#!/usr/bin/env bash
set -euo pipefail

# Reference "DVD-safe" NTSC MPEG-2 encoder.
#
# This is the known-good baseline that the DeVeDe-NG hardsub fork's
# "Compatibility (4500k)" encode profile is modelled on. It is kept here as a
# standalone tool and as a regression reference: the fork's generated ffmpeg
# command for the Compatibility profile (without subtitle burn-in) should
# produce equivalent output (mpeg2video / 720x480 / 29.97fps / AC3 192k 48kHz).
#
# It does NOT detect or burn subtitles and does NOT split long movies; those
# features live in the GUI fork (see FORK_NOTES.md).

if [ $# -lt 1 ]; then
  echo "Usage: $0 input_video"
  exit 1
fi

INPUT="$1"
BASENAME="$(basename "$INPUT")"
NAME="${BASENAME%.*}"
OUTPUT="${NAME}-dvdsafe.mpg"

echo "Input:  $INPUT"
echo "Output: $OUTPUT"
echo "Encoding DVD-safe MPEG-2 (CBR 4500k)..."

ffmpeg -y -i "$INPUT" \
-vf "scale=720:480:flags=lanczos,\
fps=30000/1001,\
format=yuv420p,\
setsar=1" \
-r 30000/1001 \
-c:v mpeg2video \
-b:v 4500k \
-minrate 4500k \
-maxrate 4500k \
-bufsize 1835k \
-g 15 \
-sc_threshold 0 \
-pix_fmt yuv420p \
-c:a ac3 \
-b:a 192k \
-ar 48000 \
-ac 2 \
"$OUTPUT"

echo "Done: $OUTPUT"