/* * Copyright (c) 2016, Alliance for Open Media. All rights reserved * * This source code is subject to the terms of the BSD 2 Clause License and * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License * was not distributed with this source code in the LICENSE file, you can * obtain it at www.aomedia.org/license/software. If the Alliance for Open * Media Patent License 1.0 was not distributed with this source code in the * PATENTS file, you can obtain it at www.aomedia.org/license/patent. */ #include <stdio.h> #include <stdlib.h> #include <memory.h> #include <math.h> #include <assert.h> #include "av1/encoder/global_motion.h" #include "av1/common/warped_motion.h" #include "av1/encoder/segmentation.h" #include "av1/encoder/corner_detect.h" #include "av1/encoder/corner_match.h" #include "av1/encoder/ransac.h" #define MAX_CORNERS 4096 #define MIN_INLIER_PROB 0.1 #define MIN_TRANS_THRESH (1 * GM_TRANS_DECODE_FACTOR) // Border over which to compute the global motion #define ERRORADV_BORDER 0 static const double erroradv_tr[] = { 0.75, 0.70, 0.65 }; static const double erroradv_prod_tr[] = { 22000, 20000, 18000 }; int is_enough_erroradvantage(double best_erroradvantage, int params_cost, int erroradv_type) { assert(erroradv_type < GM_ERRORADV_TR_TYPES); return best_erroradvantage < erroradv_tr[erroradv_type] && best_erroradvantage * params_cost < erroradv_prod_tr[erroradv_type]; } static void convert_to_params(const double *params, int32_t *model) { int i; int alpha_present = 0; model[0] = (int32_t)floor(params[0] * (1 << GM_TRANS_PREC_BITS) + 0.5); model[1] = (int32_t)floor(params[1] * (1 << GM_TRANS_PREC_BITS) + 0.5); model[0] = (int32_t)clamp(model[0], GM_TRANS_MIN, GM_TRANS_MAX) * GM_TRANS_DECODE_FACTOR; model[1] = (int32_t)clamp(model[1], GM_TRANS_MIN, GM_TRANS_MAX) * GM_TRANS_DECODE_FACTOR; for (i = 2; i < 6; ++i) { const int diag_value = ((i == 2 || i == 5) ? (1 << GM_ALPHA_PREC_BITS) : 0); model[i] = (int32_t)floor(params[i] * (1 << GM_ALPHA_PREC_BITS) + 0.5); model[i] = (int32_t)clamp(model[i] - diag_value, GM_ALPHA_MIN, GM_ALPHA_MAX); alpha_present |= (model[i] != 0); model[i] = (model[i] + diag_value) * GM_ALPHA_DECODE_FACTOR; } for (; i < 8; ++i) { model[i] = (int32_t)floor(params[i] * (1 << GM_ROW3HOMO_PREC_BITS) + 0.5); model[i] = (int32_t)clamp(model[i], GM_ROW3HOMO_MIN, GM_ROW3HOMO_MAX) * GM_ROW3HOMO_DECODE_FACTOR; alpha_present |= (model[i] != 0); } if (!alpha_present) { if (abs(model[0]) < MIN_TRANS_THRESH && abs(model[1]) < MIN_TRANS_THRESH) { model[0] = 0; model[1] = 0; } } } void convert_model_to_params(const double *params, WarpedMotionParams *model) { convert_to_params(params, model->wmmat); model->wmtype = get_gmtype(model); model->invalid = 0; } // Adds some offset to a global motion parameter and handles // all of the necessary precision shifts, clamping, and // zero-centering. static int32_t add_param_offset(int param_index, int32_t param_value, int32_t offset) { const int scale_vals[3] = { GM_TRANS_PREC_DIFF, GM_ALPHA_PREC_DIFF, GM_ROW3HOMO_PREC_DIFF }; const int clamp_vals[3] = { GM_TRANS_MAX, GM_ALPHA_MAX, GM_ROW3HOMO_MAX }; // type of param: 0 - translation, 1 - affine, 2 - homography const int param_type = (param_index < 2 ? 0 : (param_index < 6 ? 1 : 2)); const int is_one_centered = (param_index == 2 || param_index == 5); // Make parameter zero-centered and offset the shift that was done to make // it compatible with the warped model param_value = (param_value - (is_one_centered << WARPEDMODEL_PREC_BITS)) >> scale_vals[param_type]; // Add desired offset to the rescaled/zero-centered parameter param_value += offset; // Clamp the parameter so it does not overflow the number of bits allotted // to it in the bitstream param_value = (int32_t)clamp(param_value, -clamp_vals[param_type], clamp_vals[param_type]); // Rescale the parameter to WARPEDMODEL_PRECISION_BITS so it is compatible // with the warped motion library param_value *= (1 << scale_vals[param_type]); // Undo the zero-centering step if necessary return param_value + (is_one_centered << WARPEDMODEL_PREC_BITS); } static void force_wmtype(WarpedMotionParams *wm, TransformationType wmtype) { switch (wmtype) { case IDENTITY: wm->wmmat[0] = 0; wm->wmmat[1] = 0; AOM_FALLTHROUGH_INTENDED; case TRANSLATION: wm->wmmat[2] = 1 << WARPEDMODEL_PREC_BITS; wm->wmmat[3] = 0; AOM_FALLTHROUGH_INTENDED; case ROTZOOM: wm->wmmat[4] = -wm->wmmat[3]; wm->wmmat[5] = wm->wmmat[2]; AOM_FALLTHROUGH_INTENDED; case AFFINE: wm->wmmat[6] = wm->wmmat[7] = 0; break; default: assert(0); } wm->wmtype = wmtype; } int64_t refine_integerized_param(WarpedMotionParams *wm, TransformationType wmtype, int use_hbd, int bd, uint8_t *ref, int r_width, int r_height, int r_stride, uint8_t *dst, int d_width, int d_height, int d_stride, int n_refinements, int64_t best_frame_error) { static const int max_trans_model_params[TRANS_TYPES] = { 0, 2, 4, 6 }; const int border = ERRORADV_BORDER; int i = 0, p; int n_params = max_trans_model_params[wmtype]; int32_t *param_mat = wm->wmmat; int64_t step_error, best_error; int32_t step; int32_t *param; int32_t curr_param; int32_t best_param; force_wmtype(wm, wmtype); best_error = av1_warp_error(wm, use_hbd, bd, ref, r_width, r_height, r_stride, dst + border * d_stride + border, border, border, d_width - 2 * border, d_height - 2 * border, d_stride, 0, 0, best_frame_error); best_error = AOMMIN(best_error, best_frame_error); step = 1 << (n_refinements - 1); for (i = 0; i < n_refinements; i++, step >>= 1) { for (p = 0; p < n_params; ++p) { int step_dir = 0; // Skip searches for parameters that are forced to be 0 param = param_mat + p; curr_param = *param; best_param = curr_param; // look to the left *param = add_param_offset(p, curr_param, -step); step_error = av1_warp_error(wm, use_hbd, bd, ref, r_width, r_height, r_stride, dst + border * d_stride + border, border, border, d_width - 2 * border, d_height - 2 * border, d_stride, 0, 0, best_error); if (step_error < best_error) { best_error = step_error; best_param = *param; step_dir = -1; } // look to the right *param = add_param_offset(p, curr_param, step); step_error = av1_warp_error(wm, use_hbd, bd, ref, r_width, r_height, r_stride, dst + border * d_stride + border, border, border, d_width - 2 * border, d_height - 2 * border, d_stride, 0, 0, best_error); if (step_error < best_error) { best_error = step_error; best_param = *param; step_dir = 1; } *param = best_param; // look to the direction chosen above repeatedly until error increases // for the biggest step size while (step_dir) { *param = add_param_offset(p, best_param, step * step_dir); step_error = av1_warp_error(wm, use_hbd, bd, ref, r_width, r_height, r_stride, dst + border * d_stride + border, border, border, d_width - 2 * border, d_height - 2 * border, d_stride, 0, 0, best_error); if (step_error < best_error) { best_error = step_error; best_param = *param; } else { *param = best_param; step_dir = 0; } } } } force_wmtype(wm, wmtype); wm->wmtype = get_gmtype(wm); return best_error; } static INLINE RansacFunc get_ransac_type(TransformationType type) { switch (type) { case AFFINE: return ransac_affine; case ROTZOOM: return ransac_rotzoom; case TRANSLATION: return ransac_translation; default: assert(0); return NULL; } } static unsigned char *downconvert_frame(YV12_BUFFER_CONFIG *frm, int bit_depth) { int i, j; uint16_t *orig_buf = CONVERT_TO_SHORTPTR(frm->y_buffer); uint8_t *buf_8bit = frm->y_buffer_8bit; assert(buf_8bit); if (!frm->buf_8bit_valid) { for (i = 0; i < frm->y_height; ++i) { for (j = 0; j < frm->y_width; ++j) { buf_8bit[i * frm->y_stride + j] = orig_buf[i * frm->y_stride + j] >> (bit_depth - 8); } } frm->buf_8bit_valid = 1; } return buf_8bit; } int compute_global_motion_feature_based(TransformationType type, YV12_BUFFER_CONFIG *frm, YV12_BUFFER_CONFIG *ref, int bit_depth, int *num_inliers_by_motion, double *params_by_motion, int num_motions) { int i; int num_frm_corners, num_ref_corners; int num_correspondences; int *correspondences; int frm_corners[2 * MAX_CORNERS], ref_corners[2 * MAX_CORNERS]; unsigned char *frm_buffer = frm->y_buffer; unsigned char *ref_buffer = ref->y_buffer; RansacFunc ransac = get_ransac_type(type); if (frm->flags & YV12_FLAG_HIGHBITDEPTH) { // The frame buffer is 16-bit, so we need to convert to 8 bits for the // following code. We cache the result until the frame is released. frm_buffer = downconvert_frame(frm, bit_depth); } if (ref->flags & YV12_FLAG_HIGHBITDEPTH) { ref_buffer = downconvert_frame(ref, bit_depth); } // compute interest points in images using FAST features num_frm_corners = fast_corner_detect(frm_buffer, frm->y_width, frm->y_height, frm->y_stride, frm_corners, MAX_CORNERS); num_ref_corners = fast_corner_detect(ref_buffer, ref->y_width, ref->y_height, ref->y_stride, ref_corners, MAX_CORNERS); // find correspondences between the two images correspondences = (int *)malloc(num_frm_corners * 4 * sizeof(*correspondences)); num_correspondences = determine_correspondence( frm_buffer, (int *)frm_corners, num_frm_corners, ref_buffer, (int *)ref_corners, num_ref_corners, frm->y_width, frm->y_height, frm->y_stride, ref->y_stride, correspondences); ransac(correspondences, num_correspondences, num_inliers_by_motion, params_by_motion, num_motions); free(correspondences); // Set num_inliers = 0 for motions with too few inliers so they are ignored. for (i = 0; i < num_motions; ++i) { if (num_inliers_by_motion[i] < MIN_INLIER_PROB * num_correspondences) { num_inliers_by_motion[i] = 0; } } // Return true if any one of the motions has inliers. for (i = 0; i < num_motions; ++i) { if (num_inliers_by_motion[i] > 0) return 1; } return 0; }