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Labeling Handbook v0.1 — Padel Shot Taxonomy (Schema 0.2)

Companion to tools/labeler.html v0.2. One record per shot + point segments. Timestamps (t_contact_s) are the single source of truth — no frame numbers, no fps in exports.

1. Point segmentation (new in 0.2)

Two hotkeys mark point boundaries while watching:

A — point start: the moment the server begins the service motion.
E — point end: the moment the ball is dead (double bounce, ball out, into net, out of cage).

Everything outside [t_start, t_end] intervals is between points (walking back, picking up balls, discussing). Shots must lie inside a point — the labeler flags violations with ⚠. These segments later train the rally/no-rally detector and gate the score engine (Layer 4).

2. Shot hierarchy (decision tree)

serve?  ──yes──▶ (only player + outcome; rest auto-filled)
  │no
side: forehand | backhand
volley? (ball taken before ANY bounce)
  ├─ yes ──▶ overhead?
  │           ├─ yes ──▶ overhead_type: bandeja | vibora | smash | gancho | rulo | hybrid
  │           └─ no  ──▶ volley_type: block | drive | slice | drop
  │                       + direction: cross | middle | line
  │                       + depth:     short | deep
  └─ no  ──▶ groundstroke_type: normal | lob | chiquita | dejada | bajada
              + spin (only for "normal"): flat_topspin | slice
              + after_glass: no | back | side | double
outcome: winner | error | in_play

Consistency rules the hierarchy enforces:

No "overhead?" question for non-volleys. The one legitimate overhead that is not a volley is the bajada — overhead hit after the ball bounced off the back glass — and it lives under groundstroke_type. The export still sets overhead: true for bajadas so downstream code has one flag.
after_glass only exists for non-volleys (a volley by definition happens before any bounce).
Placement (direction/depth) is currently only asked for non-overhead volleys (per taxonomy decision 2026-08-03). Extend to all shots once ball tracking can pre-fill it.
A return is never a volley (rule: the serve must bounce before the receiver plays it). The labeler skips the volley question for returns and goes straight to the groundstroke branch — the FULL branch: lob, chiquita, dejada, after_glass and spin are all available on returns (a serve can run off the glass after its bounce, and returning with a lob or chiquita is common).

Placement convention (v0.3 grid)

Label from the CAMERA's point of view, referring to the target half: - left / middle / right = as seen on screen (the camera is fixed, so this is unambiguous; never mirror mentally into the hitter's perspective) - short = near the net of the target half, deep = near the back glass - Example: P4 (far right) plays a short cross volley → ball lands in the NEAR half, on the LEFT side of the image → label short_left.

Hitter-relative direction (cross / longline) is computed later in code from hitter identity + target half + side-switch events — never by the labeler.

Intercepted shots (opponent volleys the ball): placement = where the flight ended, i.e. the court position at which the opponent contacted the ball — NOT the hypothetical landing spot ("would have been deep"). Rationale: the contact position is objective and visible in the video; a hypothetical landing is a guess and produces label noise. The fact that a shot was intercepted is NOT labeled — it is derivable: the next shot in the same point has volley: true. The hypothetical landing point becomes a derived quantity once ball tracking exists (trajectory extrapolation, Phase 3).

3. Definitions

Overheads (volley branch)

Type	Definition	Cue
bandeja	Controlled slice overhead at shoulder height; goal is keeping net position, ball lands deep	sideways stance, contact next to body, no jump
vibora	Aggressive overhead with sidespin; unpredictable rebound off the glass	contact more in front, whipping arm, ball skids low
smash	Full-power finishing overhead; ideally exits the court	jump, contact above head, maximal speed
gancho	Hook-shaped overhead for lobs high over the shoulder when no other overhead is possible; often to fence/glass	hooking arm path, defensive-neutral
rulo	Around-the-head overhead with top/sidespin producing a sharp angle off the back wall	racket path around head
hybrid	Unclear between bandeja/vibora — use sparingly, better than guessing

Volleys (non-overhead)

Type	Definition	When
block	Minimal swing, firm wrist, opponent's pace does the work; redirect	under pressure, fast incoming ball
drive	Punch volley: short forward punch, flat contact, aimed deep (back third)	maintaining/building pressure
slice	Cut volley with underspin; keeps bounce low, hard to play off the glass	attacking, forcing weak lifts
drop	Drop volley (dejada de volea): soft hands, kills pace, lands short behind net	opponents pinned at the back

Groundstrokes (non-volley)

Type	Definition
normal	Standard groundstroke after the bounce (spin labeled separately)
lob	Globo — high defensive/neutralizing ball over the net players
chiquita	Short, low ball from defense onto the net players' feet
dejada	Drop shot: soft with backspin, dies just behind the net
bajada	Ball taken off the back glass (after bounce) and hit overhead with forward pressure

Edge cases (extend as they appear while labeling)

Bandeja vs. vibora: bandeja = control/position (slice, beside the body); vibora = aggression (sidespin, contact further in front). If genuinely between: hybrid.
Block vs. drive volley: decided by swing length and intent, not outcome. A firm block that flies deep is still a block.
Dejada vs. drop volley: same intent, split by branch — after bounce = dejada (groundstroke), out of the air = drop (volley_type).
Salida de pared is captured by after_glass != no on a normal groundstroke, not a separate type.

4. Known limitations / planned extensions (§5 of project brief)

Direction/depth for all shot classes (once model-assisted labeling pre-fills them)
Forced vs. unforced error split on outcome (needs careful definition first)
Wall differentiation on serve returns, contrapared as explicit type
Smash exits por tres / por cuatro

5. Sources for the volley/overhead taxonomy

Padel Underground — padel volley technique and shot selection (block/push/fizz): https://padelunderground.co.uk/technique/padel-volley/
Padel-Wien — overview of all padel shots (bandeja, vibora, gancho, rulo, bajada, chiquita, dejada): https://www.padel-wien.at/en/padel-shots/
PadelMAG — the different volleying techniques in padel: https://padel-magazine.co.uk/the-different-volley-techniques-padel/
The Padel School — the padel volley: https://thepadelschool.com/padel-tips/the-padel-volley