ffmpeg helpers: stage AI clips, all-keyframe encode, 9:16 mobile reframe
yojahny55/cinematic-scroll-kit@270f69d7f90d · 3 code file(s)

Licence notice — required by the licence; keep it with this code:

MIT License

Copyright (c) 2026 Cinematic Scroll Kit contributors

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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furnished to do so, subject to the following conditions:

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SOFTWARE.

---

Runtime dependencies (loaded via CDN, not bundled):

- Lenis (https://github.com/studio-freight/lenis) — MIT License
- GSAP + ScrollTrigger (https://greensock.com/gsap/) — free for personal and
  non-commercial use under the GreenSock standard "no charge" license. Commercial
  use requires a Club GreenSock license (https://greensock.com/club).

If you ship a commercial product using this kit, ensure you have the
appropriate GreenSock license or replace ScrollTrigger with a self-rolled
IntersectionObserver implementation.

--- encode-keyframe.sh ---
#!/usr/bin/env bash
# Encode all MP4s in SRC to DEST with all-keyframe H.264.
# Result: video.currentTime = X seeks frame-perfectly. Required for scroll-scrub.
#
# Usage: ./encode-keyframe.sh <src-dir> <dest-dir>
# Example: ./encode-keyframe.sh videos/_orig videos

set -euo pipefail

SRC="${1:-}"
DEST="${2:-}"
if [[ -z "$SRC" || -z "$DEST" ]]; then
  echo "Usage: $0 <src-dir> <dest-dir>"
  exit 1
fi

mkdir -p "$DEST"

shopt -s nullglob
for f in "$SRC"/*.mp4; do
  name="$(basename "$f")"
  echo "→ $name"
  ffmpeg -y -i "$f" \
    -an \
    -c:v libx264 -preset slow -crf 20 \
    -g 1 -keyint_min 1 -sc_threshold 0 \
    -x264-params "rc-lookahead=0:ref=1:bframes=0" \
    -pix_fmt yuv420p \
    -movflags +faststart \
    "$DEST/$name" \
    -loglevel error -stats
  size=$(stat -c%s "$DEST/$name" 2>/dev/null || stat -f%z "$DEST/$name")
  printf "  ✓ %s (%.1fM)\n" "$name" "$(echo "$size/1048576" | bc -l)"
done

echo "Done. $(ls "$DEST"/*.mp4 | wc -l) files in $DEST."

--- encode-mobile-portrait.sh ---
#!/usr/bin/env bash
# Re-encode 16:9 MP4s to 9:16 portrait (720x1280, center-cropped) for mobile autoplay-loop.
#
# Usage: ./encode-mobile-portrait.sh <src-dir> <dest-dir>
# Example: ./encode-mobile-portrait.sh videos/_orig videos/mobile

set -euo pipefail

SRC="${1:-}"
DEST="${2:-}"
if [[ -z "$SRC" || -z "$DEST" ]]; then
  echo "Usage: $0 <src-dir> <dest-dir>"
  exit 1
fi

mkdir -p "$DEST"

shopt -s nullglob
for f in "$SRC"/*.mp4; do
  name="$(basename "$f")"
  echo "→ $name (→ 720x1280 portrait)"
  ffmpeg -y -i "$f" \
    -an \
    -vf "scale=-2:1280:flags=lanczos,crop=720:1280:(iw-720)/2:0" \
    -c:v libx264 -preset slow -crf 24 \
    -g 24 -keyint_min 24 \
    -pix_fmt yuv420p \
    -movflags +faststart \
    "$DEST/$name" \
    -loglevel error -stats
  size=$(stat -c%s "$DEST/$name" 2>/dev/null || stat -f%z "$DEST/$name")
  printf "  ✓ %s (%.1fM)\n" "$name" "$(echo "$size/1048576" | bc -l)"
done

echo "Done. $(ls "$DEST"/*.mp4 | wc -l) files in $DEST."

--- stage-sources.sh ---
#!/usr/bin/env bash
# Take AI-generated clips with arbitrary names (from Kling, Runway, Sora etc.)
# and rename them into sequential 01.mp4 ... 0N.mp4 in DEST.
#
# Usage: ./stage-sources.sh <src-dir> <dest-dir>
# - <src-dir>: folder containing your generated clips (sorted by filename = scene order)
# - <dest-dir>: where the renamed sequential files go

set -euo pipefail

SRC="${1:-}"
DEST="${2:-}"
if [[ -z "$SRC" || -z "$DEST" ]]; then
  echo "Usage: $0 <src-dir> <dest-dir>"
  echo "Tip: source files should be alphabetically sortable in scene order."
  exit 1
fi

mkdir -p "$DEST"

i=1
shopt -s nullglob
for f in $(ls "$SRC"/*.mp4 | sort); do
  num=$(printf "%02d" "$i")
  cp -n "$f" "$DEST/$num.mp4"
  echo "  $f → $DEST/$num.mp4"
  i=$((i+1))
done

echo "Staged $((i-1)) clips to $DEST."