slideshow-generator

#!/usr/bin/env zsh
# 
# slideshow-generator
# 
# Generate a MP4 video from all passed images
#
# @see https://www.bogotobogo.com/FFMpeg/ffmpeg_basic_slide_show_from_images_jpeg.php
# 



SCRIPT_NAME="$(basename $0)"
SCRIPT_VERSION="0.1"

source $(dirname $0)/_base.inc.sh





########################################################################
# Usage help
# 

function usage {
	echo "Usage:"
	echo "	$SCRIPT_NAME [OPTIONS] [video.mp4] [images...]"
	echo
	echo "Options:"
	echo "	--version, -V  Display script name and version"
	echo "	--help,    -h  Show this usage help"
	echo "	--debug        Turn on debug mode (more verbose messages)"
	echo "	--dry-run, -h  Don't actually gegrate anything, just show what *WOULD*"
	echo "	               be done."
	#echo "	"
	echo
}





########################################################################
# Global defaults
# 

# How much seconds each image is shown
IMAGE_DURATION=5

# Template used by mktemp(1) to create a temporary directory
MKTEMP_TEMPLATE="${SCRIPT_NAME}_${USER}_XXXX"

# Video format details passed to ffmpeg
VIDEO_RESOLUTION="1280x720"   # resolution
VIDEO_BACKGROUND="black"      # default background color (visible if the image doesn't fit into $VIDEO_RESOLUTION
VIDEO_CODEC="libx264"         # codec used to encode the video
VIDEO_FPS=30                  # Frames per second
VIDEO_PIXEL_FORMAT="yuv420p"  # passed to ffmpeg's -pix_fmt option

# Create a temporary directory using mktemp(1)
SLIDESHOW_TMPDIR=$(mktemp -d -t "${MKTEMP_TEMPLATE}")

# Behaviour changable by command line options
DEBUG=0          # Debug mode. Enabled by "--debug"
DRY_RUN=0        # Don't generate anything with "--dry-run"|"-n"
IMAGES=()        # Declare an empty array $IMAGES

# Remove $SLIDESHOW_TMPDIR on exit
#set -o localtraps
function TRAPINT {
	#echo "\n${_ANSI_ATTR_ITALIC}SIGINT recieved.${_ANSI_ATTR_ITALIC_RESET}" >&2
	echo
	
	message_info "SIGINT received. Removing temporary directory \"$SLIDESHOW_TMPDIR\" ..."
	
	rm -rf "${SLIDESHOW_TMPDIR}" >&2
	
	# Reset text effects and cursor state
	tput sgr0
	tput cnorm
	
	# Exit with status 1
	#exit 1
	
	exit
}
#function TRAPTERM {
#	echo "\n${_ANSI_ATTR_ITALIC}SIGINT recieved.${_ANSI_ATTR_ITALIC_RESET}" >&2
#	#rm -rvf "${SLIDESHOW_TMPDIR}" >&2
#	
#	# Reset text effects and cursor state
#	tput sgr0
#	tput cnorm
#}
##function TRAPQUIT {
#function TRAPEXIT {
#	echo "\n${_ANSI_ATTR_ITALIC}TRAPEXIT() called.${_ANSI_ATTR_ITALIC_RESET}" >&2
#	
#	message_debug "Removing \"$SLIDESHOW_TMPDIR\" ..."
#	#rm -rf "${SLIDESHOW_TMPDIR}"
#	
#	# Reset text effects and cursor state
#	tput sgr0
#	tput cnorm
#}





########################################################################
# Parse command line arguments
# 

# Process all given command line arguments
while [[ $# -gt 0 ]]; do
	if [[ "$1" == "--help" || "$1" == "-h" ]]; then
		# Run usage() to display a help text and immediately exit
		usage
		exit 0
		
	elif [[ "$1" == "--version" || "$1" == "-V" ]]; then
		# Like "--help", immediately display information and exit
		version
		exit 0
		
	elif [[ "$1" == "--debug" ]]; then
		# Enable debug mode: message_debug() actually displays a message.
		# → message_debug() is a part of _base.inc.sh
		DEBUG=1
		message_debug "Debug mode enabled."
		
	elif [[ "$1" == "--dry-run" || "$1" == "-n" ]]; then
		# Dry-run mode. Display commands instead of executing them.
		message_debug "Dry-run mode enabled. Only showing what *would* be executed, without doing anything."
		DRY_RUN=1
		
	elif [[ "${1:0:1}" == "-" ]]; then
		# Exit with an error message if an unknown option is passed
		# (In contrast to parameters, options start with a “-”)
		message_error "Unknown option: $1"
		exit 1
		
	elif [[ -z "$VIDEO_OUTPUT" ]]; then
		# First argument sets $VIDEO_OUTPUT (file must not already exist)
		if [[ -f "$1" ]]; then
			message_error "Output file \"$1\" already exists!"
			exit 2
		fi
		VIDEO_OUTPUT="$1"
		
	else
		# Add given filename to $IMAGES if it exists
		if [[ ! -f "$1" ]]; then
			message_error "File not found: $1"
			exit 2
		fi
		#message_debug "Adding image \"$1\" to the queue."
		IMAGES+=$1
		
	fi
	shift
	
done

# Ensure at least one image filename was given
if [[ ${#IMAGES[@]} -lt 1 ]]; then
	usage >&2
	exit 1
fi

#message_debug "The following image filenames where specified: ${IMAGES[@]}"

# 
# Implement the dry-mode by defining the functions convert() and ffmpeg(),
# which show a message instead of launching the executable with that name.
# 
# NOTE: Use "=foo" so we always get a executable path, like which(1) — instead
# of showing function definitions like the shell builtin "which".
# 
if [[ $DRY_RUN -eq 1 ]]; then
	function dry_run_command {
		#_cmdline="convert"
		#_cmdline="$0"
		_cmdline=""
		while [[ $# -gt 0 ]]; do
			if [[ "$1" == *" "* ]]; then
			#if [[ "$1" =~ " |" ]]; then
				# argument contains whitespaces, wrap it in quotes
				_cmdline+=" \"$1\""
			else
				_cmdline+=" $1"
			fi
			shift
		done
		message_info "$(printf "$_cmdline" | stripwhite)"
	}
	alias convert="dry_run_command convert"
	alias ffmpeg="dry_run_command ffmpeg"
	
	if false; then
	function ffmpeg {
		_cmdline="convert"
		while [[ $# -gt 0 ]]; do
			#if [[ "$1" == *" "* ]]; then
			if [[ "$1" =~ " |" ]]; then
				# argument contains whitespaces, wrap it in quotes
				_cmdline+=" \"$1\""
			else
				_cmdline+=" $1"
			fi
			shift
		done
		message_info "ffmpeg $@"
	}
	fi
	
fi
#which ffmpeg; exit 42




# 
# Convert all images passed as an argument to PNG
# 
message_info "Converting images ..."
declare -i i
i=0
for img in "${IMAGES[@]}"; do
	img_converted="${SLIDESHOW_TMPDIR}/image-$(printf '%03d' "$i").png"

	convert                              \
		"$img"                           \
		-resize "$VIDEO_RESOLUTION"      \
		-background "$VIDEO_BACKGROUND"  \
		-gravity center                  \
		-extent "$VIDEO_RESOLUTION"      \
		+repage                          \
		"$img_converted"
	
	i+=1
	
done



# 
# Run ffmpeg
# 
message_info "Running ffmpeg ..."
IMAGE_FILENAME_PATTERN="${SLIDESHOW_TMPDIR}/image-%03d.png"

ffmpeg \
	-r "1/${IMAGE_DURATION}" \
	-i "${IMAGE_FILENAME_PATTERN}" \
	-c:v "${VIDEO_CODEC}" \
	-r "${VIDEO_FPS}" \
	-pix_fmt "${VIDEO_PIXEL_FORMAT}" \
	"${VIDEO_OUTPUT}"

message_debug "Removing \"$SLIDESHOW_TMPDIR\" ..."
rm -rf "${SLIDESHOW_TMPDIR}"