scripts/redact.sh

#!/usr/bin/env bash
#
# VSTAT — Apply privacy redactions (black boxes) to YouTube clips.
#
# Coordinates are in 640x360 (post-scale) space, matching the official
# VSTAT release. After this script runs, every redaction-target chunk
# lives at the canonical `videos/youtube/<cat>/<id>_pt*.mp4` path with
# the black boxes baked in. Any leftover `*_redacted.mp4` siblings from
# earlier runs are removed.
#
# Usage (run from vstat/ root):
#   ./scripts/redact.sh
#   ./scripts/redact.sh --dry-run
#

set -eo pipefail

DRY=0
for arg in "$@"; do
  case "$arg" in
    --dry-run) DRY=1 ;;
    -h|--help) sed -n '2,15p' "$0"; exit 0 ;;
    *) echo "Unknown arg: $arg" >&2; exit 1 ;;
  esac
done

# Format:  "<canonical-glob>|<ffmpeg drawbox filter>"
RULES=(
  # tennis 0001
  "videos/youtube/tennis/0001_pt*.mp4|drawbox=x=32:y=306:w=134:h=38:color=black:t=fill"
  # tennis 0002
  "videos/youtube/tennis/0002_pt*.mp4|drawbox=x=32:y=306:w=134:h=38:color=black:t=fill"
  # basketball 0002
  "videos/youtube/basketball/0002_pt*.mp4|drawbox=x=98:y=323:w=443:h=37:color=black:t=fill"
  # basketball 0003
  "videos/youtube/basketball/0003_pt*.mp4|drawbox=x=22:y=285:w=125:h=63:color=black:t=fill"
  # soccer 0002 (two boxes)
  "videos/youtube/soccer/0002_pt*.mp4|drawbox=x=0:y=0:w=122:h=19:color=black:t=fill,drawbox=x=140:y=320:w=360:h=40:color=black:t=fill"
)

if ! command -v ffmpeg >/dev/null 2>&1; then
  echo "ERROR: ffmpeg not installed. brew install ffmpeg / apt install ffmpeg" >&2
  exit 1
fi

# Expand a canonical glob to the union of canonical paths it covers,
# accounting for files that currently live with `_redacted` suffix.
# Compatible with bash 3.2 (macOS default) — no associative arrays.
canonical_paths_for_glob() {
  glob="$1"
  dir=$(dirname "$glob")
  pat=$(basename "$glob")                          # 0001_pt*.mp4
  shopt -s nullglob
  results=""
  for f in "$dir"/$pat "$dir"/${pat%.mp4}_redacted.mp4; do
    [ -e "$f" ] || continue
    case "$f" in
      *_redacted.mp4) base="${f%_redacted.mp4}.mp4" ;;
      *)              base="$f" ;;
    esac
    results="${results}${base}"$'\n'
  done
  shopt -u nullglob
  printf '%s' "$results" | sort -u | sed '/^$/d'
}

total=0; ok=0; fail=0; missing=0

for rule in "${RULES[@]}"; do
  glob="${rule%%|*}"
  filt="${rule#*|}"
  echo
  echo "=== $glob ==="
  echo "    filter: $filt"

  paths=$(canonical_paths_for_glob "$glob")
  if [ -z "$paths" ]; then
    echo "    (no matching files)"
    continue
  fi

  while IFS= read -r canon; do
    [ -z "$canon" ] && continue
    total=$((total+1))
    redacted_sibling="${canon%.mp4}_redacted.mp4"

    # Pick input: prefer existing _redacted sibling, fall back to canonical.
    if [ -f "$redacted_sibling" ]; then
      input="$redacted_sibling"
    elif [ -f "$canon" ]; then
      input="$canon"
    else
      echo "  ! missing both $canon and $redacted_sibling"
      missing=$((missing+1))
      continue
    fi

    if [ "$DRY" -eq 1 ]; then
      echo "  [DRY] $input  =[$filt]=>  $canon"
      ok=$((ok+1))
      continue
    fi

    # Write to a temp file then atomically swap.
    # `-nostdin` is REQUIRED here: without it ffmpeg consumes characters
    # from the surrounding `while read` loop's stdin, mangling later paths.
    tmp="${canon%.mp4}.redact.tmp.mp4"
    if ! ffmpeg -y -loglevel error -nostdin -i "$input" -vf "$filt" -c:a copy "$tmp"; then
      echo "  ! ffmpeg failed: $input"
      fail=$((fail+1))
      continue
    fi
    if cp -f "$tmp" "$canon" && rm -f "$tmp"; then
      :
    else
      echo "  ! could not write $canon (kept tmp at $tmp)"
      fail=$((fail+1))
      continue
    fi
    # Drop misleading `_redacted.mp4` sibling now that the canonical file
    # holds the actually-redacted content.
    if [ -f "$redacted_sibling" ] && [ "$redacted_sibling" != "$canon" ]; then
      rm -f "$redacted_sibling" 2>/dev/null || true
    fi
    ok=$((ok+1))
    echo "  -> $canon"
  done <<< "$paths"
done

echo
echo "============================================================"
echo "  total: $total   ok: $ok   fail: $fail   missing: $missing"
echo "============================================================"
[ "$fail" -eq 0 ] && [ "$missing" -eq 0 ]