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serenity/Userland/Libraries/LibVideo/VP9/Parser.cpp
Zaggy1024 befcd479ae LibVideo/VP9: Add Frame, Tile and Block context structs 
These are used to pass context needed for decoding, with mutability
scoped only to the sections that the function receiving the contexts
needs to modify. This allows lifetimes of data to be more explicit
rather than being stored in fields, as well as preventing tile threads
from modifying outside their allowed bounds.
2022-11-30 08:28:30 +01:00

1666 lines
66 KiB
C++
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/*
* Copyright (c) 2021, Hunter Salyer <thefalsehonesty@gmail.com>
* Copyright (c) 2022, Gregory Bertilson <zaggy1024@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/String.h>
#include <LibGfx/Point.h>
#include <LibGfx/Size.h>
#include "Decoder.h"
#include "Parser.h"
#include "Utilities.h"
#if defined(AK_COMPILER_GCC)
# pragma GCC optimize("O3")
#endif
namespace Video::VP9 {
#define TRY_READ(expression) DECODER_TRY(DecoderErrorCategory::Corrupted, expression)
Parser::Parser(Decoder& decoder)
: m_probability_tables(make<ProbabilityTables>())
, m_decoder(decoder)
{
}
Parser::~Parser()
{
}
Vector<size_t> Parser::parse_superframe_sizes(ReadonlyBytes frame_data)
{
if (frame_data.size() < 1)
return {};
// The decoder determines the presence of a superframe by:
// 1. parsing the final byte of the chunk and checking that the superframe_marker equals 0b110,
// If the checks in steps 1 and 3 both pass, then the chunk is determined to contain a superframe and each
// frame in the superframe is passed to the decoding process in turn.
// Otherwise, the chunk is determined to not contain a superframe, and the whole chunk is passed to the
// decoding process.
// NOTE: Reading from span data will be quicker than spinning up a BitStream.
u8 superframe_byte = frame_data[frame_data.size() - 1];
// NOTE: We have to read out of the byte from the little end first, hence the padding bits in the masks below.
u8 superframe_marker = superframe_byte & 0b1110'0000;
if (superframe_marker == 0b1100'0000) {
u8 bytes_per_framesize = ((superframe_byte >> 3) & 0b11) + 1;
u8 frames_in_superframe = (superframe_byte & 0b111) + 1;
// 2. setting the total size of the superframe_index SzIndex equal to 2 + NumFrames * SzBytes,
size_t index_size = 2 + bytes_per_framesize * frames_in_superframe;
if (index_size > frame_data.size())
return {};
auto superframe_header_data = frame_data.data() + frame_data.size() - index_size;
u8 start_superframe_byte = *(superframe_header_data++);
// 3. checking that the first byte of the superframe_index matches the final byte.
if (superframe_byte != start_superframe_byte)
return {};
Vector<size_t> result;
for (u8 i = 0; i < frames_in_superframe; i++) {
size_t frame_size = 0;
for (u8 j = 0; j < bytes_per_framesize; j++)
frame_size |= (static_cast<size_t>(*(superframe_header_data++)) << (j * 8));
result.append(frame_size);
}
return result;
}
return {};
}
/* (6.1) */
DecoderErrorOr<FrameContext> Parser::parse_frame(ReadonlyBytes frame_data)
{
m_bit_stream = make<BitStream>(frame_data.data(), frame_data.size());
m_syntax_element_counter = make<SyntaxElementCounter>();
auto frame_context = TRY(uncompressed_header());
if (!trailing_bits())
return DecoderError::corrupted("Trailing bits were non-zero"sv);
// FIXME: This should not be an error. Spec says that we consume padding bits until the end of the sample.
if (frame_context.header_size_in_bytes == 0)
return DecoderError::corrupted("Frame header is zero-sized"sv);
m_probability_tables->load_probs(m_frame_context_idx);
m_probability_tables->load_probs2(m_frame_context_idx);
m_syntax_element_counter->clear_counts();
TRY_READ(m_bit_stream->init_bool(frame_context.header_size_in_bytes));
TRY(compressed_header());
TRY_READ(m_bit_stream->exit_bool());
TRY(m_decoder.allocate_buffers(frame_context));
TRY(decode_tiles(frame_context));
TRY(refresh_probs());
m_previous_frame_size = frame_context.size();
m_previous_show_frame = m_show_frame;
return frame_context;
}
bool Parser::trailing_bits()
{
while (m_bit_stream->bits_remaining() & 7u) {
if (MUST(m_bit_stream->read_bit()))
return false;
}
return true;
}
DecoderErrorOr<void> Parser::refresh_probs()
{
if (!m_error_resilient_mode && !m_frame_parallel_decoding_mode) {
m_probability_tables->load_probs(m_frame_context_idx);
TRY(m_decoder.adapt_coef_probs());
if (!m_frame_is_intra) {
m_probability_tables->load_probs2(m_frame_context_idx);
TRY(m_decoder.adapt_non_coef_probs());
}
}
if (m_refresh_frame_context)
m_probability_tables->save_probs(m_frame_context_idx);
return {};
}
DecoderErrorOr<FrameType> Parser::read_frame_type()
{
if (TRY_READ(m_bit_stream->read_bit()))
return NonKeyFrame;
return KeyFrame;
}
DecoderErrorOr<ColorRange> Parser::read_color_range()
{
if (TRY_READ(m_bit_stream->read_bit()))
return ColorRange::Full;
return ColorRange::Studio;
}
/* (6.2) */
DecoderErrorOr<FrameContext> Parser::uncompressed_header()
{
FrameContext frame_context;
auto frame_marker = TRY_READ(m_bit_stream->read_bits(2));
if (frame_marker != 2)
return DecoderError::corrupted("uncompressed_header: Frame marker must be 2"sv);
auto profile_low_bit = TRY_READ(m_bit_stream->read_bit());
auto profile_high_bit = TRY_READ(m_bit_stream->read_bit());
frame_context.profile = (profile_high_bit << 1u) + profile_low_bit;
if (frame_context.profile == 3 && TRY_READ(m_bit_stream->read_bit()))
return DecoderError::corrupted("uncompressed_header: Profile 3 reserved bit was non-zero"sv);
if (TRY_READ(m_bit_stream->read_bit())) {
m_refresh_frame_flags = 0;
m_loop_filter_level = 0;
frame_context.set_existing_frame_to_show(TRY_READ(m_bit_stream->read_bits(3)));
return frame_context;
}
m_last_frame_type = m_frame_type;
m_frame_type = TRY(read_frame_type());
m_show_frame = TRY_READ(m_bit_stream->read_bit());
m_error_resilient_mode = TRY_READ(m_bit_stream->read_bit());
Gfx::Size<u32> frame_size;
Gfx::Size<u32> render_size;
if (m_frame_type == KeyFrame) {
TRY(frame_sync_code());
TRY(color_config(frame_context));
frame_size = TRY(parse_frame_size());
render_size = TRY(parse_render_size(frame_size));
m_refresh_frame_flags = 0xFF;
m_frame_is_intra = true;
} else {
m_frame_is_intra = !m_show_frame && TRY_READ(m_bit_stream->read_bit());
if (!m_error_resilient_mode) {
m_reset_frame_context = TRY_READ(m_bit_stream->read_bits(2));
} else {
m_reset_frame_context = 0;
}
if (m_frame_is_intra) {
TRY(frame_sync_code());
if (frame_context.profile > 0) {
TRY(color_config(frame_context));
} else {
m_color_space = Bt601;
m_subsampling_x = true;
m_subsampling_y = true;
m_bit_depth = 8;
}
m_refresh_frame_flags = TRY_READ(m_bit_stream->read_f8());
frame_size = TRY(parse_frame_size());
render_size = TRY(parse_render_size(frame_size));
} else {
m_refresh_frame_flags = TRY_READ(m_bit_stream->read_f8());
for (auto i = 0; i < 3; i++) {
m_ref_frame_idx[i] = TRY_READ(m_bit_stream->read_bits(3));
m_ref_frame_sign_bias[LastFrame + i] = TRY_READ(m_bit_stream->read_bit());
}
frame_size = TRY(parse_frame_size_with_refs());
render_size = TRY(parse_render_size(frame_size));
m_allow_high_precision_mv = TRY_READ(m_bit_stream->read_bit());
TRY(read_interpolation_filter());
}
}
DECODER_TRY_ALLOC(frame_context.set_size(frame_size));
frame_context.render_size = render_size;
TRY(compute_image_size(frame_context));
if (!m_error_resilient_mode) {
m_refresh_frame_context = TRY_READ(m_bit_stream->read_bit());
m_frame_parallel_decoding_mode = TRY_READ(m_bit_stream->read_bit());
} else {
m_refresh_frame_context = false;
m_frame_parallel_decoding_mode = true;
}
m_frame_context_idx = TRY_READ(m_bit_stream->read_bits(2));
if (m_frame_is_intra || m_error_resilient_mode) {
setup_past_independence();
if (m_frame_type == KeyFrame || m_error_resilient_mode || m_reset_frame_context == 3) {
for (auto i = 0; i < 4; i++) {
m_probability_tables->save_probs(i);
}
} else if (m_reset_frame_context == 2) {
m_probability_tables->save_probs(m_frame_context_idx);
}
m_frame_context_idx = 0;
}
TRY(loop_filter_params());
TRY(quantization_params());
TRY(segmentation_params());
TRY(tile_info(frame_context));
frame_context.header_size_in_bytes = TRY_READ(m_bit_stream->read_f16());
return frame_context;
}
DecoderErrorOr<void> Parser::frame_sync_code()
{
if (TRY_READ(m_bit_stream->read_f8()) != 0x49)
return DecoderError::corrupted("frame_sync_code: Byte 0 was not 0x49."sv);
if (TRY_READ(m_bit_stream->read_f8()) != 0x83)
return DecoderError::corrupted("frame_sync_code: Byte 1 was not 0x83."sv);
if (TRY_READ(m_bit_stream->read_f8()) != 0x42)
return DecoderError::corrupted("frame_sync_code: Byte 2 was not 0x42."sv);
return {};
}
DecoderErrorOr<void> Parser::color_config(FrameContext const& frame_context)
{
if (frame_context.profile >= 2) {
m_bit_depth = TRY_READ(m_bit_stream->read_bit()) ? 12 : 10;
} else {
m_bit_depth = 8;
}
auto color_space = TRY_READ(m_bit_stream->read_bits(3));
VERIFY(color_space <= RGB);
m_color_space = static_cast<ColorSpace>(color_space);
if (color_space != RGB) {
m_color_range = TRY(read_color_range());
if (frame_context.profile == 1 || frame_context.profile == 3) {
m_subsampling_x = TRY_READ(m_bit_stream->read_bit());
m_subsampling_y = TRY_READ(m_bit_stream->read_bit());
if (TRY_READ(m_bit_stream->read_bit()))
return DecoderError::corrupted("color_config: Subsampling reserved zero was set"sv);
} else {
m_subsampling_x = true;
m_subsampling_y = true;
}
} else {
m_color_range = ColorRange::Full;
if (frame_context.profile == 1 || frame_context.profile == 3) {
m_subsampling_x = false;
m_subsampling_y = false;
if (TRY_READ(m_bit_stream->read_bit()))
return DecoderError::corrupted("color_config: RGB reserved zero was set"sv);
}
}
return {};
}
DecoderErrorOr<Gfx::Size<u32>> Parser::parse_frame_size()
{
return Gfx::Size<u32> { TRY_READ(m_bit_stream->read_f16()) + 1, TRY_READ(m_bit_stream->read_f16()) + 1 };
}
DecoderErrorOr<Gfx::Size<u32>> Parser::parse_render_size(Gfx::Size<u32> frame_size)
{
if (!TRY_READ(m_bit_stream->read_bit()))
return frame_size;
return Gfx::Size<u32> { TRY_READ(m_bit_stream->read_f16()) + 1, TRY_READ(m_bit_stream->read_f16()) + 1 };
}
DecoderErrorOr<Gfx::Size<u32>> Parser::parse_frame_size_with_refs()
{
Optional<Gfx::Size<u32>> size;
for (auto frame_index : m_ref_frame_idx) {
if (TRY_READ(m_bit_stream->read_bit())) {
size.emplace(m_ref_frame_size[frame_index]);
break;
}
}
if (size.has_value())
return size.value();
return TRY(parse_frame_size());
}
DecoderErrorOr<void> Parser::compute_image_size(FrameContext& frame_context)
{
// 7.2.6 Compute image size semantics
// When compute_image_size is invoked, the following ordered steps occur:
// 1. If this is the first time compute_image_size is invoked, or if either FrameWidth or FrameHeight have
// changed in value compared to the previous time this function was invoked, then the segmentation map is
// cleared to all zeros by setting SegmentId[ row ][ col ] equal to 0 for row = 0..MiRows-1 and col =
// 0..MiCols-1.
// FIXME: What does this mean? SegmentIds is scoped to one frame, so it will not contain values here. It's
// also suspicious that spec refers to this as SegmentId rather than SegmentIds (plural). Is this
// supposed to refer to PrevSegmentIds?
bool first_invoke = m_is_first_compute_image_size_invoke;
m_is_first_compute_image_size_invoke = false;
bool same_size = m_previous_frame_size == frame_context.size();
// 2. The variable UsePrevFrameMvs is set equal to 1 if all of the following conditions are true:
// a. This is not the first time compute_image_size is invoked.
// b. Both FrameWidth and FrameHeight have the same value compared to the previous time this function
// was invoked.
// c. show_frame was equal to 1 the previous time this function was invoked.
// d. error_resilient_mode is equal to 0.
// e. FrameIsIntra is equal to 0.
// Otherwise, UsePrevFrameMvs is set equal to 0.
m_use_prev_frame_mvs = !first_invoke && same_size && m_previous_show_frame && !m_error_resilient_mode && !m_frame_is_intra;
return {};
}
DecoderErrorOr<void> Parser::read_interpolation_filter()
{
if (TRY_READ(m_bit_stream->read_bit())) {
m_interpolation_filter = Switchable;
} else {
m_interpolation_filter = literal_to_type[TRY_READ(m_bit_stream->read_bits(2))];
}
return {};
}
DecoderErrorOr<void> Parser::loop_filter_params()
{
m_loop_filter_level = TRY_READ(m_bit_stream->read_bits(6));
m_loop_filter_sharpness = TRY_READ(m_bit_stream->read_bits(3));
m_loop_filter_delta_enabled = TRY_READ(m_bit_stream->read_bit());
if (m_loop_filter_delta_enabled) {
if (TRY_READ(m_bit_stream->read_bit())) {
for (auto& loop_filter_ref_delta : m_loop_filter_ref_deltas) {
if (TRY_READ(m_bit_stream->read_bit()))
loop_filter_ref_delta = TRY_READ(m_bit_stream->read_s(6));
}
for (auto& loop_filter_mode_delta : m_loop_filter_mode_deltas) {
if (TRY_READ(m_bit_stream->read_bit()))
loop_filter_mode_delta = TRY_READ(m_bit_stream->read_s(6));
}
}
}
return {};
}
DecoderErrorOr<void> Parser::quantization_params()
{
m_base_q_idx = TRY_READ(m_bit_stream->read_f8());
m_delta_q_y_dc = TRY(read_delta_q());
m_delta_q_uv_dc = TRY(read_delta_q());
m_delta_q_uv_ac = TRY(read_delta_q());
m_lossless = m_base_q_idx == 0 && m_delta_q_y_dc == 0 && m_delta_q_uv_dc == 0 && m_delta_q_uv_ac == 0;
return {};
}
DecoderErrorOr<i8> Parser::read_delta_q()
{
if (TRY_READ(m_bit_stream->read_bit()))
return TRY_READ(m_bit_stream->read_s(4));
return 0;
}
DecoderErrorOr<void> Parser::segmentation_params()
{
m_segmentation_enabled = TRY_READ(m_bit_stream->read_bit());
if (!m_segmentation_enabled)
return {};
m_segmentation_update_map = TRY_READ(m_bit_stream->read_bit());
if (m_segmentation_update_map) {
for (auto& segmentation_tree_prob : m_segmentation_tree_probs)
segmentation_tree_prob = TRY(read_prob());
m_segmentation_temporal_update = TRY_READ(m_bit_stream->read_bit());
for (auto& segmentation_pred_prob : m_segmentation_pred_prob)
segmentation_pred_prob = m_segmentation_temporal_update ? TRY(read_prob()) : 255;
}
auto segmentation_update_data = (TRY_READ(m_bit_stream->read_bit()));
if (!segmentation_update_data)
return {};
m_segmentation_abs_or_delta_update = TRY_READ(m_bit_stream->read_bit());
for (auto i = 0; i < MAX_SEGMENTS; i++) {
for (auto j = 0; j < SEG_LVL_MAX; j++) {
auto feature_value = 0;
auto feature_enabled = TRY_READ(m_bit_stream->read_bit());
m_feature_enabled[i][j] = feature_enabled;
if (feature_enabled) {
auto bits_to_read = segmentation_feature_bits[j];
feature_value = TRY_READ(m_bit_stream->read_bits(bits_to_read));
if (segmentation_feature_signed[j]) {
if (TRY_READ(m_bit_stream->read_bit()))
feature_value = -feature_value;
}
}
m_feature_data[i][j] = feature_value;
}
}
return {};
}
DecoderErrorOr<u8> Parser::read_prob()
{
if (TRY_READ(m_bit_stream->read_bit()))
return TRY_READ(m_bit_stream->read_f8());
return 255;
}
DecoderErrorOr<void> Parser::tile_info(FrameContext& frame_context)
{
auto superblock_columns = frame_context.superblock_columns();
auto min_log2_tile_cols = calc_min_log2_tile_cols(superblock_columns);
auto max_log2_tile_cols = calc_max_log2_tile_cols(superblock_columns);
m_tile_cols_log2 = min_log2_tile_cols;
while (m_tile_cols_log2 < max_log2_tile_cols) {
if (TRY_READ(m_bit_stream->read_bit()))
m_tile_cols_log2++;
else
break;
}
m_tile_rows_log2 = TRY_READ(m_bit_stream->read_bit());
if (m_tile_rows_log2) {
m_tile_rows_log2 += TRY_READ(m_bit_stream->read_bit());
}
return {};
}
u16 Parser::calc_min_log2_tile_cols(u32 superblock_columns)
{
auto min_log_2 = 0u;
while ((u32)(MAX_TILE_WIDTH_B64 << min_log_2) < superblock_columns)
min_log_2++;
return min_log_2;
}
u16 Parser::calc_max_log2_tile_cols(u32 superblock_columns)
{
u16 max_log_2 = 1;
while ((superblock_columns >> max_log_2) >= MIN_TILE_WIDTH_B64)
max_log_2++;
return max_log_2 - 1;
}
void Parser::setup_past_independence()
{
for (auto i = 0; i < 8; i++) {
for (auto j = 0; j < 4; j++) {
m_feature_data[i][j] = 0;
m_feature_enabled[i][j] = false;
}
}
m_previous_block_contexts.reset();
m_segmentation_abs_or_delta_update = false;
m_loop_filter_delta_enabled = true;
m_loop_filter_ref_deltas[IntraFrame] = 1;
m_loop_filter_ref_deltas[LastFrame] = 0;
m_loop_filter_ref_deltas[GoldenFrame] = -1;
m_loop_filter_ref_deltas[AltRefFrame] = -1;
for (auto& loop_filter_mode_delta : m_loop_filter_mode_deltas)
loop_filter_mode_delta = 0;
m_probability_tables->reset_probs();
}
DecoderErrorOr<void> Parser::compressed_header()
{
TRY(read_tx_mode());
if (m_tx_mode == TXModeSelect)
TRY(tx_mode_probs());
TRY(read_coef_probs());
TRY(read_skip_prob());
if (!m_frame_is_intra) {
TRY(read_inter_mode_probs());
if (m_interpolation_filter == Switchable)
TRY(read_interp_filter_probs());
TRY(read_is_inter_probs());
TRY(frame_reference_mode());
TRY(frame_reference_mode_probs());
TRY(read_y_mode_probs());
TRY(read_partition_probs());
TRY(mv_probs());
}
return {};
}
DecoderErrorOr<void> Parser::read_tx_mode()
{
if (m_lossless) {
m_tx_mode = Only_4x4;
} else {
auto tx_mode = TRY_READ(m_bit_stream->read_literal(2));
if (tx_mode == Allow_32x32)
tx_mode += TRY_READ(m_bit_stream->read_literal(1));
m_tx_mode = static_cast<TXMode>(tx_mode);
}
return {};
}
DecoderErrorOr<void> Parser::tx_mode_probs()
{
auto& tx_probs = m_probability_tables->tx_probs();
for (auto i = 0; i < TX_SIZE_CONTEXTS; i++) {
for (auto j = 0; j < TX_SIZES - 3; j++)
tx_probs[TX_8x8][i][j] = TRY(diff_update_prob(tx_probs[TX_8x8][i][j]));
}
for (auto i = 0; i < TX_SIZE_CONTEXTS; i++) {
for (auto j = 0; j < TX_SIZES - 2; j++)
tx_probs[TX_16x16][i][j] = TRY(diff_update_prob(tx_probs[TX_16x16][i][j]));
}
for (auto i = 0; i < TX_SIZE_CONTEXTS; i++) {
for (auto j = 0; j < TX_SIZES - 1; j++)
tx_probs[TX_32x32][i][j] = TRY(diff_update_prob(tx_probs[TX_32x32][i][j]));
}
return {};
}
DecoderErrorOr<u8> Parser::diff_update_prob(u8 prob)
{
auto update_prob = TRY_READ(m_bit_stream->read_bool(252));
if (update_prob) {
auto delta_prob = TRY(decode_term_subexp());
prob = inv_remap_prob(delta_prob, prob);
}
return prob;
}
DecoderErrorOr<u8> Parser::decode_term_subexp()
{
if (TRY_READ(m_bit_stream->read_literal(1)) == 0)
return TRY_READ(m_bit_stream->read_literal(4));
if (TRY_READ(m_bit_stream->read_literal(1)) == 0)
return TRY_READ(m_bit_stream->read_literal(4)) + 16;
if (TRY_READ(m_bit_stream->read_literal(1)) == 0)
return TRY_READ(m_bit_stream->read_literal(5)) + 32;
auto v = TRY_READ(m_bit_stream->read_literal(7));
if (v < 65)
return v + 64;
return (v << 1u) - 1 + TRY_READ(m_bit_stream->read_literal(1));
}
u8 Parser::inv_remap_prob(u8 delta_prob, u8 prob)
{
u8 m = prob - 1;
auto v = inv_map_table[delta_prob];
if ((m << 1u) <= 255)
return 1 + inv_recenter_nonneg(v, m);
return 255 - inv_recenter_nonneg(v, 254 - m);
}
u8 Parser::inv_recenter_nonneg(u8 v, u8 m)
{
if (v > 2 * m)
return v;
if (v & 1u)
return m - ((v + 1u) >> 1u);
return m + (v >> 1u);
}
DecoderErrorOr<void> Parser::read_coef_probs()
{
m_max_tx_size = tx_mode_to_biggest_tx_size[m_tx_mode];
for (u8 tx_size = 0; tx_size <= m_max_tx_size; tx_size++) {
auto update_probs = TRY_READ(m_bit_stream->read_literal(1));
if (update_probs == 1) {
for (auto i = 0; i < 2; i++) {
for (auto j = 0; j < 2; j++) {
for (auto k = 0; k < 6; k++) {
auto max_l = (k == 0) ? 3 : 6;
for (auto l = 0; l < max_l; l++) {
for (auto m = 0; m < 3; m++) {
auto& prob = m_probability_tables->coef_probs()[tx_size][i][j][k][l][m];
prob = TRY(diff_update_prob(prob));
}
}
}
}
}
}
}
return {};
}
DecoderErrorOr<void> Parser::read_skip_prob()
{
for (auto i = 0; i < SKIP_CONTEXTS; i++)
m_probability_tables->skip_prob()[i] = TRY(diff_update_prob(m_probability_tables->skip_prob()[i]));
return {};
}
DecoderErrorOr<void> Parser::read_inter_mode_probs()
{
for (auto i = 0; i < INTER_MODE_CONTEXTS; i++) {
for (auto j = 0; j < INTER_MODES - 1; j++)
m_probability_tables->inter_mode_probs()[i][j] = TRY(diff_update_prob(m_probability_tables->inter_mode_probs()[i][j]));
}
return {};
}
DecoderErrorOr<void> Parser::read_interp_filter_probs()
{
for (auto i = 0; i < INTERP_FILTER_CONTEXTS; i++) {
for (auto j = 0; j < SWITCHABLE_FILTERS - 1; j++)
m_probability_tables->interp_filter_probs()[i][j] = TRY(diff_update_prob(m_probability_tables->interp_filter_probs()[i][j]));
}
return {};
}
DecoderErrorOr<void> Parser::read_is_inter_probs()
{
for (auto i = 0; i < IS_INTER_CONTEXTS; i++)
m_probability_tables->is_inter_prob()[i] = TRY(diff_update_prob(m_probability_tables->is_inter_prob()[i]));
return {};
}
DecoderErrorOr<void> Parser::frame_reference_mode()
{
// FIXME: These fields and the ones set in setup_compound_reference_mode should probably be contained by a field,
// since they are all used to set the reference frames later in one function (I think).
auto compound_reference_allowed = false;
for (size_t i = 2; i <= REFS_PER_FRAME; i++) {
if (m_ref_frame_sign_bias[i] != m_ref_frame_sign_bias[1])
compound_reference_allowed = true;
}
if (compound_reference_allowed) {
auto non_single_reference = TRY_READ(m_bit_stream->read_literal(1));
if (non_single_reference == 0) {
m_reference_mode = SingleReference;
} else {
auto reference_select = TRY_READ(m_bit_stream->read_literal(1));
if (reference_select == 0)
m_reference_mode = CompoundReference;
else
m_reference_mode = ReferenceModeSelect;
setup_compound_reference_mode();
}
} else {
m_reference_mode = SingleReference;
}
return {};
}
DecoderErrorOr<void> Parser::frame_reference_mode_probs()
{
if (m_reference_mode == ReferenceModeSelect) {
for (auto i = 0; i < COMP_MODE_CONTEXTS; i++) {
auto& comp_mode_prob = m_probability_tables->comp_mode_prob();
comp_mode_prob[i] = TRY(diff_update_prob(comp_mode_prob[i]));
}
}
if (m_reference_mode != CompoundReference) {
for (auto i = 0; i < REF_CONTEXTS; i++) {
auto& single_ref_prob = m_probability_tables->single_ref_prob();
single_ref_prob[i][0] = TRY(diff_update_prob(single_ref_prob[i][0]));
single_ref_prob[i][1] = TRY(diff_update_prob(single_ref_prob[i][1]));
}
}
if (m_reference_mode != SingleReference) {
for (auto i = 0; i < REF_CONTEXTS; i++) {
auto& comp_ref_prob = m_probability_tables->comp_ref_prob();
comp_ref_prob[i] = TRY(diff_update_prob(comp_ref_prob[i]));
}
}
return {};
}
DecoderErrorOr<void> Parser::read_y_mode_probs()
{
for (auto i = 0; i < BLOCK_SIZE_GROUPS; i++) {
for (auto j = 0; j < INTRA_MODES - 1; j++) {
auto& y_mode_probs = m_probability_tables->y_mode_probs();
y_mode_probs[i][j] = TRY(diff_update_prob(y_mode_probs[i][j]));
}
}
return {};
}
DecoderErrorOr<void> Parser::read_partition_probs()
{
for (auto i = 0; i < PARTITION_CONTEXTS; i++) {
for (auto j = 0; j < PARTITION_TYPES - 1; j++) {
auto& partition_probs = m_probability_tables->partition_probs();
partition_probs[i][j] = TRY(diff_update_prob(partition_probs[i][j]));
}
}
return {};
}
DecoderErrorOr<void> Parser::mv_probs()
{
for (auto j = 0; j < MV_JOINTS - 1; j++) {
auto& mv_joint_probs = m_probability_tables->mv_joint_probs();
mv_joint_probs[j] = TRY(update_mv_prob(mv_joint_probs[j]));
}
for (auto i = 0; i < 2; i++) {
auto& mv_sign_prob = m_probability_tables->mv_sign_prob();
mv_sign_prob[i] = TRY(update_mv_prob(mv_sign_prob[i]));
for (auto j = 0; j < MV_CLASSES - 1; j++) {
auto& mv_class_probs = m_probability_tables->mv_class_probs();
mv_class_probs[i][j] = TRY(update_mv_prob(mv_class_probs[i][j]));
}
auto& mv_class0_bit_prob = m_probability_tables->mv_class0_bit_prob();
mv_class0_bit_prob[i] = TRY(update_mv_prob(mv_class0_bit_prob[i]));
for (auto j = 0; j < MV_OFFSET_BITS; j++) {
auto& mv_bits_prob = m_probability_tables->mv_bits_prob();
mv_bits_prob[i][j] = TRY(update_mv_prob(mv_bits_prob[i][j]));
}
}
for (auto i = 0; i < 2; i++) {
for (auto j = 0; j < CLASS0_SIZE; j++) {
for (auto k = 0; k < MV_FR_SIZE - 1; k++) {
auto& mv_class0_fr_probs = m_probability_tables->mv_class0_fr_probs();
mv_class0_fr_probs[i][j][k] = TRY(update_mv_prob(mv_class0_fr_probs[i][j][k]));
}
}
for (auto k = 0; k < MV_FR_SIZE - 1; k++) {
auto& mv_fr_probs = m_probability_tables->mv_fr_probs();
mv_fr_probs[i][k] = TRY(update_mv_prob(mv_fr_probs[i][k]));
}
}
if (m_allow_high_precision_mv) {
for (auto i = 0; i < 2; i++) {
auto& mv_class0_hp_prob = m_probability_tables->mv_class0_hp_prob();
auto& mv_hp_prob = m_probability_tables->mv_hp_prob();
mv_class0_hp_prob[i] = TRY(update_mv_prob(mv_class0_hp_prob[i]));
mv_hp_prob[i] = TRY(update_mv_prob(mv_hp_prob[i]));
}
}
return {};
}
DecoderErrorOr<u8> Parser::update_mv_prob(u8 prob)
{
if (TRY_READ(m_bit_stream->read_bool(252))) {
return (TRY_READ(m_bit_stream->read_literal(7)) << 1u) | 1u;
}
return prob;
}
void Parser::setup_compound_reference_mode()
{
if (m_ref_frame_sign_bias[LastFrame] == m_ref_frame_sign_bias[GoldenFrame]) {
m_comp_fixed_ref = AltRefFrame;
m_comp_var_ref[0] = LastFrame;
m_comp_var_ref[1] = GoldenFrame;
} else if (m_ref_frame_sign_bias[LastFrame] == m_ref_frame_sign_bias[AltRefFrame]) {
m_comp_fixed_ref = GoldenFrame;
m_comp_var_ref[0] = LastFrame;
m_comp_var_ref[1] = AltRefFrame;
} else {
m_comp_fixed_ref = LastFrame;
m_comp_var_ref[0] = GoldenFrame;
m_comp_var_ref[1] = AltRefFrame;
}
}
DecoderErrorOr<void> Parser::decode_tiles(FrameContext& frame_context)
{
auto tile_cols = 1 << m_tile_cols_log2;
auto tile_rows = 1 << m_tile_rows_log2;
clear_above_context(frame_context);
for (auto tile_row = 0; tile_row < tile_rows; tile_row++) {
for (auto tile_col = 0; tile_col < tile_cols; tile_col++) {
auto last_tile = (tile_row == tile_rows - 1) && (tile_col == tile_cols - 1);
u64 tile_size;
if (last_tile)
tile_size = m_bit_stream->bytes_remaining();
else
tile_size = TRY_READ(m_bit_stream->read_bits(32));
auto rows_start = get_tile_offset(tile_row, frame_context.rows(), m_tile_rows_log2);
auto rows_end = get_tile_offset(tile_row + 1, frame_context.rows(), m_tile_rows_log2);
auto columns_start = get_tile_offset(tile_col, frame_context.columns(), m_tile_cols_log2);
auto columns_end = get_tile_offset(tile_col + 1, frame_context.columns(), m_tile_cols_log2);
auto tile_context = TileContext(frame_context, rows_start, rows_end, columns_start, columns_end);
TRY_READ(m_bit_stream->init_bool(tile_size));
TRY(decode_tile(tile_context));
TRY_READ(m_bit_stream->exit_bool());
}
}
return {};
}
template<typename T>
void Parser::clear_context(Vector<T>& context, size_t size)
{
context.resize_and_keep_capacity(size);
__builtin_memset(context.data(), 0, sizeof(T) * size);
}
template<typename T>
void Parser::clear_context(Vector<Vector<T>>& context, size_t outer_size, size_t inner_size)
{
if (context.size() < outer_size)
context.resize(outer_size);
for (auto& sub_vector : context)
clear_context(sub_vector, inner_size);
}
void Parser::clear_above_context(FrameContext& frame_context)
{
for (auto i = 0u; i < m_above_nonzero_context.size(); i++)
clear_context(m_above_nonzero_context[i], 2 * frame_context.columns());
clear_context(m_above_seg_pred_context, frame_context.columns());
clear_context(m_above_partition_context, frame_context.superblock_columns() * 8);
}
u32 Parser::get_tile_offset(u32 tile_num, u32 mis, u32 tile_size_log2)
{
u32 super_blocks = (mis + 7) >> 3u;
u32 offset = ((tile_num * super_blocks) >> tile_size_log2) << 3u;
return min(offset, mis);
}
DecoderErrorOr<void> Parser::decode_tile(TileContext& tile_context)
{
for (auto row = tile_context.rows_start; row < tile_context.rows_end; row += 8) {
clear_left_context(tile_context);
for (auto col = tile_context.columns_start; col < tile_context.columns_end; col += 8) {
TRY(decode_partition(tile_context, row, col, Block_64x64));
}
}
return {};
}
void Parser::clear_left_context(TileContext& tile_context)
{
for (auto i = 0u; i < m_left_nonzero_context.size(); i++)
clear_context(m_left_nonzero_context[i], 2 * tile_context.frame_context.rows());
clear_context(m_left_seg_pred_context, tile_context.frame_context.rows());
clear_context(m_left_partition_context, tile_context.frame_context.superblock_rows() * 8);
}
DecoderErrorOr<void> Parser::decode_partition(TileContext& tile_context, u32 row, u32 column, BlockSubsize subsize)
{
if (row >= tile_context.frame_context.rows() || column >= tile_context.frame_context.columns())
return {};
u8 num_8x8 = num_8x8_blocks_wide_lookup[subsize];
auto half_block_8x8 = num_8x8 >> 1;
bool has_rows = (row + half_block_8x8) < tile_context.frame_context.rows();
bool has_cols = (column + half_block_8x8) < tile_context.frame_context.columns();
auto partition = TRY_READ(TreeParser::parse_partition(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter, has_rows, has_cols, subsize, num_8x8, m_above_partition_context, m_left_partition_context, row, column, m_frame_is_intra));
auto child_subsize = subsize_lookup[partition][subsize];
if (child_subsize < Block_8x8 || partition == PartitionNone) {
TRY(decode_block(tile_context, row, column, child_subsize));
} else if (partition == PartitionHorizontal) {
TRY(decode_block(tile_context, row, column, child_subsize));
if (has_rows)
TRY(decode_block(tile_context, row + half_block_8x8, column, child_subsize));
} else if (partition == PartitionVertical) {
TRY(decode_block(tile_context, row, column, child_subsize));
if (has_cols)
TRY(decode_block(tile_context, row, column + half_block_8x8, child_subsize));
} else {
TRY(decode_partition(tile_context, row, column, child_subsize));
TRY(decode_partition(tile_context, row, column + half_block_8x8, child_subsize));
TRY(decode_partition(tile_context, row + half_block_8x8, column, child_subsize));
TRY(decode_partition(tile_context, row + half_block_8x8, column + half_block_8x8, child_subsize));
}
if (subsize == Block_8x8 || partition != PartitionSplit) {
auto above_context = 15 >> b_width_log2_lookup[child_subsize];
auto left_context = 15 >> b_height_log2_lookup[child_subsize];
for (size_t i = 0; i < num_8x8; i++) {
m_above_partition_context[column + i] = above_context;
m_left_partition_context[row + i] = left_context;
}
}
return {};
}
size_t Parser::get_image_index(FrameContext const& frame_context, u32 row, u32 column) const
{
VERIFY(row < frame_context.rows() && column < frame_context.columns());
return row * frame_context.columns() + column;
}
DecoderErrorOr<void> Parser::decode_block(TileContext& tile_context, u32 row, u32 column, BlockSubsize subsize)
{
auto above_context = row > 0 ? tile_context.frame_block_contexts().at(row - 1, column) : FrameBlockContext();
auto left_context = column > tile_context.columns_start ? tile_context.frame_block_contexts().at(row, column - 1) : FrameBlockContext();
auto block_context = BlockContext(tile_context, row, column, subsize);
TRY(mode_info(block_context, above_context, left_context));
auto had_residual_tokens = TRY(residual(block_context, above_context.is_available, left_context.is_available));
if (m_is_inter && subsize >= Block_8x8 && !had_residual_tokens)
m_skip = true;
for (size_t y = 0; y < block_context.contexts_view.height(); y++) {
for (size_t x = 0; x < block_context.contexts_view.width(); x++) {
auto sub_block_context = FrameBlockContext { true, m_skip, m_tx_size, m_y_mode, m_block_sub_modes, m_interp_filter, m_ref_frame, m_block_mvs, m_segment_id };
block_context.contexts_view.at(y, x) = sub_block_context;
VERIFY(block_context.frame_block_contexts().at(row + y, column + x).tx_size == sub_block_context.tx_size);
}
}
return {};
}
DecoderErrorOr<void> Parser::mode_info(BlockContext& block_context, FrameBlockContext above_context, FrameBlockContext left_context)
{
if (m_frame_is_intra)
TRY(intra_frame_mode_info(block_context, above_context, left_context));
else
TRY(inter_frame_mode_info(block_context, above_context, left_context));
return {};
}
DecoderErrorOr<void> Parser::intra_frame_mode_info(BlockContext& block_context, FrameBlockContext above_context, FrameBlockContext left_context)
{
TRY(intra_segment_id());
TRY(read_skip(above_context, left_context));
TRY(read_tx_size(block_context, above_context, left_context, true));
m_ref_frame[0] = IntraFrame;
m_ref_frame[1] = None;
m_is_inter = false;
// FIXME: This if statement is also present in parse_default_intra_mode. The selection of parameters for
// the probability table lookup should be inlined here.
if (block_context.size >= Block_8x8) {
m_y_mode = TRY_READ(TreeParser::parse_default_intra_mode(*m_bit_stream, *m_probability_tables, block_context.size, above_context, left_context, m_block_sub_modes, 0, 0));
for (auto& block_sub_mode : m_block_sub_modes)
block_sub_mode = m_y_mode;
} else {
m_num_4x4_w = num_4x4_blocks_wide_lookup[block_context.size];
m_num_4x4_h = num_4x4_blocks_high_lookup[block_context.size];
for (auto idy = 0; idy < 2; idy += m_num_4x4_h) {
for (auto idx = 0; idx < 2; idx += m_num_4x4_w) {
auto sub_mode = TRY_READ(TreeParser::parse_default_intra_mode(*m_bit_stream, *m_probability_tables, block_context.size, above_context, left_context, m_block_sub_modes, idx, idy));
for (auto y = 0; y < m_num_4x4_h; y++) {
for (auto x = 0; x < m_num_4x4_w; x++) {
auto index = (idy + y) * 2 + idx + x;
m_block_sub_modes[index] = sub_mode;
}
}
}
}
m_y_mode = m_block_sub_modes.last();
}
m_uv_mode = TRY_READ(TreeParser::parse_default_uv_mode(*m_bit_stream, *m_probability_tables, m_y_mode));
return {};
}
DecoderErrorOr<void> Parser::intra_segment_id()
{
if (m_segmentation_enabled && m_segmentation_update_map)
m_segment_id = TRY_READ(TreeParser::parse_segment_id(*m_bit_stream, m_segmentation_tree_probs));
else
m_segment_id = 0;
return {};
}
DecoderErrorOr<void> Parser::read_skip(FrameBlockContext above_context, FrameBlockContext left_context)
{
if (seg_feature_active(SEG_LVL_SKIP)) {
m_skip = true;
} else {
m_skip = TRY_READ(TreeParser::parse_skip(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter, above_context, left_context));
}
return {};
}
bool Parser::seg_feature_active(u8 feature)
{
return m_segmentation_enabled && m_feature_enabled[m_segment_id][feature];
}
DecoderErrorOr<void> Parser::read_tx_size(BlockContext const& block_context, FrameBlockContext above_context, FrameBlockContext left_context, bool allow_select)
{
// FIXME: This probably doesn't need to set max_tx_size, and can also return the TXSize it reads.
m_max_tx_size = max_txsize_lookup[block_context.size];
if (allow_select && m_tx_mode == TXModeSelect && block_context.size >= Block_8x8)
m_tx_size = TRY_READ(TreeParser::parse_tx_size(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter, m_max_tx_size, above_context, left_context));
else
m_tx_size = min(m_max_tx_size, tx_mode_to_biggest_tx_size[m_tx_mode]);
return {};
}
DecoderErrorOr<void> Parser::inter_frame_mode_info(BlockContext& block_context, FrameBlockContext above_context, FrameBlockContext left_context)
{
TRY(inter_segment_id(block_context));
TRY(read_skip(above_context, left_context));
TRY(read_is_inter(above_context, left_context));
TRY(read_tx_size(block_context, above_context, left_context, !m_skip || !m_is_inter));
if (m_is_inter) {
TRY(inter_block_mode_info(block_context, above_context, left_context));
} else {
TRY(intra_block_mode_info(block_context));
}
return {};
}
DecoderErrorOr<void> Parser::inter_segment_id(BlockContext const& block_context)
{
if (!m_segmentation_enabled) {
m_segment_id = 0;
return {};
}
auto predicted_segment_id = get_segment_id(block_context);
if (!m_segmentation_update_map) {
m_segment_id = predicted_segment_id;
return {};
}
if (!m_segmentation_temporal_update) {
m_segment_id = TRY_READ(TreeParser::parse_segment_id(*m_bit_stream, m_segmentation_tree_probs));
return {};
}
auto seg_id_predicted = TRY_READ(TreeParser::parse_segment_id_predicted(*m_bit_stream, m_segmentation_pred_prob, m_left_seg_pred_context[block_context.row], m_above_seg_pred_context[block_context.column]));
if (seg_id_predicted)
m_segment_id = predicted_segment_id;
else
m_segment_id = TRY_READ(TreeParser::parse_segment_id(*m_bit_stream, m_segmentation_tree_probs));
for (size_t i = 0; i < num_8x8_blocks_wide_lookup[block_context.size]; i++) {
auto index = block_context.column + i;
// (7.4.1) AboveSegPredContext[ i ] only needs to be set to 0 for i = 0..MiCols-1.
if (index < m_above_seg_pred_context.size())
m_above_seg_pred_context[index] = seg_id_predicted;
}
for (size_t i = 0; i < num_8x8_blocks_high_lookup[block_context.size]; i++) {
auto index = block_context.row + i;
// (7.4.1) LeftSegPredContext[ i ] only needs to be set to 0 for i = 0..MiRows-1.
if (index < m_above_seg_pred_context.size())
m_left_seg_pred_context[block_context.row + i] = seg_id_predicted;
}
return {};
}
u8 Parser::get_segment_id(BlockContext const& block_context)
{
auto bw = num_8x8_blocks_wide_lookup[block_context.size];
auto bh = num_8x8_blocks_high_lookup[block_context.size];
auto xmis = min(block_context.frame_context.columns() - block_context.column, (u32)bw);
auto ymis = min(block_context.frame_context.rows() - block_context.row, (u32)bh);
u8 segment = 7;
for (size_t y = 0; y < ymis; y++) {
for (size_t x = 0; x < xmis; x++) {
segment = min(segment, m_previous_block_contexts.index_at(block_context.row + y, block_context.column + x));
}
}
return segment;
}
DecoderErrorOr<void> Parser::read_is_inter(FrameBlockContext above_context, FrameBlockContext left_context)
{
if (seg_feature_active(SEG_LVL_REF_FRAME))
m_is_inter = m_feature_data[m_segment_id][SEG_LVL_REF_FRAME] != IntraFrame;
else
m_is_inter = TRY_READ(TreeParser::parse_block_is_inter_predicted(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter, above_context, left_context));
return {};
}
DecoderErrorOr<void> Parser::intra_block_mode_info(BlockContext& block_context)
{
m_ref_frame[0] = IntraFrame;
m_ref_frame[1] = None;
if (block_context.size >= Block_8x8) {
m_y_mode = TRY_READ(TreeParser::parse_intra_mode(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter, block_context.size));
for (auto& block_sub_mode : m_block_sub_modes)
block_sub_mode = m_y_mode;
} else {
m_num_4x4_w = num_4x4_blocks_wide_lookup[block_context.size];
m_num_4x4_h = num_4x4_blocks_high_lookup[block_context.size];
PredictionMode sub_intra_mode;
for (auto idy = 0; idy < 2; idy += m_num_4x4_h) {
for (auto idx = 0; idx < 2; idx += m_num_4x4_w) {
sub_intra_mode = TRY_READ(TreeParser::parse_sub_intra_mode(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter));
for (auto y = 0; y < m_num_4x4_h; y++) {
for (auto x = 0; x < m_num_4x4_w; x++)
m_block_sub_modes[(idy + y) * 2 + idx + x] = sub_intra_mode;
}
}
}
m_y_mode = sub_intra_mode;
}
m_uv_mode = TRY_READ(TreeParser::parse_uv_mode(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter, m_y_mode));
return {};
}
DecoderErrorOr<void> Parser::inter_block_mode_info(BlockContext& block_context, FrameBlockContext above_context, FrameBlockContext left_context)
{
TRY(read_ref_frames(above_context, left_context));
for (auto j = 0; j < 2; j++) {
if (m_ref_frame[j] > IntraFrame) {
find_mv_refs(block_context, m_ref_frame[j], -1);
find_best_ref_mvs(block_context, j);
}
}
auto is_compound = m_ref_frame[1] > IntraFrame;
if (seg_feature_active(SEG_LVL_SKIP)) {
m_y_mode = PredictionMode::ZeroMv;
} else if (block_context.size >= Block_8x8) {
m_y_mode = TRY_READ(TreeParser::parse_inter_mode(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter, m_mode_context[m_ref_frame[0]]));
}
if (m_interpolation_filter == Switchable)
m_interp_filter = TRY_READ(TreeParser::parse_interpolation_filter(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter, above_context, left_context));
else
m_interp_filter = m_interpolation_filter;
if (block_context.size < Block_8x8) {
m_num_4x4_w = num_4x4_blocks_wide_lookup[block_context.size];
m_num_4x4_h = num_4x4_blocks_high_lookup[block_context.size];
for (auto idy = 0; idy < 2; idy += m_num_4x4_h) {
for (auto idx = 0; idx < 2; idx += m_num_4x4_w) {
m_y_mode = TRY_READ(TreeParser::parse_inter_mode(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter, m_mode_context[m_ref_frame[0]]));
if (m_y_mode == PredictionMode::NearestMv || m_y_mode == PredictionMode::NearMv) {
for (auto j = 0; j < 1 + is_compound; j++)
append_sub8x8_mvs(block_context, idy * 2 + idx, j);
}
TRY(assign_mv(is_compound));
for (auto y = 0; y < m_num_4x4_h; y++) {
for (auto x = 0; x < m_num_4x4_w; x++) {
auto block = (idy + y) * 2 + idx + x;
for (auto ref_list = 0; ref_list < 1 + is_compound; ref_list++) {
m_block_mvs[ref_list][block] = m_mv[ref_list];
}
}
}
}
}
return {};
}
TRY(assign_mv(is_compound));
for (auto ref_list = 0; ref_list < 1 + is_compound; ref_list++) {
for (auto block = 0; block < 4; block++) {
m_block_mvs[ref_list][block] = m_mv[ref_list];
}
}
return {};
}
DecoderErrorOr<void> Parser::read_ref_frames(FrameBlockContext above_context, FrameBlockContext left_context)
{
if (seg_feature_active(SEG_LVL_REF_FRAME)) {
m_ref_frame[0] = static_cast<ReferenceFrameType>(m_feature_data[m_segment_id][SEG_LVL_REF_FRAME]);
m_ref_frame[1] = None;
return {};
}
ReferenceMode comp_mode;
if (m_reference_mode == ReferenceModeSelect)
comp_mode = TRY_READ(TreeParser::parse_comp_mode(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter, m_comp_fixed_ref, above_context, left_context));
else
comp_mode = m_reference_mode;
if (comp_mode == CompoundReference) {
// FIXME: Make reference frame pairs be indexed by an enum of FixedReference or VariableReference?
auto fixed_reference_index = m_ref_frame_sign_bias[m_comp_fixed_ref];
auto variable_reference_index = fixed_reference_index == 0 ? 1 : 0;
// FIXME: Create an enum for compound frame references using names Primary and Secondary.
auto comp_ref = TRY_READ(TreeParser::parse_comp_ref(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter, m_comp_fixed_ref, m_comp_var_ref, variable_reference_index, above_context, left_context));
m_ref_frame[fixed_reference_index] = m_comp_fixed_ref;
m_ref_frame[variable_reference_index] = m_comp_var_ref[comp_ref];
return {};
}
// FIXME: Maybe consolidate this into a tree. Context is different between part 1 and 2 but still, it would look nice here.
auto single_ref_p1 = TRY_READ(TreeParser::parse_single_ref_part_1(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter, above_context, left_context));
if (single_ref_p1) {
auto single_ref_p2 = TRY_READ(TreeParser::parse_single_ref_part_2(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter, above_context, left_context));
m_ref_frame[0] = single_ref_p2 ? AltRefFrame : GoldenFrame;
} else {
m_ref_frame[0] = LastFrame;
}
m_ref_frame[1] = None;
return {};
}
DecoderErrorOr<void> Parser::assign_mv(bool is_compound)
{
m_mv[1] = {};
for (auto i = 0; i < 1 + is_compound; i++) {
if (m_y_mode == PredictionMode::NewMv) {
TRY(read_mv(i));
} else if (m_y_mode == PredictionMode::NearestMv) {
m_mv[i] = m_nearest_mv[i];
} else if (m_y_mode == PredictionMode::NearMv) {
m_mv[i] = m_near_mv[i];
} else {
m_mv[i] = {};
}
}
return {};
}
DecoderErrorOr<void> Parser::read_mv(u8 ref)
{
m_use_hp = m_allow_high_precision_mv && use_mv_hp(m_best_mv[ref]);
MotionVector diff_mv;
auto mv_joint = TRY_READ(TreeParser::parse_motion_vector_joint(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter));
if (mv_joint == MvJointHzvnz || mv_joint == MvJointHnzvnz)
diff_mv.set_row(TRY(read_mv_component(0)));
if (mv_joint == MvJointHnzvz || mv_joint == MvJointHnzvnz)
diff_mv.set_column(TRY(read_mv_component(1)));
// FIXME: We probably don't need to assign MVs to a field, these can just
// be returned and assigned where they are requested.
m_mv[ref] = m_best_mv[ref] + diff_mv;
return {};
}
DecoderErrorOr<i32> Parser::read_mv_component(u8 component)
{
auto mv_sign = TRY_READ(TreeParser::parse_motion_vector_sign(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter, component));
auto mv_class = TRY_READ(TreeParser::parse_motion_vector_class(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter, component));
u32 magnitude;
if (mv_class == MvClass0) {
auto mv_class0_bit = TRY_READ(TreeParser::parse_motion_vector_class0_bit(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter, component));
auto mv_class0_fr = TRY_READ(TreeParser::parse_motion_vector_class0_fr(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter, component, mv_class0_bit));
auto mv_class0_hp = TRY_READ(TreeParser::parse_motion_vector_class0_hp(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter, component, m_use_hp));
magnitude = ((mv_class0_bit << 3) | (mv_class0_fr << 1) | mv_class0_hp) + 1;
} else {
u32 bits = 0;
for (u8 i = 0; i < mv_class; i++) {
auto mv_bit = TRY_READ(TreeParser::parse_motion_vector_bit(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter, component, i));
bits |= mv_bit << i;
}
magnitude = CLASS0_SIZE << (mv_class + 2);
auto mv_fr = TRY_READ(TreeParser::parse_motion_vector_fr(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter, component));
auto mv_hp = TRY_READ(TreeParser::parse_motion_vector_hp(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter, component, m_use_hp));
magnitude += ((bits << 3) | (mv_fr << 1) | mv_hp) + 1;
}
return (mv_sign ? -1 : 1) * static_cast<i32>(magnitude);
}
Gfx::Point<size_t> Parser::get_decoded_point_for_plane(FrameContext const& frame_context, u32 column, u32 row, u8 plane)
{
(void)frame_context;
if (plane == 0)
return { column * 8, row * 8 };
return { (column * 8) >> m_subsampling_x, (row * 8) >> m_subsampling_y };
}
Gfx::Size<size_t> Parser::get_decoded_size_for_plane(FrameContext const& frame_context, u8 plane)
{
auto point = get_decoded_point_for_plane(frame_context, frame_context.columns(), frame_context.rows(), plane);
return { point.x(), point.y() };
}
DecoderErrorOr<bool> Parser::residual(BlockContext& block_context, bool has_block_above, bool has_block_left)
{
bool had_residual_tokens = false;
auto block_size = block_context.size < Block_8x8 ? Block_8x8 : block_context.size;
for (u8 plane = 0; plane < 3; plane++) {
auto tx_size = (plane > 0) ? get_uv_tx_size(block_context.size) : m_tx_size;
auto step = 1 << tx_size;
auto plane_size = get_plane_block_size(block_size, plane);
auto num_4x4_w = num_4x4_blocks_wide_lookup[plane_size];
auto num_4x4_h = num_4x4_blocks_high_lookup[plane_size];
auto sub_x = (plane > 0) ? m_subsampling_x : 0;
auto sub_y = (plane > 0) ? m_subsampling_y : 0;
auto base_x = (block_context.column * 8) >> sub_x;
auto base_y = (block_context.row * 8) >> sub_y;
if (m_is_inter) {
if (block_context.size < Block_8x8) {
for (auto y = 0; y < num_4x4_h; y++) {
for (auto x = 0; x < num_4x4_w; x++) {
TRY(m_decoder.predict_inter(plane, block_context, base_x + (4 * x), base_y + (4 * y), 4, 4, (y * num_4x4_w) + x));
}
}
} else {
TRY(m_decoder.predict_inter(plane, block_context, base_x, base_y, num_4x4_w * 4, num_4x4_h * 4, 0));
}
}
auto max_x = (block_context.frame_context.columns() * 8) >> sub_x;
auto max_y = (block_context.frame_context.rows() * 8) >> sub_y;
auto block_index = 0;
for (auto y = 0; y < num_4x4_h; y += step) {
for (auto x = 0; x < num_4x4_w; x += step) {
auto start_x = base_x + (4 * x);
auto start_y = base_y + (4 * y);
auto non_zero = false;
if (start_x < max_x && start_y < max_y) {
if (!m_is_inter)
TRY(m_decoder.predict_intra(plane, block_context, start_x, start_y, has_block_left || x > 0, has_block_above || y > 0, (x + step) < num_4x4_w, tx_size, block_index));
if (!m_skip) {
non_zero = TRY(tokens(block_context, plane, start_x, start_y, tx_size, block_index));
had_residual_tokens = had_residual_tokens || non_zero;
TRY(m_decoder.reconstruct(plane, block_context, start_x, start_y, tx_size));
}
}
auto& above_sub_context = m_above_nonzero_context[plane];
auto above_sub_context_index = start_x >> 2;
auto above_sub_context_end = min(above_sub_context_index + step, above_sub_context.size());
for (; above_sub_context_index < above_sub_context_end; above_sub_context_index++)
above_sub_context[above_sub_context_index] = non_zero;
auto& left_sub_context = m_left_nonzero_context[plane];
auto left_sub_context_index = start_y >> 2;
auto left_sub_context_end = min(left_sub_context_index + step, left_sub_context.size());
for (; left_sub_context_index < left_sub_context_end; left_sub_context_index++)
left_sub_context[left_sub_context_index] = non_zero;
block_index++;
}
}
}
return had_residual_tokens;
}
TXSize Parser::get_uv_tx_size(BlockSubsize size)
{
if (size < Block_8x8)
return TX_4x4;
return min(m_tx_size, max_txsize_lookup[get_plane_block_size(size, 1)]);
}
BlockSubsize Parser::get_plane_block_size(u32 subsize, u8 plane)
{
auto sub_x = (plane > 0) ? m_subsampling_x : 0;
auto sub_y = (plane > 0) ? m_subsampling_y : 0;
return ss_size_lookup[subsize][sub_x][sub_y];
}
DecoderErrorOr<bool> Parser::tokens(BlockContext& block_context, size_t plane, u32 start_x, u32 start_y, TXSize tx_size, u32 block_index)
{
u32 segment_eob = 16 << (tx_size << 1);
auto const* scan = get_scan(block_context, plane, tx_size, block_index);
auto check_eob = true;
u32 c = 0;
for (; c < segment_eob; c++) {
auto pos = scan[c];
auto band = (tx_size == TX_4x4) ? coefband_4x4[c] : coefband_8x8plus[c];
auto tokens_context = TreeParser::get_tokens_context(m_subsampling_x, m_subsampling_y, block_context.frame_context.rows(), block_context.frame_context.columns(), m_above_nonzero_context, m_left_nonzero_context, m_token_cache, tx_size, m_tx_type, plane, start_x, start_y, pos, m_is_inter, band, c);
if (check_eob) {
auto more_coefs = TRY_READ(TreeParser::parse_more_coefficients(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter, tokens_context));
if (!more_coefs)
break;
}
auto token = TRY_READ(TreeParser::parse_token(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter, tokens_context));
m_token_cache[pos] = energy_class[token];
if (token == ZeroToken) {
m_tokens[pos] = 0;
check_eob = false;
} else {
i32 coef = TRY(read_coef(token));
bool sign_bit = TRY_READ(m_bit_stream->read_literal(1));
m_tokens[pos] = sign_bit ? -coef : coef;
check_eob = true;
}
}
for (u32 i = c; i < segment_eob; i++)
m_tokens[scan[i]] = 0;
return c > 0;
}
u32 const* Parser::get_scan(BlockContext const& block_context, size_t plane, TXSize tx_size, u32 block_index)
{
if (plane > 0 || tx_size == TX_32x32) {
m_tx_type = DCT_DCT;
} else if (tx_size == TX_4x4) {
if (m_lossless || m_is_inter)
m_tx_type = DCT_DCT;
else
m_tx_type = mode_to_txfm_map[to_underlying(block_context.size < Block_8x8 ? m_block_sub_modes[block_index] : m_y_mode)];
} else {
m_tx_type = mode_to_txfm_map[to_underlying(m_y_mode)];
}
if (tx_size == TX_4x4) {
if (m_tx_type == ADST_DCT)
return row_scan_4x4;
if (m_tx_type == DCT_ADST)
return col_scan_4x4;
return default_scan_4x4;
}
if (tx_size == TX_8x8) {
if (m_tx_type == ADST_DCT)
return row_scan_8x8;
if (m_tx_type == DCT_ADST)
return col_scan_8x8;
return default_scan_8x8;
}
if (tx_size == TX_16x16) {
if (m_tx_type == ADST_DCT)
return row_scan_16x16;
if (m_tx_type == DCT_ADST)
return col_scan_16x16;
return default_scan_16x16;
}
return default_scan_32x32;
}
DecoderErrorOr<i32> Parser::read_coef(Token token)
{
auto cat = extra_bits[token][0];
auto num_extra = extra_bits[token][1];
u32 coef = extra_bits[token][2];
if (token == DctValCat6) {
for (size_t e = 0; e < (u8)(m_bit_depth - 8); e++) {
auto high_bit = TRY_READ(m_bit_stream->read_bool(255));
coef += high_bit << (5 + m_bit_depth - e);
}
}
for (size_t e = 0; e < num_extra; e++) {
auto coef_bit = TRY_READ(m_bit_stream->read_bool(cat_probs[cat][e]));
coef += coef_bit << (num_extra - 1 - e);
}
return coef;
}
static bool is_inside(TileContext const& tile_context, MotionVector vector)
{
if (vector.row() < 0)
return false;
if (vector.column() < 0)
return false;
u32 row_positive = vector.row();
u32 column_positive = vector.column();
return row_positive < tile_context.frame_context.rows() && column_positive >= tile_context.columns_start && column_positive < tile_context.columns_end;
}
void Parser::add_mv_ref_list(u8 ref_list)
{
if (m_ref_mv_count >= 2)
return;
if (m_ref_mv_count > 0 && m_candidate_mv[ref_list] == m_ref_list_mv[0])
return;
m_ref_list_mv[m_ref_mv_count] = m_candidate_mv[ref_list];
m_ref_mv_count++;
}
void Parser::get_block_mv(BlockContext const& block_context, MotionVector candidate_vector, u8 ref_list, bool use_prev)
{
if (use_prev) {
auto const& prev_context = m_previous_block_contexts.at(candidate_vector.row(), candidate_vector.column());
m_candidate_mv[ref_list] = prev_context.primary_motion_vector_pair[ref_list];
m_candidate_frame[ref_list] = prev_context.ref_frames[ref_list];
} else {
auto const& current_context = block_context.frame_block_contexts().at(candidate_vector.row(), candidate_vector.column());
m_candidate_mv[ref_list] = current_context.primary_motion_vector_pair()[ref_list];
m_candidate_frame[ref_list] = current_context.ref_frames[ref_list];
}
}
void Parser::if_same_ref_frame_add_mv(BlockContext const& block_context, MotionVector candidate_vector, ReferenceFrameType ref_frame, bool use_prev)
{
for (auto ref_list = 0u; ref_list < 2; ref_list++) {
get_block_mv(block_context, candidate_vector, ref_list, use_prev);
if (m_candidate_frame[ref_list] == ref_frame) {
add_mv_ref_list(ref_list);
return;
}
}
}
void Parser::scale_mv(u8 ref_list, ReferenceFrameType ref_frame)
{
auto candidate_frame = m_candidate_frame[ref_list];
if (m_ref_frame_sign_bias[candidate_frame] != m_ref_frame_sign_bias[ref_frame])
m_candidate_mv[ref_list] *= -1;
}
void Parser::if_diff_ref_frame_add_mv(BlockContext const& block_context, MotionVector candidate_vector, ReferenceFrameType ref_frame, bool use_prev)
{
for (auto ref_list = 0u; ref_list < 2; ref_list++)
get_block_mv(block_context, candidate_vector, ref_list, use_prev);
auto mvs_are_same = m_candidate_mv[0] == m_candidate_mv[1];
if (m_candidate_frame[0] > ReferenceFrameType::IntraFrame && m_candidate_frame[0] != ref_frame) {
scale_mv(0, ref_frame);
add_mv_ref_list(0);
}
if (m_candidate_frame[1] > ReferenceFrameType::IntraFrame && m_candidate_frame[1] != ref_frame && !mvs_are_same) {
scale_mv(1, ref_frame);
add_mv_ref_list(1);
}
}
MotionVector Parser::clamp_mv(BlockContext const& block_context, MotionVector vector, i32 border)
{
i32 blocks_high = num_8x8_blocks_high_lookup[block_context.size];
// Casts must be done here to prevent subtraction underflow from wrapping the values.
i32 mb_to_top_edge = -8 * (static_cast<i32>(block_context.row) * MI_SIZE);
i32 mb_to_bottom_edge = 8 * ((static_cast<i32>(block_context.frame_context.rows()) - blocks_high - static_cast<i32>(block_context.row)) * MI_SIZE);
i32 blocks_wide = num_8x8_blocks_wide_lookup[block_context.size];
i32 mb_to_left_edge = -8 * (static_cast<i32>(block_context.column) * MI_SIZE);
i32 mb_to_right_edge = 8 * ((static_cast<i32>(block_context.frame_context.columns()) - blocks_wide - static_cast<i32>(block_context.column)) * MI_SIZE);
return {
clip_3(mb_to_top_edge - border, mb_to_bottom_edge + border, vector.row()),
clip_3(mb_to_left_edge - border, mb_to_right_edge + border, vector.column())
};
}
void Parser::clamp_mv_ref(BlockContext const& block_context, u8 i)
{
// FIXME: This seems silly and should probably just be written inline in the one place it's used.
MotionVector& vector = m_ref_list_mv[i];
vector = clamp_mv(block_context, vector, MV_BORDER);
}
// 6.5.1 Find MV refs syntax
void Parser::find_mv_refs(BlockContext& block_context, ReferenceFrameType reference_frame, i32 block)
{
m_ref_mv_count = 0;
bool different_ref_found = false;
u8 context_counter = 0;
m_ref_list_mv[0] = {};
m_ref_list_mv[1] = {};
MotionVector base_coordinates = MotionVector(block_context.row, block_context.column);
for (auto i = 0u; i < 2; i++) {
auto offset_vector = mv_ref_blocks[block_context.size][i];
auto candidate = base_coordinates + offset_vector;
if (is_inside(block_context.tile_context, candidate)) {
different_ref_found = true;
auto context = block_context.frame_block_contexts().at(candidate.row(), candidate.column());
context_counter += mode_2_counter[to_underlying(context.y_mode)];
for (auto ref_list = 0u; ref_list < 2; ref_list++) {
if (context.ref_frames[ref_list] == reference_frame) {
// This section up until add_mv_ref_list() is defined in spec as get_sub_block_mv().
constexpr u8 idx_n_column_to_subblock[4][2] = {
{ 1, 2 },
{ 1, 3 },
{ 3, 2 },
{ 3, 3 }
};
auto index = block >= 0 ? idx_n_column_to_subblock[block][offset_vector.column() == 0] : 3;
m_candidate_mv[ref_list] = context.sub_block_motion_vectors[ref_list][index];
add_mv_ref_list(ref_list);
break;
}
}
}
}
for (auto i = 2u; i < MVREF_NEIGHBOURS; i++) {
MotionVector candidate = base_coordinates + mv_ref_blocks[block_context.size][i];
if (is_inside(block_context.tile_context, candidate)) {
different_ref_found = true;
if_same_ref_frame_add_mv(block_context, candidate, reference_frame, false);
}
}
if (m_use_prev_frame_mvs)
if_same_ref_frame_add_mv(block_context, base_coordinates, reference_frame, true);
if (different_ref_found) {
for (auto i = 0u; i < MVREF_NEIGHBOURS; i++) {
MotionVector candidate = base_coordinates + mv_ref_blocks[block_context.size][i];
if (is_inside(block_context.tile_context, candidate))
if_diff_ref_frame_add_mv(block_context, candidate, reference_frame, false);
}
}
if (m_use_prev_frame_mvs)
if_diff_ref_frame_add_mv(block_context, base_coordinates, reference_frame, true);
m_mode_context[reference_frame] = counter_to_context[context_counter];
for (auto i = 0u; i < MAX_MV_REF_CANDIDATES; i++)
clamp_mv_ref(block_context, i);
}
bool Parser::use_mv_hp(MotionVector const& vector)
{
return (abs(vector.row()) >> 3) < COMPANDED_MVREF_THRESH && (abs(vector.column()) >> 3) < COMPANDED_MVREF_THRESH;
}
void Parser::find_best_ref_mvs(BlockContext& block_context, u8 ref_list)
{
for (auto i = 0u; i < MAX_MV_REF_CANDIDATES; i++) {
auto delta = m_ref_list_mv[i];
auto delta_row = delta.row();
auto delta_column = delta.column();
if (!m_allow_high_precision_mv || !use_mv_hp(delta)) {
if (delta_row & 1)
delta_row += delta_row > 0 ? -1 : 1;
if (delta_column & 1)
delta_column += delta_column > 0 ? -1 : 1;
}
delta = { delta_row, delta_column };
m_ref_list_mv[i] = clamp_mv(block_context, delta, (BORDERINPIXELS - INTERP_EXTEND) << 3);
}
m_nearest_mv[ref_list] = m_ref_list_mv[0];
m_near_mv[ref_list] = m_ref_list_mv[1];
m_best_mv[ref_list] = m_ref_list_mv[0];
}
void Parser::append_sub8x8_mvs(BlockContext& block_context, i32 block, u8 ref_list)
{
MotionVector sub_8x8_mvs[2];
find_mv_refs(block_context, m_ref_frame[ref_list], block);
auto destination_index = 0;
if (block == 0) {
for (auto i = 0u; i < 2; i++)
sub_8x8_mvs[destination_index++] = m_ref_list_mv[i];
} else if (block <= 2) {
sub_8x8_mvs[destination_index++] = m_block_mvs[ref_list][0];
} else {
sub_8x8_mvs[destination_index++] = m_block_mvs[ref_list][2];
for (auto index = 1; index >= 0 && destination_index < 2; index--) {
auto block_vector = m_block_mvs[ref_list][index];
if (block_vector != sub_8x8_mvs[0])
sub_8x8_mvs[destination_index++] = block_vector;
}
}
for (auto n = 0u; n < 2 && destination_index < 2; n++) {
auto ref_list_vector = m_ref_list_mv[n];
if (ref_list_vector != sub_8x8_mvs[0])
sub_8x8_mvs[destination_index++] = ref_list_vector;
}
if (destination_index < 2)
sub_8x8_mvs[destination_index++] = {};
m_nearest_mv[ref_list] = sub_8x8_mvs[0];
m_near_mv[ref_list] = sub_8x8_mvs[1];
}
}
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