#!/bin/sh

# Give a file with images and timecodes and creates a video slideshow of them.
#
# Timecodes must be in format 00:00:00.
#
# Imagemagick and ffmpeg required.

# TODO:
#  - add the ability to include text, using imagemagick text to image feature.


[ -z "$1" ] && echo "Usage:
	first arg:	file with timecodes
	second arg:	audio file (optional)" && exit 1

prepdir="$1-src"
prepfile="$prepdir/$1.prep"
outfile="$1.mp4"

totaldur="$(ffmpeg -i "$2" 2>&1 | awk '/Duration/ {print $2}' | sed s/,//)"
totseconds="$(date '+%s' -d "$totaldur")"

mkdir -p "$prepdir"

echo "Preparing images... May take a while depending on the number of files."
{

while read -r x;
do
	# Get the time from the first column.
	time="${x%%	*}"
	seconds="$(date '+%s' -d "$time")"
	# Duration is not used on the first looped item.
	duration="$((seconds - prevseconds))"

	# Get the filename from the rest.
	filename="${x#*	}"
	base="$(basename "$filename")"
	base="${base%.*}.jpg"

	# Resize and read the image file, but not if already done.
	[ ! -f "$prepdir/$base" ] &&
		convert -size 1920x1080 canvas:black -gravity center "$filename" -resize 1920x1080 -composite "$prepdir/$base"

	# If the first line, do not write yet.
	[ "$time" = "00:00:00" ] || echo "file '$prevbase'
duration $duration"

	# Keep the information required for the next file.
	prevbase="$base"
	prevtime="$time"
	prevseconds="$(date '+%s' -d "$prevtime")"
done < "$1"
# Do last file which must be given twice as follows
echo "file '$base'
duration $((totseconds-seconds))
file '$base'"
} > "$prepfile"

if [ -f "$2" ]; then
	ffmpeg -y -f concat -safe 0 -i "$prepfile" -i "$2" -c:a aac -vsync vfr -c:v libx264 -pix_fmt yuv420p "$outfile"
else
	ffmpeg -y -f concat -safe 0 -i "$prepfile" -vsync vfr -c:v libx264 -pix_fmt yuv420p "$outfile"
fi

# Might also try:
# -vf "fps=${fps:-24},format=yuv420p" "$outfile"
# but has given some problems.