Showcase Video Builder

Turn screenshots and images into polished demo videos with Ken Burns pan/zoom effects, crossfade transitions, and text overlays. Built for hackathon teams and OSS projects that need showcase content without video editing software.

Core Patterns

Image Slideshow with Crossfades

ffmpeg -loop 1 -t 4 -i slide1.png \
       -loop 1 -t 4 -i slide2.png \
       -loop 1 -t 4 -i slide3.png \
       -filter_complex \
       "[0:v]scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2,setsar=1,fade=t=out:st=3:d=1[v0]; \
        [1:v]scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2,setsar=1,fade=t=in:st=0:d=1,fade=t=out:st=3:d=1[v1]; \
        [2:v]scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2,setsar=1,fade=t=in:st=0:d=1[v2]; \
        [v0][v1][v2]concat=n=3:v=1:a=0[out]" \
       -map "[out]" -c:v libx264 -pix_fmt yuv420p output.mp4

Ken Burns (Slow Zoom)

# Slow zoom in over 5 seconds
ffmpeg -loop 1 -t 5 -i image.png -filter_complex \
  "scale=8000:-1,zoompan=z='min(zoom+0.0015,1.5)':x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)':d=150:s=1920x1080:fps=30" \
  -c:v libx264 -pix_fmt yuv420p -t 5 zoomed.mp4

Text Overlay

# macOS: use /System/Library/Fonts/Helvetica.ttc
ffmpeg -i input.mp4 -vf \
  "drawtext=text='Built in 48 Hours':fontfile=/System/Library/Fonts/Helvetica.ttc:fontsize=48:fontcolor=white:x=(w-text_w)/2:y=h-80:enable='between(t,2,5)'" \
  -c:v libx264 -c:a copy output.mp4

Title Card (Solid Colour + Text)

ffmpeg -f lavfi -i "color=c=0x6366F1:s=1920x1080:d=3" -vf \
  "drawtext=text='Your Project Name':fontfile=/System/Library/Fonts/Helvetica.ttc:fontsize=72:fontcolor=white:x=(w-text_w)/2:y=(h-text_h)/2" \
  -c:v libx264 -pix_fmt yuv420p title.mp4

Concatenate Segments

# Create concat list
echo "file 'title.mp4'" > concat.txt
echo "file 'slides.mp4'" >> concat.txt
echo "file 'closing.mp4'" >> concat.txt

ffmpeg -f concat -safe 0 -i concat.txt -c copy final.mp4

Platform Tips

• LinkedIn: Autoplays muted — don't rely on audio. Use text overlays for key messages.
• Twitter/X: 2:20 max (free tier). 280 char caption limit. Media upload needs OAuth 1.0a.
• Resize for embedding: Avatars 150px, screenshots 600px, composites 700px. Keeps file under 5MB.

Lessons

• macOS font path: /System/Library/Fonts/Helvetica.ttc — if drawtext fails, check this first
• Always use -pix_fmt yuv420p — without it, some players show a green screen
• Ken Burns on large images is slow — pre-scale to 2x target resolution, not 8x
• ffmpeg 8.1 on macOS (Homebrew, arm64) does NOT have drawtext — no libfreetype built in. Use PIL/Pillow to generate title card PNGs instead: from PIL import Image, ImageDraw, ImageFont
• -shortest cuts video at audio end — when VO is shorter than video, always pad audio: -af "apad=whole_dur=90" or generate silence to fill
• Timed VO with adelay — generate each narration line separately, then mix with adelay=<ms>|<ms> and amix=inputs=N:duration=longest:normalize=0, then add apad to hit target duration
• Ken Burns frame count — zoompan needs explicit d=<frames> where frames = duration * fps. Calculate with python3 -c "print(int(dur * 30))"

Files

• scripts/build_showcase.sh — Complete showcase builder script with configurable sections