summaryrefslogtreecommitdiffstats
path: root/third_party/aom/aom_dsp/prob.c
diff options
context:
space:
mode:
Diffstat (limited to 'third_party/aom/aom_dsp/prob.c')
-rw-r--r--third_party/aom/aom_dsp/prob.c236
1 files changed, 236 insertions, 0 deletions
diff --git a/third_party/aom/aom_dsp/prob.c b/third_party/aom/aom_dsp/prob.c
new file mode 100644
index 000000000..c60bfdac5
--- /dev/null
+++ b/third_party/aom/aom_dsp/prob.c
@@ -0,0 +1,236 @@
+/*
+ * 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 "./aom_config.h"
+
+#if CONFIG_EC_MULTISYMBOL
+#include <string.h>
+#endif
+
+#include "aom_dsp/prob.h"
+
+const uint8_t aom_norm[256] = {
+ 0, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
+ 3, 3, 3, 3, 3, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+};
+
+static unsigned int tree_merge_probs_impl(unsigned int i,
+ const aom_tree_index *tree,
+ const aom_prob *pre_probs,
+ const unsigned int *counts,
+ aom_prob *probs) {
+ const int l = tree[i];
+ const unsigned int left_count =
+ (l <= 0) ? counts[-l]
+ : tree_merge_probs_impl(l, tree, pre_probs, counts, probs);
+ const int r = tree[i + 1];
+ const unsigned int right_count =
+ (r <= 0) ? counts[-r]
+ : tree_merge_probs_impl(r, tree, pre_probs, counts, probs);
+ const unsigned int ct[2] = { left_count, right_count };
+ probs[i >> 1] = mode_mv_merge_probs(pre_probs[i >> 1], ct);
+ return left_count + right_count;
+}
+
+void aom_tree_merge_probs(const aom_tree_index *tree, const aom_prob *pre_probs,
+ const unsigned int *counts, aom_prob *probs) {
+ tree_merge_probs_impl(0, tree, pre_probs, counts, probs);
+}
+
+#if CONFIG_EC_MULTISYMBOL
+typedef struct tree_node tree_node;
+
+struct tree_node {
+ aom_tree_index index;
+ uint8_t probs[16];
+ uint8_t prob;
+ int path;
+ int len;
+ int l;
+ int r;
+ aom_cdf_prob pdf;
+};
+
+/* Compute the probability of this node in Q23 */
+static uint32_t tree_node_prob(tree_node n, int i) {
+ uint32_t prob;
+ /* 1.0 in Q23 */
+ prob = 16777216;
+ for (; i < n.len; i++) {
+ prob = prob * n.probs[i] >> 8;
+ }
+ return prob;
+}
+
+static int tree_node_cmp(tree_node a, tree_node b) {
+ int i;
+ uint32_t pa;
+ uint32_t pb;
+ for (i = 0; i < AOMMIN(a.len, b.len) && a.probs[i] == b.probs[i]; i++) {
+ }
+ pa = tree_node_prob(a, i);
+ pb = tree_node_prob(b, i);
+ return pa > pb ? 1 : pa < pb ? -1 : 0;
+}
+
+/* Given a Q15 probability for symbol subtree rooted at tree[n], this function
+ computes the probability of each symbol (defined as a node that has no
+ children). */
+static aom_cdf_prob tree_node_compute_probs(tree_node *tree, int n,
+ aom_cdf_prob pdf) {
+ if (tree[n].l == 0) {
+ /* This prevents probability computations in Q15 that underflow from
+ producing a symbol that has zero probability. */
+ if (pdf == 0) pdf = 1;
+ tree[n].pdf = pdf;
+ return pdf;
+ } else {
+ /* We process the smaller probability first, */
+ if (tree[n].prob < 128) {
+ aom_cdf_prob lp;
+ aom_cdf_prob rp;
+ lp = (((uint32_t)pdf) * tree[n].prob + 128) >> 8;
+ lp = tree_node_compute_probs(tree, tree[n].l, lp);
+ rp = tree_node_compute_probs(tree, tree[n].r, lp > pdf ? 0 : pdf - lp);
+ return lp + rp;
+ } else {
+ aom_cdf_prob rp;
+ aom_cdf_prob lp;
+ rp = (((uint32_t)pdf) * (256 - tree[n].prob) + 128) >> 8;
+ rp = tree_node_compute_probs(tree, tree[n].r, rp);
+ lp = tree_node_compute_probs(tree, tree[n].l, rp > pdf ? 0 : pdf - rp);
+ return lp + rp;
+ }
+ }
+}
+
+static int tree_node_extract(tree_node *tree, int n, int symb,
+ aom_cdf_prob *pdf, aom_tree_index *index,
+ int *path, int *len) {
+ if (tree[n].l == 0) {
+ pdf[symb] = tree[n].pdf;
+ if (index != NULL) index[symb] = tree[n].index;
+ if (path != NULL) path[symb] = tree[n].path;
+ if (len != NULL) len[symb] = tree[n].len;
+ return symb + 1;
+ } else {
+ symb = tree_node_extract(tree, tree[n].l, symb, pdf, index, path, len);
+ return tree_node_extract(tree, tree[n].r, symb, pdf, index, path, len);
+ }
+}
+
+int tree_to_cdf(const aom_tree_index *tree, const aom_prob *probs,
+ aom_tree_index root, aom_cdf_prob *cdf, aom_tree_index *index,
+ int *path, int *len) {
+ tree_node symb[2 * 16 - 1];
+ int nodes;
+ int next[16];
+ int size;
+ int nsymbs;
+ int i;
+ /* Create the root node with probability 1 in Q15. */
+ symb[0].index = root;
+ symb[0].path = 0;
+ symb[0].len = 0;
+ symb[0].l = symb[0].r = 0;
+ nodes = 1;
+ next[0] = 0;
+ size = 1;
+ nsymbs = 1;
+ while (size > 0 && nsymbs < 16) {
+ int m;
+ tree_node n;
+ aom_tree_index j;
+ uint8_t prob;
+ m = 0;
+ /* Find the internal node with the largest probability. */
+ for (i = 1; i < size; i++) {
+ if (tree_node_cmp(symb[next[i]], symb[next[m]]) > 0) m = i;
+ }
+ i = next[m];
+ memmove(&next[m], &next[m + 1], sizeof(*next) * (size - (m + 1)));
+ size--;
+ /* Split this symbol into two symbols */
+ n = symb[i];
+ j = n.index;
+ prob = probs[j >> 1];
+ /* Left */
+ n.index = tree[j];
+ n.path <<= 1;
+ n.len++;
+ n.probs[n.len - 1] = prob;
+ symb[nodes] = n;
+ if (n.index > 0) {
+ next[size++] = nodes;
+ }
+ /* Right */
+ n.index = tree[j + 1];
+ n.path += 1;
+ n.probs[n.len - 1] = 256 - prob;
+ symb[nodes + 1] = n;
+ if (n.index > 0) {
+ next[size++] = nodes + 1;
+ }
+ symb[i].prob = prob;
+ symb[i].l = nodes;
+ symb[i].r = nodes + 1;
+ nodes += 2;
+ nsymbs++;
+ }
+ /* Compute the probabilities of each symbol in Q15 */
+ tree_node_compute_probs(symb, 0, CDF_PROB_TOP);
+ /* Extract the cdf, index, path and length */
+ tree_node_extract(symb, 0, 0, cdf, index, path, len);
+ /* Convert to CDF */
+ cdf[0] = AOM_ICDF(cdf[0]);
+ for (i = 1; i < nsymbs; i++) {
+ cdf[i] = AOM_ICDF(AOM_ICDF(cdf[i - 1]) + cdf[i]);
+ }
+// Store symbol count at the end of the CDF
+#if CONFIG_EC_ADAPT
+ cdf[nsymbs] = 0;
+#endif
+ return nsymbs;
+}
+
+/* This code assumes that tree contains as unique leaf nodes the integer values
+ 0 to len - 1 and produces the forward and inverse mapping tables in ind[]
+ and inv[] respectively. */
+static void tree_to_index(int *stack_index, int *ind, int *inv,
+ const aom_tree_index *tree, int value, int index) {
+ value *= 2;
+
+ do {
+ const aom_tree_index content = tree[index];
+ ++index;
+ if (content <= 0) {
+ inv[*stack_index] = -content;
+ ind[-content] = *stack_index;
+ ++(*stack_index);
+ } else {
+ tree_to_index(stack_index, ind, inv, tree, value, content);
+ }
+ } while (++value & 1);
+}
+
+void av1_indices_from_tree(int *ind, int *inv, const aom_tree_index *tree) {
+ int stack_index = 0;
+ tree_to_index(&stack_index, ind, inv, tree, 0, 0);
+}
+#endif