diff options
Diffstat (limited to 'media/libaom/src/av1/encoder/global_motion.c')
| -rw-r--r-- | media/libaom/src/av1/encoder/global_motion.c | 298 |
1 files changed, 298 insertions, 0 deletions
diff --git a/media/libaom/src/av1/encoder/global_motion.c b/media/libaom/src/av1/encoder/global_motion.c new file mode 100644 index 000000000..e9f8b0bb4 --- /dev/null +++ b/media/libaom/src/av1/encoder/global_motion.c @@ -0,0 +1,298 @@ +/* + * 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[] = { 0.65, 0.60, 0.55 }; +static const double erroradv_prod_tr[] = { 20000, 18000, 16000 }; + +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; +} |