vpx/vp9/encoder/vp9_treewriter.c
Ronald S. Bultje 790fb13215 Use above/left (instead of previous in scan-order) as token context.
Pearson correlation for above or left is significantly higher than for
previous-in-scan-order (absolute values depend on position in scan, but
in general, we gain about 0.1-0.2 by using either above or left; using
both basically just makes this even better). For eob branch skipping,
we continue to use the previous token in scan order.

This helps about 0.9% on derf after re-training on a limited data set.
Full re-training and results on larger-resolution clips are pending.

Note that this commit breaks trellis, so we can probably get further
gains out of it by fixing trellis at some later point.

Change-Id: Iead68e296fc3a105cca746b5e3da9555d6010cfe
2013-03-26 16:46:09 -07:00

43 lines
1.0 KiB
C

/*
* Copyright (c) 2010 The WebM project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "vp9/encoder/vp9_treewriter.h"
#include "vp9/common/vp9_common.h"
static void cost(
int *const C,
vp9_tree T,
const vp9_prob *const P,
int i,
int c
) {
const vp9_prob p = P [i >> 1];
do {
const vp9_tree_index j = T[i];
const int d = c + vp9_cost_bit(p, i & 1);
if (j <= 0)
C[-j] = d;
else
cost(C, T, P, j, d);
} while (++i & 1);
}
void vp9_cost_tokens(int *c, const vp9_prob *p, vp9_tree t) {
cost(c, t, p, 0, 0);
}
void vp9_cost_tokens_skip(int *c, const vp9_prob *p, vp9_tree t) {
assert(t[1] > 0 && t[0] <= 0);
c[-t[0]] = vp9_cost_bit(p[0], 0);
cost(c, t, p, 2, 0);
}