# Real VT1200 boot recording — reference material

Source: `video/DEC VT1200 Hardware X11 terminal boot and demo. [j_mJB3asDgE].mkv`
(201 MB, **gitignored** — it is a YouTube download and trivially re-obtainable).

Everything committed here is **derived** from it: contact sheets for navigation,
full-resolution frames for detail.

## Regenerating

```sh
V="video/DEC VT1200 Hardware X11 terminal boot and demo. [j_mJB3asDgE].mkv"
# contact sheets: one frame per 2 s, 6x6 tiles
ffmpeg -v error -y -i "$V" -vf "fps=1/2,scale=320:-1,tile=6x6" sheet_%02d.png
# full-resolution frame at a chosen time — OUTPUT seek; input seek (-ss before -i)
# fails on this filename with "Invalid argument"
ffmpeg -v error -y -i "$V" -ss 26 -frames:v 1 real_t26.png
```

## The real boot timeline

This is the ground truth the harness is compared against.

| video time | what is on screen |
|---|---|
| 0:00–0:12 | **nothing** — the monitor's own blue no-signal backdrop |
| ~0:13 | the terminal starts driving the display |
| 0:14–0:44 | the self-test **pie / progress disc** sweeping to completion |
| ~0:45 | wipe to black |
| ~0:48 | a **dialog box** (the Terminal Manager) |
| ~1:08 | a light (mostly white) screen |

The harness reaches the X11 weave and the Terminal Manager via
`VT1200_SKIP_LEVEL1=1`; on real hardware level 1 passes, so it goes further.

## One correction kept deliberately

The low-resolution contact sheets *appeared* to show a **text block** at ~0:14, and
that was briefly reported as a real screen. A full-resolution crop
(`real_text_crop.png`, taken at 0:14.2) shows the screen is **blank blue** — the
monitor's no-signal state. The "text" was a scaling/compression artefact of a
320-pixel tile.

**A contact sheet tells you *when* something happens, not *what* it says.** Crop and
up-scale before reading anything off one — the same class of mistake as concluding
"it never paints" from a single frame.