fade-title

#!/bin/sh

#===============================================================================
# fade-title
# fade video, audio add title from video filename
#===============================================================================

# dependencies:
# ffmpeg file awk grep bc cut tail

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

usage ()
{
# if argument passed to function echo it
[ -z "${1}" ] || echo "! ${1}"
# display help
echo "\
# fade video, audio add title from video filename

$(basename "$0") -i input.(mp4|mkv|mov|m4v) -d (0.[0-9]|1) -s 000 -e 000 -o output.mp4

-i input.(mp4|mkv|mov|m4v)
-d (0.[0-9]|1) : from 0.1 to 0.9 or 1 :optional argument # if option not provided defaults to 0.5
-s 000         : from 000 to 999
-e 000         : from 000 to 999
-o output.mp4  : optional argument # if option not provided defaults to input-name-title-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'
TITLE_FADE_ERR='title end must be after title start'


#===============================================================================
# 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:d:s:e:o:h' opt
do
  case ${opt} in
     i) infile="${OPTARG}";;
     d) dur="${OPTARG}";;
     s) title_start="${OPTARG}";;
     e) title_end="${OPTARG}";;
     o) outfile="${OPTARG}";;
     h) usage;;
     \?) usage "${INVALID_OPT_ERR} ${OPTARG}" 1>&2;;
     :) usage "${INVALID_OPT_ERR} ${OPTARG} ${REQ_ARG_ERR}" 1>&2;;
  esac
done
shift $((OPTIND-1))


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

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

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

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

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

# defaults for variables if not defined
outfile_default="${infile_name}-title-$(date +"%Y-%m-%d-%H-%M-%S").mp4"
duration_default="0.5"

# print analyzing file
echo '+ Analyzing file with ffmpeg'

# ffmpeg loudnorm get stats from file
normalize=$(ffmpeg \
-hide_banner \
-i "${infile}" \
-af "loudnorm=I=-16:dual_mono=true:TP=-1.5:LRA=11:print_format=summary" \
-f null - 2>&1 | tail -n 12)

# read the output of normalize line by line and store in variables
for line in "${normalize}"; do
    measured_I=$(echo "${line}" | awk -F' ' '/Input Integrated:/ {print $3}')
    measured_TP=$(echo "${line}" | awk -F' ' '/Input True Peak:/ {print $4}')
    measured_LRA=$(echo "${line}" | awk -F' ' '/Input LRA:/ {print $3}')
    measured_thresh=$(echo "${line}" | awk -F' ' '/Input Threshold:/ {print $3}')
    offset=$(echo "${line}" | awk -F' ' '/Target Offset:/ {print $3}')
done

# video duration and video offset minus 1 second for fade out
video_dur=$(ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 "${infile}" | cut -d\. -f1)
vid_offset=$(echo "${video_dur}-${dur:=${duration_default}}" | bc -l)

# video height
video_size=$(ffprobe -v error -show_entries stream=height -of default=noprint_wrappers=1:nokey=1 "${infile}")

# video title from filename
title="${infile_name}"

# video title variables
font="OpenSans-Regular.ttf"
font_color="white"
boxcolor="black@0.4"

# video title fade
DS="${title_start}" # display start
DE="${title_end}" # display end, number of seconds after start
FID="${dur:=${duration_default}}" # fade in duration
FOD="${dur:=${duration_default}}" # fade out duration

# check title end is a number larger than title start
if [ "${DE}" -le "${DS}" ]; then
    echo "${TITLE_FADE_ERR}" && usage
fi

# calculate drawbox and drawtext size based on video height
case "${video_size}" in
    1080) # 1080 height
    drawbox_height=$(echo "${video_size}/13.4" | bc)
    drawtext_size=$(echo "${drawbox_height}/2" | bc)
    ;;
    720) # 720 height
    drawbox_height=$(echo "${video_size}/9" | bc)
    drawtext_size=$(echo "${drawbox_height}/2" | bc)
    ;;
    *) # all other heights
    drawbox_height=$(echo "${video_size}/9" | bc)
    drawtext_size=$(echo "${drawbox_height}/2" | bc)
    ;;
esac

# drawbox, drawtext size
boxheight="${drawbox_height}"
font_size="${drawtext_size}"

# 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
#===============================================================================

# video function
video () {
    ffmpeg \
    -hide_banner \
    -stats -v panic \
    -i "${infile}" \
    -filter_complex \
    "[0:a] afade=t=in:st=0:d=${dur:=${duration_default}},afade=t=out:st='${vid_offset}':d=${dur:=${duration_default}},
    compand=attacks=0:points=-70/-90|-24/-12|0/-6|20/-6,
    highpass=f=60,
    lowpass=f=13700,
    afftdn=nt=w,
    adeclick,
    deesser,
    loudnorm=I=-16:
    dual_mono=true:
    TP=-1.5:
    LRA=11:
    measured_I=${measured_I}:
    measured_LRA=${measured_LRA}:
    measured_TP=${measured_TP}:
    measured_thresh=${measured_thresh}:
    offset=${offset}:
    linear=true:
    print_format=summary [audio];
    [0:v] fade=t=in:st=0:d=${dur:=${duration_default}},fade=t=out:st='${vid_offset}':d=${dur:=${duration_default}}, \
    format=yuv444p, 
    drawbox=enable='between(t,${DS},${DE})':
    y=(ih-h/PHI)-(${boxheight}):
    color=${boxcolor}:
    width=iw:height=${boxheight}:t=fill,
    drawtext=fontfile=${font}:
    text=${title}: 
    fontcolor=${font_color}:fontsize=${font_size}:
    x=20:
    y=h-(${boxheight})-(${boxheight}/2)+th/4:
    :fontcolor_expr=fdfdfd%{eif\\\\: clip(255*(1*between(t\\, $DS + $FID\\, $DE - $FOD) + ((t - $DS)/$FID)*between(t\\, $DS\\, $DS + $FID) + (-(t - $DE)/$FOD)*between(t\\, $DE - $FOD\\, $DE) )\\, 0\\, 255) \\\\: x\\\\: 2 }, \
     format=yuv420p[video]" \
    -map "[video]" -map "[audio]" \
    -c:a "${aac}" -ar 44100 \
    -c:v libx264 -preset fast \
    -profile:v high \
    -crf 18 -coder 1 \
    -pix_fmt yuv420p \
    -movflags +faststart \
    -f mp4 \
    "${outfile:=${outfile_default}}"
}

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