output-format-decision

Purpose

Avoid mismatched output formats (e.g., JPEG for VFX, EXR for web, TIFF for social). Match format to consumer pipeline.

Quick start

• name the consumer
• pick one format per output stream
• pin bit depth + compression + alpha rules
• emit a 4-line config

When to use

• before render
• when consumer requires specific format
• when transparency / HDR / loss tolerance matters

When not to use

• raw modeling without rendering → use ../cycles-vs-eevee-decision/SKILL.md (Delegates out-of-scope requests to cycles-vs-eevee-decision)
• 3D/GLB exports (out of scope — use glb-web-handoff, mobile-glb-budget, or glb-animation-handoff) → use ../glb-animation-handoff/SKILL.md (out of scope — use glb-web-handoff, mobile-glb-budget, or glb-animation-handoff)
• verifying saved files on disk after rendering → use ../render-export-evidence/SKILL.md (use render-export-evidence)

Trigger phrases

• "PNG or JPEG"
• "do we need EXR"
• "what format for the web"

Prerequisites / readiness

• consumer pipeline known
• color management decision made (color-management-decision)

Input schema

Required inputs

Optional inputs

Assumptions to confirm

• The consumer pipeline can read the chosen container/codec (verify if non-default).
• Lossy compression is acceptable when chosen.

Output schema

Primary output

A 4-line format record per output stream: format, bit depth, compression, alpha.

Secondary output

• per-output stream rules
• caveats per choice
• evidence label

Evidence / caveat output

Runtime status: Not Run | Attempted | Produced | Verified | Failed
Artifact status: Not Produced | Produced | Verified | Failed
Evidence used: <links, paths, logs, or "none">
Limitations: <known gaps>

• Default states for this decision skill: Runtime status: Not Run, Artifact status: Not Produced.
• Truth states are downgrade-only, never upgrade. Pinning a format never produces a file.

Required laws

• ../../laws/evidence-before-done.md
• ../../laws/non-blender-user-language.md
• ../../laws/no-arbitrary-python-interface.md
• ../../laws/official-runtime-only.md

Official runtime boundary

Decision skill — does not run Blender. Pins format; operator applies to scene render output.

Operating procedure

1. Identify consumer pipeline + consume color config from color-management-decision.
2. Select format per references/format-decision-matrix.md.
3. Pin bit depth + compression + alpha per output stream.
4. List stream rules and caveats.
5. Hand off format record to operator (and to resolution-aspect-decision if resolution is unpinned, or render-export-evidence once rendered).

Decision tree

Web hero (consuming sRGB config)?
  → PNG (lossless) or WebP (lossy/lossless); 8-bit; alpha if needed
JPEG-only consumer?
  → JPG; 8-bit; no alpha; lossy quality 85-95
VFX / film pipeline (consuming Linear config)?
  → OpenEXR; 16-bit half float; ZIP compression; alpha as channel
Print?
  → TIFF; 16-bit; LZW or no compression; alpha optional per print prep
Social / mobile (WebP-first)?
  → WebP; 8-bit; alpha optional; lossy quality 85-90
HDR display delivery?
  → PNG 16-bit or OpenEXR; verify consumer supports HDR container

Playbooks

Playbook A: Web hero PNG

PNG, 8-bit per channel, lossless compression, alpha if needed (consumes color config from color-management-decision).

Playbook B: VFX EXR

OpenEXR, 16-bit half float, ZIP compression, alpha as channel. Multi-pass support (consumes Linear config from color-management-decision).

Playbook C: Mobile-first social

WebP, 8-bit, quality 85-90 compression, alpha optional (consumes color config from color-management-decision).

Playbook D: Print

TIFF, 16-bit, LZW or no compression, alpha optional (consumes color config from color-management-decision; resolution owned by resolution-aspect-decision).

Mode handling

Text-only mode

Emit format record + per-stream rules + caveats (Runtime status: Not Run, Artifact status: Not Produced).

Runtime-ready mode

Emit format record for the operator to apply in Blender render output settings. Pinning a format never produces or verifies a file; hand off post-render file verification to render-export-evidence.

Blocked runtime mode

Emit format record only (Runtime status: Not Run, Artifact status: Not Produced).

Validation checklist

• Consumer + color config identified
• Format chosen
• Bit depth chosen
• Compression chosen
• Alpha rule explicit
• Caveats listed

Pass / Warn / Fail rubric

Failure handling

• Consumer unknown → ask once; if still unknown, default to PNG, 8-bit, lossless compression, alpha enabled (paired with upstream color-management-decision).
• Multiple consumers → define one format record per output stream (or pin the most restrictive format if single-stream delivery is required).

Troubleshooting

Best practices

• Define one format record per consumer output stream; never convert or re-encode files post-render.
• For web: use WebP or PNG based on consumer support and alpha/compression requirements.
• For VFX: always pin OpenEXR; never pin JPG or 8-bit PNG for compositing pipelines.
• Pass the pinned format record to render-export-evidence for post-render verification.

Good examples

• "Web hero stream: PNG, 8-bit, lossless compression, alpha enabled (using upstream color config from color-management-decision)."

Bad examples

• "Save as PNG." — missing bit depth, compression, and alpha rules.

User-facing response template

Consumer: <web / VFX / print / social / mobile>
Color config: <reference color-management-decision output>

Output(s):
  <stream>: <format>, <bit depth>, <compression>, <alpha>

Caveats: <list>
Limitations: <gaps>
Next: render-export-evidence

Anti-patterns

• "Any format will work."
• JPEG for VFX.
• 8-bit for HDR delivery.
• Lossy compression where archival is required.

Cross-skill handoff

• [upstream_reference] Color management → ../color-management-decision/SKILL.md
• [upstream_reference] Resolution & aspect ratio → ../resolution-aspect-decision/SKILL.md
• [upstream_reference] Engine choice → ../cycles-vs-eevee-decision/SKILL.md
• [progression] Render file verification → ../render-export-evidence/SKILL.md
• [progression] 3D / GLB exports (out of scope here) (glb-animation-handoff) → ../glb-animation-handoff/SKILL.md
• [boundary_delegation] 3D / GLB exports (out of scope here) (mobile-glb-budget) → ../mobile-glb-budget/SKILL.md
• [progression] 3D / GLB exports (out of scope here) (glb-web-handoff) → ../glb-web-handoff/SKILL.md

Non-goals

• Convert formats post-render.
• Run Blender.
• Compress / re-encode files.

References

• references/format-decision-matrix.md
• references/bit-depth-rules.md
• references/compression-tradeoffs.md
• ../../docs/skill-system.md