Import aom library

This is the reference implementation for the Alliance for Open Media's av1 video code.

The commit used was 4d668d7feb1f8abd809d1bca0418570a7f142a36.

1 files changed, 319 insertions, 0 deletions

diff --git a/third_party/aom/av1/encoder/global_motion.c b/third_party/aom/av1/encoder/global_motion.c
new file mode 100644
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+++ b/third_party/aom/av1/encoder/global_motion.c
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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;
+    case TRANSLATION:
+      wm->wmmat[2] = 1 << WARPEDMODEL_PREC_BITS;
+      wm->wmmat[3] = 0;
+    case ROTZOOM: wm->wmmat[4] = -wm->wmmat[3]; wm->wmmat[5] = wm->wmmat[2];
+    case AFFINE: wm->wmmat[6] = wm->wmmat[7] = 0; break;
+    case HORTRAPEZOID: wm->wmmat[6] = wm->wmmat[4] = 0; break;
+    case VERTRAPEZOID: wm->wmmat[7] = wm->wmmat[3] = 0; break;
+    case HOMOGRAPHY: break;
+    default: assert(0);
+  }
+  wm->wmtype = wmtype;
+}
+
+double 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) {
+  static const int max_trans_model_params[TRANS_TYPES] = {
+    0, 2, 4, 6, 8, 8, 8
+  };
+  const int border = ERRORADV_BORDER;
+  int i = 0, p;
+  int n_params = max_trans_model_params[wmtype];
+  int32_t *param_mat = wm->wmmat;
+  double step_error;
+  int32_t step;
+  int32_t *param;
+  int32_t curr_param;
+  int32_t best_param;
+  double best_error;
+
+  force_wmtype(wm, wmtype);
+  best_error = av1_warp_erroradv(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, 16, 16);
+  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
+      if (wmtype == HORTRAPEZOID && (p == 4 || p == 6)) continue;
+      if (wmtype == VERTRAPEZOID && (p == 3 || p == 7)) continue;
+      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_erroradv(
+          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, 16, 16);
+      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_erroradv(
+          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, 16, 16);
+      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_erroradv(
+            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, 16, 16);
+        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 HOMOGRAPHY: return ransac_homography;
+    case HORTRAPEZOID: return ransac_hortrapezoid;
+    case VERTRAPEZOID: return ransac_vertrapezoid;
+    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 = malloc(frm->y_height * frm->y_stride * sizeof(*buf));
+
+  for (i = 0; i < frm->y_height; ++i)
+    for (j = 0; j < frm->y_width; ++j)
+      buf[i * frm->y_stride + j] =
+          orig_buf[i * frm->y_stride + j] >> (bit_depth - 8);
+
+  return buf;
+}
+#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.
+    if (frm->y_buffer_8bit)
+      frm_buffer = frm->y_buffer_8bit;
+    else
+      frm_buffer = frm->y_buffer_8bit = downconvert_frame(frm, bit_depth);
+  }
+  if (ref->flags & YV12_FLAG_HIGHBITDEPTH) {
+    if (ref->y_buffer_8bit)
+      ref_buffer = ref->y_buffer_8bit;
+    else
+      ref_buffer = ref->y_buffer_8bit = 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;
+}