#!/usr/bin/env python
# -*- coding: utf-8 -*-

# Copyright (C) 2012-2013 Hector Martin "marcan" <hector@marcansoft.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 or version 3.
#
# This program 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 this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

import sys, numpy, ffms, math

N = 32 # image size
M = 8 # number of DCT coefficients

k = math.sqrt(2.0 / N)
dct_k = numpy.matrix([
	[k * math.cos((math.pi / 2 / N) * y * (2 * x + 1)) for x in xrange(N)]
	for y in xrange(1,M)
])
dct_k_t = numpy.transpose(dct_k)

source_file = sys.argv[1]
out_file = open(sys.argv[1] + ".txt","w")
print "Loading", source_file
vsource = ffms.VideoSource(source_file)
vsource.set_output_format([ffms.get_pix_fmt("gray")], width=N, height=N)

print "Hashing", source_file

for frameno in xrange(vsource.properties.NumFrames):
	data = vsource.get_frame(frameno).planes[0].reshape((N,N)).astype(float)
	coefs = numpy.array(dct_k * data * dct_k_t).flatten()
	median = numpy.median(coefs)
	h = sum((1<<i) for i,j in enumerate(coefs) if j > median)
	out_file.write("#%d: %016x\n" % (frameno, h))
out_file.close()