// Paragraph 9.9
void VP8ParseProba(VP8BitReader* const br, VP8Decoder* const dec) {
VP8Proba* const proba = &dec->proba_;
int t, b, c, p;
for (t = 0; t < NUM_TYPES; ++t) {
for (b = 0; b < NUM_BANDS; ++b) {
for (c = 0; c < NUM_CTX; ++c) {
for (p = 0; p < NUM_PROBAS; ++p) {
const int v = VP8GetBit(br, CoeffsUpdateProba[t][b][c][p]) ?
VP8GetValue(br, 8) : CoeffsProba0[t][b][c][p];
proba->bands_[t][b].probas_[c][p] = v;
}
}
}
}
dec->use_skip_proba_ = VP8Get(br);
if (dec->use_skip_proba_) {
dec->skip_p_ = VP8GetValue(br, 8);
}
}
// Paragraph 9.9
void VP8ParseProba(VP8BitReader* const br, VP8Decoder* const dec) {
VP8Proba* const proba = &dec->proba_;
int t, b, c, p;
for (t = 0; t < NUM_TYPES; ++t) {
for (b = 0; b < NUM_BANDS; ++b) {
for (c = 0; c < NUM_CTX; ++c) {
for (p = 0; p < NUM_PROBAS; ++p) {
if (VP8GetBit(br, CoeffsUpdateProba[t][b][c][p])) {
proba->coeffs_[t][b][c][p] = VP8GetValue(br, 8);
}
}
}
}
}
dec->use_skip_proba_ = VP8Get(br);
if (dec->use_skip_proba_) {
dec->skip_p_ = VP8GetValue(br, 8);
}
#ifndef ONLY_KEYFRAME_CODE
if (!dec->frm_hdr_.key_frame_) {
int i;
dec->intra_p_ = VP8GetValue(br, 8);
dec->last_p_ = VP8GetValue(br, 8);
dec->golden_p_ = VP8GetValue(br, 8);
if (VP8Get(br)) { // update y-mode
for (i = 0; i < 4; ++i) {
proba->ymode_[i] = VP8GetValue(br, 8);
}
}
if (VP8Get(br)) { // update uv-mode
for (i = 0; i < 3; ++i) {
proba->uvmode_[i] = VP8GetValue(br, 8);
}
}
// update MV
for (i = 0; i < 2; ++i) {
int k;
for (k = 0; k < NUM_MV_PROBAS; ++k) {
if (VP8GetBit(br, MVUpdateProba[i][k])) {
const int v = VP8GetValue(br, 7);
proba->mv_[i][k] = v ? v << 1 : 1;
}
}
}
}
#endif
}
void VP8ParseQuant(VP8Decoder* const dec) {
VP8BitReader* const br = &dec->br_;
const int base_q0 = VP8GetValue(br, 7);
const int dqy1_dc = VP8Get(br) ? VP8GetSignedValue(br, 4) : 0;
const int dqy2_dc = VP8Get(br) ? VP8GetSignedValue(br, 4) : 0;
const int dqy2_ac = VP8Get(br) ? VP8GetSignedValue(br, 4) : 0;
const int dquv_dc = VP8Get(br) ? VP8GetSignedValue(br, 4) : 0;
const int dquv_ac = VP8Get(br) ? VP8GetSignedValue(br, 4) : 0;
const VP8SegmentHeader* const hdr = &dec->segment_hdr_;
int i;
for (i = 0; i < NUM_MB_SEGMENTS; ++i) {
int q;
if (hdr->use_segment_) {
q = hdr->quantizer_[i];
if (!hdr->absolute_delta_) {
q += base_q0;
}
} else {
if (i > 0) {
dec->dqm_[i] = dec->dqm_[0];
continue;
} else {
q = base_q0;
}
}
{
VP8QuantMatrix* const m = &dec->dqm_[i];
m->y1_mat_[0] = kDcTable[clip(q + dqy1_dc, 127)];
m->y1_mat_[1] = kAcTable[clip(q + 0, 127)];
m->y2_mat_[0] = kDcTable[clip(q + dqy2_dc, 127)] * 2;
// For all x in [0..284], x*155/100 is bitwise equal to (x*101581) >> 16.
// The smallest precision for that is '(x*6349) >> 12' but 16 is a good
// word size.
m->y2_mat_[1] = (kAcTable[clip(q + dqy2_ac, 127)] * 101581) >> 16;
if (m->y2_mat_[1] < 8) m->y2_mat_[1] = 8;
m->uv_mat_[0] = kDcTable[clip(q + dquv_dc, 117)];
m->uv_mat_[1] = kAcTable[clip(q + dquv_ac, 127)];
m->uv_quant_ = q + dquv_ac; // for dithering strength evaluation
}
}
}
int32_t VP8GetSignedValue(VP8BitReader* const br, int bits) {
const int value = VP8GetValue(br, bits);
return VP8Get(br) ? -value : value;
}