#!/usr/bin/env python
#
# theora-intro: adds an introduction to an existing Ogg/Theora video
# Run theora-intro --help for usage details
#
# Home page: http://free-electrons.com/community/tools/utils/theora-intro/
# Version 0.9
# Copyright (C) 2009 Free Electrons
# Author: Michael Opdenacker <michael@free-electrons.com>
#
# Huge thanks to Yoern Seger <yorn@gmx.net> for his useful tools
# and for investigating the issues I faced.
#
# Many thanks to ogg.k.ogg.k@googlemail.com for his great help
# on the theora@xiph.org mailing list.
#
# gen_silence function:
# Copyright (C) 2009 Lino Mastrodomenico <l.mastrodomenico@gmail.com> 
#
# This program 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 2 of the License, or (at your
# option) any later version.
# 
# THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
# WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
# NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
# ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
# 
# You should have received a copy of the  GNU General Public License along
# with this program; if not, write  to the Free Software Foundation, Inc.,
# 675 Mass Ave, Cambridge, MA 02139, USA.

import sys, os, optparse, commands, re, tempfile, struct, shutil

global tmpdir, tmp_image_pattern

import struct, sys

def gen_silence(freq, duration, output_file):

    # Generates a silent WAV file
    # Usage: gen_silence(frequency_in_Hz, duration_in_seconds, output.wav)
 
    size = int(round(duration * freq)) * 4
    f = open(output_file, 'wb')
    header = ('RIFF', size + 36, 'WAVEfmt \x10\0\0\0\1\0\2\0',
          freq, freq * 4, '\4\0\x10\0data', size)
    f.write(struct.pack('< 4s I 16s 2I 8s I', *header))
    f.write(struct.pack('B', 0) * size)
    f.close()

##########################################################
# Common routines
##########################################################

def which(program):

    def is_exe(fpath):
        return os.path.exists(fpath) and os.access(fpath, os.X_OK)

    for path in os.environ["PATH"].split(os.pathsep):
        exe_file = os.path.join(path, program)
        if is_exe(exe_file):
           return exe_file

    return None

def check_command(command, tip):
 
    if which(command) == None:
       print 'ERROR: missing', command, 'executable'
       print tip
       sys.exit()

def run_command(command):

    info('Running command:' + command)

    status, output = commands.getstatusoutput(command)

    if status != 0:
       print "ERROR: failed to execute the below command:"
       print command
       print output
       os.removedirs(tmpdir)
       sys.exit()
    
    return output

def video_info(info, key, mandatory=True):

    for line in info.splitlines():
	line = line.strip()
	pos = line.find(key)
	
	if pos != -1:
           value = line[pos+len(key):]
	   return value.strip()  

    if mandatory:
       print 'ERROR: could not find ', key, ' information about the video file.'
       print 'Not a valid Ogg/Theora file?'
       sys.exit()
    else:
       return None

def video_width(info):
    return video_info(info, 'Width:')

def video_height(info):
    return video_info(info, 'Height:')

def audio_sample_freq(info):
    return video_info(info, 'Rate:')

def audio_bitrate(info):
    value=video_info(info, 'Nominal bitrate:')
    rate=value.split()[0]
    return str(int(float(rate)))

def video_fps(info):
    value = video_info(info, 'Framerate')
    match = re.search('.*[(]([0-9]*).00 fps[)]', value)
    return match.group(1)

def imgfile(index):
    # Generates the name of an image file used in the intro
    return tmp_image_pattern % index

def info(msg):
    if options.verbose:
	print 'INFO:', msg

##########################################################
# Main program
##########################################################

# Define and check command line arguments

usage = 'usage: %prog [options] input-video title-image output-video'
description = 'Adds an introduction to a source Ogg/Theora video, using the given title image'

parser = optparse.OptionParser(usage=usage, version='theora-intro 0.9', description=description)

parser.add_option('-v', '--verbose', action='store_true', dest='verbose',
                     help='Verbose mode')

metadata = ['artist', 'title', 'date', 'location', 'organization', 'copyright', 'license', 'contact']

for field in metadata:
    parser.add_option('--'+field, action='store', dest=field, help='Overrides the '+field.upper()+' Ogg metadata')

(options, args) = parser.parse_args()

# Argument and option checks

if len(args) != 3:
	parser.error('incorrect number of arguments')

input_video = args[0]
title_image = args[1]
output_video = args[2]

for file in [input_video, title_image]:
    if not os.path.lexists(file):
       print 'ERROR: the', file, 'file does not exist'
       sys.exit()

# Environment checks

check_command('ogginfo', 'Try to install the vorbis-tools package')
check_command('convert', 'Try to install the imagemagick package')
check_command('ffmpeg2theora', 'Try to install the ffmpeg2theora package')
check_command('oggzmerge', 'Try to install the oggz-tools package')
check_command('oggResize', 'Please install the Ogg Video Tools from http://dev.streamnik.de/oggvideotools.html')

# Inits

tmpdir = tempfile.mkdtemp('','tmp.',os.path.dirname(output_video))
tmp_image_pattern = tmpdir + '/img-%03d.png'
tmp_intro_video = tmpdir + '/intro-noaudio.ogv'
silence_wav = tmpdir + '/silence.wav'
silence_ogg = tmpdir + '/silence.ogg'
intro_video = tmpdir + '/intro.ogv'
intro_video_resampled = tmpdir + '/intro-resampled.ogv'
video_resampled = tmpdir + '/video-resampled.ogv'

info('Creating temporary files in ' + tmpdir)

# Get audio / video information

ogginfo = run_command('ogginfo ' + input_video)

width = video_width(ogginfo)
height = video_height(ogginfo)
audio_sample_freq = audio_sample_freq(ogginfo)
audio_bitrate = audio_bitrate(ogginfo)
fps = video_fps(ogginfo)

info('VIDEO DETAILS')
info('Resolution: ' + width + 'x' + height)
info('Frames per second: ' + fps)
info('Audio sample rate: '  + audio_sample_freq)
info('Audio nominal bitrate: '  + audio_bitrate)

# Metadata inits

ff2t_opts = ''

for field in metadata:
	
    opt_value = getattr(options, field)

    if opt_value is None:
       value = video_info(ogginfo, field.upper() + '=', False)
       if value != None:
          ff2t_opts += ' --' + field + ' "' + value + ' "'
    else:
       ff2t_opts += ' --' + field + ' "' + opt_value + ' "'

# Generate introduction images ############################################

count = 0
info('Generating intro frame images')

# Generate 50 fade-in frames 

for i in range(100, 0, -2):
	count += 1
	info('Generating intro frame image ' + imgfile(count))
	run_command('convert -fill black -colorize ' + str(i) + '% ' + title_image + ' ' + imgfile(count))

# Generate 50 identical frames

count += 1
ref_image = imgfile(count)

shutil.copy(title_image, ref_image)

for i in range(2, 50):
	count += 1
	info('Generating intro frame image ' + imgfile(count))
	os.link(ref_image, imgfile(count))

# Generate 50 fade-out frames 

for i in range(100, 0, -2):
	count += 1
	info('Generating intro frame image ' + imgfile(count))
	os.link(imgfile(i / 2), imgfile(count))


# Generate the intro video

run_command('ffmpeg2theora' + ff2t_opts + ' -v 10 -x ' + width + ' -y ' + height + ' -F ' + fps + ' ' + tmp_image_pattern + ' -o ' + tmp_intro_video)

# Generate the audio track for the intro video

intro_duration = 150.0 / int(fps)
gen_silence(int(audio_sample_freq), intro_duration, silence_wav) 
run_command('oggenc --managed --bitrate ' + audio_bitrate + ' -o ' + silence_ogg + ' ' + silence_wav)

# Merge the video and audio for the intro
run_command('oggzmerge -o ' + intro_video + ' ' + silence_ogg + ' ' + tmp_intro_video)

# Postprocess the audio on both streams (required before oggCat)
run_command('oggResize -D' + audio_sample_freq + ' ' + intro_video + ' ' + intro_video_resampled)
run_command('oggResize -D' + audio_sample_freq + ' ' + input_video + ' ' + video_resampled)
 
# Merging the intro and the main video
run_command('oggCat ' + output_video + ' ' + intro_video_resampled + ' ' + video_resampled) 

# Remove the temporary directory

os.removedirs(tmpdir)