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new-game intro has a name Q9, answered twice over -- once from the disc and once from frames I had already captured and not used. The movie manifest's first eight slots are the whole boot-side flow, and the slot key is the role: LOGO1-4 -> logo1-4.wmv (not on the disc, which is why the splash is a screen), ADVERTISE_MOVIE -> ADV.wmv, STAFF_ROLL -> the credits reel, MS00A -> S00A.wmv, MS01A -> S01A.wmv. So the new-game intro is S00A.wmv, decoded -- which is the half I could not test at runtime, because A on NEW GAME hangs the emulator. And there is no separate boot-intro slot: ADV.wmv IS the advertise movie, the boot just plays it first. Confirmed independently by matching 19 attract frames against five candidates -- 15 hit ADV with a playhead that advances monotonically at the sampling rate and ends at 137 s, its full length, with the title back on the next sample. So the attract movie plays to its end; nothing cuts it short. That corrects me. Two iterations ago I recorded the attract movie as "~85 s, so probably not ADV.wmv" -- arithmetic on a start I never observed, since sampling began 39 s in. REFUTED and METHOD both take it, along with the matcher's real failure mode: a near-black frame has no signature, and its runner-up is not evidence. Skippability I did NOT settle, and the corpus contradicts itself: one page says A skips a movie every time, while the boot harness deliberately never taps during one because it breaks the title. Named the one-boot test rather than picking a side.
172 lines
9.9 KiB
Markdown
172 lines
9.9 KiB
Markdown
# Method traps already paid for
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Each line cost an iteration at least once. They are general — they are not about
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Sylpheed, they are about how this kind of measurement goes wrong.
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Like [`REFUTED.md`](REFUTED.md), this list had been living in the autonomous
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agent's loop prompt, i.e. nowhere durable. See [`README.md`](README.md) for the
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✅/🟡/❔ confidence convention itself.
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## Controls
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* **Every result needs a control. A control that fails kills the instrument.**
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* **Run the known-positive through a new filter FIRST.** Three filters have been
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killed by their own control. When one fails, **read the known-good's
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disassembly** before assuming a shape.
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* **A measured negative is a result** — but a negative is only as strong as the
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route you ran, so **state its reach**.
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* **A null result needs its cause shown to have happened.**
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* **A result with NO unknowns is suspicious.**
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* **Census the whole set; always run the other population as the control.**
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**Zero partials is stronger than a majority.**
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* **A 2×2 partition is the sharpest general tool** — both off-diagonals empty is
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a law.
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* **Re-derive a doc's own numbers as the control.**
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## Inference
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* **Never conclude from ONE sample.**
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* **A law proved on one population is a hypothesis on the next.**
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* **Finding one exception does not imply a family.**
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* **Consistency is not proof. A suggestive coincidence is a coincidence until
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measured.** **An analogy is not a measurement.**
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* **Same layout ≠ same instance.** **Same record-name set ≠ same object.**
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* **A marker is only proven by what it leaves out.**
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* **A high-confidence SCORE is not a high-confidence MECHANISM.**
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* **Knowing HOW MANY is not knowing WHICH.**
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* **Round numbers matching is weak evidence — unless you read the constant.**
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* **My own last-turn result is a hypothesis too.**
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* **A global partition can understate a per-owner one.**
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* **A residual is measured against a population — name it.**
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## Searching and tooling
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* **A search that returns thousands has no power; state the reach.**
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* **A substring match is not a hit.** **A regex miss looks like a null result —
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print one raw sample before believing a zero.**
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* **A derived table can be a cross product — measure its shape first.**
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* **After refuting an instrument, sweep everything that depended on it.**
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* **Before measuring how wrong a tool is, read what the tool actually does.**
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* **The instrument must pass its own control.**
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* **Classify a bulk before mining it. The residual is the prize.**
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* **Rank by similarity — the cliff is the finding.** But **read the values
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before trusting the rank.**
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* **Grep the nouns before designing the experiment — and believe it.**
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* **Grep gives you a file list — read *every* file on it.**
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* **The answer is often already in the doc that owns the subject — read it end
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to end.** A 🟡 often names its own route.
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* **Before re-trying a blocked idea, check whether the blocker's own doc already
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tried it.**
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* **Ship a regenerator with every artefact.** An artefact that moves by a pure
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reorder is a tool bug.
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* **Never print per-entry lines from a disc-wide sweep — aggregate.**
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## Reading the data
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* **Read what a loader NAMES, not where it stores.**
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* **A field the disc never values still gets named by the loader.**
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* **An indexed read beats a deduped-pool adjacency read.**
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* **Check the whole string set, not the one matching word.**
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* **A dict keyed by record name across a multi-entry pak is a lie.**
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* **A set-difference over names hides reuse — join per USER.**
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* **A self-index names records, not files.**
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* **Case-insensitive hashing means two spellings can be one entry.**
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* **An "unresolved" name may be the wrong kind, namespace or prefix — or part of
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a cut asset.**
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* **A garbled value may be a real string in another encoding.**
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* **Two of my own counts disagreeing is a grammar clue.**
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* **A game's own typo is a join key.**
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* **A bias constant in the code is a join key.**
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* **A prefix trap: enumerate maximal `[A-Za-z0-9_]` runs, not `startswith`.**
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* **Re-deriving a format is not a finding — asking whether its values *resolve*
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is.**
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## Mechanics that have bitten
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* **Never hand-convert a decimal VA — print `hex()`.**
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* **`grep -c` counts LINES** — use `grep -o | wc -l`.
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* **`Counter.most_common()` tie-breaks by insertion order — use `sorted()`.**
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* **Raw grep cannot see inside compressed pak entries.**
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* **Commit messages go in a file** (`git commit -F`); a literal `|` in a table
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cell needs escaping; `git log --all -- <path>` can hang.
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## Runtime / emulator
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* **Look at the PNG** — and check its dimensions.
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* **"Animating" is not "still in a mission".**
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* **Dedup entity enumerations by position value.**
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* **Do not diagnose timing or liveness under gdb.** `ps %cpu` is cumulative.
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* **Classify screens by whole-image statistics, not named pixels** — a named
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pixel is only valid while the image sits at a known place, and nothing errors
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when it moves.
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* **Do not poll faster than the guest updates** — it manufactures a clean curve
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out of noise.
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* **A probe that never performs the action will "prove" the action does not
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exist.**
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* **The container's Canary binary can be older than the Canary source tree, and
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the failure mode is a hang, not an error.** After a merge into `sylpheed-re`
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the prebuilt `xenia_canary` had no `log_ui_draws`, no `mem_watch`, no
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`create_profile_if_none` — and an unknown cvar makes xenia open an SDL message
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box before logging is up, which headless is an unexplained freeze. Check before
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trusting a harness flag: `nm -C <binary> | grep cvars::<flag>`, and
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`build-canary Release` if it is missing.
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* **A capture armed *at* a screen only ever sees the steady state.** Anything
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about how a screen is built or animated has to be armed *before* it exists.
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Re-arming every few seconds and keeping every log tiles the approach: each F10
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opens a new numbered file and closes the previous one complete.
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* **Measure animation in submitted frames, not in seconds.** `VdSwap` counts are
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the guest's own frames, so an emulator at 80 % of real time does not move them;
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a stopwatch reading does, silently and by an unknown factor.
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* **~~This game's menus drop d-pad presses shorter than ~0.3 s.~~ WITHDRAWN
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2026-08-28 — the menu WRAPS, and I had not measured that.** The claim came from
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reading a cursor that ended up "one item short"; once wrap-around at both ends
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was measured ([`menu-navigation-semantics.md`](menu-navigation-semantics.md)),
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every one of those press counts is exactly right — four presses at 0.12 s moved
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four steps *through the bottom*, which lands one above where a non-wrapping
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menu would put it. **No press was ever dropped.** The real lesson is the
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general one: *a step count is only readable once you know the topology*, and I
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invented a hardware-flakiness story rather than testing the ends of the list.
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Still true and worth keeping: screenshot after every step and read the cursor,
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rather than trusting arithmetic over the press count.
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* **A screenshot taken right after a transition can catch a screen mid-fade.**
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A grab 2.5 s after Ⓑ returned the game to the title showed the title art with
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no `PRESS Ⓐ BUTTON` plate; one second later the plate was there. That very
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nearly went into the corpus as "the returned title has no plate". Sample a
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changing screen several times before writing down what it does *not* contain.
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* **Do not identify a menu cursor by label brightness.** The obvious oracle —
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"the focused label is the brightest row" — fails on this game's menus, because
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the background art is brighter behind some rows than the highlight is. It
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confidently named the wrong item on a frame whose ring was plainly elsewhere.
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Detect the **focus ring** in the gutter left of the labels instead
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(`tools/re-capture/menu_focus.py`, 254 vs <82 — no threshold tuning needed),
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and look at the PNG before believing either.
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* **`screenshot` samples at 0.5 Hz — it cannot time an animation.** Measured:
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~2 s per grab (an `import` of the root plus an ImageMagick crop). A 0.4 s fade
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falls entirely between two samples, which is why a 40-frame burst across a
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screen change looked like an instant cut. For anything timed, record the
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display instead: `ffmpeg -f x11grab -framerate 30 -video_size <W>x<H> -i
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:98+<X>,<Y> -t <secs>`, then read per-frame statistics off the file. Take the
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geometry from `xwininfo -root -tree`, the same way `bin/screenshot` does.
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* **A screen's brightness curve is not its fade quad.** The incoming screen's own
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elements animate in *after* the transition quad has cleared, so mean luminance
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keeps rising long after the fade is over — 1.47 s against a declared 0.97 s on
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one screen. Time the fade from where the frame is *pure black*, and take the
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ramp itself from the keyframes.
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* **A `sound.pak` entry is not a bank.** Entry windows straddle bank boundaries
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(the leading-region effect), so a naive "walk the RIFFs in this entry" gives
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the tail of the previous bank, then one of your own, then the *next* bank's
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header. It looks like a bank with the wrong number of waves. The tell is a
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`BANK id=` that is not the entry's own number, and the fix is the `seek` packet
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counts — they pin each wave's join exactly, so a straddle can be realigned
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rather than thrown away. 4 of 32 BGM banks look like counterexamples until this
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is applied.
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* **Do not time a video whose start you did not see.** An attract cycle sampled
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from partway through measured "≈85 s", which was used to argue it was not the
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137 s `ADV.wmv`. It was `ADV.wmv`; the sampling began 39 s in. Identify a video
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by **content** — match frames against the candidates and check the matched
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playhead advances monotonically — before reasoning about its duration.
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* **A near-black frame has no signature.** In frame-matching, low-contrast frames
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drive every correlation toward zero and the ranking becomes noise; one control
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frame scored 0.000 and another tied the wrong movie at 0.98. Read a dark
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frame's runner-up as *no evidence*, not as evidence for the runner-up.
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