correct-clip

#!/bin/sh

#===============================================================================
# correct-clip
# correct a video clip by using a gimp curve
#===============================================================================

# code based on:
# https://video.stackexchange.com/questions/16352/converting-gimp-curves-files-to-photoshop-acv-for-ffmpeg/20005#20005

# converted into a ffmpeg curves filter command
# to adjust the levels and white balance

# requires a curve file created with the following script
# https://github.com/NapoleonWils0n/curve2ffmpeg

# dependencies:
# ffmpeg file grep

#===============================================================================
# script usage
#===============================================================================

usage()
{
# if argument passed to function echo it
[ -z "${1}" ] || echo "! ${1}"
echo "\
# correct a video clip by using a gimp curve

# requires a curve file created with the following script
# https://github.com/NapoleonWils0n/curve2ffmpeg

$(basename "$0") -i input.(mp4|mkv|mov|m4v) -c curve.txt -o output.mp4
-i input.(mp4|mkv|mov|m4v)
-c curve.txt
-o output.mp4 : optional argument # if option not provided defaults to input-name-corrected-date-time"
exit 2
}


#===============================================================================
# error messages
#===============================================================================

INVALID_OPT_ERR='Invalid option:'
REQ_ARG_ERR='requires an argument'
WRONG_ARGS_ERR='wrong number of arguments passed to script'
NOT_MEDIA_FILE_ERR='is not a media file'
NOT_TEXT_FILE_ERR='is not a text file'


#===============================================================================
# check the number of arguments passed to the script
#===============================================================================

[ $# -gt 0 ] || usage "${WRONG_ARGS_ERR}"


#===============================================================================
# getopts check the options passed to the script
#===============================================================================

while getopts ':i:c:o:h' opt
do
  case ${opt} in
     i) infile="${OPTARG}";;
     c) text="${OPTARG}";;
     o) outfile="${OPTARG}";;
     h) usage;;
     \?) echo "${INVALID_OPT_ERR} ${OPTARG}" 1>&2 && usage;;
     :) echo "${INVALID_OPT_ERR} ${OPTARG} ${REQ_ARG_ERR}" 1>&2 && usage;;
  esac
done
shift $((OPTIND-1))


#===============================================================================
# variables
#===============================================================================

# input, input name
infile_nopath="${infile##*/}"
infile_name="${infile_nopath%.*}"

# defaults for variables
outfile_default="${infile_name}-corrected-$(date +"%Y-%m-%d-%H-%M-%S").mp4"
# check if the libfdk_aac codec is installed, if not fall back to the aac codec
aac_codec="$(ffmpeg -hide_banner -stats -v panic -h encoder=libfdk_aac)"
aac_error="Codec 'libfdk_aac' is not recognized by FFmpeg."
aac_check="$(echo "${aac_codec}" | grep "${aac_error}")"

# check ffmpeg aac codecs
if [ -z "${aac_check}" ]; then
   aac='libfdk_aac' # libfdk_aac codec is installed
else
   aac='aac' # libfdk_aac codec isnt installed, fall back to aac codec
fi


#===============================================================================
# functions
#===============================================================================

correct_v () {
    ffmpeg \
    -hide_banner \
    -stats -v panic \
    -i "${infile}" \
    -filter_complex \
    "[0:v]${text_contents}[video]" \
    -map "[video]" \
    -c:v libx264 -preset fast \
    -profile:v high \
    -crf 18 -coder 1 \
    -pix_fmt yuv420p \
    -movflags +faststart \
    -f mp4 \
    "${outfile:=${outfile_default}}"
}

# correct video and audio tracks
correct_va () {
    ffmpeg \
    -hide_banner \
    -stats -v panic \
    -i "${infile}" \
    -filter_complex \
    "[0:v]${text_contents}[video]" \
    -map "[video]" -map 0:a \
    -c:a "${aac}" \
    -c:v libx264 -preset fast \
    -profile:v high \
    -crf 18 -coder 1 \
    -pix_fmt yuv420p \
    -movflags +faststart \
    -f mp4 \
    "${outfile:=${outfile_default}}"
}

# file command check input file mime type
filetype="$(file --mime-type -b "${infile}")"
textfile="$(file --mime-type -b "${text}")"

# video mimetypes
mov_mime='video/quicktime'
mkv_mime='video/x-matroska'
mp4_mime='video/mp4'
m4v_mime='video/x-m4v'

# text mimetype
txt_mime='text/plain'

# check the files mime type is a video
case "${filetype}" in
    "${mov_mime}"|"${mkv_mime}"|"${mp4_mime}"|"${m4v_mime}");;
    *) usage "${infile} ${NOT_MEDIA_FILE_ERR}";;
esac

# check the text file mime type is a text
case "${textfile}" in
    "${txt_mime}");;
    *) usage "${textfile} ${NOT_TEXT_FILE_ERR}";;
esac

# read the contents of the curve text file and store in a variable
text_contents="$(while IFS= read -r line; do echo "${line}"; done < "${text}")"

# check if video has an audio track
audio_check="$(ffprobe -i "${infile}" -show_streams -select_streams a -loglevel error)"

# check if audio_check is null which means the video doesnt have an audio track
if [ -z "${audio_check}" ]; then
   correct_v "${infile}" # null value
else
   correct_va "${infile}" # non null value
fi