Feature Walkthrough Video Generation

Generate polished demo videos from Playwright test suites. Perfect for showcasing features, onboarding flows, or creating documentation videos.

Prerequisites

Required tools (verify before starting):

• Playwright - Already configured in the project
• ffmpeg - Video processing
• ImageMagick - Title card generation

# Verify prerequisites
which ffmpeg && which convert

Working Directory

All intermediate files are stored in /tmp/walkthrough/{session-id}/ to:

• Preserve context between Claude sessions
• Avoid accidentally checking artifacts into source control
• Allow inspection of intermediate files for debugging

/tmp/walkthrough/{session-id}/
  config.json           # Session configuration
  playwright-video.config.ts  # Generated Playwright config
  recordings/           # Raw Playwright video output
  build/               # Intermediate processing files
    *.png              # Title card images
    *.mp4              # Title card videos + slowed clips
    concat_list.txt    # ffmpeg concat manifest
  {output-name}.mp4    # Final video (copied to user's output dir)

Workflow Phases

Phase 1: Discovery & Configuration

1. Identify test suite

   • Ask user which tests to include (spec file, glob pattern, or specific tests)
   • Run npx playwright test --list to enumerate available tests
   • Confirm test selection with user

2. Gather configuration

   • Output directory (required - where final video goes)
   • Output filename (default: derived from feature name)
   • Slowdown factor (default: 10x - tests run fast, demos need to be watchable)
   • Title card duration (default: 3 seconds)
   • Main title and subtitle for intro card
   • Per-test titles/subtitles (or auto-generate from test names)

3. Create session

   • Generate session-id slug from feature description
   • Create /tmp/walkthrough/{session-id}/ directory structure
   • Write config.json with all settings

Phase 2: Test Execution with Video Recording

1. Generate Playwright config

   Create a temporary config that enables video recording:

   import { defineConfig, devices } from '@playwright/test'
   
   export default defineConfig({
     // Inherit from project's existing config where possible
     fullyParallel: false,  // Sequential for predictable ordering
     retries: 0,            // No retries - we want clean recordings
     workers: 1,            // Single worker for consistent capture
     reporter: [['list']],
     use: {
       video: 'on',         // Always record (not just on failure)
       trace: 'off',        // Reduce overhead
     },
     projects: [
       {
         name: 'chromium',
         use: { ...devices['Desktop Chrome'] },
       },
     ],
     outputDir: '/tmp/walkthrough/{session-id}/recordings/',
     timeout: 120 * 1000,   // Generous timeout for recording
   })
   

2. Run selected tests

   npx playwright test {test-pattern} --config=/tmp/walkthrough/{session-id}/playwright-video.config.ts
   

3. Verify recordings exist

   • Check each test directory for video.webm
   • Report any missing recordings
   • Map test names to video files for ordering

Phase 3: Video Processing

1. Detect video dimensions

   ffprobe -v error -select_streams v:0 -show_entries stream=width,height \
     -of csv=p=0 {first-video}.webm
   

   Store dimensions for title card generation.

2. Convert WebM to MP4

   for webm in recordings/**/video.webm; do
     mp4="${webm%.webm}.mp4"
     ffmpeg -i "$webm" -c:v libx264 -c:a aac -y "$mp4" 2>/dev/null
   done
   

3. Create title cards with ImageMagick

   Main intro title (larger text):

   convert -size {WIDTH}x{HEIGHT} xc:'#1e293b' \
     -font DejaVu-Sans-Bold -pointsize 48 -fill white -gravity center \
     -annotate +0-20 "{MAIN_TITLE}" \
     -font DejaVu-Sans -pointsize 20 -fill '#94a3b8' \
     -annotate +0+40 "{SUBTITLE}" \
     build/title_main.png
   

   Section titles:

   convert -size {WIDTH}x{HEIGHT} xc:'#1e293b' \
     -font DejaVu-Sans-Bold -pointsize 36 -fill white -gravity center \
     -annotate +0-30 "{SECTION_TITLE}" \
     -font DejaVu-Sans -pointsize 20 -fill '#94a3b8' \
     -annotate +0+30 "{SECTION_SUBTITLE}" \
     build/title_{NN}.png
   

4. Convert title cards to video clips

   ffmpeg -loop 1 -i build/title_{NN}.png \
     -c:v libx264 -t {TITLE_DURATION} -pix_fmt yuv420p -r 30 \
     build/title_{NN}.mp4 -y 2>/dev/null
   

5. Slow down test recordings

   ffmpeg -i recordings/{test}/video.mp4 \
     -filter:v "setpts={SLOWDOWN_FACTOR}*PTS" -r 30 \
     build/slow_{NN}.mp4 -y 2>/dev/null
   

Phase 4: Concatenation

1. Create concat manifest

   file 'title_main.mp4'
   file 'title_01.mp4'
   file 'slow_01.mp4'
   file 'title_02.mp4'
   file 'slow_02.mp4'
   ...
   

2. Concatenate with ffmpeg

   cd build && ffmpeg -f concat -safe 0 -i concat_list.txt \
     -c:v libx264 -preset medium -crf 23 \
     "../{OUTPUT_NAME}.mp4" -y
   

3. Copy to output directory

   cp /tmp/walkthrough/{session-id}/{OUTPUT_NAME}.mp4 {USER_OUTPUT_DIR}/
   

Phase 5: Report & Cleanup

1. Report results

   Feature Walkthrough Complete
   
   Output: {USER_OUTPUT_DIR}/{OUTPUT_NAME}.mp4
   Duration: {DURATION} seconds
   Tests included: {COUNT}
   
   Working files preserved at: /tmp/walkthrough/{session-id}/
   (Safe to delete when satisfied with output)
   

2. Preserve working directory

   • Keep /tmp/walkthrough/{session-id}/ for debugging
   • User can manually delete when satisfied

Configuration Options

Test Selection Strategies

By spec file:

/feature-walkthrough tests/integration/onboarding.spec.ts

By grep pattern:

/feature-walkthrough --grep "checkout"

By specific test names:

/feature-walkthrough "login flow" "signup flow" "password reset"

Title Generation

Auto-generate from test names:

• Test: should complete checkout flow → Title: "Complete Checkout Flow"
• Test: displays validation errors on empty form → Title: "Form Validation Errors"

Manual override: User can provide custom titles per test for clearer demos.

Error Handling

Test Failures

• If a test fails, still process its video (shows what happened)
• Report which tests failed in final summary
• User decides whether to include failed test videos

Missing Videos

• Skip tests that didn't produce video files
• Report missing recordings
• Continue with available videos

Font Issues

• Fall back to default fonts if specified fonts unavailable
• Warn user about font substitution

Quality Checks

Before marking complete:

• All selected tests ran
• All video files converted successfully
• Title cards match video dimensions
• Final video plays without errors
• Output copied to user's specified directory
• Duration reported accurately

Example Session

User: /feature-walkthrough for the new onboarding feature, output to ~/Videos

Claude:
1. Found tests/integration/onboarding.spec.ts with 5 tests
2. Tests to record:
   - should show phone entry form
   - should validate phone number
   - should send OTP
   - should verify identity
   - should show approval screen

   Proceed with these tests?

User: yes, use "Onboarding Flow Demo" as the main title

Claude:
[Runs tests with video recording]
[Processes videos]

Feature Walkthrough Complete

Output: ~/Videos/onboarding-flow-demo.mp4
Duration: 4 minutes 32 seconds
Tests included: 5

Working files preserved at: /tmp/walkthrough/onboarding-flow-demo/

Useful ffmpeg Commands

# Get video info
ffprobe -v error -show_format -show_streams video.mp4

# Get duration
ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 video.mp4

# Get dimensions
ffprobe -v error -select_streams v:0 -show_entries stream=width,height -of csv=p=0 video.mp4

# Extract single frame
ffmpeg -i video.mp4 -ss 00:00:05 -frames:v 1 frame.png

# Add fade in/out
ffmpeg -i input.mp4 -vf "fade=t=in:st=0:d=1,fade=t=out:st=4:d=1" output.mp4