javicle/bin/jspeed

#!/bin/bash
#
# Adjust the speed of a video, optionally adjusting the audio as well.
#
# Usage:
#
#    jspeed [-n|--no-exec] in-file out-file speed-factor [audio-speed]
#
# -n or --no-exec : if set, do not execute ffmpeg but print what would have run
# in-file         : input video file
# out-file        : write output file here
# speed-factor    : factor=1 is unchanged, factor>1 is faster, factor<1 is slower
# audio-speed     : can be: silent (default), unchanged, or match
#
# Note: if audio-speed is match, then speed-factor must be between 0.5 and 100
#
SCRIPT="${0}"
SCRIPT_DIR="$(cd "$(dirname "${SCRIPT}")" && pwd)"
. "${SCRIPT_DIR}"/jvc_common

IN_FILE="${1?no video-file provided}"
OUT_FILE="${2?no out-file provided}"
SPEED_FACTOR="${3?no speed-factor provided}"
AUDIO_SPEED="${4}"

echo "
{
  \"assets\": [
    { \"name\": \"input\", \"path\": \"${IN_FILE}\" }
  ],
  \"operations\": [
    {
      \"operation\": \"adjust-speed\",
      \"creates\": {
        \"name\": \"speed_adjusted\",
        \"dest\": \"${OUT_FILE}\"
      },
      \"source\": \"input\",
      \"factor\": \"${SPEED_FACTOR}\"$(if [[ -n "${AUDIO_SPEED}" ]] ; then echo ",
      \"audio\": \"${AUDIO_SPEED}\"" ; fi)
    }
  ]
}
" | "${SCRIPT_DIR}"/jvc ${JVC_OPTIONS}