VCR Standard Operating Procedure (SOP)

This document outlines the mandatory procedures for developing and verifying VCR elements (shaders, manifests, and assets) to ensure high-fidelity, centered, and non-clipping renders.

1. Visual Verification Loop

CRITICAL: Every new VCR element MUST pass a Visual Verification check before a final render is performed or delivered.

Step 1: Snapshot Preview

Render a short clip and extract a keyframe snapshot (Frame 0).

cargo run --release -- render manifests/[id].vcr --output renders/preview.mov
ffmpeg -y -i renders/preview.mov -vf "select=eq(n\,0)" -vframes 1 renders/preview_snapshot.png

Check: Is the object centered? Is it touching any edges?

Step 2: Contact Sheet Verification

Generate a 3x3 contact sheet to inspect the animation at start, middle, and end.

./.tmp_venv/bin/python3 scripts/vcr_contact_sheet.py renders/preview.mov renders/contact_sheet.png

Check: Does the object remain in frame and stable throughout the entire 10-second duration?

2. Framing Requirements (9:16 Vertical)

• Target Aspect: 1080x1920 (9:16).
• Safe Zones: Maintain at least a 10% margin from all edges.
• Raymarching Tips:
  • Use ro.z distances of -15.0 to -25.0 for safe framing.
  • Adjust focal_length (rd calculation) to compensate for camera distance.
  • Prefer "Capsule Chain" or robust global mapping over high-frequency analytic SDFs.

3. Tooling Reference

• vcr_contact_sheet.py: Python helper for mosaic generation.
• ffprobe: Use signalstats to verify alpha channel transparency.