Use Daala entropy coder to code trees.
When building with --enable-daala_ec, calls to aom_write_tree() and
aom_read_tree() will convert a aom_tree_index structure with associated
aom_prob probabilities into a CDF on the fly for use with the
od_ec_encode_cdf_q15().
The number of symbols in the CDF is capped at 16, and trees that contain
more than 16 leaf nodes are handled by splitting the most likely, e.g.,
highest probability symbols, first and coding multiple symbols if
necessary.
ntt-short-1:
MEDIUM (%) HIGH (%)
PSNR 0.000227 0.000213
PSNRHVS 0.000215 0.000205
SSIM 0.000229 0.000209
FASTSSIM 0.000229 0.000214
subset1:
RATE (%) DSNR (dB)
PSNR -0.00026 0.00002
PSNRHVS -0.00026 0.00002
SSIM -0.00026 0.00001
FASTSSIM -0.00026 0.00001
Change-Id: Icb1a8cb854fd81fdd88fbe4bc6761c7eb4757dfe
diff --git a/aom_dsp/prob.c b/aom_dsp/prob.c
index 20c82c6..3485929 100644
--- a/aom_dsp/prob.c
+++ b/aom_dsp/prob.c
@@ -9,8 +9,16 @@
* PATENTS file, you can obtain it at www.aomedia.org/license/patent.
*/
+#if CONFIG_DAALA_EC
+#include <string.h>
+#endif
+
#include "aom_dsp/prob.h"
+#if CONFIG_DAALA_EC
+#include "aom_dsp/entcode.h"
+#endif
+
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,
@@ -46,3 +54,153 @@
const unsigned int *counts, aom_prob *probs) {
tree_merge_probs_impl(0, tree, pre_probs, counts, probs);
}
+
+#if CONFIG_DAALA_EC
+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;
+ uint16_t 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 < OD_MINI(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 uint16_t tree_node_compute_probs(tree_node *tree, int n, uint16_t 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) {
+ uint16_t lp;
+ uint16_t 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 {
+ uint16_t rp;
+ uint16_t 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, uint16_t *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, uint16_t *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, 32768);
+ /* Extract the cdf, index, path and length */
+ tree_node_extract(symb, 0, 0, cdf, index, path, len);
+ /* Convert to CDF */
+ for (i = 1; i < nsymbs; i++) {
+ cdf[i] = cdf[i - 1] + cdf[i];
+ }
+ return nsymbs;
+}
+#endif
