render-qa-and-surgical-changes

name	render-qa-and-surgical-changes
description	Verify final video renders and make tiny safe edits without breaking approved sync, including proof frames, contact sheets, media probing, stale theme scans, exact timestamp checks, carryover-frame refreshes, and re-render-only-affected-scenes workflows. Use when a user asks for final QA, HD/render verification, a small text/audio/color change, or regression checks after approved timing.

Render QA And Surgical Changes

Use this skill when the video is nearly done or already approved and changes must be controlled.

Surgical Edit Rules

• Patch source artifacts, not the final MP4, when source scenes and assembly scripts exist.
• Re-render only affected scene(s).
• Rebuild the final assembly from the current approved timeline.
• Do not redesign, retime, or re-sync unrelated sections.
• Search for duplicated/carryover frames before declaring done.
• Extract proof frames at exact timestamps requested by the user.

Use templates/change-request.md before implementing a final tiny change.

QA Sequence

1. Probe the final render.

   • Duration.
   • Resolution.
   • Frame rate.
   • Audio stream.
   • Sample rate and channels.

2. Extract proof frames.

   • Scene boundaries.
   • Changed timestamps.
   • Caption style frames.
   • Final CTA or ending frame.

3. Build a contact sheet.

   • Include all risky timestamps.
   • Include before/after frames for surgical changes.

4. Check audio.

   • Narration present.
   • Music bed audible where intended.
   • Final silence or fade timing correct.
   • No clipped words after trims.

5. Check theme and text.

   • Search for stale colors.
   • Search duplicated labels in carryover scenes.
   • Verify logos and product footage were not recolored accidentally.

Read references/failure-modes.md for common regressions.

Scripts

Use repo scripts when available:

• scripts/probe_media.py
• scripts/extract_proof_frames.py
• scripts/make_contact_sheet.py
• scripts/build_ass_captions.py
• scripts/scan_theme_colors.py
• scripts/timeline_manifest_to_ffmpeg.py

Acceptance

Report:

• Final video path.
• Probe summary.
• Proof frame/contact sheet paths.
• Files changed.
• Exact checks performed.
• Any unverified subjective item.

Exact Timestamp Checks

When the user names a timestamp:

• Extract a frame at that exact time.
• Extract one frame slightly before if appearance timing matters.
• Extract one frame slightly after if disappearance timing matters.
• Inspect the rendered final, not only the source scene.
• If the same visual appears in the next scene, extract the boundary frame too.

Source Search Checklist

Before patching:

• Search all source scene files for the text or color.
• Search assembly scripts for audio paths and durations.
• Search caption scripts for old wording.
• Search templates/examples only if public repo docs need updating.
• Ignore generated renders unless doing visual QA.

Safe Audio Replacement

For replacing one narration clip:

• Probe old clip duration.
• Probe new clip duration.
• If same duration, replace path and rebuild.
• If slightly different, decide whether to tempo-fit or retime visuals.
• Confirm no downstream scene start moves unless requested.
• Regenerate captions if spoken wording changed.

Safe Text Replacement

For replacing visible text:

• Patch source scene.
• Search next scene for carryover copy.
• Search old captions if spoken wording changed.
• Re-render affected scene.
• Rebuild final.
• Extract proof frames at visible times.

Safe Theme Replacement

For color cleanup:

• Use a theme scanner.
• Patch editable source only.
• Do not recolor logos.
• Do not recolor product-demo recordings.
• Check SVG values.
• Check next-scene carryovers.

QA Output Bundle

Produce:

• probe.txt or console summary.
• proof-*.png.
• contact-sheet.jpg.
• preview-*.mp4 for moving sync checks.
• final render path.

Generated QA files do not need to be committed unless they are public examples.

Stop Conditions

Stop and ask if:

• The requested change conflicts with locked scene approval.
• The source asset for the visible final frame cannot be found.
• A text/audio change implies a script change the user has not approved.
• A logo recolor is requested but brand ownership is unclear.

Otherwise make the smallest safe change and verify it.