ref: 52bf93479c30bc15d6d3d6d1b813a0284ae5adfc
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_common *sfc) {
return val * sfc->x_scale_fp >> REF_SCALE_SHIFT;
}
static INLINE int scaled_y(int val, const struct scale_factors_common *sfc) {
return val * sfc->y_scale_fp >> REF_SCALE_SHIFT;
}
static int unscaled_value(int val, const struct scale_factors_common *sfc) {
(void) sfc;
return val;
}
static MV32 scaled_mv(const MV *mv, const struct scale_factors *scale) {
const MV32 res = {
scaled_y(mv->row, scale->sfc) + scale->y_offset_q4,
scaled_x(mv->col, scale->sfc) + scale->x_offset_q4
};
return res;
}
static MV32 unscaled_mv(const MV *mv, const struct scale_factors *scale) {
const MV32 res = {
mv->row,
mv->col
};
return res;
}
static void set_offsets_with_scaling(struct scale_factors *scale,
int row, int col) {
scale->x_offset_q4 = scaled_x(col << SUBPEL_BITS, scale->sfc) & SUBPEL_MASK;
scale->y_offset_q4 = scaled_y(row << SUBPEL_BITS, scale->sfc) & SUBPEL_MASK;
}
static void set_offsets_without_scaling(struct scale_factors *scale,
int row, int col) {
scale->x_offset_q4 = 0;
scale->y_offset_q4 = 0;
}
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;
}
static int check_scale_factors(int other_w, int other_h,
int this_w, int this_h) {
return 2 * this_w >= other_w &&
2 * this_h >= other_h &&
this_w <= 16 * other_w &&
this_h <= 16 * other_h;
}
void vp9_setup_scale_factors_for_frame(struct scale_factors *scale,
struct scale_factors_common *scale_comm,
int other_w, int other_h,
int this_w, int this_h) {
if (!check_scale_factors(other_w, other_h, this_w, this_h)) {
scale_comm->x_scale_fp = REF_INVALID_SCALE;
scale_comm->y_scale_fp = REF_INVALID_SCALE;
return;
}
scale_comm->x_scale_fp = get_fixed_point_scale_factor(other_w, this_w);
scale_comm->y_scale_fp = get_fixed_point_scale_factor(other_h, this_h);
scale_comm->x_step_q4 = scaled_x(16, scale_comm);
scale_comm->y_step_q4 = scaled_y(16, scale_comm);
if (vp9_is_scaled(scale_comm)) {
scale_comm->scale_value_x = scaled_x;
scale_comm->scale_value_y = scaled_y;
scale_comm->set_scaled_offsets = set_offsets_with_scaling;
scale_comm->scale_mv = scaled_mv;
} else {
scale_comm->scale_value_x = unscaled_value;
scale_comm->scale_value_y = unscaled_value;
scale_comm->set_scaled_offsets = set_offsets_without_scaling;
scale_comm->scale_mv = unscaled_mv;
}
// 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 (scale_comm->x_step_q4 == 16) {
if (scale_comm->y_step_q4 == 16) {
// No scaling in either direction.
scale_comm->predict[0][0][0] = vp9_convolve_copy;
scale_comm->predict[0][0][1] = vp9_convolve_avg;
scale_comm->predict[0][1][0] = vp9_convolve8_vert;
scale_comm->predict[0][1][1] = vp9_convolve8_avg_vert;
scale_comm->predict[1][0][0] = vp9_convolve8_horiz;
scale_comm->predict[1][0][1] = vp9_convolve8_avg_horiz;
} else {
// No scaling in x direction. Must always scale in the y direction.
scale_comm->predict[0][0][0] = vp9_convolve8_vert;
scale_comm->predict[0][0][1] = vp9_convolve8_avg_vert;
scale_comm->predict[0][1][0] = vp9_convolve8_vert;
scale_comm->predict[0][1][1] = vp9_convolve8_avg_vert;
scale_comm->predict[1][0][0] = vp9_convolve8;
scale_comm->predict[1][0][1] = vp9_convolve8_avg;
}
} else {
if (scale_comm->y_step_q4 == 16) {
// No scaling in the y direction. Must always scale in the x direction.
scale_comm->predict[0][0][0] = vp9_convolve8_horiz;
scale_comm->predict[0][0][1] = vp9_convolve8_avg_horiz;
scale_comm->predict[0][1][0] = vp9_convolve8;
scale_comm->predict[0][1][1] = vp9_convolve8_avg;
scale_comm->predict[1][0][0] = vp9_convolve8_horiz;
scale_comm->predict[1][0][1] = vp9_convolve8_avg_horiz;
} else {
// Must always scale in both directions.
scale_comm->predict[0][0][0] = vp9_convolve8;
scale_comm->predict[0][0][1] = vp9_convolve8_avg;
scale_comm->predict[0][1][0] = vp9_convolve8;
scale_comm->predict[0][1][1] = vp9_convolve8_avg;
scale_comm->predict[1][0][0] = vp9_convolve8;
scale_comm->predict[1][0][1] = vp9_convolve8_avg;
}
}
// 2D subpel motion always gets filtered in both directions
scale_comm->predict[1][1][0] = vp9_convolve8;
scale_comm->predict[1][1][1] = vp9_convolve8_avg;
scale->sfc = scale_comm;
scale->x_offset_q4 = 0; // calculated per block
scale->y_offset_q4 = 0; // calculated per block
}