make a video smooth (60fp) using ffmpeg

smoothify.sh

#!/usr/bin/env bash


##############################################################
# Demo script to make a any-fps movie to 60fps
#
# Usage: > ./smoothify.sh <FilePath> (<tmpdir>)
# 
# Output file will be the input one _SMOOTHED, at the same dir
#
#########################################

set -e # stop on first error
#set -x

Required_commands=("ffmpeg" "awk" "sed" "ffprobe" "getconf")

for cmd in "${commands[@]}"
do
  if ! command -v "$cmd" >/dev/null 2>&1 ; then
    echo "Command '$cmd' not available, please install it."
    exit 1
  fi
done

get_numberOfCPU(){
	getconf _NPROCESSORS_ONLN
}
get_keyFrames(){
	local FileName="$1"
	ffprobe -select_streams v:0 -skip_frame nokey -v quiet -of default=noprint_wrappers=1 -show_entries frame=best_effort_timestamp_time "$FileName" | sed 's/best_effort_timestamp_time=//'
}
get_FrameRate(){
	local FileName="$1"
	ffprobe -select_streams v:0 -v quiet -of default=noprint_wrappers=1 -show_entries stream=r_frame_rate "$FileName" | sed 's/r_frame_rate=//'
}
get_FrameRateNumber(){
	local FileName="$1"
	FrameRate=$(get_FrameRate "$FileName")
	SegmentSize=$(awk "BEGIN { print ($FrameRate) }")
	echo "$SegmentSize"
}
get_FrameTime(){
	local FileName="$1"
	FrameRate=$(get_FrameRate "$FileName")
	SegmentSize=$(awk "BEGIN { print (1/($FrameRate)) }")
	echo "$SegmentSize"
}
get_NearestTime(){
	local RequestedTime="$1"
	shift #to reference dataset array at first arg position
	local DataSet=("$@"); IFS=: # IFS is used to delimit array
	# using awk to process the array in one command (using awk in a loop is too slow)
	echo "$RequestedTime" | awk -v dataset="${DataSet[*]}"  '{
		n_dataset=split(dataset, _dataset, "[:]")
		for (i=1; i<=length(_dataset); i++)
		{
			if ($RequestedTime < _dataset[i])
			{
				printf "%s\n%s",_dataset[i],_dataset[i]
				exit
			}
		}
		print "/!\ Can not find a NearestTime" > "/dev/stderr"
		exit 1
	}'
}

File="$1"
echo "using File: $File"
FileOut=$( echo "$File" | sed 's|\([^/]*\)\.\([^.]*\)$|\1_SMOOTHED.\2|g')
echo "using FileOut: $FileOut"
NumberOfCut=$(get_numberOfCPU)
TmpDirEx=$(mktemp -d)
TmpDir=${2:-$TmpDirEx}
echo "Using TmpDir: $TmpDir"
TmpConcatList=$(mktemp)
EncodeNice=10
tagetFPS=48


function finish {
	rm -Rf $TmpDirEx || true #/!\ DO NOT rm user provided $TmpDir cause user can make mistake
	rm "$TmpConcatList" || true
	for (( CutIndex=0; CutIndex<"${#SegmentKeyFrames[@]}"; CutIndex=CutIndex+2  )); do
		rm "$TmpDir/chunk_$CutIndex.mp4" >/dev/null 2>&1 || true
	done
}
trap finish EXIT

#TranscodeOpt="-c:v copy" # <= DO NOT DO THAT ! codec have to be reencoded to allow time cut ...  :-/
# normal transcode 
TranscodeOptBase="-c:v libx264 -preset slower -tune film -crf 16"
# very fast
#TranscodeOptBase="-c:v libx264 -preset faster -crf 30"

# super cool but super slow
TranscodeOptFilter="-filter:v minterpolate=fps=$tagetFPS:scd=none:mi_mode=mci:mc_mode=aobmc:me_mode=bidir:me=epzs:search_param=16:vsbmc=1"
# well.. do not change that much
#TranscodeOptFilter="-filter:v tblend -r $tagetFPS"
# disable
#TranscodeOptFilter=""

TranscodeOpt="$TranscodeOptBase $TranscodeOptFilter"

FrameTime=$(get_FrameTime "$File")
echo "[DEBUG] FrameTime is $FrameTime"
FrameRateNumber=$(get_FrameRateNumber "$File")
echo "[DEBUG] FrameRateNumber is $FrameRateNumber"
FrameRate=$(get_FrameRate "$File")
echo "[DEBUG] FrameRate is $FrameRate"

echo "[INFO] Expected number of cuts: $NumberOfCut"

echo "[INFO] Extracting Keyframes..."
mapfile -t keyframes < <(get_keyFrames "$File")
echo "[INFO] Done"

FirstValue=0
LastValue="${keyframes[-1]}"

echo "[INFO] Cutting file from $FirstValue sec to $LastValue sec, in $NumberOfCut segments."
SegmentSize=$(awk -v var1="$LastValue" -v var2="$NumberOfCut"  'BEGIN { print  ( var1 / var2 ) }')
echo "[INFO] Computed approx segments size is $SegmentSize sec"

SegmentKeyFrames=(0)

for (( CutIndex=1; CutIndex<"$NumberOfCut"; CutIndex++ )); do
	TargetKeyFrame=$(awk -v var1="$CutIndex" -v var2="$SegmentSize"  'BEGIN { print  ( var1*var2 ) }')
	echo "[DEBUG] TargetKeyFrame is $TargetKeyFrame"
	SegmentKeyFrames+=($(get_NearestTime "$TargetKeyFrame" "${keyframes[@]}"))
done
SegmentKeyFrames+=("$LastValue")

echo "[INFO] Done."

echo "[INFO] Final SegmentKeyFrames are:"
for keytime in "${SegmentKeyFrames[@]}"; do
	echo "[INFO] $keytime"
done

echo "[INFO] Cutting input file."
pids=""
RESULT=0
for (( CutIndex=0; CutIndex<"${#SegmentKeyFrames[@]}"; CutIndex=CutIndex+2 )); do
	echo "[DEBUG] Processing Section from ${SegmentKeyFrames[CutIndex]} to ${SegmentKeyFrames[CutIndex+1]}..."
	Duration=$(awk -v var1="${SegmentKeyFrames[CutIndex+1]}" -v var2="${SegmentKeyFrames[CutIndex]}"  'BEGIN { print  ( var1-var2 ) }')
	echo "[DEBUG] Duration is $Duration"
	nice -n "$EncodeNice" ffmpeg -ss "${SegmentKeyFrames[CutIndex]}" -to "${SegmentKeyFrames[CutIndex+1]}" -i "$File" -map 0   -fflags +genpts -avoid_negative_ts 1 $TranscodeOpt  "$TmpDir/chunk_$CutIndex.mp4"  &>/dev/null  & 
	pids="$pids $!"
	
done
echo "[INFO] Waiting Jobs to finish"
for pid in $pids; do
    wait $pid || let "RESULT=1"
done

if [ "$RESULT" == "1" ];
    then
       exit 1
fi
echo "[INFO] Done."

echo "[INFO] Reconstructing file."
for (( CutIndex=0; CutIndex<"${#SegmentKeyFrames[@]}"; CutIndex=CutIndex+2  )); do
	Duration=$(awk -v var1="${SegmentKeyFrames[CutIndex+1]} " -v var2="${SegmentKeyFrames[CutIndex]}"  'BEGIN { print  ( var1-var2 ) }')
	echo "file $TmpDir/chunk_$CutIndex.mp4" >> "$TmpConcatList"
	echo "duration $Duration" >> "$TmpConcatList"
done
ffmpeg -f concat -safe 0 -i "$TmpConcatList"  -c copy "$FileOut"
echo "[INFO] Done."

echo "[INFO] Cleaning"

echo "[INFO] Done."
echo "[INFO] Finished !"