docs: usage section for the preset node
Moves the actionable part above the ~60 lines of rationale. Covers the basic wiring, that either empty-latent node works (comfy/sample.py's fix_empty_latent_channels repeats an all-zero latent out to the model's channel count), what the megapixels/label outputs are for, and three concrete pipelines: Krea 2 stills downscaled to 1080p, H3 video with the 2048x1152-vs-1536x864 trade-off, and a Krea 2 Edit character reference fed at native resolution with no downscale on that branch. Adds a "when to use the other two nodes" note, since the preset node is an alternative to Resolution Selector rather than a stage before it -- chaining them is meaningless, as the selector takes a ratio and a budget rather than dimensions. The old "Wiring it up" subsection now points at Usage and keeps only the ffmpeg delivery detail. Also fixes the header diagram's box border, which was one column short of its content. Verified: every "ratio · W × H · MP · TAG" string quoted anywhere in the README resolves to a real generated preset; box borders equal width; both cross-link anchors exist; all 69 megapixel-table rows still re-derive through the solver. Docs only -- no version bump, so this does not republish. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01CdgKVDqEbD14EJ4RC3GPmg
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dreevelle
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Claude Opus 5
Claude Opus 5
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@@ -12,12 +12,82 @@ Three nodes, no dependencies:
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```
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Resolution Preset
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┌──────────────────────────────────────────────────┐
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│ preset 16:9 · 2048 × 1152 · 2.36 MP · K2+H3+SDXL│
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└──────────────────────────────────────────────────┘
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┌────────────────────────────────────────────────────┐
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│ preset 16:9 · 2048 × 1152 · 2.36 MP · K2+H3+SDXL │
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└────────────────────────────────────────────────────┘
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↳ width 2048 height 1152 megapixels 2.36 label "2048x1152"
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```
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## Usage
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Pick a preset, wire `width` and `height` into whatever takes dimensions. That's the
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whole thing:
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```
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Resolution Preset ──┬── width ──▶ Empty Latent · width
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└── height ─▶ Empty Latent · height
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```
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Either empty-latent node works. `EmptySD3LatentImage` is the nominally correct one for
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Krea 2 (`[B, 16, H//8, W//8]`, matching its 16-channel Wan21 format), but the legacy
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4-channel `EmptyLatentImage` is fine too: `comfy/sample.py` runs
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`fix_empty_latent_channels`, which detects an all-zero latent and repeats it out to the
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model's channel count. Same for the MiniMax H3 nodes — feed `width`/`height` straight
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into `MiniMax H3 Image to Video`.
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`megapixels` and `label` are there when useful and cost nothing left unconnected.
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`label` gives `"2048x1152"`, handy wired into a `filename_prefix` so saved files carry
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their resolution.
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### Three concrete pipelines
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**Krea 2 stills, delivered to a 1920×1080 screen** — pick `16:9 · 2048 × 1152`, then
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downscale once at the very end:
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```
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Resolution Preset 16:9 · 2048 × 1152 · 2.36 MP · K2+H3+SDXL
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│ width, height
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▼
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EmptySD3LatentImage → KSampler → VAEDecode
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▼
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Upscale Image lanczos · 1920 × 1080 · crop disabled
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▼
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Save Image
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```
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**MiniMax H3 video** — same front end into the H3 nodes. `2048 × 1152` if you want the
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crop-free downscale to 1080p; `1536 × 864` if you want to stay nearer H3's 1.03 MP
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native canvas and accept a ×1.25 upscale. See
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[Delivering to a fixed screen size](#delivering-to-a-fixed-screen-size) for the
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trade-off, which is about 5 dB of preserved detail.
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**Krea 2 Edit character reference** — pick a portrait preset and feed it at native
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resolution, with **no** `Upscale Image` on that branch:
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```
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Resolution Preset 9:16 · 1152 × 2048 · 2.36 MP · K2+H3+SDXL
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│ width, height
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▼
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(generate) → VAEEncode → ReferenceLatent → Edit Model Reference Method
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```
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Reference and generation resolutions are independent — the DiT gives each reference its
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own slot in the positional ids, so a portrait reference conditioning a landscape
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generation is the intended design. Do not downscale a reference to your delivery size:
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`ReferenceLatent` never resizes, so whatever you hand it is what conditions the model,
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and 1080 is not a multiple of 16 anyway.
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### When to use the other two nodes
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**Resolution Selector (Real MP)** — a ratio or size the preset list doesn't carry: a
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custom ratio, an exact pixel budget, or 21:9 at 2352×1008 (on grid 16, while the 21:9
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presets use grid 64). It's an alternative to the preset node, not a stage after it;
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chaining them is meaningless, since it takes a ratio and a budget rather than
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dimensions.
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**Align Resolution to Grid** — dimensions you didn't choose. An img2img or ControlNet
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source, or an upscale chain where multiplying by 1.5 lands off-grid.
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## Why
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### 1. "Megapixels" usually isn't megapixels
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@@ -279,26 +349,11 @@ is just what `1920/2048` happens to equal; it isn't a number you need to carry a
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### Wiring it up
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Stills (Krea 2):
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Graphs for the common cases are under [Usage](#usage). The delivery-side detail:
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```
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Resolution Selector (Real MP) aspect 16:9 · megapixels 2.36 · alignment 32 · exact_ratio true
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│ width, height → 2048 × 1152
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▼
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EmptySD3LatentImage → KSampler → VAEDecode
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▼
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Upscale Image lanczos · width 1920 · height 1080 · crop disabled
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▼
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Save Image
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```
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`EmptySD3LatentImage` is the right latent node for Krea 2 — `[B, 16, H//8, W//8]`,
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matching its 16-channel Wan21 latent format.
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Video (MiniMax H3): same front end into the H3 nodes' `width`/`height`. `Upscale Image`
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handles a `[B,H,W,C]` batch frame by frame, but if you are dumping a PNG sequence and
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encoding with ffmpeg anyway, fold the resize into that pass instead — it avoids an
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intermediate 8-bit round trip and ffmpeg's lanczos is full precision:
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`Upscale Image` handles a `[B,H,W,C]` video batch frame by frame, but if you are dumping
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a PNG sequence and encoding with ffmpeg anyway, fold the resize into that pass instead —
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it avoids an intermediate 8-bit round trip and ffmpeg's lanczos is full precision:
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```bash
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ffmpeg -framerate 24 -i raw_%05d.png \
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