#!/bin/bash
# FFmpeg video speed wrapper
# Args: input output speed_factor
INPUT="$1"
OUTPUT="$2"
SPEED="${3:-1.0}"

# Calculate pts factor as 1/speed
PTS=$(echo "scale=6; 1 / $SPEED" | bc 2>/dev/null || python3 -c "print(1/$SPEED)" 2>/dev/null || awk "BEGIN {print 1/$SPEED}")

ffmpeg -y -i "$INPUT" \
  -filter_complex "[0:v]setpts=${PTS}*PTS[v];[0:a]atempo=${SPEED}[a]" \
  -map "[v]" -map "[a]" \
  "$OUTPUT"
