#!/bin/sh
#------------------------------------------------------------------------------
# =========                 |
# \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
#  \\    /   O peration     |
#   \\  /    A nd           | Copyright (C) 2015 OpenFOAM Foundation
#    \\/     M anipulation  |
#-------------------------------------------------------------------------------
# License
#     This file is part of OpenFOAM.
#
#     OpenFOAM is free software: you can redistribute it and/or modify it
#     under the terms of the GNU General Public License as published by
#     the Free Software Foundation, either version 3 of the License, or
#     (at your option) any later version.
#
#     OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
#     ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
#     FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
#     for more details.
#
#     You should have received a copy of the GNU General Public License
#     along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
#
# Script
#     foamCreateVideo
#
# Description
#     Creates an MPEG-4 compressed (.mp4) video file from PNG images
#     - requires mencoder
#
#------------------------------------------------------------------------------

usage () {
    exec 1>&2
    while [ "$#" -ge 1 ]; do echo "$1"; shift; done
    cat <<USAGE

Usage: ${0##*/} [OPTIONS] ...
options:
  -d | -dir <dir>     directory containing png images (default local dir)
  -f | -fps <fps>     frames per second (default = 10)
  -h | -help          help
  -i | -image <name>  name of image sequence (default = image)
  -o | -out <name>    name of output video file (default = video)

Creates an MPEG-4 compressed (.mp4) video file from a sequence of PNG images
- A sequence named "image" will expect files image.0000.png, image.0001.png, etc
- An output video named "video" will produce a file video.mp4
- By default the video codec is high resolution (x264) but there is an option to
  select a medium resolution codec (lavc)

Requires mencoder

USAGE
    exit 1
}


# Default settings
DIR='.'
IMAGE='image'
VIDEO='video'
FPS=10
VCODEC=x264


while [ "$#" -gt 0 ]
do
   case "$1" in
   -h | -help)
      usage
      ;;
   -d | -directory)
      [ "$#" -ge 2 ] || usage "'$1' option requires an argument"
      DIR=$2
      shift 2
      ;;
   -f | -fps)
      [ "$#" -ge 2 ] || usage "'$1' option requires an argument"
      FPS=$2
      shift 2
      ;;
   -i | -image)
      [ "$#" -ge 2 ] || usage "'$1' option requires an argument"
      IMAGE=$2
      shift 2
      ;;
   -o | -out)
      [ "$#" -ge 2 ] || usage "'$1' option requires an argument"
      VIDEO=$2
      shift 2
      ;;
   -*)
      usage "invalid option '$1'"
      ;;
   *)
      break
      ;;
    esac
done

#
# MAIN
#

[ -f "$(ls -1 $DIR/$IMAGE.*.png | head -1)" ] || usage "Cannot find first file in image sequence"

if command -v mencoder >/dev/null 2>&1; then
    mencoder \
        "mf://$DIR/$IMAGE.*.png" \
        -mf fps=$FPS \
        -o $VIDEO.mp4 \
        -ovc $VCODEC
else
    usage "Please install mencoder"
fi