majiayu000 Video Assembly Skill
The Visual Wrapper for the Audio Journey
This skill handles assembling the final video from mastered audio, scene images, and VTT subtitles.
Purpose
Create YouTube-ready video files that complement the hypnotic audio experience.
Video Standards
| Parameter | Standard |
|---|---|
| Resolution | 1920x1080 (Full HD) |
| Aspect Ratio | 16:9 |
| Codec | H.264 |
| Frame Rate | 24 fps (cinematic) |
| Audio Codec | AAC 320kbps |
| Container | MP4 |
Input Requirements
| Input | File | Required |
|---|---|---|
| Master Audio | {session}_MASTER.mp3 |
Yes |
| Scene Images | images/uploaded/*.png |
Yes |
| Subtitles | output/subtitles.vtt |
Yes |
Scene Image Generation
Primary Method: Stable Diffusion (Default)
python3 scripts/core/generate_scene_images.py sessions/{session}/
Alternative: Midjourney Prompts
python3 scripts/core/generate_scene_images.py sessions/{session}/ --midjourney-only
Alternative: Stock Images
python3 scripts/core/generate_scene_images.py sessions/{session}/ --method stock
Image Specifications
| Property | Requirement |
|---|---|
| Resolution | 1920x1080 minimum |
| Format | PNG or JPEG |
| Aspect Ratio | 16:9 |
| Naming | scene_01.png, scene_02.png, etc. |
VTT Subtitle Generation
python3 scripts/ai/vtt_generator.py sessions/{session}
VTT Format
WEBVTT
Kind: captions
Language: en
1
00:00:00.000 --> 00:00:05.500
Welcome to this healing journey.
2
00:00:06.000 --> 00:00:12.000
Find a comfortable position and
allow your eyes to close.
Subtitle Guidelines
| Guideline | Value |
|---|---|
| Max lines per caption | 2 |
| Max characters per line | ~80 |
| Min duration | 1.5 seconds |
| Max duration | 7 seconds |
Video Assembly Command
python3 scripts/core/assemble_session_video.py sessions/{session}/
This automatically:
- Sequences images based on script sections
- Adds cross-fade transitions
- Syncs subtitles to audio
- Outputs to
output/video/session_final.mp4
Manual FFmpeg Assembly
For custom control:
# Create video from images with audio
ffmpeg -y \
-framerate 1/10 \
-pattern_type glob -i 'images/uploaded/*.png' \
-i output/{session}_MASTER.mp3 \
-c:v libx264 -r 24 -pix_fmt yuv420p \
-c:a aac -b:a 320k \
-shortest \
output/video/session_final.mp4
Image-to-Section Mapping
Images should correspond to script sections:
| Image | Section | Timing |
|---|---|---|
scene_01.png |
Pre-Talk | 0:00-3:00 |
scene_02.png |
Induction | 3:00-8:00 |
scene_03.png |
Deepening | 8:00-12:00 |
scene_04.png |
Journey Start | 12:00-17:00 |
scene_05.png |
Journey Core | 17:00-22:00 |
scene_06.png |
Helm/Deepest | 22:00-25:00 |
scene_07.png |
Integration | 25:00-28:00 |
scene_08.png |
Emergence | 28:00-30:00 |
Transition Effects
| Transition | Duration | Use For |
|---|---|---|
| Cross-dissolve | 2-3 seconds | Section transitions |
| Fade from black | 3 seconds | Opening |
| Fade to black | 3 seconds | Closing |
Output Files
| File | Location | Purpose |
|---|---|---|
| Final video | output/video/session_final.mp4 |
Direct use |
| YouTube copy | output/youtube_package/final_video.mp4 |
Upload ready |
Video Overlay Generation
Generate supporting graphics:
python3 scripts/core/generate_video_images.py sessions/{session}/ --all
Creates:
title_card.png- Video intro screensections/section_*.png- Chapter transitionsoutro.png- End screensocial_preview.png- Social sharing
Quality Verification
After assembly:
# Check video properties
ffprobe -v error -show_format -show_streams output/video/session_final.mp4
# Play with VLC to verify sync
vlc output/video/session_final.mp4
Quality Checklist
- Resolution is 1920x1080
- Frame rate is 24 fps
- Audio syncs with subtitles
- Transitions are smooth
- No visible artifacts
- Duration matches audio
- File size reasonable (<2GB for 30 min)
Troubleshooting
| Issue | Cause | Solution |
|---|---|---|
| Audio/video desync | Different durations | Use -shortest flag |
| Pixelated video | Wrong pixel format | Use -pix_fmt yuv420p |
| Green frames | Image format issue | Convert images to PNG |
| Subtitle timing off | VTT not scaled | Regenerate VTT with actual audio duration |
| File too large | Bitrate too high | Use -crf 23 for smaller file |
Integration with Pipeline
Before (dependencies):
- Audio mastered (
{session}_MASTER.mp3) - Scene images ready (
images/uploaded/) - VTT subtitles generated (
output/subtitles.vtt)
After (next steps):
- YouTube packaging
Related Resources
- Skill:
tier3-production/audio-mixing/(input) - Skill:
tier3-production/youtube-packaging/(next step) - Doc:
docs/STOCK_IMAGE_SOP.md - Script:
scripts/core/assemble_session_video.py