Shorts Generator

Shorts Generator

This skill creates polished, vertical short videos with captions from your selected clips.

When to Use This Skill

• After selecting clips from highlight-finder
• Ready to create final short videos
• Need to add captions/subtitles
• Want to format for specific platforms

What This Skill Does

1. Extract Clips: Cuts selected segments from source video
2. Format Video: Converts to vertical 9:16 aspect ratio
3. Add Captions: Burns in styled subtitles
4. Enhance Audio: Normalizes and enhances speech
5. Export: Creates platform-ready files

How to Use

Create Single Short

Create a short video from 02:34 to 03:15 of VIDEO_ID

Create with Captions

Create a short with Chinese captions from clip 1

Batch Create

Create shorts from all recommended clips

Instructions

Step 1: Extract the Clip

# Extract video segment
ffmpeg -i "./output/downloads/VIDEO_ID.mp4" \
  -ss 00:02:34 -to 00:03:15 \
  -c:v libx264 -c:a aac \
  "./temp/clip_raw.mp4"

Step 2: Convert to Vertical Format

Option A: Crop Center (for horizontal video)

ffmpeg -i "./temp/clip_raw.mp4" \
  -vf "crop=ih*9/16:ih,scale=1080:1920" \
  -c:a copy \
  "./temp/clip_vertical.mp4"

Option B: Add Blur Background (preserves full frame)

ffmpeg -i "./temp/clip_raw.mp4" \
  -vf "[0:v]scale=1080:1920:force_original_aspect_ratio=increase,crop=1080:1920,boxblur=20[bg];[0:v]scale=1080:-1[fg];[bg][fg]overlay=(W-w)/2:(H-h)/2" \
  -c:a copy \
  "./temp/clip_vertical.mp4"

Step 3: Extract Segment Subtitles

From the full SRT, extract only the relevant portion and adjust timestamps:

# Use ffmpeg to extract subtitle segment
ffmpeg -i "./output/transcripts/VIDEO_ID.srt" \
  -ss 00:02:34 -to 00:03:15 \
  "./temp/clip_subtitles.srt"

Step 4: Style and Burn Captions

ffmpeg -i "./temp/clip_vertical.mp4" \
  -vf "subtitles=./temp/clip_subtitles.srt:force_style='FontName=Arial Bold,FontSize=24,PrimaryColour=&HFFFFFF,OutlineColour=&H000000,Outline=2,Alignment=2,MarginV=50'" \
  -c:a copy \
  "./temp/clip_captioned.mp4"

Caption Style Options:

• Standard: White text, black outline, bottom center
• Trendy: Yellow highlight box, word-by-word animation
• Minimal: Small text, top or bottom
• Bold: Large text, center screen

Step 5: Enhance Audio

ffmpeg -i "./temp/clip_captioned.mp4" \
  -af "loudnorm=I=-16:TP=-1.5:LRA=11" \
  -c:v copy \
  "./output/shorts/short_001.mp4"

Step 6: Generate Thumbnail

# Extract frame at 1 second for thumbnail
ffmpeg -i "./output/shorts/short_001.mp4" \
  -ss 00:00:01 -vframes 1 \
  "./output/shorts/short_001_thumbnail.jpg"

Step 7: Report to User

## ✅ Short Video Created!

**File**: ./output/shorts/short_001.mp4
**Duration**: 41 seconds
**Format**: 1080x1920 (9:16 vertical)
**Captions**: Burned in (White + Black outline)

**Thumbnail**: ./output/shorts/short_001_thumbnail.jpg

### Preview Info
- **Resolution**: 1080x1920
- **Frame Rate**: 30 fps
- **Audio**: AAC, normalized
- **File Size**: XX MB

### Platform Compatibility
- ✅ TikTok (ready to upload)
- ✅ YouTube Shorts (ready to upload)
- ✅ Instagram Reels (ready to upload)
- ✅ 抖音 (ready to upload)

**Next steps**:
1. Review the video in ./output/shorts/
2. Create more shorts from other clips
3. Adjust caption style if needed

Output

• Short video: ./output/shorts/short_XXX.mp4
• Thumbnail: ./output/shorts/short_XXX_thumbnail.jpg

Caption Styles

Style 1: Classic (Default)

FontName=Arial Bold
FontSize=24
PrimaryColour=&HFFFFFF (White)
OutlineColour=&H000000 (Black)
Outline=2

Style 2: Modern

FontName=Montserrat Bold
FontSize=28
PrimaryColour=&H00FFFF (Yellow)
BackColour=&H80000000 (Semi-transparent black)
BorderStyle=4

Style 3: Minimal

FontName=Helvetica
FontSize=18
PrimaryColour=&HFFFFFF
Outline=1
MarginV=30

Quality Presets

• High Quality: 1080x1920, 8Mbps, best for YouTube
• Standard: 1080x1920, 4Mbps, balanced
• Fast Upload: 720x1280, 2Mbps, smaller file size