// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Note: ported from Chromium commit head: 2de6929
#include "vp9_compressed_header_parser.h"
#include "base/logging.h"
namespace media {
namespace {
// 6.3.6 Inv recenter noneg syntax, inv_recenter_nonneg().
int InvRecenterNonneg(int v, int m) {
DCHECK_LE(m, kVp9MaxProb / 2);
if (v > 2 * m)
return v;
if (v & 1)
return m - ((v + 1) >> 1);
return m + (v >> 1);
}
// 6.3.5 Inv remap prob syntax, inv_remap_prob().
Vp9Prob InvRemapProb(uint8_t delta_prob, uint8_t prob) {
static uint8_t inv_map_table[kVp9MaxProb] = {
7, 20, 33, 46, 59, 72, 85, 98, 111, 124, 137, 150, 163, 176,
189, 202, 215, 228, 241, 254, 1, 2, 3, 4, 5, 6, 8, 9,
10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 24,
25, 26, 27, 28, 29, 30, 31, 32, 34, 35, 36, 37, 38, 39,
40, 41, 42, 43, 44, 45, 47, 48, 49, 50, 51, 52, 53, 54,
55, 56, 57, 58, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69,
70, 71, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84,
86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 99, 100,
101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 112, 113, 114, 115,
116, 117, 118, 119, 120, 121, 122, 123, 125, 126, 127, 128, 129, 130,
131, 132, 133, 134, 135, 136, 138, 139, 140, 141, 142, 143, 144, 145,
146, 147, 148, 149, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160,
161, 162, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175,
177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 190, 191,
192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 203, 204, 205, 206,
207, 208, 209, 210, 211, 212, 213, 214, 216, 217, 218, 219, 220, 221,
222, 223, 224, 225, 226, 227, 229, 230, 231, 232, 233, 234, 235, 236,
237, 238, 239, 240, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251,
252, 253, 253};
uint8_t m = prob;
uint8_t v = delta_prob;
DCHECK_GE(m, 1);
DCHECK_LE(m, kVp9MaxProb);
DCHECK_LT(v, arraysize(inv_map_table));
v = inv_map_table[v];
m--;
if ((m << 1) <= kVp9MaxProb) {
return 1 + InvRecenterNonneg(v, m);
} else {
return kVp9MaxProb - InvRecenterNonneg(v, kVp9MaxProb - 1 - m);
}
}
} // namespace
Vp9CompressedHeaderParser::Vp9CompressedHeaderParser() = default;
// 6.3.1 Tx mode syntax
void Vp9CompressedHeaderParser::ReadTxMode(Vp9FrameHeader* fhdr) {
int tx_mode;
if (fhdr->quant_params.IsLossless()) {
tx_mode = Vp9CompressedHeader::ONLY_4X4;
} else {
tx_mode = reader_.ReadLiteral(2);
if (tx_mode == Vp9CompressedHeader::ALLOW_32X32)
tx_mode += reader_.ReadLiteral(1);
}
fhdr->compressed_header.tx_mode =
static_cast<Vp9CompressedHeader::Vp9TxMode>(tx_mode);
}
// 6.3.4 Decode term subexp syntax
uint8_t Vp9CompressedHeaderParser::DecodeTermSubexp() {
if (reader_.ReadLiteral(1) == 0)
return reader_.ReadLiteral(4);
if (reader_.ReadLiteral(1) == 0)
return reader_.ReadLiteral(4) + 16;
if (reader_.ReadLiteral(1) == 0)
return reader_.ReadLiteral(5) + 32;
uint8_t v = reader_.ReadLiteral(7);
if (v < 65)
return v + 64;
return (v << 1) - 1 + reader_.ReadLiteral(1);
}
// 6.3.3 Diff update prob syntax
void Vp9CompressedHeaderParser::DiffUpdateProb(Vp9Prob* prob) {
const Vp9Prob kUpdateProb = 252;
if (reader_.ReadBool(kUpdateProb)) {
uint8_t delta_prob = DecodeTermSubexp();
*prob = InvRemapProb(delta_prob, *prob);
}
}
// Helper function to DiffUpdateProb an array of probs.
template <int N>
void Vp9CompressedHeaderParser::DiffUpdateProbArray(Vp9Prob (&prob_array)[N]) {
for (auto& x : prob_array) {
DiffUpdateProb(&x);
}
}
// 6.3.2 Tx mode probs syntax
void Vp9CompressedHeaderParser::ReadTxModeProbs(
Vp9FrameContext* frame_context) {
for (auto& a : frame_context->tx_probs_8x8) {
DiffUpdateProbArray(a);
}
for (auto& a : frame_context->tx_probs_16x16) {
DiffUpdateProbArray(a);
}
for (auto& a : frame_context->tx_probs_32x32) {
DiffUpdateProbArray(a);
}
}
// 6.3.7 Coef probs syntax
void Vp9CompressedHeaderParser::ReadCoefProbs(Vp9FrameHeader* fhdr) {
const int tx_mode_to_biggest_tx_size[Vp9CompressedHeader::TX_MODES] = {
0, 1, 2, 3, 3,
};
const int max_tx_size =
tx_mode_to_biggest_tx_size[fhdr->compressed_header.tx_mode];
for (int tx_size = 0; tx_size <= max_tx_size; tx_size++) {
if (reader_.ReadLiteral(1) == 0)
continue;
for (auto& ai : fhdr->frame_context.coef_probs[tx_size]) {
for (auto& aj : ai) {
for (auto& ak : aj) {
int max_l = (ak == aj[0]) ? 3 : 6;
for (int l = 0; l < max_l; l++) {
DiffUpdateProbArray(ak[l]);
}
}
}
}
}
}
// 6.3.8 Skip probs syntax
void Vp9CompressedHeaderParser::ReadSkipProb(Vp9FrameContext* frame_context) {
DiffUpdateProbArray(frame_context->skip_prob);
}
// 6.3.9 Inter mode probs syntax
void Vp9CompressedHeaderParser::ReadInterModeProbs(
Vp9FrameContext* frame_context) {
for (auto& a : frame_context->inter_mode_probs)
DiffUpdateProbArray(a);
}
// 6.3.10 Interp filter probs syntax
void Vp9CompressedHeaderParser::ReadInterpFilterProbs(
Vp9FrameContext* frame_context) {
for (auto& a : frame_context->interp_filter_probs)
DiffUpdateProbArray(a);
}
// 6.3.11 Intra inter probs syntax
void Vp9CompressedHeaderParser::ReadIsInterProbs(
Vp9FrameContext* frame_context) {
DiffUpdateProbArray(frame_context->is_inter_prob);
}
// 6.3.12 Frame reference mode syntax
void Vp9CompressedHeaderParser::ReadFrameReferenceMode(Vp9FrameHeader* fhdr) {
bool compound_reference_allowed = false;
for (int i = VP9_FRAME_LAST + 1; i < VP9_FRAME_MAX; i++)
if (fhdr->ref_frame_sign_bias[i] != fhdr->ref_frame_sign_bias[1])
compound_reference_allowed = true;
if (compound_reference_allowed && reader_.ReadLiteral(1)) {
fhdr->compressed_header.reference_mode =
reader_.ReadLiteral(1) ? REFERENCE_MODE_SELECT : COMPOUND_REFERENCE;
} else {
fhdr->compressed_header.reference_mode = SINGLE_REFERENCE;
}
}
// 6.3.13 Frame reference mode probs syntax
void Vp9CompressedHeaderParser::ReadFrameReferenceModeProbs(
Vp9FrameHeader* fhdr) {
Vp9FrameContext* frame_context = &fhdr->frame_context;
if (fhdr->compressed_header.reference_mode == REFERENCE_MODE_SELECT)
DiffUpdateProbArray(frame_context->comp_mode_prob);
if (fhdr->compressed_header.reference_mode != COMPOUND_REFERENCE)
for (auto& a : frame_context->single_ref_prob)
DiffUpdateProbArray(a);
if (fhdr->compressed_header.reference_mode != SINGLE_REFERENCE)
DiffUpdateProbArray(frame_context->comp_ref_prob);
}
// 6.3.14 Y mode probs syntax
void Vp9CompressedHeaderParser::ReadYModeProbs(Vp9FrameContext* frame_context) {
for (auto& a : frame_context->y_mode_probs)
DiffUpdateProbArray(a);
}
// 6.3.15 Partition probs syntax
void Vp9CompressedHeaderParser::ReadPartitionProbs(
Vp9FrameContext* frame_context) {
for (auto& a : frame_context->partition_probs)
DiffUpdateProbArray(a);
}
// 6.3.16 MV probs syntax
void Vp9CompressedHeaderParser::ReadMvProbs(bool allow_high_precision_mv,
Vp9FrameContext* frame_context) {
UpdateMvProbArray(frame_context->mv_joint_probs);
for (int i = 0; i < 2; i++) {
UpdateMvProb(&frame_context->mv_sign_prob[i]);
UpdateMvProbArray(frame_context->mv_class_probs[i]);
UpdateMvProb(&frame_context->mv_class0_bit_prob[i]);
UpdateMvProbArray(frame_context->mv_bits_prob[i]);
}
for (int i = 0; i < 2; i++) {
for (auto& a : frame_context->mv_class0_fr_probs[i])
UpdateMvProbArray(a);
UpdateMvProbArray(frame_context->mv_fr_probs[i]);
}
if (allow_high_precision_mv) {
for (int i = 0; i < 2; i++) {
UpdateMvProb(&frame_context->mv_class0_hp_prob[i]);
UpdateMvProb(&frame_context->mv_hp_prob[i]);
}
}
}
// 6.3.17 Update mv prob syntax
void Vp9CompressedHeaderParser::UpdateMvProb(Vp9Prob* prob) {
if (reader_.ReadBool(252))
*prob = reader_.ReadLiteral(7) << 1 | 1;
}
// Helper function to UpdateMvProb an array of probs.
template <int N>
void Vp9CompressedHeaderParser::UpdateMvProbArray(Vp9Prob (&prob_array)[N]) {
for (auto& x : prob_array) {
UpdateMvProb(&x);
}
}
// 6.3 Compressed header syntax
bool Vp9CompressedHeaderParser::Parse(const uint8_t* stream,
off_t frame_size,
Vp9FrameHeader* fhdr) {
DVLOG(2) << "Vp9CompressedHeaderParser::Parse";
if (!reader_.Initialize(stream, frame_size))
return false;
ReadTxMode(fhdr);
if (fhdr->compressed_header.tx_mode == Vp9CompressedHeader::TX_MODE_SELECT)
ReadTxModeProbs(&fhdr->frame_context);
ReadCoefProbs(fhdr);
ReadSkipProb(&fhdr->frame_context);
if (!fhdr->IsIntra()) {
ReadInterModeProbs(&fhdr->frame_context);
if (fhdr->interpolation_filter == SWITCHABLE)
ReadInterpFilterProbs(&fhdr->frame_context);
ReadIsInterProbs(&fhdr->frame_context);
ReadFrameReferenceMode(fhdr);
ReadFrameReferenceModeProbs(fhdr);
ReadYModeProbs(&fhdr->frame_context);
ReadPartitionProbs(&fhdr->frame_context);
ReadMvProbs(fhdr->allow_high_precision_mv, &fhdr->frame_context);
}
if (!reader_.IsValid()) {
DVLOG(1) << "parser reads beyond the end of buffer";
return false;
}
if (!reader_.ConsumePaddingBits()) {
DVLOG(1) << "padding bits are not zero";
return false;
}
return true;
}
} // namespace media