minterpolate

#!/bin/bash

# Multicore minterpolate in ffmpeg
# Just slice & process & concat
# NB: The concat points between slices may be weird

# Default arguments
ff=/usr/bin/ffmpeg
fps=60
dur=00:00:10
enc=libx264
[ "${OSTYPE}" == "darwin"* ] && task=$(( $(sysctl -n hw.logicalcpu) - 2 )) || task=$(( $(nproc --all) - 2 ))

# Reference: https://ffmpeg.org/ffmpeg-filters.html#minterpolate
m_args=":mi_mode=mci:mc_mode=aobmc:me_mode=bidir:vsbmc=1"

ff_args=( -hide_banner -loglevel level+warning -nostats -y )
ff_args_enc=( -crf 20 -preset slow )

################################################################################

# Usage notes
err_args () {
	printf "\nUsage: %s -i INPUT_FILE [ARGUMENTS] OUTPUT_FILENAME\n" "$(basename "${0}")"
	printf "\n"
	printf "Arguments:\t\t\t\t\t[default values]\n"
	echo
  printf "\t-b str\tffmpeg binary path\t\t[%s]\n" "${ff}"
  printf "\t-d hms\tSlices duration [hour:min:sec]\t[%s]\n" "${dur}"
	printf "\t-e str\tEncoder name\t\t\t[%s]\n" "${enc}"
  printf "\t-f str\tffmpeg encoding arguments\t[%s]\n" "'${ff_args_enc[*]}'"
  printf "\t-p int\tProcess/thread count. 0 is max\t[%s]\n" "${task}"
	printf "\t-r int\tTarget FPS\t\t\t[%s]\n" "${fps}"
  printf "\t-m str\tminterpolate arguments\t\t[%s]\n" "'${m_args}'"
  printf "\t-s hms\tStart point of source video\t[00:00:00]\n"
	printf "\t-t hms\tEnd point of source video\t[until end of the video]\n"
  echo
	exit 1
}

# Clean slices and temporary files
clean () {
	rm -f _cut.mp4
	rm -f _s_?????.mp4
	rm -f _m__s_?????.mp4
	rm -f _list.txt
}

while getopts 'i:r:s:t:e:p:d:b:m:f' OPTION; do
	case $OPTION in
		i)
			in=$OPTARG # input file
			;;
		r)
			fps=$OPTARG # target fps, fraction is also OK
			;;
		s)
			ss=$OPTARG # begin time of input
			;;
		t)
			to=$OPTARG # end time of input
			;;
		e)
			enc=$OPTARG # encoder
			;;
		p)
			task=$((OPTARG)) # process count, xargs use max when it is 0
			;;
		d)
			dur=$OPTARG # parallel block length
			;;
		b)
			ff=$OPTARG # ffmpeg binary
			;;
    m)
			m_args=$OPTARG # minterpolate arguments
			;;
    f)
			ff_args_enc=$OPTARG # ffmpeg encoding arguments
			;;
		*)
			err_args
			;;
	esac
done
shift $((OPTIND - 1))

# Set output file
out="${1}"

# Select input file
temp="${in}"

# Check arguments and files
if [ -z "${in}" ]; then
  echo
	echo "$(basename ${0}): missing input file"
	err_args
fi

if [ -z "${out}" ]; then
  echo
	echo "$(basename ${0}): missing output filename"
	err_args
fi

# Set start and end duration for minterpolation
duration=()

if [ -n "${ss}" ]; then
	duration+=(-ss)
	duration+=("${ss}")
	temp=_cut.mp4
fi

if [ -n "${to}" ]; then
	duration+=(-to)
	duration+=("${to}")
	temp=_cut.mp4
fi

################################################################################

clean

echo
echo "Processing ${in} ..."
echo

# Use origin file or cut a part from origin file
if [ "${temp}" == _cut.mp4 ]; then
	"${ff}" "${ff_args[@]}" "${duration[@]}" -i "${in}" -c copy "${temp}"
fi

# Make slices for parallel use
"${ff}" "${ff_args[@]}" -i "${temp}" -c copy -f segment -segment_time "${dur}" '_s_%05d.mp4'

xargs_cmd="/usr/bin/nice -n 19 ${ff} ${ff_args[@]} -i _fname -vf minterpolate=fps=${fps}${m_args} -c:a copy -c:v ${enc} ${ff_args_enc[@]} _m__fname"

# Minterpolate the slices. Get coffee, go out and exercise, or sleep. This will a while.
find . -name '_s_?????.mp4' | sed 's@^.*/@@g' | xargs -I "_fname" -t -P ${task} -- ${xargs_cmd} && echo "Processed slice: $(ls _m__s_?????.mp4 | wc -l) of $(ls _s_?????.mp4 | wc -l) ..."

# Make a list of minterpolated slices
printf "file '%s'\n" ./_m__s_?????.mp4 > _list.txt

# Concatenate the result
"${ff}" "${ff_args[@]}" -f concat -safe 0 -i _list.txt -c copy "${out}"

echo
echo "Processing of ${in} complete. Created ${out}."
echo
echo "################################################################################"
echo

clean