Render QA And Surgical Changes

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.