ref: c2c03f2b58cc4c821cd0ac38e5eb6de705fff415
dir: /vp9/common/vp9_scale.c/
/*
* Copyright (c) 2013 The WebM project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "./vp9_rtcd.h"
#include "vp9/common/vp9_filter.h"
#include "vp9/common/vp9_scale.h"
static INLINE int scaled_x(int val, const struct scale_factors *sf) {
return (int)((int64_t)val * sf->x_scale_fp >> REF_SCALE_SHIFT);
}
static INLINE int scaled_y(int val, const struct scale_factors *sf) {
return (int)((int64_t)val * sf->y_scale_fp >> REF_SCALE_SHIFT);
}
static int unscaled_value(int val, const struct scale_factors *sf) {
(void) sf;
return val;
}
static int get_fixed_point_scale_factor(int other_size, int this_size) {
// Calculate scaling factor once for each reference frame
// and use fixed point scaling factors in decoding and encoding routines.
// Hardware implementations can calculate scale factor in device driver
// and use multiplication and shifting on hardware instead of division.
return (other_size << REF_SCALE_SHIFT) / this_size;
}
MV32 vp9_scale_mv(const MV *mv, int x, int y, const struct scale_factors *sf) {
const int x_off_q4 = scaled_x(x << SUBPEL_BITS, sf) & SUBPEL_MASK;
const int y_off_q4 = scaled_y(y << SUBPEL_BITS, sf) & SUBPEL_MASK;
const MV32 res = {
scaled_y(mv->row, sf) + y_off_q4,
scaled_x(mv->col, sf) + x_off_q4
};
return res;
}
void vp9_setup_scale_factors_for_frame(struct scale_factors *sf,
int other_w, int other_h,
int this_w, int this_h) {
if (!valid_ref_frame_size(other_w, other_h, this_w, this_h)) {
sf->x_scale_fp = REF_INVALID_SCALE;
sf->y_scale_fp = REF_INVALID_SCALE;
return;
}
sf->x_scale_fp = get_fixed_point_scale_factor(other_w, this_w);
sf->y_scale_fp = get_fixed_point_scale_factor(other_h, this_h);
sf->x_step_q4 = scaled_x(16, sf);
sf->y_step_q4 = scaled_y(16, sf);
if (vp9_is_scaled(sf)) {
sf->scale_value_x = scaled_x;
sf->scale_value_y = scaled_y;
} else {
sf->scale_value_x = unscaled_value;
sf->scale_value_y = unscaled_value;
}
// TODO(agrange): Investigate the best choice of functions to use here
// for EIGHTTAP_SMOOTH. Since it is not interpolating, need to choose what
// to do at full-pel offsets. The current selection, where the filter is
// applied in one direction only, and not at all for 0,0, seems to give the
// best quality, but it may be worth trying an additional mode that does
// do the filtering on full-pel.
if (sf->x_step_q4 == 16) {
if (sf->y_step_q4 == 16) {
// No scaling in either direction.
sf->predict[0][0][0] = vp9_convolve_copy;
sf->predict[0][0][1] = vp9_convolve_avg;
sf->predict[0][1][0] = vp9_convolve8_vert;
sf->predict[0][1][1] = vp9_convolve8_avg_vert;
sf->predict[1][0][0] = vp9_convolve8_horiz;
sf->predict[1][0][1] = vp9_convolve8_avg_horiz;
} else {
// No scaling in x direction. Must always scale in the y direction.
sf->predict[0][0][0] = vp9_convolve8_vert;
sf->predict[0][0][1] = vp9_convolve8_avg_vert;
sf->predict[0][1][0] = vp9_convolve8_vert;
sf->predict[0][1][1] = vp9_convolve8_avg_vert;
sf->predict[1][0][0] = vp9_convolve8;
sf->predict[1][0][1] = vp9_convolve8_avg;
}
} else {
if (sf->y_step_q4 == 16) {
// No scaling in the y direction. Must always scale in the x direction.
sf->predict[0][0][0] = vp9_convolve8_horiz;
sf->predict[0][0][1] = vp9_convolve8_avg_horiz;
sf->predict[0][1][0] = vp9_convolve8;
sf->predict[0][1][1] = vp9_convolve8_avg;
sf->predict[1][0][0] = vp9_convolve8_horiz;
sf->predict[1][0][1] = vp9_convolve8_avg_horiz;
} else {
// Must always scale in both directions.
sf->predict[0][0][0] = vp9_convolve8;
sf->predict[0][0][1] = vp9_convolve8_avg;
sf->predict[0][1][0] = vp9_convolve8;
sf->predict[0][1][1] = vp9_convolve8_avg;
sf->predict[1][0][0] = vp9_convolve8;
sf->predict[1][0][1] = vp9_convolve8_avg;
}
}
// 2D subpel motion always gets filtered in both directions
sf->predict[1][1][0] = vp9_convolve8;
sf->predict[1][1][1] = vp9_convolve8_avg;
}