4d0ec7aacd
Add a function clip_pixel() to clip a pixel value to the [0,255] range
of allowed values, and use this where-ever appropriate (e.g. prediction,
reconstruction). Likewise, consistently use the recently added function
clip_prob(), which calculates a binary probability in the [1,255] range.
If possible, try to use get_prob() or its sister get_binary_prob() to
calculate binary probabilities, for consistency.
Since in some places, this means that binary probability calculations
are changed (we use {255,256}*count0/(total) in a range of places,
and all of these are now changed to use 256*count0+(total>>1)/total),
this changes the encoding result, so this patch warrants some extensive
testing.
Change-Id: Ibeeff8d886496839b8e0c0ace9ccc552351f7628
114 lines
2.4 KiB
C
114 lines
2.4 KiB
C
/*
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* Copyright (c) 2010 The WebM project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "vpx_config.h"
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#if defined(CONFIG_DEBUG) && CONFIG_DEBUG
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#include <assert.h>
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#endif
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#include <stdio.h>
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#include "vp9/common/vp9_treecoder.h"
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static void tree2tok(
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struct vp9_token_struct *const p,
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vp9_tree t,
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int i,
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int v,
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int L
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) {
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v += v;
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++L;
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do {
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const vp9_tree_index j = t[i++];
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if (j <= 0) {
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p[-j].value = v;
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p[-j].Len = L;
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} else
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tree2tok(p, t, j, v, L);
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} while (++v & 1);
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}
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void vp9_tokens_from_tree(struct vp9_token_struct *p, vp9_tree t) {
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tree2tok(p, t, 0, 0, 0);
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}
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void vp9_tokens_from_tree_offset(struct vp9_token_struct *p, vp9_tree t,
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int offset) {
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tree2tok(p - offset, t, 0, 0, 0);
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}
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static void branch_counts(
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int n, /* n = size of alphabet */
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vp9_token tok [ /* n */ ],
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vp9_tree tree,
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unsigned int branch_ct [ /* n-1 */ ] [2],
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const unsigned int num_events[ /* n */ ]
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) {
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const int tree_len = n - 1;
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int t = 0;
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#if CONFIG_DEBUG
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assert(tree_len);
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#endif
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do {
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branch_ct[t][0] = branch_ct[t][1] = 0;
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} while (++t < tree_len);
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t = 0;
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do {
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int L = tok[t].Len;
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const int enc = tok[t].value;
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const unsigned int ct = num_events[t];
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vp9_tree_index i = 0;
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do {
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const int b = (enc >> --L) & 1;
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const int j = i >> 1;
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#if CONFIG_DEBUG
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assert(j < tree_len && 0 <= L);
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#endif
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branch_ct [j] [b] += ct;
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i = tree[ i + b];
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} while (i > 0);
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#if CONFIG_DEBUG
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assert(!L);
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#endif
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} while (++t < n);
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}
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void vp9_tree_probs_from_distribution(
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int n, /* n = size of alphabet */
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vp9_token tok [ /* n */ ],
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vp9_tree tree,
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vp9_prob probs [ /* n-1 */ ],
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unsigned int branch_ct [ /* n-1 */ ] [2],
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const unsigned int num_events[ /* n */ ]
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) {
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const int tree_len = n - 1;
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int t = 0;
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branch_counts(n, tok, tree, branch_ct, num_events);
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do {
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probs[t] = get_binary_prob(branch_ct[t][0], branch_ct[t][1]);
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} while (++t < tree_len);
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}
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