media/libvpx/vp9/common/vp9_scale.c

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1 /*
2 * Copyright (c) 2013 The WebM project authors. All Rights Reserved.
3 *
4 * Use of this source code is governed by a BSD-style license
5 * that can be found in the LICENSE file in the root of the source
6 * tree. An additional intellectual property rights grant can be found
7 * in the file PATENTS. All contributing project authors may
8 * be found in the AUTHORS file in the root of the source tree.
9 */
10
11 #include "./vp9_rtcd.h"
12 #include "vp9/common/vp9_filter.h"
13 #include "vp9/common/vp9_scale.h"
14
15 static INLINE int scaled_x(int val, const struct scale_factors_common *sfc) {
16 return val * sfc->x_scale_fp >> REF_SCALE_SHIFT;
17 }
18
19 static INLINE int scaled_y(int val, const struct scale_factors_common *sfc) {
20 return val * sfc->y_scale_fp >> REF_SCALE_SHIFT;
21 }
22
23 static int unscaled_value(int val, const struct scale_factors_common *sfc) {
24 (void) sfc;
25 return val;
26 }
27
28 static MV32 scaled_mv(const MV *mv, const struct scale_factors *scale) {
29 const MV32 res = {
30 scaled_y(mv->row, scale->sfc) + scale->y_offset_q4,
31 scaled_x(mv->col, scale->sfc) + scale->x_offset_q4
32 };
33 return res;
34 }
35
36 static MV32 unscaled_mv(const MV *mv, const struct scale_factors *scale) {
37 const MV32 res = {
38 mv->row,
39 mv->col
40 };
41 return res;
42 }
43
44 static void set_offsets_with_scaling(struct scale_factors *scale,
45 int row, int col) {
46 scale->x_offset_q4 = scaled_x(col << SUBPEL_BITS, scale->sfc) & SUBPEL_MASK;
47 scale->y_offset_q4 = scaled_y(row << SUBPEL_BITS, scale->sfc) & SUBPEL_MASK;
48 }
49
50 static void set_offsets_without_scaling(struct scale_factors *scale,
51 int row, int col) {
52 scale->x_offset_q4 = 0;
53 scale->y_offset_q4 = 0;
54 }
55
56 static int get_fixed_point_scale_factor(int other_size, int this_size) {
57 // Calculate scaling factor once for each reference frame
58 // and use fixed point scaling factors in decoding and encoding routines.
59 // Hardware implementations can calculate scale factor in device driver
60 // and use multiplication and shifting on hardware instead of division.
61 return (other_size << REF_SCALE_SHIFT) / this_size;
62 }
63
64 static int check_scale_factors(int other_w, int other_h,
65 int this_w, int this_h) {
66 return 2 * this_w >= other_w &&
67 2 * this_h >= other_h &&
68 this_w <= 16 * other_w &&
69 this_h <= 16 * other_h;
70 }
71
72 void vp9_setup_scale_factors_for_frame(struct scale_factors *scale,
73 struct scale_factors_common *scale_comm,
74 int other_w, int other_h,
75 int this_w, int this_h) {
76 if (!check_scale_factors(other_w, other_h, this_w, this_h)) {
77 scale_comm->x_scale_fp = REF_INVALID_SCALE;
78 scale_comm->y_scale_fp = REF_INVALID_SCALE;
79 return;
80 }
81
82 scale_comm->x_scale_fp = get_fixed_point_scale_factor(other_w, this_w);
83 scale_comm->y_scale_fp = get_fixed_point_scale_factor(other_h, this_h);
84 scale_comm->x_step_q4 = scaled_x(16, scale_comm);
85 scale_comm->y_step_q4 = scaled_y(16, scale_comm);
86
87 if (vp9_is_scaled(scale_comm)) {
88 scale_comm->scale_value_x = scaled_x;
89 scale_comm->scale_value_y = scaled_y;
90 scale_comm->set_scaled_offsets = set_offsets_with_scaling;
91 scale_comm->scale_mv = scaled_mv;
92 } else {
93 scale_comm->scale_value_x = unscaled_value;
94 scale_comm->scale_value_y = unscaled_value;
95 scale_comm->set_scaled_offsets = set_offsets_without_scaling;
96 scale_comm->scale_mv = unscaled_mv;
97 }
98
99 // TODO(agrange): Investigate the best choice of functions to use here
100 // for EIGHTTAP_SMOOTH. Since it is not interpolating, need to choose what
101 // to do at full-pel offsets. The current selection, where the filter is
102 // applied in one direction only, and not at all for 0,0, seems to give the
103 // best quality, but it may be worth trying an additional mode that does
104 // do the filtering on full-pel.
105 if (scale_comm->x_step_q4 == 16) {
106 if (scale_comm->y_step_q4 == 16) {
107 // No scaling in either direction.
108 scale_comm->predict[0][0][0] = vp9_convolve_copy;
109 scale_comm->predict[0][0][1] = vp9_convolve_avg;
110 scale_comm->predict[0][1][0] = vp9_convolve8_vert;
111 scale_comm->predict[0][1][1] = vp9_convolve8_avg_vert;
112 scale_comm->predict[1][0][0] = vp9_convolve8_horiz;
113 scale_comm->predict[1][0][1] = vp9_convolve8_avg_horiz;
114 } else {
115 // No scaling in x direction. Must always scale in the y direction.
116 scale_comm->predict[0][0][0] = vp9_convolve8_vert;
117 scale_comm->predict[0][0][1] = vp9_convolve8_avg_vert;
118 scale_comm->predict[0][1][0] = vp9_convolve8_vert;
119 scale_comm->predict[0][1][1] = vp9_convolve8_avg_vert;
120 scale_comm->predict[1][0][0] = vp9_convolve8;
121 scale_comm->predict[1][0][1] = vp9_convolve8_avg;
122 }
123 } else {
124 if (scale_comm->y_step_q4 == 16) {
125 // No scaling in the y direction. Must always scale in the x direction.
126 scale_comm->predict[0][0][0] = vp9_convolve8_horiz;
127 scale_comm->predict[0][0][1] = vp9_convolve8_avg_horiz;
128 scale_comm->predict[0][1][0] = vp9_convolve8;
129 scale_comm->predict[0][1][1] = vp9_convolve8_avg;
130 scale_comm->predict[1][0][0] = vp9_convolve8_horiz;
131 scale_comm->predict[1][0][1] = vp9_convolve8_avg_horiz;
132 } else {
133 // Must always scale in both directions.
134 scale_comm->predict[0][0][0] = vp9_convolve8;
135 scale_comm->predict[0][0][1] = vp9_convolve8_avg;
136 scale_comm->predict[0][1][0] = vp9_convolve8;
137 scale_comm->predict[0][1][1] = vp9_convolve8_avg;
138 scale_comm->predict[1][0][0] = vp9_convolve8;
139 scale_comm->predict[1][0][1] = vp9_convolve8_avg;
140 }
141 }
142 // 2D subpel motion always gets filtered in both directions
143 scale_comm->predict[1][1][0] = vp9_convolve8;
144 scale_comm->predict[1][1][1] = vp9_convolve8_avg;
145
146 scale->sfc = scale_comm;
147 scale->x_offset_q4 = 0; // calculated per block
148 scale->y_offset_q4 = 0; // calculated per block
149 }

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