uvg266/tools/generate_ref_pixel_tables.py
2021-11-23 08:46:06 +02:00

154 lines
5.1 KiB
Python

"""This is a script that generates tables for Kvazaar HEVC encoder.
/*****************************************************************************
* This file is part of uvg266 VVC encoder.
*
* Copyright (c) 2021, Tampere University, ITU/ISO/IEC, project contributors
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
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* list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice, this
* list of conditions and the following disclaimer in the documentation and/or
* other materials provided with the distribution.
*
* * Neither the name of the Tampere University or ITU/ISO/IEC nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* INCLUDING NEGLIGENCE OR OTHERWISE ARISING IN ANY WAY OUT OF THE USE OF THIS
****************************************************************************/
This script is provided as reference, in case we ever need to change the tables
or generate more similar tables.
Because the CUs are coded in Z-order a particular index in the LCU will always
have the same number of coded reference pixels, except if the PU is on the very
top or left edge of the LCU.
"""
import numpy
def make_z_order_table(width, coord = None, zid=0, min_width=4, result=None):
"""Return a table with the quadtree z-order.
Args:
width: width of the area (LCU)
coord: numpy.array with index 0 as x and 1 as y
min_width: width at which the recursion is stopped
result: numpy.array with the current table
Returns: numpy.array with the quadtree z-order.
"""
if coord is None:
coord = numpy.array([0, 0])
if result is None:
num_pu = width / min_width
result = numpy.zeros((num_pu, num_pu), numpy.int16)
offset = width / 2
if offset >= min_width:
# Recurse in quadtree z-order.
offsets = map(numpy.array, [[0,0],[1,0],[0,1],[1,1]])
for num, os in enumerate(offsets):
num_pu = offset**2 / min_width**2
result = make_z_order_table(offset, coord + os * offset,
zid + num * num_pu, min_width, result)
else:
pu = coord / min_width
result[pu[1]][pu[0]] = zid
return result
def num_lessed_zid_on_left(table, x, y):
"""Z-order table + coord -> number of ref PUs on the left."""
i = 0
while True:
if x == 0:
return 16
if y + i >= 16 or table[y + i][x - 1] > table[y][x]:
return i
i = i + 1
def num_lessed_zid_on_top(table, x, y):
"""Z-order table + coord -> number of ref PUs on the top."""
i = 0
while True:
if y == 0:
return 16
if x + i >= 16 or table[y - 1][x + i] > table[y][x]:
return i
i = i + 1
def matrix_to_initializer_list(table):
"""Output a list of lists as an initializer list in C syntax.
Args:
table: list(list(int)) representing 2d array
Returns:
str
"""
# Convert the numbers into strings and pad them to be 2-chars wide to make
# the table look nicer.
str_nums = (("{0: >2}".format(x) for x in line) for line in table)
# Get the lines with all the numbers divided by commas.
lines = (", ".join(line) for line in str_nums)
# Join the lines with commas and newlines in between.
result = "{ %s }" % (" },\n{ ".join(lines))
return result
def main():
zid_table = make_z_order_table(64)
num_pu = 16
left_table = numpy.zeros((num_pu, num_pu), numpy.int16)
top_table = numpy.zeros((num_pu, num_pu), numpy.int16)
for y in range(16):
for x in range(16):
left_table[y][x] = num_lessed_zid_on_left(zid_table, x, y)
top_table[y][x] = num_lessed_zid_on_top(zid_table, x, y)
print zid_table
print left_table
print top_table
# Multiply by number of pixels in a PU
left_table = left_table * 4
top_table = top_table * 4
print
print "left"
print matrix_to_initializer_list(left_table)
print
print "top"
print matrix_to_initializer_list(top_table)
print
if __name__ == '__main__':
main()