1 /*
2 * Copyright (c) 2016, Alliance for Open Media. All rights reserved.
3 *
4 * This source code is subject to the terms of the BSD 2 Clause License and
5 * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
6 * was not distributed with this source code in the LICENSE file, you can
7 * obtain it at www.aomedia.org/license/software. If the Alliance for Open
8 * Media Patent License 1.0 was not distributed with this source code in the
9 * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
10 */
11
12 #include "config/aom_dsp_rtcd.h"
13 #include "config/av1_rtcd.h"
14
15 #include "av1/common/filter.h"
16 #include "av1/common/scale.h"
17 #include "aom_dsp/aom_filter.h"
18
get_fixed_point_scale_factor(int other_size,int this_size)19 static int get_fixed_point_scale_factor(int other_size, int this_size) {
20 // Calculate scaling factor once for each reference frame
21 // and use fixed point scaling factors in decoding and encoding routines.
22 // Hardware implementations can calculate scale factor in device driver
23 // and use multiplication and shifting on hardware instead of division.
24 return ((other_size << REF_SCALE_SHIFT) + this_size / 2) / this_size;
25 }
26
27 // Given the fixed point scale, calculate coarse point scale.
fixed_point_scale_to_coarse_point_scale(int scale_fp)28 static int fixed_point_scale_to_coarse_point_scale(int scale_fp) {
29 return ROUND_POWER_OF_TWO(scale_fp, REF_SCALE_SHIFT - SCALE_SUBPEL_BITS);
30 }
31
32 // Note: x and y are integer precision, mvq4 is q4 precision.
av1_scale_mv(const MV * mvq4,int x,int y,const struct scale_factors * sf)33 MV32 av1_scale_mv(const MV *mvq4, int x, int y,
34 const struct scale_factors *sf) {
35 const int x_off_q4 = av1_scaled_x(x << SUBPEL_BITS, sf);
36 const int y_off_q4 = av1_scaled_y(y << SUBPEL_BITS, sf);
37 const MV32 res = {
38 av1_scaled_y((y << SUBPEL_BITS) + mvq4->row, sf) - y_off_q4,
39 av1_scaled_x((x << SUBPEL_BITS) + mvq4->col, sf) - x_off_q4
40 };
41 return res;
42 }
43
av1_setup_scale_factors_for_frame(struct scale_factors * sf,int other_w,int other_h,int this_w,int this_h)44 void av1_setup_scale_factors_for_frame(struct scale_factors *sf, int other_w,
45 int other_h, int this_w, int this_h) {
46 if (!valid_ref_frame_size(other_w, other_h, this_w, this_h)) {
47 sf->x_scale_fp = REF_INVALID_SCALE;
48 sf->y_scale_fp = REF_INVALID_SCALE;
49 return;
50 }
51
52 sf->x_scale_fp = get_fixed_point_scale_factor(other_w, this_w);
53 sf->y_scale_fp = get_fixed_point_scale_factor(other_h, this_h);
54
55 sf->x_step_q4 = fixed_point_scale_to_coarse_point_scale(sf->x_scale_fp);
56 sf->y_step_q4 = fixed_point_scale_to_coarse_point_scale(sf->y_scale_fp);
57 }
58