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LibVideo/VP9: Implement parsing Token and MoreCoefs trees

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These elements were being used in the new tokens implementation, so
support for them in the TreeParser has been added.

Additionally, this uncovered a bug where the nonzero contexts were
being cleared with the wrong size.
This commit is contained in:
FalseHonesty 2021-06-27 11:49:46 -04:00 committed by Andreas Kling
parent aa27ca1b16
commit 074fbd1b06
Notes: sideshowbarker 2024-07-18 09:23:26 +09:00 
Author: https://github.com/FalseHonesty
Commit: https://github.com/SerenityOS/serenity/commit/074fbd1b068
Pull-request: https://github.com/SerenityOS/serenity/pull/8349
Reviewed-by: https://github.com/Lubrsi
3 changed files with 86 additions and 10 deletions
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8
Userland/Libraries/LibVideo/VP9/Parser.cpp
View file

@ -752,7 +752,7 @@ void Parser::clear_context(Vector<Vector<u8>>& context, size_t outer_size, size_
bool Parser::clear_above_context()
{
clear_context(m_above_nonzero_context, 2 * m_mi_cols, 3);
clear_context(m_above_nonzero_context, 3, 2 * m_mi_cols);
clear_context(m_above_seg_pred_context, m_mi_cols);
clear_context(m_above_partition_context, m_sb64_cols * 8);
return true;
@ -780,7 +780,7 @@ bool Parser::decode_tile()
bool Parser::clear_left_context()
{
clear_context(m_left_nonzero_context, 2 * m_mi_rows, 3);
clear_context(m_left_nonzero_context, 3, 2 * m_mi_rows);
clear_context(m_left_seg_pred_context, m_mi_rows);
clear_context(m_left_partition_context, m_sb64_rows * 8);
return true;
@ -1193,7 +1193,7 @@ BlockSubsize Parser::get_plane_block_size(u32 subsize, u8 plane)
bool Parser::tokens(size_t plane, u32 start_x, u32 start_y, TXSize tx_size, u32 block_index)
{
m_tree_parser->set_more_coefs_variables(start_x, start_y);
m_tree_parser->set_start_x_and_y(start_x, start_y);
size_t segment_eob = 16 << (tx_size << 1);
auto scan = get_scan(plane, tx_size, block_index);
auto check_eob = true;
@ -1201,7 +1201,7 @@ bool Parser::tokens(size_t plane, u32 start_x, u32 start_y, TXSize tx_size, u32
for (; c < segment_eob; c++) {
auto pos = scan[c];
auto band = (tx_size == TX_4x4) ? coefband_4x4[c] : coefband_8x8plus[c];
m_tree_parser->set_band(band);
m_tree_parser->set_tokens_variables(band, c, plane, tx_size, pos);
if (check_eob) {
auto more_coefs = m_tree_parser->parse_tree<bool>(SyntaxElementType::MoreCoefs);
if (!more_coefs)

71
Userland/Libraries/LibVideo/VP9/TreeParser.cpp
View file

@ -159,9 +159,9 @@ u8 TreeParser::select_tree_probability(SyntaxElementType type, u8 node)
case SyntaxElementType::MVHP:
break;
case SyntaxElementType::Token:
break;
return calculate_token_probability(node);
case SyntaxElementType::MoreCoefs:
break;
return calculate_more_coefs_probability();
}
TODO();
}
@ -561,6 +561,67 @@ u8 TreeParser::calculate_interp_filter_probability(u8 node)
return m_decoder.m_probability_tables->interp_filter_probs()[m_ctx][node];
}
u8 TreeParser::calculate_token_probability(u8 node)
{
auto prob = m_decoder.m_probability_tables->coef_probs()[m_tx_size][m_plane > 0][m_decoder.m_is_inter][m_band][m_ctx][min(2, 1 + node)];
if (node < 2)
return prob;
auto x = (prob - 1) / 2;
auto& pareto_table = m_decoder.m_probability_tables->pareto_table();
if (prob & 1)
return pareto_table[x][node - 2];
return (pareto_table[x][node - 2] + pareto_table[x + 1][node - 2]) >> 1;
}
u8 TreeParser::calculate_more_coefs_probability()
{
if (m_c == 0) {
auto sx = m_plane > 0 ? m_decoder.m_subsampling_x : 0;
auto sy = m_plane > 0 ? m_decoder.m_subsampling_y : 0;
auto max_x = (2 * m_decoder.m_mi_cols) >> sx;
auto max_y = (2 * m_decoder.m_mi_rows) >> sy;
u8 numpts = 1 << m_tx_size;
auto x4 = m_start_x >> 2;
auto y4 = m_start_y >> 2;
u32 above = 0;
u32 left = 0;
for (size_t i = 0; i < numpts; i++) {
if (x4 + i < max_x)
above |= m_decoder.m_above_nonzero_context[m_plane][x4 + i];
if (y4 + i < max_y)
left |= m_decoder.m_left_nonzero_context[m_plane][y4 + i];
}
m_ctx = above + left;
} else {
u32 neighbor_0, neighbor_1;
auto n = 4 << m_tx_size;
auto i = m_pos / n;
auto j = m_pos % n;
auto a = (i - 1) * n + j;
auto a2 = i * n + j - 1;
if (i > 0 && j > 0) {
if (m_decoder.m_tx_type == DCT_ADST) {
neighbor_0 = a;
neighbor_1 = a;
} else if (m_decoder.m_tx_type == ADST_DCT) {
neighbor_0 = a2;
neighbor_1 = a2;
} else {
neighbor_0 = a;
neighbor_1 = a2;
}
} else if (i > 0) {
neighbor_0 = a;
neighbor_1 = a;
} else {
neighbor_0 = a2;
neighbor_1 = a2;
}
m_ctx = (1 + m_decoder.m_token_cache[neighbor_0] + m_decoder.m_token_cache[neighbor_1]) >> 1;
}
return m_decoder.m_probability_tables->coef_probs()[m_tx_size][m_plane > 0][m_decoder.m_is_inter][m_band][m_ctx][0];
}
void TreeParser::count_syntax_element(SyntaxElementType type, int value)
{
switch (type) {
@ -621,9 +682,11 @@ void TreeParser::count_syntax_element(SyntaxElementType type, int value)
case SyntaxElementType::MVHP:
break;
case SyntaxElementType::Token:
break;
m_decoder.m_syntax_element_counter->m_counts_token[m_tx_size][m_plane > 0][m_decoder.m_is_inter][m_band][m_ctx][min(2, value)]++;
return;
case SyntaxElementType::MoreCoefs:
break;
m_decoder.m_syntax_element_counter->m_counts_more_coefs[m_tx_size][m_plane > 0][m_decoder.m_is_inter][m_band][m_ctx][value]++;
return;
case SyntaxElementType::DefaultIntraMode:
case SyntaxElementType::DefaultUVMode:
case SyntaxElementType::SegmentID:

17
Userland/Libraries/LibVideo/VP9/TreeParser.h
View file

@ -57,9 +57,16 @@ public:
m_idy = idy;
}
void set_band(u8 band) { m_band = band; }
void set_tokens_variables(u8 band, u32 c, u32 plane, TXSize tx_size, u32 pos)
{
m_band = band;
m_c = c;
m_plane = plane;
m_tx_size = tx_size;
m_pos = pos;
}
void set_more_coefs_variables(u32 start_x, u32 start_y)
void set_start_x_and_y(u32 start_x, u32 start_y)
{
m_start_x = start_x;
m_start_y = start_y;
@ -83,6 +90,8 @@ private:
u8 calculate_tx_size_probability(u8 node);
u8 calculate_inter_mode_probability(u8 node);
u8 calculate_interp_filter_probability(u8 node);
u8 calculate_token_probability(u8 node);
u8 calculate_more_coefs_probability();
Parser& m_decoder;
// m_ctx is a member variable because it is required for syntax element counting (section 9.3.4)
@ -95,6 +104,10 @@ private:
u8 m_band { 0 };
u32 m_start_x { 0 };
u32 m_start_y { 0 };
u32 m_c { 0 };
u32 m_plane { 0 };
TXSize m_tx_size;
u32 m_pos { 0 };
};
}