gramps
bd396e488c
Root cause (measured, not guessed): the take-3 'rebase on overrun' reset
nextTick to wall-now, erasing every missed slot. Pump delivered 215-219/300
per 5s (~43fps) but rawvideo carries no timestamps — ffmpeg muxes by frame
count at -framerate 60, so every recording played fast with honest-looking
stats. A second pacer, ffmpeg -re, throttled the demux separately
('Resumed reading ... after a lag' 0.79s->4.82s).
Fix follows libobs video-io.c (https://github.com/obsproject/obs-studio)
- the video thread never resets its deadline; one frame per interval slot,
a late render repeats content (judder), never skips time:
1. FramePump: count-based emission, while(now>=nextTick){Submit; nextTick+=I}
2. FfmpegArgs: -re removed - the pump is the pacer
Muxed duration is now frame-count/fps == wall time by construction. Covers
game background + webcam (one shared pump). 0 warnings; suite 288/289 -
the one failure (Composite_FullScene_MasterPixels 1380,700) also fails with
this change stashed: pre-existing, untouched, recorded as follow-up.
58 lines
3.3 KiB
Markdown
58 lines
3.3 KiB
Markdown
# HANDOFF — 2026-09-10
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## Branch / Commit State
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`main` HEAD = `1a39b09`, ahead of origin by 12, working tree carries THE recording-timing
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fix (uncommitted): count-based CFR emission in `FramePump.cs` + `-re` removal in
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`FfmpegArgs.cs`, plus this handoff / `ai.md` slice 9 / `MyMistakes.md` recipe correction.
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`tools/` holds `ticker.c` + the built `ticker` (WSL, unused by git yet).
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## Recording TIMING — the fix (the "plays too fast" saga)
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**Root cause, proven by measurement (not guessed):** the pump's take-3 "rebase on overrun"
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reset `nextTick` to wall-now every time it fell behind, silently erasing missed slots. The
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pump delivered `215-219/300 per 5s` (~43fps) but ffmpeg muxes rawvideo by frame count at
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`-framerate 60` — no per-frame timestamps — so every recording played ~1.4x fast with
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stats that looked honest (a rebased frame is never "late"). `-re` on the demux was a second
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fighting pacer ("Resumed reading … after a lag" grew 0.79s→4.82s).
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**Fix (the OBS `video-io.c` shape — one frame per interval slot, deadline never reset):**
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1. `FramePump.PumpAsync`: `while (now >= nextTick) { SubmitFrame(frame); nextTick += intervalTicks; }`
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— one submit per crossed slot; a slow render re-writes the current composite (judder,
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never a skip). `nextTick` NEVER rebases to wall-now.
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2. `FfmpegArgs`: `-re` deleted from the rawvideo input; the pump is the pacer.
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**Verified:** build 0 warnings; full suite 288/289 — the sole failure
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(`Composite_FullScene_MasterPixels` line 109, pixel (1380,700) cyan vs magenta) ALSO fails
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with this fix stashed, i.e. pre-existing and untouched by it. DO NOT fix it here; it is a
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separate compositor investigation.
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## NEXT STEP (ONE user run required)
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Record ~30s with the WSL ticker visible in the preview (`cd tools && ./ticker` in a terminal,
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Ctrl-C to stop), then check:
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- recording duration ≈ wall time (should be, by frame-count construction)
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- `%APPDATA%\ytLlive\startup.log` "FramePump stats:" shows ≈ n/n per 5s, n = 300 @60fps
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- NO "Resumed reading … after a lag" lines remain
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- ticker advances ~1s per second of footage
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## Still Open
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- Web overlay: the pre-parse transparency injection (committed `1a39b09`) is NOT yet proven
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— both recorded diagnostic PNGs (`%TEMP%\ytLive-web-<id>.png`) were 100% alpha=0 AND
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RGB=0 (an EMPTY capture, not an opaque one). Diagnosis "capture is empty" needs a fresh
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run; the first-capture dump may be the pre-load about:blank frame. Frozen pending the
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timing verification.
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- Audio silence: `no audio.mp4` measured -91dB (digital silence), 3KiB muxed audio stream —
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the named-pipe audio delivered ~nothing. Separate from timing; not yet touched.
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- Pre-existing: `Composite_FullScene_MasterPixels` (see above).
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## Landmines
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- testhost shares startup.log with app — filter by time when triaging
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- testhost/exe lock DLLs: `taskkill /F /IM testhost.exe /IM ytLive.exe` before rebuild
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- Build via the Windows dotnet host: `/mnt/c/Program Files/dotnet/dotnet.exe build …`
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- Kill app before build: `/mnt/c/Windows/System32/taskkill.exe /F /IM ytLive.exe`
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- No Linux ffmpeg / no sudo on this box — probing uses `/mnt/c/Program Files/Krita (x64)/bin/ffmpeg.exe`
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via WSL interop; frames landed in `/mnt/c/Users/gramp/AppData/Local/Temp/ylf/`
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- `tools/ticker`: constant ~+982ms offset on the FIRST line is cosmetic (t0 captured a beat late) |