generic-library/vpx
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity
vpx/vp10/decoder/detokenize.c
Ronald S. Bultje 3461e8ce64 vp10: skip unreachable cat6 token extrabits. 
We have historically added new bits to cat6 whenever we added a new
transform size (or bitdepth, for that matter). However, we have
always coded these new bits regardless of the actual transform size,
which means that for smaller transforms, we code bits that cannot
possibly be set. The coding (quality) impact of this is negligible,
but the bigger issue is that this allows creating bitstreams with
coefficient values that are nonsensible and can cause int overflows,
which then de facto become part of the bitstream spec. By not coding
these bits, we remove this possibility.

See issue 1065.

Change-Id: Ib3186eca2df6a7a15ddc60c8b55af182aadd964d
2015-10-05 20:58:32 -04:00

277 lines
8.9 KiB
C
Raw Blame History

/*
* 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 "vpx_mem/vpx_mem.h"
#include "vpx_ports/mem.h"
#include "vp10/common/blockd.h"
#include "vp10/common/common.h"
#include "vp10/common/entropy.h"
#if CONFIG_COEFFICIENT_RANGE_CHECKING
#include "vp10/common/idct.h"
#endif
#include "vp10/decoder/detokenize.h"
#define EOB_CONTEXT_NODE 0
#define ZERO_CONTEXT_NODE 1
#define ONE_CONTEXT_NODE 2
#define LOW_VAL_CONTEXT_NODE 0
#define TWO_CONTEXT_NODE 1
#define THREE_CONTEXT_NODE 2
#define HIGH_LOW_CONTEXT_NODE 3
#define CAT_ONE_CONTEXT_NODE 4
#define CAT_THREEFOUR_CONTEXT_NODE 5
#define CAT_THREE_CONTEXT_NODE 6
#define CAT_FIVE_CONTEXT_NODE 7
#define INCREMENT_COUNT(token) \
do { \
if (counts) \
++coef_counts[band][ctx][token]; \
} while (0)
static INLINE int read_coeff(const vpx_prob *probs, int n, vpx_reader *r) {
int i, val = 0;
for (i = 0; i < n; ++i)
val = (val << 1) | vpx_read(r, probs[i]);
return val;
}
static int decode_coefs(const MACROBLOCKD *xd,
PLANE_TYPE type,
tran_low_t *dqcoeff, TX_SIZE tx_size, const int16_t *dq,
int ctx, const int16_t *scan, const int16_t *nb,
vpx_reader *r) {
FRAME_COUNTS *counts = xd->counts;
const int max_eob = 16 << (tx_size << 1);
const FRAME_CONTEXT *const fc = xd->fc;
const int ref = is_inter_block(&xd->mi[0]->mbmi);
int band, c = 0;
const vpx_prob (*coef_probs)[COEFF_CONTEXTS][UNCONSTRAINED_NODES] =
fc->coef_probs[tx_size][type][ref];
const vpx_prob *prob;
unsigned int (*coef_counts)[COEFF_CONTEXTS][UNCONSTRAINED_NODES + 1];
unsigned int (*eob_branch_count)[COEFF_CONTEXTS];
uint8_t token_cache[32 * 32];
const uint8_t *band_translate = get_band_translate(tx_size);
const int dq_shift = (tx_size == TX_32X32);
int v, token;
int16_t dqv = dq[0];
const uint8_t *cat1_prob;
const uint8_t *cat2_prob;
const uint8_t *cat3_prob;
const uint8_t *cat4_prob;
const uint8_t *cat5_prob;
const uint8_t *cat6_prob;
if (counts) {
coef_counts = counts->coef[tx_size][type][ref];
eob_branch_count = counts->eob_branch[tx_size][type][ref];
}
#if CONFIG_VP9_HIGHBITDEPTH
if (xd->bd > VPX_BITS_8) {
if (xd->bd == VPX_BITS_10) {
cat1_prob = vp10_cat1_prob_high10;
cat2_prob = vp10_cat2_prob_high10;
cat3_prob = vp10_cat3_prob_high10;
cat4_prob = vp10_cat4_prob_high10;
cat5_prob = vp10_cat5_prob_high10;
cat6_prob = vp10_cat6_prob_high10;
} else {
cat1_prob = vp10_cat1_prob_high12;
cat2_prob = vp10_cat2_prob_high12;
cat3_prob = vp10_cat3_prob_high12;
cat4_prob = vp10_cat4_prob_high12;
cat5_prob = vp10_cat5_prob_high12;
cat6_prob = vp10_cat6_prob_high12;
}
} else {
cat1_prob = vp10_cat1_prob;
cat2_prob = vp10_cat2_prob;
cat3_prob = vp10_cat3_prob;
cat4_prob = vp10_cat4_prob;
cat5_prob = vp10_cat5_prob;
cat6_prob = vp10_cat6_prob;
}
#else
cat1_prob = vp10_cat1_prob;
cat2_prob = vp10_cat2_prob;
cat3_prob = vp10_cat3_prob;
cat4_prob = vp10_cat4_prob;
cat5_prob = vp10_cat5_prob;
cat6_prob = vp10_cat6_prob;
#endif
while (c < max_eob) {
int val = -1;
band = *band_translate++;
prob = coef_probs[band][ctx];
if (counts)
++eob_branch_count[band][ctx];
if (!vpx_read(r, prob[EOB_CONTEXT_NODE])) {
INCREMENT_COUNT(EOB_MODEL_TOKEN);
break;
}
while (!vpx_read(r, prob[ZERO_CONTEXT_NODE])) {
INCREMENT_COUNT(ZERO_TOKEN);
dqv = dq[1];
token_cache[scan[c]] = 0;
++c;
if (c >= max_eob)
return c; // zero tokens at the end (no eob token)
ctx = get_coef_context(nb, token_cache, c);
band = *band_translate++;
prob = coef_probs[band][ctx];
}
if (!vpx_read(r, prob[ONE_CONTEXT_NODE])) {
INCREMENT_COUNT(ONE_TOKEN);
token = ONE_TOKEN;
val = 1;
} else {
INCREMENT_COUNT(TWO_TOKEN);
token = vpx_read_tree(r, vp10_coef_con_tree,
vp10_pareto8_full[prob[PIVOT_NODE] - 1]);
switch (token) {
case TWO_TOKEN:
case THREE_TOKEN:
case FOUR_TOKEN:
val = token;
break;
case CATEGORY1_TOKEN:
val = CAT1_MIN_VAL + read_coeff(cat1_prob, 1, r);
break;
case CATEGORY2_TOKEN:
val = CAT2_MIN_VAL + read_coeff(cat2_prob, 2, r);
break;
case CATEGORY3_TOKEN:
val = CAT3_MIN_VAL + read_coeff(cat3_prob, 3, r);
break;
case CATEGORY4_TOKEN:
val = CAT4_MIN_VAL + read_coeff(cat4_prob, 4, r);
break;
case CATEGORY5_TOKEN:
val = CAT5_MIN_VAL + read_coeff(cat5_prob, 5, r);
break;
case CATEGORY6_TOKEN: {
#if CONFIG_MISC_FIXES
const int skip_bits = TX_SIZES - 1 - tx_size;
#else
const int skip_bits = 0;
#endif
const uint8_t *cat6p = cat6_prob + skip_bits;
#if CONFIG_VP9_HIGHBITDEPTH
switch (xd->bd) {
case VPX_BITS_8:
val = CAT6_MIN_VAL + read_coeff(cat6p, 14 - skip_bits, r);
break;
case VPX_BITS_10:
val = CAT6_MIN_VAL + read_coeff(cat6p, 16 - skip_bits, r);
break;
case VPX_BITS_12:
val = CAT6_MIN_VAL + read_coeff(cat6p, 18 - skip_bits, r);
break;
default:
assert(0);
return -1;
}
#else
val = CAT6_MIN_VAL + read_coeff(cat6p, 14 - skip_bits, r);
#endif
break;
}
}
}
v = (val * dqv) >> dq_shift;
#if CONFIG_COEFFICIENT_RANGE_CHECKING
#if CONFIG_VP9_HIGHBITDEPTH
dqcoeff[scan[c]] = highbd_check_range((vpx_read_bit(r) ? -v : v),
xd->bd);
#else
dqcoeff[scan[c]] = check_range(vpx_read_bit(r) ? -v : v);
#endif // CONFIG_VP9_HIGHBITDEPTH
#else
dqcoeff[scan[c]] = vpx_read_bit(r) ? -v : v;
#endif // CONFIG_COEFFICIENT_RANGE_CHECKING
token_cache[scan[c]] = vp10_pt_energy_class[token];
++c;
ctx = get_coef_context(nb, token_cache, c);
dqv = dq[1];
}
return c;
}
// TODO(slavarnway): Decode version of vp10_set_context. Modify vp10_set_context
// after testing is complete, then delete this version.
static
void dec_set_contexts(const MACROBLOCKD *xd, struct macroblockd_plane *pd,
TX_SIZE tx_size, int has_eob,
int aoff, int loff) {
ENTROPY_CONTEXT *const a = pd->above_context + aoff;
ENTROPY_CONTEXT *const l = pd->left_context + loff;
const int tx_size_in_blocks = 1 << tx_size;
// above
if (has_eob && xd->mb_to_right_edge < 0) {
int i;
const int blocks_wide = pd->n4_w +
(xd->mb_to_right_edge >> (5 + pd->subsampling_x));
int above_contexts = tx_size_in_blocks;
if (above_contexts + aoff > blocks_wide)
above_contexts = blocks_wide - aoff;
for (i = 0; i < above_contexts; ++i)
a[i] = has_eob;
for (i = above_contexts; i < tx_size_in_blocks; ++i)
a[i] = 0;
} else {
memset(a, has_eob, sizeof(ENTROPY_CONTEXT) * tx_size_in_blocks);
}
// left
if (has_eob && xd->mb_to_bottom_edge < 0) {
int i;
const int blocks_high = pd->n4_h +
(xd->mb_to_bottom_edge >> (5 + pd->subsampling_y));
int left_contexts = tx_size_in_blocks;
if (left_contexts + loff > blocks_high)
left_contexts = blocks_high - loff;
for (i = 0; i < left_contexts; ++i)
l[i] = has_eob;
for (i = left_contexts; i < tx_size_in_blocks; ++i)
l[i] = 0;
} else {
memset(l, has_eob, sizeof(ENTROPY_CONTEXT) * tx_size_in_blocks);
}
}
int vp10_decode_block_tokens(MACROBLOCKD *xd,
int plane, const scan_order *sc,
int x, int y,
TX_SIZE tx_size, vpx_reader *r,
int seg_id) {
struct macroblockd_plane *const pd = &xd->plane[plane];
const int16_t *const dequant = pd->seg_dequant[seg_id];
const int ctx = get_entropy_context(tx_size, pd->above_context + x,
pd->left_context + y);
const int eob = decode_coefs(xd, pd->plane_type,
pd->dqcoeff, tx_size,
dequant, ctx, sc->scan, sc->neighbors, r);
dec_set_contexts(xd, pd, tx_size, eob > 0, x, y);
return eob;
}
Reference in New Issue View Git Blame Copy Permalink