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/*
* 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
#define ERRORADV_MAX_THRESH 0.995
#define ERRORADV_COST_PRODUCT_THRESH 26000
int is_enough_erroradvantage(double best_erroradvantage, int params_cost) {
return best_erroradvantage < ERRORADV_MAX_THRESH &&
best_erroradvantage * params_cost < ERRORADV_COST_PRODUCT_THRESH;
}
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);
}
// 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,
#if CONFIG_HIGHBITDEPTH
int use_hbd, int bd,
#endif // CONFIG_HIGHBITDEPTH
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,
#if CONFIG_HIGHBITDEPTH
use_hbd, bd,
#endif // CONFIG_HIGHBITDEPTH
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,
#if CONFIG_HIGHBITDEPTH
use_hbd, bd,
#endif // CONFIG_HIGHBITDEPTH
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,
#if CONFIG_HIGHBITDEPTH
use_hbd, bd,
#endif // CONFIG_HIGHBITDEPTH
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,
#if CONFIG_HIGHBITDEPTH
use_hbd, bd,
#endif // CONFIG_HIGHBITDEPTH
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;
}
}
#if CONFIG_HIGHBITDEPTH
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;
}
#endif
int compute_global_motion_feature_based(
TransformationType type, YV12_BUFFER_CONFIG *frm, YV12_BUFFER_CONFIG *ref,
#if CONFIG_HIGHBITDEPTH
int bit_depth,
#endif
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 CONFIG_HIGHBITDEPTH
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);
}
#endif
// 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;
}