
Also: leadIndex called opts() on every invocation - ~14 DOM reads, once per
strip thumbnail, so ~1000 per redraw at 74 frames. It reads a cached scalar now.
The "different pose" assertion checks the whole track rather than one pair:
synthetic poses hold for nine-frame beats, so a single pair can legitimately be
identical while the shift works correctly.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
MediaPipe normalises x by image WIDTH and y by image HEIGHT, so for a 1080x1920
clip one unit of x is 1080px and one unit of y is 1920px. makeXform applied a
single scale to both, stretching everything horizontally by H/W - 1.78x on this
footage. The photo underlay looked equally squashed because frameAffine divided
x by imgW, matching the equally wrong vector shapes rather than disagreeing
with them.
Fixed at ingest: landmarks convert to an isotropic space whose unit is one image
height (x *= W/H), so equal numbers mean equal pixels everywhere downstream.
Pixel mapping follows - both axes divide by imgH.
This also silently fixes head roll. fitSimilarity was fitting a rotation in a
sheared space, so the "similarity" it recovered was not one, and stabilisation
of rolled heads was subtly wrong.
selftest: a shape circular in pixel space must stay circular in raster space,
checked at 1080x1920, 1920x1080 and 640x640. Fails at ratio 1.78 without the
conversion.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Sparseness was being applied for two different reasons at once. Aesthetic
sparseness is set by the extraction rate; labour sparseness only binds on the
plate, because a human draws each one. The mouth is traced and therefore free,
and in limited animation lip sync is routinely the densest element - on 1s
while heads hold on 2s and 3s.
So: the mouth gets a key on every frame, and the frame strip is now the
editing surface for deciding which frames need their own plate drawing. All
frames start kept; delete the ones you don't want.
- strip of face-cropped thumbnails, keep/drop per frame, keyboard driven
- worksheet panel lists the drawings needed and the range each one holds
- Suggest runs error-tolerance decimation on head pose as a starting point
- export writes sparse plate keys + dense mouth keys, with a hold manifest
- smoothContours: bounded exception to "never smooth the contour", which held
only while keys were sparse enough to reject detector noise by sampling
- averages are now a RADIUS in frames: 0 is off, 1 is +-1
- GPU delegate falls back to CPU instead of failing
- #synth / #frames autorun for headless smoke tests
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Analysis half of the pipeline in docs/roto-puppet.md. Stabilises a face out
of a clip via a similarity fit on rigid landmarks, reduces the lip contour to
a fixed vertex budget, selects sparse keys on velocity minima, and previews
the result as flat indexed fills so timing can be judged without an Animator
Pro render.
- landmarks.js ordered lip/oval rings; slot position is vertex identity
- mathutil.js closed-form 2D similarity, Procrustes mean, transform smoothing
- pipeline.js stabilise -> subsample -> key-select
- raster.js indexed scanline fill, no antialiasing
- take.js take-file writer
- selftest.js 29 assertions, incl. ring simplicity at every vertex budget
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
