57 lines
2.3 KiB
C
57 lines
2.3 KiB
C
/*
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* Copyright (c) 2016, Alliance for Open Media. All rights reserved
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*
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* This source code is subject to the terms of the BSD 2 Clause License and
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* the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
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* was not distributed with this source code in the LICENSE file, you can
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* obtain it at www.aomedia.org/license/software. If the Alliance for Open
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* Media Patent License 1.0 was not distributed with this source code in the
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* PATENTS file, you can obtain it at www.aomedia.org/license/patent.
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*/
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#include "config/aom_dsp_rtcd.h"
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#include "config/av1_rtcd.h"
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#include "av1/common/filter.h"
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#include "av1/common/scale.h"
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#include "aom_dsp/aom_filter.h"
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static int get_fixed_point_scale_factor(int other_size, int this_size) {
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// Calculate scaling factor once for each reference frame
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// and use fixed point scaling factors in decoding and encoding routines.
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// Hardware implementations can calculate scale factor in device driver
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// and use multiplication and shifting on hardware instead of division.
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return ((other_size << REF_SCALE_SHIFT) + this_size / 2) / this_size;
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}
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// Given the fixed point scale, calculate coarse point scale.
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static int fixed_point_scale_to_coarse_point_scale(int scale_fp) {
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return ROUND_POWER_OF_TWO(scale_fp, REF_SCALE_SHIFT - SCALE_SUBPEL_BITS);
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}
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// Note: x and y are integer precision, mvq4 is q4 precision.
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MV32 av1_scale_mv(const MV *mvq4, int x, int y,
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const struct scale_factors *sf) {
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const int x_off_q4 = av1_scaled_x(x << SUBPEL_BITS, sf);
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const int y_off_q4 = av1_scaled_y(y << SUBPEL_BITS, sf);
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const MV32 res = {
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av1_scaled_y((y << SUBPEL_BITS) + mvq4->row, sf) - y_off_q4,
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av1_scaled_x((x << SUBPEL_BITS) + mvq4->col, sf) - x_off_q4
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};
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return res;
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}
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void av1_setup_scale_factors_for_frame(struct scale_factors *sf, int other_w,
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int other_h, int this_w, int this_h) {
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if (!valid_ref_frame_size(other_w, other_h, this_w, this_h)) {
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sf->x_scale_fp = REF_INVALID_SCALE;
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sf->y_scale_fp = REF_INVALID_SCALE;
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return;
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}
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sf->x_scale_fp = get_fixed_point_scale_factor(other_w, this_w);
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sf->y_scale_fp = get_fixed_point_scale_factor(other_h, this_h);
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sf->x_step_q4 = fixed_point_scale_to_coarse_point_scale(sf->x_scale_fp);
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sf->y_step_q4 = fixed_point_scale_to_coarse_point_scale(sf->y_scale_fp);
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}
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