michael@0: /*
michael@0:  *  Copyright (c) 2013 The WebM project authors. All Rights Reserved.
michael@0:  *
michael@0:  *  Use of this source code is governed by a BSD-style license
michael@0:  *  that can be found in the LICENSE file in the root of the source
michael@0:  *  tree. An additional intellectual property rights grant can be found
michael@0:  *  in the file PATENTS.  All contributing project authors may
michael@0:  *  be found in the AUTHORS file in the root of the source tree.
michael@0:  */
michael@0: 
michael@0: #include "./vp9_rtcd.h"
michael@0: #include "vp9/common/vp9_filter.h"
michael@0: #include "vp9/common/vp9_scale.h"
michael@0: 
michael@0: static INLINE int scaled_x(int val, const struct scale_factors_common *sfc) {
michael@0:   return val * sfc->x_scale_fp >> REF_SCALE_SHIFT;
michael@0: }
michael@0: 
michael@0: static INLINE int scaled_y(int val, const struct scale_factors_common *sfc) {
michael@0:   return val * sfc->y_scale_fp >> REF_SCALE_SHIFT;
michael@0: }
michael@0: 
michael@0: static int unscaled_value(int val, const struct scale_factors_common *sfc) {
michael@0:   (void) sfc;
michael@0:   return val;
michael@0: }
michael@0: 
michael@0: static MV32 scaled_mv(const MV *mv, const struct scale_factors *scale) {
michael@0:   const MV32 res = {
michael@0:     scaled_y(mv->row, scale->sfc) + scale->y_offset_q4,
michael@0:     scaled_x(mv->col, scale->sfc) + scale->x_offset_q4
michael@0:   };
michael@0:   return res;
michael@0: }
michael@0: 
michael@0: static MV32 unscaled_mv(const MV *mv, const struct scale_factors *scale) {
michael@0:   const MV32 res = {
michael@0:     mv->row,
michael@0:     mv->col
michael@0:   };
michael@0:   return res;
michael@0: }
michael@0: 
michael@0: static void set_offsets_with_scaling(struct scale_factors *scale,
michael@0:                                      int row, int col) {
michael@0:   scale->x_offset_q4 = scaled_x(col << SUBPEL_BITS, scale->sfc) & SUBPEL_MASK;
michael@0:   scale->y_offset_q4 = scaled_y(row << SUBPEL_BITS, scale->sfc) & SUBPEL_MASK;
michael@0: }
michael@0: 
michael@0: static void set_offsets_without_scaling(struct scale_factors *scale,
michael@0:                                         int row, int col) {
michael@0:   scale->x_offset_q4 = 0;
michael@0:   scale->y_offset_q4 = 0;
michael@0: }
michael@0: 
michael@0: static int get_fixed_point_scale_factor(int other_size, int this_size) {
michael@0:   // Calculate scaling factor once for each reference frame
michael@0:   // and use fixed point scaling factors in decoding and encoding routines.
michael@0:   // Hardware implementations can calculate scale factor in device driver
michael@0:   // and use multiplication and shifting on hardware instead of division.
michael@0:   return (other_size << REF_SCALE_SHIFT) / this_size;
michael@0: }
michael@0: 
michael@0: static int check_scale_factors(int other_w, int other_h,
michael@0:                                int this_w, int this_h) {
michael@0:   return 2 * this_w >= other_w &&
michael@0:          2 * this_h >= other_h &&
michael@0:          this_w <= 16 * other_w &&
michael@0:          this_h <= 16 * other_h;
michael@0: }
michael@0: 
michael@0: void vp9_setup_scale_factors_for_frame(struct scale_factors *scale,
michael@0:                                        struct scale_factors_common *scale_comm,
michael@0:                                        int other_w, int other_h,
michael@0:                                        int this_w, int this_h) {
michael@0:   if (!check_scale_factors(other_w, other_h, this_w, this_h)) {
michael@0:     scale_comm->x_scale_fp = REF_INVALID_SCALE;
michael@0:     scale_comm->y_scale_fp = REF_INVALID_SCALE;
michael@0:     return;
michael@0:   }
michael@0: 
michael@0:   scale_comm->x_scale_fp = get_fixed_point_scale_factor(other_w, this_w);
michael@0:   scale_comm->y_scale_fp = get_fixed_point_scale_factor(other_h, this_h);
michael@0:   scale_comm->x_step_q4 = scaled_x(16, scale_comm);
michael@0:   scale_comm->y_step_q4 = scaled_y(16, scale_comm);
michael@0: 
michael@0:   if (vp9_is_scaled(scale_comm)) {
michael@0:     scale_comm->scale_value_x = scaled_x;
michael@0:     scale_comm->scale_value_y = scaled_y;
michael@0:     scale_comm->set_scaled_offsets = set_offsets_with_scaling;
michael@0:     scale_comm->scale_mv = scaled_mv;
michael@0:   } else {
michael@0:     scale_comm->scale_value_x = unscaled_value;
michael@0:     scale_comm->scale_value_y = unscaled_value;
michael@0:     scale_comm->set_scaled_offsets = set_offsets_without_scaling;
michael@0:     scale_comm->scale_mv = unscaled_mv;
michael@0:   }
michael@0: 
michael@0:   // TODO(agrange): Investigate the best choice of functions to use here
michael@0:   // for EIGHTTAP_SMOOTH. Since it is not interpolating, need to choose what
michael@0:   // to do at full-pel offsets. The current selection, where the filter is
michael@0:   // applied in one direction only, and not at all for 0,0, seems to give the
michael@0:   // best quality, but it may be worth trying an additional mode that does
michael@0:   // do the filtering on full-pel.
michael@0:   if (scale_comm->x_step_q4 == 16) {
michael@0:     if (scale_comm->y_step_q4 == 16) {
michael@0:       // No scaling in either direction.
michael@0:       scale_comm->predict[0][0][0] = vp9_convolve_copy;
michael@0:       scale_comm->predict[0][0][1] = vp9_convolve_avg;
michael@0:       scale_comm->predict[0][1][0] = vp9_convolve8_vert;
michael@0:       scale_comm->predict[0][1][1] = vp9_convolve8_avg_vert;
michael@0:       scale_comm->predict[1][0][0] = vp9_convolve8_horiz;
michael@0:       scale_comm->predict[1][0][1] = vp9_convolve8_avg_horiz;
michael@0:     } else {
michael@0:       // No scaling in x direction. Must always scale in the y direction.
michael@0:       scale_comm->predict[0][0][0] = vp9_convolve8_vert;
michael@0:       scale_comm->predict[0][0][1] = vp9_convolve8_avg_vert;
michael@0:       scale_comm->predict[0][1][0] = vp9_convolve8_vert;
michael@0:       scale_comm->predict[0][1][1] = vp9_convolve8_avg_vert;
michael@0:       scale_comm->predict[1][0][0] = vp9_convolve8;
michael@0:       scale_comm->predict[1][0][1] = vp9_convolve8_avg;
michael@0:     }
michael@0:   } else {
michael@0:     if (scale_comm->y_step_q4 == 16) {
michael@0:       // No scaling in the y direction. Must always scale in the x direction.
michael@0:       scale_comm->predict[0][0][0] = vp9_convolve8_horiz;
michael@0:       scale_comm->predict[0][0][1] = vp9_convolve8_avg_horiz;
michael@0:       scale_comm->predict[0][1][0] = vp9_convolve8;
michael@0:       scale_comm->predict[0][1][1] = vp9_convolve8_avg;
michael@0:       scale_comm->predict[1][0][0] = vp9_convolve8_horiz;
michael@0:       scale_comm->predict[1][0][1] = vp9_convolve8_avg_horiz;
michael@0:     } else {
michael@0:       // Must always scale in both directions.
michael@0:       scale_comm->predict[0][0][0] = vp9_convolve8;
michael@0:       scale_comm->predict[0][0][1] = vp9_convolve8_avg;
michael@0:       scale_comm->predict[0][1][0] = vp9_convolve8;
michael@0:       scale_comm->predict[0][1][1] = vp9_convolve8_avg;
michael@0:       scale_comm->predict[1][0][0] = vp9_convolve8;
michael@0:       scale_comm->predict[1][0][1] = vp9_convolve8_avg;
michael@0:     }
michael@0:   }
michael@0:   // 2D subpel motion always gets filtered in both directions
michael@0:   scale_comm->predict[1][1][0] = vp9_convolve8;
michael@0:   scale_comm->predict[1][1][1] = vp9_convolve8_avg;
michael@0: 
michael@0:   scale->sfc = scale_comm;
michael@0:   scale->x_offset_q4 = 0;  // calculated per block
michael@0:   scale->y_offset_q4 = 0;  // calculated per block
michael@0: }