framefiller

#!/usr/bin/env python

#
#  Copyright 2009 Claudio Pisa (claudio dot pisa at uniroma2 dot it)
#
#  This file is part of SVEF (SVC Streaming Evaluation Framework).
#
#  SVEF 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.
#
#  SVEF 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 SVEF.  If not, see <http://www.gnu.org/licenses/>.
#

# Simple error concealing script. Requires the dd utility.

import sys
import commands
import tempfile
from nalulib import *

if(len(sys.argv) < 6):
		print """

		Perform frame filling (a naive form of concealing) on a received YUV video.

		Usage: %s <filtered received stream's trace> <bytes per frame>
		<total frames> <distorted YUV> <concealed YUV (output)> 

		Where:

		<filtered received stream's trace>: the trace file obtained from the
		NAL unit dependency filtering process. For example:
		$ nalufilter originaltrace.txt receivedtrace.txt > filteredtrace.txt

		<bytes per frame>: length in bytes of each YUV frame, obtained from
		width*height*1.5. i.e. 152064 for CIF, 608256 for 4CIF, 4866048 for HD.

		<total frames>: total number of frames in the original video.

		<distorted YUV>: the received YUV, reconstructed from the filtered
		trace file using the JSVM tools. For example: 
		$ BitstreamExtractorStatic foreman.264 foreman-d.264 -et filtered.txt 
		$ H264AVCDecoderLibTestStatic foreman-d.264 foreman-d.yuv

		<concealed YUV (output)>: the file containing the YUV resulting from
		the frame filling process. For each missing frame, the previously
		available frame is inserted.
				
		Example: $ %s filteredtrace.txt 152064 1490 foreman-d.yuv foreman-c.yuv
		""" % (os.path.basename(sys.argv[0]), os.path.basename(sys.argv[0]))
		sys.exit(1)

filteredtracefilename = sys.argv[1]
bytesperframe = int(sys.argv[2])
totalframes = int(sys.argv[3])
distortedyuvfilename = sys.argv[4]
concealedyuvfilename = sys.argv[5]

# collect the frames that are present in the filtered trace file
frameset = set()
filteredfile = open(filteredtracefilename)
for line in filteredfile:
		newnalu = NALU(line)
		try:
				if newnalu.frame_number >= 0:
						frameset.add(newnalu.frame_number)
		except KeyError:
				pass
filteredfile.close()

if len(frameset) == totalframes:
		print "%d frames in the filtered trace file. No concealing needed. Hardlinking the distorted YUV." % len(frameset)
		command1 = "ln %s %s" % (distortedyuvfilename, concealedyuvfilename)
		dothem([command1])
		sys.exit(0)

framelist = list(frameset)
framelist.sort()
#print "%d frames in the filtered received trace: " % len(framelist), framelist

#numberofframes = 1 + max(framelist)
numberofframes = totalframes 

def findsubstituteframe(currentframe):
		# search backwards
		i = currentframe - 1
		while i >= 0:
				if i in	framelist:
						return i
				i-=1
		# search forward
		i = currentframe + 1
		while i < numberofframes:
				if i in framelist:
						return i
				i+=1
		# not found
		raise NALUException("frame not found: %s" % currentframe)

# create a sequence of frames from the distorted YUV, as will appear in the concealed YUV
missingframes = []
framesequence = []
addcounter = 0
for i in range(numberofframes):
		if i in framelist:
				framesequence.append(i)
		else:
				missingframes.append(i)
				concframe = findsubstituteframe(i)
				framesequence.append(concframe)
				addcounter += 1

print "Sequence: ", framesequence
assert len(framesequence) == numberofframes

# make and get a temporary directory
tmpdir = tempfile.mkdtemp("","/tmp/wicloconc",".")

# mince the filtered video
mince(distortedyuvfilename, bytesperframe, tmpdir, framelist)

# create the concealed video
command1 = "touch %s" % concealedyuvfilename
command2 = "rm %s" % concealedyuvfilename
command3 = "touch %s" % concealedyuvfilename
dothem([command1, command2, command3])

for frame in framesequence:
		framefilename = "%s/%d.yuv" % (tmpdir, frame)
		command = "cat %s >> %s" % (framefilename, concealedyuvfilename)
		dothem([command])

print "Missing Frames: %s " % missingframes

print """Statistics:
		%d frames in original video
		%d frames in distorted video
		%d frames added
		""" % (numberofframes, len(framelist), addcounter)

assert numberofframes == len(framelist) + addcounter 

srconcealed = os.stat(concealedyuvfilename)
assert srconcealed.st_size == bytesperframe * numberofframes 

command = "rm -rf %s/" % (tmpdir,)
dothem([command])