1233d2500723e5594f3e7c70896ffeeef32b9c950ywan/*
2233d2500723e5594f3e7c70896ffeeef32b9c950ywan *  Copyright (c) 2014 The WebM project authors. All Rights Reserved.
3233d2500723e5594f3e7c70896ffeeef32b9c950ywan *
4233d2500723e5594f3e7c70896ffeeef32b9c950ywan *  Use of this source code is governed by a BSD-style license
5233d2500723e5594f3e7c70896ffeeef32b9c950ywan *  that can be found in the LICENSE file in the root of the source
6233d2500723e5594f3e7c70896ffeeef32b9c950ywan *  tree. An additional intellectual property rights grant can be found
7233d2500723e5594f3e7c70896ffeeef32b9c950ywan *  in the file PATENTS.  All contributing project authors may
8233d2500723e5594f3e7c70896ffeeef32b9c950ywan *  be found in the AUTHORS file in the root of the source tree.
9233d2500723e5594f3e7c70896ffeeef32b9c950ywan */
10233d2500723e5594f3e7c70896ffeeef32b9c950ywan
11233d2500723e5594f3e7c70896ffeeef32b9c950ywan#include <assert.h>
12233d2500723e5594f3e7c70896ffeeef32b9c950ywan#include <limits.h>
13233d2500723e5594f3e7c70896ffeeef32b9c950ywan#include <math.h>
14233d2500723e5594f3e7c70896ffeeef32b9c950ywan#include <stdio.h>
15233d2500723e5594f3e7c70896ffeeef32b9c950ywan#include <stdlib.h>
16233d2500723e5594f3e7c70896ffeeef32b9c950ywan#include <string.h>
17233d2500723e5594f3e7c70896ffeeef32b9c950ywan
18233d2500723e5594f3e7c70896ffeeef32b9c950ywan#include "vp9/common/vp9_common.h"
19233d2500723e5594f3e7c70896ffeeef32b9c950ywan#include "vp9/encoder/vp9_resize.h"
20233d2500723e5594f3e7c70896ffeeef32b9c950ywan
21233d2500723e5594f3e7c70896ffeeef32b9c950ywan#define FILTER_BITS               7
22233d2500723e5594f3e7c70896ffeeef32b9c950ywan
23233d2500723e5594f3e7c70896ffeeef32b9c950ywan#define INTERP_TAPS               8
24233d2500723e5594f3e7c70896ffeeef32b9c950ywan#define SUBPEL_BITS               5
25233d2500723e5594f3e7c70896ffeeef32b9c950ywan#define SUBPEL_MASK               ((1 << SUBPEL_BITS) - 1)
26233d2500723e5594f3e7c70896ffeeef32b9c950ywan#define INTERP_PRECISION_BITS     32
27233d2500723e5594f3e7c70896ffeeef32b9c950ywan
28233d2500723e5594f3e7c70896ffeeef32b9c950ywantypedef int16_t interp_kernel[INTERP_TAPS];
29233d2500723e5594f3e7c70896ffeeef32b9c950ywan
30233d2500723e5594f3e7c70896ffeeef32b9c950ywan// Filters for interpolation (0.5-band) - note this also filters integer pels.
31233d2500723e5594f3e7c70896ffeeef32b9c950ywanconst interp_kernel vp9_filteredinterp_filters500[(1 << SUBPEL_BITS)] = {
32233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-3,  0, 35, 64, 35,  0, -3, 0},
33233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-3, -1, 34, 64, 36,  1, -3, 0},
34233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-3, -1, 32, 64, 38,  1, -3, 0},
35233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-2, -2, 31, 63, 39,  2, -3, 0},
36233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-2, -2, 29, 63, 41,  2, -3, 0},
37233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-2, -2, 28, 63, 42,  3, -4, 0},
38233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-2, -3, 27, 63, 43,  4, -4, 0},
39233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-2, -3, 25, 62, 45,  5, -4, 0},
40233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-2, -3, 24, 62, 46,  5, -4, 0},
41233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-2, -3, 23, 61, 47,  6, -4, 0},
42233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-2, -3, 21, 60, 49,  7, -4, 0},
43233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1, -4, 20, 60, 50,  8, -4, -1},
44233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1, -4, 19, 59, 51,  9, -4, -1},
45233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1, -4, 17, 58, 52, 10, -4, 0},
46233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1, -4, 16, 57, 53, 12, -4, -1},
47233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1, -4, 15, 56, 54, 13, -4, -1},
48233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1, -4, 14, 55, 55, 14, -4, -1},
49233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1, -4, 13, 54, 56, 15, -4, -1},
50233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1, -4, 12, 53, 57, 16, -4, -1},
51233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0, -4, 10, 52, 58, 17, -4, -1},
52233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1, -4,  9, 51, 59, 19, -4, -1},
53233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1, -4,  8, 50, 60, 20, -4, -1},
54233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0, -4,  7, 49, 60, 21, -3, -2},
55233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0, -4,  6, 47, 61, 23, -3, -2},
56233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0, -4,  5, 46, 62, 24, -3, -2},
57233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0, -4,  5, 45, 62, 25, -3, -2},
58233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0, -4,  4, 43, 63, 27, -3, -2},
59233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0, -4,  3, 42, 63, 28, -2, -2},
60233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0, -3,  2, 41, 63, 29, -2, -2},
61233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0, -3,  2, 39, 63, 31, -2, -2},
62233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0, -3,  1, 38, 64, 32, -1, -3},
63233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0, -3,  1, 36, 64, 34, -1, -3}
64233d2500723e5594f3e7c70896ffeeef32b9c950ywan};
65233d2500723e5594f3e7c70896ffeeef32b9c950ywan
66233d2500723e5594f3e7c70896ffeeef32b9c950ywan// Filters for interpolation (0.625-band) - note this also filters integer pels.
67233d2500723e5594f3e7c70896ffeeef32b9c950ywanconst interp_kernel vp9_filteredinterp_filters625[(1 << SUBPEL_BITS)] = {
68233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1, -8, 33, 80, 33, -8, -1, 0},
69233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1, -8, 30, 80, 35, -8, -1, 1},
70233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1, -8, 28, 80, 37, -7, -2, 1},
71233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0, -8, 26, 79, 39, -7, -2, 1},
72233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0, -8, 24, 79, 41, -7, -2, 1},
73233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0, -8, 22, 78, 43, -6, -2, 1},
74233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0, -8, 20, 78, 45, -5, -3, 1},
75233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0, -8, 18, 77, 48, -5, -3, 1},
76233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0, -8, 16, 76, 50, -4, -3, 1},
77233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0, -8, 15, 75, 52, -3, -4, 1},
78233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0, -7, 13, 74, 54, -3, -4, 1},
79233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0, -7, 11, 73, 56, -2, -4, 1},
80233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0, -7, 10, 71, 58, -1, -4, 1},
81233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -7,  8, 70, 60,  0, -5, 1},
82233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -6,  6, 68, 62,  1, -5, 1},
83233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -6,  5, 67, 63,  2, -5, 1},
84233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -6,  4, 65, 65,  4, -6, 1},
85233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -5,  2, 63, 67,  5, -6, 1},
86233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -5,  1, 62, 68,  6, -6, 1},
87233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -5,  0, 60, 70,  8, -7, 1},
88233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -4, -1, 58, 71, 10, -7, 0},
89233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -4, -2, 56, 73, 11, -7, 0},
90233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -4, -3, 54, 74, 13, -7, 0},
91233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -4, -3, 52, 75, 15, -8, 0},
92233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -3, -4, 50, 76, 16, -8, 0},
93233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -3, -5, 48, 77, 18, -8, 0},
94233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -3, -5, 45, 78, 20, -8, 0},
95233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -2, -6, 43, 78, 22, -8, 0},
96233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -2, -7, 41, 79, 24, -8, 0},
97233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -2, -7, 39, 79, 26, -8, 0},
98233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -2, -7, 37, 80, 28, -8, -1},
99233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -1, -8, 35, 80, 30, -8, -1},
100233d2500723e5594f3e7c70896ffeeef32b9c950ywan};
101233d2500723e5594f3e7c70896ffeeef32b9c950ywan
102233d2500723e5594f3e7c70896ffeeef32b9c950ywan// Filters for interpolation (0.75-band) - note this also filters integer pels.
103233d2500723e5594f3e7c70896ffeeef32b9c950ywanconst interp_kernel vp9_filteredinterp_filters750[(1 << SUBPEL_BITS)] = {
104233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {2, -11,  25,  96,  25, -11,   2, 0},
105233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {2, -11,  22,  96,  28, -11,   2, 0},
106233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {2, -10,  19,  95,  31, -11,   2, 0},
107233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {2, -10,  17,  95,  34, -12,   2, 0},
108233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {2,  -9,  14,  94,  37, -12,   2, 0},
109233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {2,  -8,  12,  93,  40, -12,   1, 0},
110233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {2,  -8,   9,  92,  43, -12,   1, 1},
111233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {2,  -7,   7,  91,  46, -12,   1, 0},
112233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {2,  -7,   5,  90,  49, -12,   1, 0},
113233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {2,  -6,   3,  88,  52, -12,   0, 1},
114233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {2,  -5,   1,  86,  55, -12,   0, 1},
115233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {2,  -5,  -1,  84,  58, -11,   0, 1},
116233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {2,  -4,  -2,  82,  61, -11,  -1, 1},
117233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {2,  -4,  -4,  80,  64, -10,  -1, 1},
118233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -3, -5, 77, 67, -9, -1, 1},
119233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -3, -6, 75, 70, -8, -2, 1},
120233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -2, -7, 72, 72, -7, -2, 1},
121233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -2, -8, 70, 75, -6, -3, 1},
122233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1, -1, -9, 67, 77, -5, -3, 1},
123233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1,  -1, -10,  64,  80,  -4,  -4, 2},
124233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1,  -1, -11,  61,  82,  -2,  -4, 2},
125233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1,   0, -11,  58,  84,  -1,  -5, 2},
126233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1,   0, -12,  55,  86,   1,  -5, 2},
127233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1,   0, -12,  52,  88,   3,  -6, 2},
128233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0,   1, -12,  49,  90,   5,  -7, 2},
129233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0,   1, -12,  46,  91,   7,  -7, 2},
130233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1,   1, -12,  43,  92,   9,  -8, 2},
131233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0,   1, -12,  40,  93,  12,  -8, 2},
132233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0,   2, -12,  37,  94,  14,  -9, 2},
133233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0,   2, -12,  34,  95,  17, -10, 2},
134233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0,   2, -11,  31,  95,  19, -10, 2},
135233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0,   2, -11,  28,  96,  22, -11, 2}
136233d2500723e5594f3e7c70896ffeeef32b9c950ywan};
137233d2500723e5594f3e7c70896ffeeef32b9c950ywan
138233d2500723e5594f3e7c70896ffeeef32b9c950ywan// Filters for interpolation (0.875-band) - note this also filters integer pels.
139233d2500723e5594f3e7c70896ffeeef32b9c950ywanconst interp_kernel vp9_filteredinterp_filters875[(1 << SUBPEL_BITS)] = {
140233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {3,  -8,  13, 112,  13,  -8,   3, 0},
141233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {3,  -7,  10, 112,  17,  -9,   3, -1},
142233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {2,  -6,   7, 111,  21,  -9,   3, -1},
143233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {2,  -5,   4, 111,  24, -10,   3, -1},
144233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {2,  -4,   1, 110,  28, -11,   3, -1},
145233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1,  -3,  -1, 108,  32, -12,   4, -1},
146233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1,  -2,  -3, 106,  36, -13,   4, -1},
147233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1,  -1,  -6, 105,  40, -14,   4, -1},
148233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1,  -1,  -7, 102,  44, -14,   4, -1},
149233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1,   0,  -9, 100,  48, -15,   4, -1},
150233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {1,   1, -11,  97,  53, -16,   4, -1},
151233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0,   1, -12,  95,  57, -16,   4, -1},
152233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0,   2, -13,  91,  61, -16,   4, -1},
153233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0,   2, -14,  88,  65, -16,   4, -1},
154233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0,   3, -15,  84,  69, -17,   4, 0},
155233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0,   3, -16,  81,  73, -16,   3, 0},
156233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0,   3, -16,  77,  77, -16,   3, 0},
157233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0,   3, -16,  73,  81, -16,   3, 0},
158233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0,   4, -17,  69,  84, -15,   3, 0},
159233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   4, -16,  65,  88, -14,   2, 0},
160233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   4, -16,  61,  91, -13,   2, 0},
161233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   4, -16,  57,  95, -12,   1, 0},
162233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   4, -16,  53,  97, -11,   1, 1},
163233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   4, -15,  48, 100,  -9,   0, 1},
164233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   4, -14,  44, 102,  -7,  -1, 1},
165233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   4, -14,  40, 105,  -6,  -1, 1},
166233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   4, -13,  36, 106,  -3,  -2, 1},
167233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   4, -12,  32, 108,  -1,  -3, 1},
168233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   3, -11,  28, 110,   1,  -4, 2},
169233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   3, -10,  24, 111,   4,  -5, 2},
170233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   3,  -9,  21, 111,   7,  -6, 2},
171233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   3,  -9,  17, 112,  10,  -7, 3}
172233d2500723e5594f3e7c70896ffeeef32b9c950ywan};
173233d2500723e5594f3e7c70896ffeeef32b9c950ywan
174233d2500723e5594f3e7c70896ffeeef32b9c950ywan// Filters for interpolation (full-band) - no filtering for integer pixels
175233d2500723e5594f3e7c70896ffeeef32b9c950ywanconst interp_kernel vp9_filteredinterp_filters1000[(1 << SUBPEL_BITS)] = {
176233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0,   0,   0, 128,   0,   0,   0, 0},
177233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0,   1,  -3, 128,   3,  -1,   0, 0},
178233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   2,  -6, 127,   7,  -2,   1, 0},
179233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   3,  -9, 126,  12,  -4,   1, 0},
180233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   4, -12, 125,  16,  -5,   1, 0},
181233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   4, -14, 123,  20,  -6,   2, 0},
182233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   5, -15, 120,  25,  -8,   2, 0},
183233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   5, -17, 118,  30,  -9,   3, -1},
184233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   6, -18, 114,  35, -10,   3, -1},
185233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   6, -19, 111,  41, -12,   3, -1},
186233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   6, -20, 107,  46, -13,   4, -1},
187233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   6, -21, 103,  52, -14,   4, -1},
188233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   6, -21,  99,  57, -16,   5, -1},
189233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   6, -21,  94,  63, -17,   5, -1},
190233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   6, -20,  89,  68, -18,   5, -1},
191233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   6, -20,  84,  73, -19,   6, -1},
192233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   6, -20,  79,  79, -20,   6, -1},
193233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   6, -19,  73,  84, -20,   6, -1},
194233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   5, -18,  68,  89, -20,   6, -1},
195233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   5, -17,  63,  94, -21,   6, -1},
196233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   5, -16,  57,  99, -21,   6, -1},
197233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   4, -14,  52, 103, -21,   6, -1},
198233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   4, -13,  46, 107, -20,   6, -1},
199233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   3, -12,  41, 111, -19,   6, -1},
200233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   3, -10,  35, 114, -18,   6, -1},
201233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {-1,   3,  -9,  30, 118, -17,   5, -1},
202233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0,   2,  -8,  25, 120, -15,   5, -1},
203233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0,   2,  -6,  20, 123, -14,   4, -1},
204233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0,   1,  -5,  16, 125, -12,   4, -1},
205233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0,   1,  -4,  12, 126,  -9,   3, -1},
206233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0,   1,  -2,   7, 127,  -6,   2, -1},
207233d2500723e5594f3e7c70896ffeeef32b9c950ywan  {0,   0,  -1,   3, 128,  -3,   1, 0}
208233d2500723e5594f3e7c70896ffeeef32b9c950ywan};
209233d2500723e5594f3e7c70896ffeeef32b9c950ywan
210233d2500723e5594f3e7c70896ffeeef32b9c950ywan// Filters for factor of 2 downsampling.
211233d2500723e5594f3e7c70896ffeeef32b9c950ywanstatic const int16_t vp9_down2_symeven_half_filter[] = {56, 12, -3, -1};
212233d2500723e5594f3e7c70896ffeeef32b9c950ywanstatic const int16_t vp9_down2_symodd_half_filter[] = {64, 35, 0, -3};
213233d2500723e5594f3e7c70896ffeeef32b9c950ywan
214233d2500723e5594f3e7c70896ffeeef32b9c950ywanstatic const interp_kernel *choose_interp_filter(int inlength, int outlength) {
215233d2500723e5594f3e7c70896ffeeef32b9c950ywan  int outlength16 = outlength * 16;
216233d2500723e5594f3e7c70896ffeeef32b9c950ywan  if (outlength16 >= inlength * 16)
217233d2500723e5594f3e7c70896ffeeef32b9c950ywan    return vp9_filteredinterp_filters1000;
218233d2500723e5594f3e7c70896ffeeef32b9c950ywan  else if (outlength16 >= inlength * 13)
219233d2500723e5594f3e7c70896ffeeef32b9c950ywan    return vp9_filteredinterp_filters875;
220233d2500723e5594f3e7c70896ffeeef32b9c950ywan  else if (outlength16 >= inlength * 11)
221233d2500723e5594f3e7c70896ffeeef32b9c950ywan    return vp9_filteredinterp_filters750;
222233d2500723e5594f3e7c70896ffeeef32b9c950ywan  else if (outlength16 >= inlength * 9)
223233d2500723e5594f3e7c70896ffeeef32b9c950ywan    return vp9_filteredinterp_filters625;
224233d2500723e5594f3e7c70896ffeeef32b9c950ywan  else
225233d2500723e5594f3e7c70896ffeeef32b9c950ywan    return vp9_filteredinterp_filters500;
226233d2500723e5594f3e7c70896ffeeef32b9c950ywan}
227233d2500723e5594f3e7c70896ffeeef32b9c950ywan
228233d2500723e5594f3e7c70896ffeeef32b9c950ywanstatic void interpolate(const uint8_t *const input, int inlength,
229233d2500723e5594f3e7c70896ffeeef32b9c950ywan                        uint8_t *output, int outlength) {
230233d2500723e5594f3e7c70896ffeeef32b9c950ywan  const int64_t delta = (((uint64_t)inlength << 32) + outlength / 2) /
231233d2500723e5594f3e7c70896ffeeef32b9c950ywan      outlength;
232233d2500723e5594f3e7c70896ffeeef32b9c950ywan  const int64_t offset = inlength > outlength ?
233233d2500723e5594f3e7c70896ffeeef32b9c950ywan      (((int64_t)(inlength - outlength) << 31) + outlength / 2) / outlength :
234233d2500723e5594f3e7c70896ffeeef32b9c950ywan      -(((int64_t)(outlength - inlength) << 31) + outlength / 2) / outlength;
235233d2500723e5594f3e7c70896ffeeef32b9c950ywan  uint8_t *optr = output;
236233d2500723e5594f3e7c70896ffeeef32b9c950ywan  int x, x1, x2, sum, k, int_pel, sub_pel;
237233d2500723e5594f3e7c70896ffeeef32b9c950ywan  int64_t y;
238233d2500723e5594f3e7c70896ffeeef32b9c950ywan
239233d2500723e5594f3e7c70896ffeeef32b9c950ywan  const interp_kernel *interp_filters =
240233d2500723e5594f3e7c70896ffeeef32b9c950ywan      choose_interp_filter(inlength, outlength);
241233d2500723e5594f3e7c70896ffeeef32b9c950ywan
242233d2500723e5594f3e7c70896ffeeef32b9c950ywan  x = 0;
243233d2500723e5594f3e7c70896ffeeef32b9c950ywan  y = offset;
244233d2500723e5594f3e7c70896ffeeef32b9c950ywan  while ((y >> INTERP_PRECISION_BITS) < (INTERP_TAPS / 2 - 1)) {
245233d2500723e5594f3e7c70896ffeeef32b9c950ywan    x++;
246233d2500723e5594f3e7c70896ffeeef32b9c950ywan    y += delta;
247233d2500723e5594f3e7c70896ffeeef32b9c950ywan  }
248233d2500723e5594f3e7c70896ffeeef32b9c950ywan  x1 = x;
249233d2500723e5594f3e7c70896ffeeef32b9c950ywan  x = outlength - 1;
250233d2500723e5594f3e7c70896ffeeef32b9c950ywan  y = delta * x + offset;
251233d2500723e5594f3e7c70896ffeeef32b9c950ywan  while ((y >> INTERP_PRECISION_BITS) +
252233d2500723e5594f3e7c70896ffeeef32b9c950ywan         (int64_t)(INTERP_TAPS / 2) >= inlength) {
253233d2500723e5594f3e7c70896ffeeef32b9c950ywan    x--;
254233d2500723e5594f3e7c70896ffeeef32b9c950ywan    y -= delta;
255233d2500723e5594f3e7c70896ffeeef32b9c950ywan  }
256233d2500723e5594f3e7c70896ffeeef32b9c950ywan  x2 = x;
257233d2500723e5594f3e7c70896ffeeef32b9c950ywan  if (x1 > x2) {
258233d2500723e5594f3e7c70896ffeeef32b9c950ywan    for (x = 0, y = offset; x < outlength; ++x, y += delta) {
259233d2500723e5594f3e7c70896ffeeef32b9c950ywan      const int16_t *filter;
260233d2500723e5594f3e7c70896ffeeef32b9c950ywan      int_pel = y >> INTERP_PRECISION_BITS;
261233d2500723e5594f3e7c70896ffeeef32b9c950ywan      sub_pel = (y >> (INTERP_PRECISION_BITS - SUBPEL_BITS)) & SUBPEL_MASK;
262233d2500723e5594f3e7c70896ffeeef32b9c950ywan      filter = interp_filters[sub_pel];
263233d2500723e5594f3e7c70896ffeeef32b9c950ywan      sum = 0;
264233d2500723e5594f3e7c70896ffeeef32b9c950ywan      for (k = 0; k < INTERP_TAPS; ++k) {
265233d2500723e5594f3e7c70896ffeeef32b9c950ywan        const int pk = int_pel - INTERP_TAPS / 2 + 1 + k;
266233d2500723e5594f3e7c70896ffeeef32b9c950ywan        sum += filter[k] * input[(pk < 0 ? 0 :
267233d2500723e5594f3e7c70896ffeeef32b9c950ywan                                  (pk >= inlength ? inlength - 1 : pk))];
268233d2500723e5594f3e7c70896ffeeef32b9c950ywan      }
269233d2500723e5594f3e7c70896ffeeef32b9c950ywan      *optr++ = clip_pixel(ROUND_POWER_OF_TWO(sum, FILTER_BITS));
270233d2500723e5594f3e7c70896ffeeef32b9c950ywan    }
271233d2500723e5594f3e7c70896ffeeef32b9c950ywan  } else {
272233d2500723e5594f3e7c70896ffeeef32b9c950ywan    // Initial part.
273233d2500723e5594f3e7c70896ffeeef32b9c950ywan    for (x = 0, y = offset; x < x1; ++x, y += delta) {
274233d2500723e5594f3e7c70896ffeeef32b9c950ywan      const int16_t *filter;
275233d2500723e5594f3e7c70896ffeeef32b9c950ywan      int_pel = y >> INTERP_PRECISION_BITS;
276233d2500723e5594f3e7c70896ffeeef32b9c950ywan      sub_pel = (y >> (INTERP_PRECISION_BITS - SUBPEL_BITS)) & SUBPEL_MASK;
277233d2500723e5594f3e7c70896ffeeef32b9c950ywan      filter = interp_filters[sub_pel];
278233d2500723e5594f3e7c70896ffeeef32b9c950ywan      sum = 0;
279233d2500723e5594f3e7c70896ffeeef32b9c950ywan      for (k = 0; k < INTERP_TAPS; ++k)
280233d2500723e5594f3e7c70896ffeeef32b9c950ywan        sum += filter[k] * input[(int_pel - INTERP_TAPS / 2 + 1 + k < 0 ?
281233d2500723e5594f3e7c70896ffeeef32b9c950ywan                                  0 :
282233d2500723e5594f3e7c70896ffeeef32b9c950ywan                                  int_pel - INTERP_TAPS / 2 + 1 + k)];
283233d2500723e5594f3e7c70896ffeeef32b9c950ywan      *optr++ = clip_pixel(ROUND_POWER_OF_TWO(sum, FILTER_BITS));
284233d2500723e5594f3e7c70896ffeeef32b9c950ywan    }
285233d2500723e5594f3e7c70896ffeeef32b9c950ywan    // Middle part.
286233d2500723e5594f3e7c70896ffeeef32b9c950ywan    for (; x <= x2; ++x, y += delta) {
287233d2500723e5594f3e7c70896ffeeef32b9c950ywan      const int16_t *filter;
288233d2500723e5594f3e7c70896ffeeef32b9c950ywan      int_pel = y >> INTERP_PRECISION_BITS;
289233d2500723e5594f3e7c70896ffeeef32b9c950ywan      sub_pel = (y >> (INTERP_PRECISION_BITS - SUBPEL_BITS)) & SUBPEL_MASK;
290233d2500723e5594f3e7c70896ffeeef32b9c950ywan      filter = interp_filters[sub_pel];
291233d2500723e5594f3e7c70896ffeeef32b9c950ywan      sum = 0;
292233d2500723e5594f3e7c70896ffeeef32b9c950ywan      for (k = 0; k < INTERP_TAPS; ++k)
293233d2500723e5594f3e7c70896ffeeef32b9c950ywan        sum += filter[k] * input[int_pel - INTERP_TAPS / 2 + 1 + k];
294233d2500723e5594f3e7c70896ffeeef32b9c950ywan      *optr++ = clip_pixel(ROUND_POWER_OF_TWO(sum, FILTER_BITS));
295233d2500723e5594f3e7c70896ffeeef32b9c950ywan    }
296233d2500723e5594f3e7c70896ffeeef32b9c950ywan    // End part.
297233d2500723e5594f3e7c70896ffeeef32b9c950ywan    for (; x < outlength; ++x, y += delta) {
298233d2500723e5594f3e7c70896ffeeef32b9c950ywan      const int16_t *filter;
299233d2500723e5594f3e7c70896ffeeef32b9c950ywan      int_pel = y >> INTERP_PRECISION_BITS;
300233d2500723e5594f3e7c70896ffeeef32b9c950ywan      sub_pel = (y >> (INTERP_PRECISION_BITS - SUBPEL_BITS)) & SUBPEL_MASK;
301233d2500723e5594f3e7c70896ffeeef32b9c950ywan      filter = interp_filters[sub_pel];
302233d2500723e5594f3e7c70896ffeeef32b9c950ywan      sum = 0;
303233d2500723e5594f3e7c70896ffeeef32b9c950ywan      for (k = 0; k < INTERP_TAPS; ++k)
304233d2500723e5594f3e7c70896ffeeef32b9c950ywan        sum += filter[k] * input[(int_pel - INTERP_TAPS / 2 + 1 + k >=
305233d2500723e5594f3e7c70896ffeeef32b9c950ywan                                  inlength ?  inlength - 1 :
306233d2500723e5594f3e7c70896ffeeef32b9c950ywan                                  int_pel - INTERP_TAPS / 2 + 1 + k)];
307233d2500723e5594f3e7c70896ffeeef32b9c950ywan      *optr++ = clip_pixel(ROUND_POWER_OF_TWO(sum, FILTER_BITS));
308233d2500723e5594f3e7c70896ffeeef32b9c950ywan    }
309233d2500723e5594f3e7c70896ffeeef32b9c950ywan  }
310233d2500723e5594f3e7c70896ffeeef32b9c950ywan}
311233d2500723e5594f3e7c70896ffeeef32b9c950ywan
312233d2500723e5594f3e7c70896ffeeef32b9c950ywanstatic void down2_symeven(const uint8_t *const input, int length,
313233d2500723e5594f3e7c70896ffeeef32b9c950ywan                          uint8_t *output) {
314233d2500723e5594f3e7c70896ffeeef32b9c950ywan  // Actual filter len = 2 * filter_len_half.
315233d2500723e5594f3e7c70896ffeeef32b9c950ywan  static const int16_t *filter = vp9_down2_symeven_half_filter;
316233d2500723e5594f3e7c70896ffeeef32b9c950ywan  const int filter_len_half = sizeof(vp9_down2_symeven_half_filter) / 2;
317233d2500723e5594f3e7c70896ffeeef32b9c950ywan  int i, j;
318233d2500723e5594f3e7c70896ffeeef32b9c950ywan  uint8_t *optr = output;
319233d2500723e5594f3e7c70896ffeeef32b9c950ywan  int l1 = filter_len_half;
320233d2500723e5594f3e7c70896ffeeef32b9c950ywan  int l2 = (length - filter_len_half);
321233d2500723e5594f3e7c70896ffeeef32b9c950ywan  l1 += (l1 & 1);
322233d2500723e5594f3e7c70896ffeeef32b9c950ywan  l2 += (l2 & 1);
323233d2500723e5594f3e7c70896ffeeef32b9c950ywan  if (l1 > l2) {
324233d2500723e5594f3e7c70896ffeeef32b9c950ywan    // Short input length.
325233d2500723e5594f3e7c70896ffeeef32b9c950ywan    for (i = 0; i < length; i += 2) {
326233d2500723e5594f3e7c70896ffeeef32b9c950ywan      int sum = (1 << (FILTER_BITS - 1));
327233d2500723e5594f3e7c70896ffeeef32b9c950ywan      for (j = 0; j < filter_len_half; ++j) {
328233d2500723e5594f3e7c70896ffeeef32b9c950ywan        sum += (input[(i - j < 0 ? 0 : i - j)] +
329233d2500723e5594f3e7c70896ffeeef32b9c950ywan                input[(i + 1 + j >= length ? length - 1 : i + 1 + j)]) *
330233d2500723e5594f3e7c70896ffeeef32b9c950ywan            filter[j];
331233d2500723e5594f3e7c70896ffeeef32b9c950ywan      }
332233d2500723e5594f3e7c70896ffeeef32b9c950ywan      sum >>= FILTER_BITS;
333233d2500723e5594f3e7c70896ffeeef32b9c950ywan      *optr++ = clip_pixel(sum);
334233d2500723e5594f3e7c70896ffeeef32b9c950ywan    }
335233d2500723e5594f3e7c70896ffeeef32b9c950ywan  } else {
336233d2500723e5594f3e7c70896ffeeef32b9c950ywan    // Initial part.
337233d2500723e5594f3e7c70896ffeeef32b9c950ywan    for (i = 0; i < l1; i += 2) {
338233d2500723e5594f3e7c70896ffeeef32b9c950ywan      int sum = (1 << (FILTER_BITS - 1));
339233d2500723e5594f3e7c70896ffeeef32b9c950ywan      for (j = 0; j < filter_len_half; ++j) {
340233d2500723e5594f3e7c70896ffeeef32b9c950ywan        sum += (input[(i - j < 0 ? 0 : i - j)] + input[i + 1 + j]) * filter[j];
341233d2500723e5594f3e7c70896ffeeef32b9c950ywan      }
342233d2500723e5594f3e7c70896ffeeef32b9c950ywan      sum >>= FILTER_BITS;
343233d2500723e5594f3e7c70896ffeeef32b9c950ywan      *optr++ = clip_pixel(sum);
344233d2500723e5594f3e7c70896ffeeef32b9c950ywan    }
345233d2500723e5594f3e7c70896ffeeef32b9c950ywan    // Middle part.
346233d2500723e5594f3e7c70896ffeeef32b9c950ywan    for (; i < l2; i += 2) {
347233d2500723e5594f3e7c70896ffeeef32b9c950ywan      int sum = (1 << (FILTER_BITS - 1));
348233d2500723e5594f3e7c70896ffeeef32b9c950ywan      for (j = 0; j < filter_len_half; ++j) {
349233d2500723e5594f3e7c70896ffeeef32b9c950ywan        sum += (input[i - j] + input[i + 1 + j]) * filter[j];
350233d2500723e5594f3e7c70896ffeeef32b9c950ywan      }
351233d2500723e5594f3e7c70896ffeeef32b9c950ywan      sum >>= FILTER_BITS;
352233d2500723e5594f3e7c70896ffeeef32b9c950ywan      *optr++ = clip_pixel(sum);
353233d2500723e5594f3e7c70896ffeeef32b9c950ywan    }
354233d2500723e5594f3e7c70896ffeeef32b9c950ywan    // End part.
355233d2500723e5594f3e7c70896ffeeef32b9c950ywan    for (; i < length; i += 2) {
356233d2500723e5594f3e7c70896ffeeef32b9c950ywan      int sum = (1 << (FILTER_BITS - 1));
357233d2500723e5594f3e7c70896ffeeef32b9c950ywan      for (j = 0; j < filter_len_half; ++j) {
358233d2500723e5594f3e7c70896ffeeef32b9c950ywan        sum += (input[i - j] +
359233d2500723e5594f3e7c70896ffeeef32b9c950ywan                input[(i + 1 + j >= length ? length - 1 : i + 1 + j)]) *
360233d2500723e5594f3e7c70896ffeeef32b9c950ywan            filter[j];
361233d2500723e5594f3e7c70896ffeeef32b9c950ywan      }
362233d2500723e5594f3e7c70896ffeeef32b9c950ywan      sum >>= FILTER_BITS;
363233d2500723e5594f3e7c70896ffeeef32b9c950ywan      *optr++ = clip_pixel(sum);
364233d2500723e5594f3e7c70896ffeeef32b9c950ywan    }
365233d2500723e5594f3e7c70896ffeeef32b9c950ywan  }
366233d2500723e5594f3e7c70896ffeeef32b9c950ywan}
367233d2500723e5594f3e7c70896ffeeef32b9c950ywan
368233d2500723e5594f3e7c70896ffeeef32b9c950ywanstatic void down2_symodd(const uint8_t *const input, int length,
369233d2500723e5594f3e7c70896ffeeef32b9c950ywan                         uint8_t *output) {
370233d2500723e5594f3e7c70896ffeeef32b9c950ywan  // Actual filter len = 2 * filter_len_half - 1.
371233d2500723e5594f3e7c70896ffeeef32b9c950ywan  static const int16_t *filter = vp9_down2_symodd_half_filter;
372233d2500723e5594f3e7c70896ffeeef32b9c950ywan  const int filter_len_half = sizeof(vp9_down2_symodd_half_filter) / 2;
373233d2500723e5594f3e7c70896ffeeef32b9c950ywan  int i, j;
374233d2500723e5594f3e7c70896ffeeef32b9c950ywan  uint8_t *optr = output;
375233d2500723e5594f3e7c70896ffeeef32b9c950ywan  int l1 = filter_len_half - 1;
376233d2500723e5594f3e7c70896ffeeef32b9c950ywan  int l2 = (length - filter_len_half + 1);
377233d2500723e5594f3e7c70896ffeeef32b9c950ywan  l1 += (l1 & 1);
378233d2500723e5594f3e7c70896ffeeef32b9c950ywan  l2 += (l2 & 1);
379233d2500723e5594f3e7c70896ffeeef32b9c950ywan  if (l1 > l2) {
380233d2500723e5594f3e7c70896ffeeef32b9c950ywan    // Short input length.
381233d2500723e5594f3e7c70896ffeeef32b9c950ywan    for (i = 0; i < length; i += 2) {
382233d2500723e5594f3e7c70896ffeeef32b9c950ywan      int sum = (1 << (FILTER_BITS - 1)) + input[i] * filter[0];
383233d2500723e5594f3e7c70896ffeeef32b9c950ywan      for (j = 1; j < filter_len_half; ++j) {
384233d2500723e5594f3e7c70896ffeeef32b9c950ywan        sum += (input[(i - j < 0 ? 0 : i - j)] +
385233d2500723e5594f3e7c70896ffeeef32b9c950ywan                input[(i + j >= length ? length - 1 : i + j)]) *
386233d2500723e5594f3e7c70896ffeeef32b9c950ywan            filter[j];
387233d2500723e5594f3e7c70896ffeeef32b9c950ywan      }
388233d2500723e5594f3e7c70896ffeeef32b9c950ywan      sum >>= FILTER_BITS;
389233d2500723e5594f3e7c70896ffeeef32b9c950ywan      *optr++ = clip_pixel(sum);
390233d2500723e5594f3e7c70896ffeeef32b9c950ywan    }
391233d2500723e5594f3e7c70896ffeeef32b9c950ywan  } else {
392233d2500723e5594f3e7c70896ffeeef32b9c950ywan    // Initial part.
393233d2500723e5594f3e7c70896ffeeef32b9c950ywan    for (i = 0; i < l1; i += 2) {
394233d2500723e5594f3e7c70896ffeeef32b9c950ywan      int sum = (1 << (FILTER_BITS - 1)) + input[i] * filter[0];
395233d2500723e5594f3e7c70896ffeeef32b9c950ywan      for (j = 1; j < filter_len_half; ++j) {
396233d2500723e5594f3e7c70896ffeeef32b9c950ywan        sum += (input[(i - j < 0 ? 0 : i - j)] + input[i + j]) * filter[j];
397233d2500723e5594f3e7c70896ffeeef32b9c950ywan      }
398233d2500723e5594f3e7c70896ffeeef32b9c950ywan      sum >>= FILTER_BITS;
399233d2500723e5594f3e7c70896ffeeef32b9c950ywan      *optr++ = clip_pixel(sum);
400233d2500723e5594f3e7c70896ffeeef32b9c950ywan    }
401233d2500723e5594f3e7c70896ffeeef32b9c950ywan    // Middle part.
402233d2500723e5594f3e7c70896ffeeef32b9c950ywan    for (; i < l2; i += 2) {
403233d2500723e5594f3e7c70896ffeeef32b9c950ywan      int sum = (1 << (FILTER_BITS - 1)) + input[i] * filter[0];
404233d2500723e5594f3e7c70896ffeeef32b9c950ywan      for (j = 1; j < filter_len_half; ++j) {
405233d2500723e5594f3e7c70896ffeeef32b9c950ywan        sum += (input[i - j] + input[i + j]) * filter[j];
406233d2500723e5594f3e7c70896ffeeef32b9c950ywan      }
407233d2500723e5594f3e7c70896ffeeef32b9c950ywan      sum >>= FILTER_BITS;
408233d2500723e5594f3e7c70896ffeeef32b9c950ywan      *optr++ = clip_pixel(sum);
409233d2500723e5594f3e7c70896ffeeef32b9c950ywan    }
410233d2500723e5594f3e7c70896ffeeef32b9c950ywan    // End part.
411233d2500723e5594f3e7c70896ffeeef32b9c950ywan    for (; i < length; i += 2) {
412233d2500723e5594f3e7c70896ffeeef32b9c950ywan      int sum = (1 << (FILTER_BITS - 1)) + input[i] * filter[0];
413233d2500723e5594f3e7c70896ffeeef32b9c950ywan      for (j = 1; j < filter_len_half; ++j) {
414233d2500723e5594f3e7c70896ffeeef32b9c950ywan        sum += (input[i - j] + input[(i + j >= length ? length - 1 : i + j)]) *
415233d2500723e5594f3e7c70896ffeeef32b9c950ywan            filter[j];
416233d2500723e5594f3e7c70896ffeeef32b9c950ywan      }
417233d2500723e5594f3e7c70896ffeeef32b9c950ywan      sum >>= FILTER_BITS;
418233d2500723e5594f3e7c70896ffeeef32b9c950ywan      *optr++ = clip_pixel(sum);
419233d2500723e5594f3e7c70896ffeeef32b9c950ywan    }
420233d2500723e5594f3e7c70896ffeeef32b9c950ywan  }
421233d2500723e5594f3e7c70896ffeeef32b9c950ywan}
422233d2500723e5594f3e7c70896ffeeef32b9c950ywan
423233d2500723e5594f3e7c70896ffeeef32b9c950ywanstatic int get_down2_length(int length, int steps) {
424233d2500723e5594f3e7c70896ffeeef32b9c950ywan  int s;
425233d2500723e5594f3e7c70896ffeeef32b9c950ywan  for (s = 0; s < steps; ++s)
426233d2500723e5594f3e7c70896ffeeef32b9c950ywan    length = (length + 1) >> 1;
427233d2500723e5594f3e7c70896ffeeef32b9c950ywan  return length;
428233d2500723e5594f3e7c70896ffeeef32b9c950ywan}
429233d2500723e5594f3e7c70896ffeeef32b9c950ywan
430233d2500723e5594f3e7c70896ffeeef32b9c950ywanint get_down2_steps(int in_length, int out_length) {
431233d2500723e5594f3e7c70896ffeeef32b9c950ywan  int steps = 0;
432233d2500723e5594f3e7c70896ffeeef32b9c950ywan  int proj_in_length;
433233d2500723e5594f3e7c70896ffeeef32b9c950ywan  while ((proj_in_length = get_down2_length(in_length, 1)) >= out_length) {
434233d2500723e5594f3e7c70896ffeeef32b9c950ywan    ++steps;
435233d2500723e5594f3e7c70896ffeeef32b9c950ywan    in_length = proj_in_length;
436233d2500723e5594f3e7c70896ffeeef32b9c950ywan  }
437233d2500723e5594f3e7c70896ffeeef32b9c950ywan  return steps;
438233d2500723e5594f3e7c70896ffeeef32b9c950ywan}
439233d2500723e5594f3e7c70896ffeeef32b9c950ywan
440233d2500723e5594f3e7c70896ffeeef32b9c950ywanstatic void resize_multistep(const uint8_t *const input,
441233d2500723e5594f3e7c70896ffeeef32b9c950ywan                             int length,
442233d2500723e5594f3e7c70896ffeeef32b9c950ywan                             uint8_t *output,
443233d2500723e5594f3e7c70896ffeeef32b9c950ywan                             int olength,
444233d2500723e5594f3e7c70896ffeeef32b9c950ywan                             uint8_t *buf) {
445233d2500723e5594f3e7c70896ffeeef32b9c950ywan  int steps;
446233d2500723e5594f3e7c70896ffeeef32b9c950ywan  if (length == olength) {
447233d2500723e5594f3e7c70896ffeeef32b9c950ywan    memcpy(output, input, sizeof(uint8_t) * length);
448233d2500723e5594f3e7c70896ffeeef32b9c950ywan    return;
449233d2500723e5594f3e7c70896ffeeef32b9c950ywan  }
450233d2500723e5594f3e7c70896ffeeef32b9c950ywan  steps = get_down2_steps(length, olength);
451233d2500723e5594f3e7c70896ffeeef32b9c950ywan
452233d2500723e5594f3e7c70896ffeeef32b9c950ywan  if (steps > 0) {
453233d2500723e5594f3e7c70896ffeeef32b9c950ywan    int s;
454233d2500723e5594f3e7c70896ffeeef32b9c950ywan    uint8_t *out = NULL;
455233d2500723e5594f3e7c70896ffeeef32b9c950ywan    uint8_t *tmpbuf = NULL;
456233d2500723e5594f3e7c70896ffeeef32b9c950ywan    uint8_t *otmp, *otmp2;
457233d2500723e5594f3e7c70896ffeeef32b9c950ywan    int filteredlength = length;
458233d2500723e5594f3e7c70896ffeeef32b9c950ywan    if (!tmpbuf) {
459233d2500723e5594f3e7c70896ffeeef32b9c950ywan      tmpbuf = (uint8_t *)malloc(sizeof(uint8_t) * length);
460233d2500723e5594f3e7c70896ffeeef32b9c950ywan      otmp = tmpbuf;
461233d2500723e5594f3e7c70896ffeeef32b9c950ywan    } else {
462233d2500723e5594f3e7c70896ffeeef32b9c950ywan      otmp = buf;
463233d2500723e5594f3e7c70896ffeeef32b9c950ywan    }
464233d2500723e5594f3e7c70896ffeeef32b9c950ywan    otmp2 = otmp + get_down2_length(length, 1);
465233d2500723e5594f3e7c70896ffeeef32b9c950ywan    for (s = 0; s < steps; ++s) {
466233d2500723e5594f3e7c70896ffeeef32b9c950ywan      const int proj_filteredlength = get_down2_length(filteredlength, 1);
467233d2500723e5594f3e7c70896ffeeef32b9c950ywan      const uint8_t *const in = (s == 0 ? input : out);
468233d2500723e5594f3e7c70896ffeeef32b9c950ywan      if (s == steps - 1 && proj_filteredlength == olength)
469233d2500723e5594f3e7c70896ffeeef32b9c950ywan        out = output;
470233d2500723e5594f3e7c70896ffeeef32b9c950ywan      else
471233d2500723e5594f3e7c70896ffeeef32b9c950ywan        out = (s & 1 ? otmp2 : otmp);
472233d2500723e5594f3e7c70896ffeeef32b9c950ywan      if (filteredlength & 1)
473233d2500723e5594f3e7c70896ffeeef32b9c950ywan        down2_symodd(in, filteredlength, out);
474233d2500723e5594f3e7c70896ffeeef32b9c950ywan      else
475233d2500723e5594f3e7c70896ffeeef32b9c950ywan        down2_symeven(in, filteredlength, out);
476233d2500723e5594f3e7c70896ffeeef32b9c950ywan      filteredlength = proj_filteredlength;
477233d2500723e5594f3e7c70896ffeeef32b9c950ywan    }
478233d2500723e5594f3e7c70896ffeeef32b9c950ywan    if (filteredlength != olength) {
479233d2500723e5594f3e7c70896ffeeef32b9c950ywan      interpolate(out, filteredlength, output, olength);
480233d2500723e5594f3e7c70896ffeeef32b9c950ywan    }
481233d2500723e5594f3e7c70896ffeeef32b9c950ywan    if (tmpbuf)
482233d2500723e5594f3e7c70896ffeeef32b9c950ywan      free(tmpbuf);
483233d2500723e5594f3e7c70896ffeeef32b9c950ywan  } else {
484233d2500723e5594f3e7c70896ffeeef32b9c950ywan    interpolate(input, length, output, olength);
485233d2500723e5594f3e7c70896ffeeef32b9c950ywan  }
486233d2500723e5594f3e7c70896ffeeef32b9c950ywan}
487233d2500723e5594f3e7c70896ffeeef32b9c950ywan
488233d2500723e5594f3e7c70896ffeeef32b9c950ywanstatic void fill_col_to_arr(uint8_t *img, int stride, int len, uint8_t *arr) {
489233d2500723e5594f3e7c70896ffeeef32b9c950ywan  int i;
490233d2500723e5594f3e7c70896ffeeef32b9c950ywan  uint8_t *iptr = img;
491233d2500723e5594f3e7c70896ffeeef32b9c950ywan  uint8_t *aptr = arr;
492233d2500723e5594f3e7c70896ffeeef32b9c950ywan  for (i = 0; i < len; ++i, iptr += stride) {
493233d2500723e5594f3e7c70896ffeeef32b9c950ywan    *aptr++ = *iptr;
494233d2500723e5594f3e7c70896ffeeef32b9c950ywan  }
495233d2500723e5594f3e7c70896ffeeef32b9c950ywan}
496233d2500723e5594f3e7c70896ffeeef32b9c950ywan
497233d2500723e5594f3e7c70896ffeeef32b9c950ywanstatic void fill_arr_to_col(uint8_t *img, int stride, int len, uint8_t *arr) {
498233d2500723e5594f3e7c70896ffeeef32b9c950ywan  int i;
499233d2500723e5594f3e7c70896ffeeef32b9c950ywan  uint8_t *iptr = img;
500233d2500723e5594f3e7c70896ffeeef32b9c950ywan  uint8_t *aptr = arr;
501233d2500723e5594f3e7c70896ffeeef32b9c950ywan  for (i = 0; i < len; ++i, iptr += stride) {
502233d2500723e5594f3e7c70896ffeeef32b9c950ywan    *iptr = *aptr++;
503233d2500723e5594f3e7c70896ffeeef32b9c950ywan  }
504233d2500723e5594f3e7c70896ffeeef32b9c950ywan}
505233d2500723e5594f3e7c70896ffeeef32b9c950ywan
506233d2500723e5594f3e7c70896ffeeef32b9c950ywanvoid vp9_resize_plane(const uint8_t *const input,
507233d2500723e5594f3e7c70896ffeeef32b9c950ywan                      int height,
508233d2500723e5594f3e7c70896ffeeef32b9c950ywan                      int width,
509233d2500723e5594f3e7c70896ffeeef32b9c950ywan                      int in_stride,
510233d2500723e5594f3e7c70896ffeeef32b9c950ywan                      uint8_t *output,
511233d2500723e5594f3e7c70896ffeeef32b9c950ywan                      int height2,
512233d2500723e5594f3e7c70896ffeeef32b9c950ywan                      int width2,
513233d2500723e5594f3e7c70896ffeeef32b9c950ywan                      int out_stride) {
514233d2500723e5594f3e7c70896ffeeef32b9c950ywan  int i;
515233d2500723e5594f3e7c70896ffeeef32b9c950ywan  uint8_t *intbuf = (uint8_t *)malloc(sizeof(uint8_t) * width2 * height);
516233d2500723e5594f3e7c70896ffeeef32b9c950ywan  uint8_t *tmpbuf = (uint8_t *)malloc(sizeof(uint8_t) *
517233d2500723e5594f3e7c70896ffeeef32b9c950ywan                                      (width < height ? height : width));
518233d2500723e5594f3e7c70896ffeeef32b9c950ywan  uint8_t *arrbuf = (uint8_t *)malloc(sizeof(uint8_t) * (height + height2));
519233d2500723e5594f3e7c70896ffeeef32b9c950ywan  for (i = 0; i < height; ++i)
520233d2500723e5594f3e7c70896ffeeef32b9c950ywan    resize_multistep(input + in_stride * i, width,
521233d2500723e5594f3e7c70896ffeeef32b9c950ywan                        intbuf + width2 * i, width2, tmpbuf);
522233d2500723e5594f3e7c70896ffeeef32b9c950ywan  for (i = 0; i < width2; ++i) {
523233d2500723e5594f3e7c70896ffeeef32b9c950ywan    fill_col_to_arr(intbuf + i, width2, height, arrbuf);
524233d2500723e5594f3e7c70896ffeeef32b9c950ywan    resize_multistep(arrbuf, height, arrbuf + height, height2, tmpbuf);
525233d2500723e5594f3e7c70896ffeeef32b9c950ywan    fill_arr_to_col(output + i, out_stride, height2, arrbuf + height);
526233d2500723e5594f3e7c70896ffeeef32b9c950ywan  }
527233d2500723e5594f3e7c70896ffeeef32b9c950ywan  free(intbuf);
528233d2500723e5594f3e7c70896ffeeef32b9c950ywan  free(tmpbuf);
529233d2500723e5594f3e7c70896ffeeef32b9c950ywan  free(arrbuf);
530233d2500723e5594f3e7c70896ffeeef32b9c950ywan}
531233d2500723e5594f3e7c70896ffeeef32b9c950ywan
532233d2500723e5594f3e7c70896ffeeef32b9c950ywanvoid vp9_resize_frame420(const uint8_t *const y,
533233d2500723e5594f3e7c70896ffeeef32b9c950ywan                         int y_stride,
534233d2500723e5594f3e7c70896ffeeef32b9c950ywan                         const uint8_t *const u, const uint8_t *const v,
535233d2500723e5594f3e7c70896ffeeef32b9c950ywan                         int uv_stride,
536233d2500723e5594f3e7c70896ffeeef32b9c950ywan                         int height, int width,
537233d2500723e5594f3e7c70896ffeeef32b9c950ywan                         uint8_t *oy, int oy_stride,
538233d2500723e5594f3e7c70896ffeeef32b9c950ywan                         uint8_t *ou, uint8_t *ov, int ouv_stride,
539233d2500723e5594f3e7c70896ffeeef32b9c950ywan                         int oheight, int owidth) {
540233d2500723e5594f3e7c70896ffeeef32b9c950ywan  vp9_resize_plane(y, height, width, y_stride,
541233d2500723e5594f3e7c70896ffeeef32b9c950ywan                   oy, oheight, owidth, oy_stride);
542233d2500723e5594f3e7c70896ffeeef32b9c950ywan  vp9_resize_plane(u, height / 2, width / 2, uv_stride,
543233d2500723e5594f3e7c70896ffeeef32b9c950ywan                   ou, oheight / 2, owidth / 2, ouv_stride);
544233d2500723e5594f3e7c70896ffeeef32b9c950ywan  vp9_resize_plane(v, height / 2, width / 2, uv_stride,
545233d2500723e5594f3e7c70896ffeeef32b9c950ywan                   ov, oheight / 2, owidth / 2, ouv_stride);
546233d2500723e5594f3e7c70896ffeeef32b9c950ywan}
547233d2500723e5594f3e7c70896ffeeef32b9c950ywan
548233d2500723e5594f3e7c70896ffeeef32b9c950ywanvoid vp9_resize_frame422(const uint8_t *const y, int y_stride,
549233d2500723e5594f3e7c70896ffeeef32b9c950ywan                         const uint8_t *const u, const uint8_t *const v,
550233d2500723e5594f3e7c70896ffeeef32b9c950ywan                         int uv_stride,
551233d2500723e5594f3e7c70896ffeeef32b9c950ywan                         int height, int width,
552233d2500723e5594f3e7c70896ffeeef32b9c950ywan                         uint8_t *oy, int oy_stride,
553233d2500723e5594f3e7c70896ffeeef32b9c950ywan                         uint8_t *ou, uint8_t *ov, int ouv_stride,
554233d2500723e5594f3e7c70896ffeeef32b9c950ywan                         int oheight, int owidth) {
555233d2500723e5594f3e7c70896ffeeef32b9c950ywan  vp9_resize_plane(y, height, width, y_stride,
556233d2500723e5594f3e7c70896ffeeef32b9c950ywan                   oy, oheight, owidth, oy_stride);
557233d2500723e5594f3e7c70896ffeeef32b9c950ywan  vp9_resize_plane(u, height, width / 2, uv_stride,
558233d2500723e5594f3e7c70896ffeeef32b9c950ywan                   ou, oheight, owidth / 2, ouv_stride);
559233d2500723e5594f3e7c70896ffeeef32b9c950ywan  vp9_resize_plane(v, height, width / 2, uv_stride,
560233d2500723e5594f3e7c70896ffeeef32b9c950ywan                   ov, oheight, owidth / 2, ouv_stride);
561233d2500723e5594f3e7c70896ffeeef32b9c950ywan}
562233d2500723e5594f3e7c70896ffeeef32b9c950ywan
563233d2500723e5594f3e7c70896ffeeef32b9c950ywanvoid vp9_resize_frame444(const uint8_t *const y, int y_stride,
564233d2500723e5594f3e7c70896ffeeef32b9c950ywan                         const uint8_t *const u, const uint8_t *const v,
565233d2500723e5594f3e7c70896ffeeef32b9c950ywan                         int uv_stride,
566233d2500723e5594f3e7c70896ffeeef32b9c950ywan                         int height, int width,
567233d2500723e5594f3e7c70896ffeeef32b9c950ywan                         uint8_t *oy, int oy_stride,
568233d2500723e5594f3e7c70896ffeeef32b9c950ywan                         uint8_t *ou, uint8_t *ov, int ouv_stride,
569233d2500723e5594f3e7c70896ffeeef32b9c950ywan                         int oheight, int owidth) {
570233d2500723e5594f3e7c70896ffeeef32b9c950ywan  vp9_resize_plane(y, height, width, y_stride,
571233d2500723e5594f3e7c70896ffeeef32b9c950ywan                   oy, oheight, owidth, oy_stride);
572233d2500723e5594f3e7c70896ffeeef32b9c950ywan  vp9_resize_plane(u, height, width, uv_stride,
573233d2500723e5594f3e7c70896ffeeef32b9c950ywan                   ou, oheight, owidth, ouv_stride);
574233d2500723e5594f3e7c70896ffeeef32b9c950ywan  vp9_resize_plane(v, height, width, uv_stride,
575233d2500723e5594f3e7c70896ffeeef32b9c950ywan                   ov, oheight, owidth, ouv_stride);
576233d2500723e5594f3e7c70896ffeeef32b9c950ywan}
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