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LibVideo/VP9: Move quantizer indices into FrameContext

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This also renames (most?) of the related quantizer functions and
variables to make more sense. I haven't determined what AC/DC stands
for here, but it may be just an arbitrary naming scheme for the first
and subsequent coefficients used to quantize the residuals for a block.
This commit is contained in:
Zaggy1024 2022-11-23 06:26:02 -06:00 • committed by Andreas Kling
parent 0df5c1f32f
commit f4e835635f
5 changed files with 50 additions and 42 deletions
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10
Userland/Libraries/LibVideo/VP9/Context.h
View file

@ -311,6 +311,16 @@ public:
Array<i8, MAX_REF_FRAMES> loop_filter_reference_deltas;
Array<i8, 2> loop_filter_mode_deltas;
u8 base_quantizer_index { 0 };
i8 y_dc_quantizer_index_delta { 0 };
i8 uv_dc_quantizer_index_delta { 0 };
i8 uv_ac_quantizer_index_delta { 0 };
bool is_lossless() const
{
// From quantization_params( ) in the spec.
return base_quantizer_index == 0 && y_dc_quantizer_index_delta == 0 && uv_dc_quantizer_index_delta == 0 && uv_ac_quantizer_index_delta == 0;
}
u16 header_size_in_bytes { 0 };
private:

44
Userland/Libraries/LibVideo/VP9/Decoder.cpp
View file

@ -1018,7 +1018,7 @@ u16 Decoder::ac_q(u8 bit_depth, u8 b)
return ac_qlookup[(bit_depth - 8) >> 1][clip_3<u8>(0, 255, b)];
}
u8 Decoder::get_qindex()
u8 Decoder::get_base_quantizer_index(BlockContext const& block_context)
{
// The function get_qindex( ) returns the quantizer index for the current block and is specified by the following:
// − If seg_feature_active( SEG_LVL_ALT_Q ) is equal to 1 the following ordered steps apply:
@ -1028,7 +1028,7 @@ u8 Decoder::get_qindex()
// 2. If segmentation_abs_or_delta_update is equal to 0, set data equal to base_q_idx + data
if (!m_parser->m_segmentation_abs_or_delta_update) {
data += m_parser->m_base_q_idx;
data += block_context.frame_context.base_quantizer_index;
}
// 3. Return Clip3( 0, 255, data ).
@ -1036,29 +1036,33 @@ u8 Decoder::get_qindex()
}
// − Otherwise, return base_q_idx.
return m_parser->m_base_q_idx;
return block_context.frame_context.base_quantizer_index;
}
u16 Decoder::get_dc_quant(u8 bit_depth, u8 plane)
u16 Decoder::get_dc_quantizer(BlockContext const& block_context, u8 plane)
{
// FIXME: The result of this function can be cached. This does not change per frame.
// The function get_dc_quant( plane ) returns the quantizer value for the dc coefficient for a particular plane and
// is derived as follows:
// − If plane is equal to 0, return dc_q( get_qindex( ) + delta_q_y_dc ).
// − Otherwise, return dc_q( get_qindex( ) + delta_q_uv_dc ).
// Instead of if { return }, select the value to add and return.
i8 offset = plane == 0 ? m_parser->m_delta_q_y_dc : m_parser->m_delta_q_uv_dc;
return dc_q(bit_depth, static_cast<u8>(get_qindex() + offset));
i8 offset = plane == 0 ? block_context.frame_context.y_dc_quantizer_index_delta : block_context.frame_context.uv_dc_quantizer_index_delta;
return dc_q(block_context.frame_context.color_config.bit_depth, static_cast<u8>(get_base_quantizer_index(block_context) + offset));
}
u16 Decoder::get_ac_quant(u8 bit_depth, u8 plane)
u16 Decoder::get_ac_quantizer(BlockContext const& block_context, u8 plane)
{
// FIXME: The result of this function can be cached. This does not change per frame.
// The function get_ac_quant( plane ) returns the quantizer value for the ac coefficient for a particular plane and
// is derived as follows:
// − If plane is equal to 0, return ac_q( get_qindex( ) ).
// − Otherwise, return ac_q( get_qindex( ) + delta_q_uv_ac ).
// Instead of if { return }, select the value to add and return.
i8 offset = plane == 0 ? 0 : m_parser->m_delta_q_uv_ac;
return ac_q(bit_depth, static_cast<u8>(get_qindex() + offset));
i8 offset = plane == 0 ? 0 : block_context.frame_context.uv_ac_quantizer_index_delta;
return ac_q(block_context.frame_context.color_config.bit_depth, static_cast<u8>(get_base_quantizer_index(block_context) + offset));
}
DecoderErrorOr<void> Decoder::reconstruct(u8 plane, BlockContext const& block_context, u32 transform_block_x, u32 transform_block_y, TXSize transform_block_size)
@ -1075,7 +1079,7 @@ DecoderErrorOr<void> Decoder::reconstruct(u8 plane, BlockContext const& block_co
// 1. Dequant[ i ][ j ] is set equal to ( Tokens[ i * n0 + j ] * get_ac_quant( plane ) ) / dqDenom
// for i = 0..(n0-1), for j = 0..(n0-1)
Array<Intermediate, maximum_transform_size> dequantized;
Intermediate ac_quant = get_ac_quant(block_context.frame_context.color_config.bit_depth, plane);
Intermediate ac_quant = get_ac_quantizer(block_context, plane);
for (auto i = 0u; i < block_size; i++) {
for (auto j = 0u; j < block_size; j++) {
auto index = index_from_row_and_column(i, j, block_size);
@ -1086,7 +1090,7 @@ DecoderErrorOr<void> Decoder::reconstruct(u8 plane, BlockContext const& block_co
}
// 2. Dequant[ 0 ][ 0 ] is set equal to ( Tokens[ 0 ] * get_dc_quant( plane ) ) / dqDenom
dequantized[0] = (m_parser->m_tokens[0] * get_dc_quant(block_context.frame_context.color_config.bit_depth, plane)) / dq_denominator;
dequantized[0] = (m_parser->m_tokens[0] * get_dc_quantizer(block_context, plane)) / dq_denominator;
// It is a requirement of bitstream conformance that the values written into the Dequant array in steps 1 and 2
// are representable by a signed integer with 8 + BitDepth bits.
@ -1095,7 +1099,7 @@ DecoderErrorOr<void> Decoder::reconstruct(u8 plane, BlockContext const& block_co
// 3. Invoke the 2D inverse transform block process defined in section 8.7.2 with the variable n as input.
// The inverse transform outputs are stored back to the Dequant buffer.
TRY(inverse_transform_2d(block_context.frame_context.color_config.bit_depth, dequantized, log2_of_block_size));
TRY(inverse_transform_2d(block_context, dequantized, log2_of_block_size));
// 4. CurrFrame[ plane ][ y + i ][ x + j ] is set equal to Clip1( CurrFrame[ plane ][ y + i ][ x + j ] + Dequant[ i ][ j ] )
// for i = 0..(n0-1) and j = 0..(n0-1).
@ -1648,7 +1652,7 @@ inline DecoderErrorOr<void> Decoder::inverse_asymmetric_discrete_sine_transform(
return inverse_asymmetric_discrete_sine_transform_16(bit_depth, data);
}
DecoderErrorOr<void> Decoder::inverse_transform_2d(u8 bit_depth, Span<Intermediate> dequantized, u8 log2_of_block_size)
DecoderErrorOr<void> Decoder::inverse_transform_2d(BlockContext const& block_context, Span<Intermediate> dequantized, u8 log2_of_block_size)
{
// This process performs a 2D inverse transform for an array of size 2^n by 2^n stored in the 2D array Dequant.
// The input to this process is a variable n (log2_of_block_size) that specifies the base 2 logarithm of the width of the transform.
@ -1667,7 +1671,7 @@ DecoderErrorOr<void> Decoder::inverse_transform_2d(u8 bit_depth, Span<Intermedia
// 2. If Lossless is equal to 1, invoke the Inverse WHT process as specified in section 8.7.1.10 with shift equal
// to 2.
if (m_parser->m_lossless) {
if (block_context.frame_context.is_lossless()) {
TRY(inverse_walsh_hadamard_transform(row, log2_of_block_size, 2));
continue;
}
@ -1679,13 +1683,13 @@ DecoderErrorOr<void> Decoder::inverse_transform_2d(u8 bit_depth, Span<Intermedia
// 1. Invoke the inverse DCT permutation process as specified in section 8.7.1.2 with the input variable n.
TRY(inverse_discrete_cosine_transform_array_permutation(row, log2_of_block_size));
// 2. Invoke the inverse DCT process as specified in section 8.7.1.3 with the input variable n.
TRY(inverse_discrete_cosine_transform(bit_depth, row, log2_of_block_size));
TRY(inverse_discrete_cosine_transform(block_context.frame_context.color_config.bit_depth, row, log2_of_block_size));
break;
case DCT_ADST:
case ADST_ADST:
// 4. Otherwise (TxType is equal to DCT_ADST or TxType is equal to ADST_ADST), invoke the inverse ADST
// process as specified in section 8.7.1.9 with input variable n.
TRY(inverse_asymmetric_discrete_sine_transform(bit_depth, row, log2_of_block_size));
TRY(inverse_asymmetric_discrete_sine_transform(block_context.frame_context.color_config.bit_depth, row, log2_of_block_size));
break;
default:
return DecoderError::corrupted("Unknown tx_type"sv);
@ -1707,7 +1711,7 @@ DecoderErrorOr<void> Decoder::inverse_transform_2d(u8 bit_depth, Span<Intermedia
// 2. If Lossless is equal to 1, invoke the Inverse WHT process as specified in section 8.7.1.10 with shift equal
// to 0.
if (m_parser->m_lossless) {
if (block_context.frame_context.is_lossless()) {
TRY(inverse_walsh_hadamard_transform(column, log2_of_block_size, 2));
continue;
}
@ -1719,13 +1723,13 @@ DecoderErrorOr<void> Decoder::inverse_transform_2d(u8 bit_depth, Span<Intermedia
// 1. Invoke the inverse DCT permutation process as specified in section 8.7.1.2 with the input variable n.
TRY(inverse_discrete_cosine_transform_array_permutation(column, log2_of_block_size));
// 2. Invoke the inverse DCT process as specified in section 8.7.1.3 with the input variable n.
TRY(inverse_discrete_cosine_transform(bit_depth, column, log2_of_block_size));
TRY(inverse_discrete_cosine_transform(block_context.frame_context.color_config.bit_depth, column, log2_of_block_size));
break;
case ADST_DCT:
case ADST_ADST:
// 4. Otherwise (TxType is equal to ADST_DCT or TxType is equal to ADST_ADST), invoke the inverse ADST
// process as specified in section 8.7.1.9 with input variable n.
TRY(inverse_asymmetric_discrete_sine_transform(bit_depth, column, log2_of_block_size));
TRY(inverse_asymmetric_discrete_sine_transform(block_context.frame_context.color_config.bit_depth, column, log2_of_block_size));
break;
default:
VERIFY_NOT_REACHED();
@ -1737,7 +1741,7 @@ DecoderErrorOr<void> Decoder::inverse_transform_2d(u8 bit_depth, Span<Intermedia
// 6. Otherwise (Lossless is equal to 0), set Dequant[ i ][ j ] equal to Round2( T[ i ], Min( 6, n + 2 ) )
// for i = 0..(n0-1).
if (!m_parser->m_lossless) {
if (!block_context.frame_context.is_lossless()) {
for (auto i = 0u; i < block_size; i++) {
auto index = index_from_row_and_column(i, j, block_size);
dequantized[index] = round_2(dequantized[index], min(6, log2_of_block_size + 2));

8
Userland/Libraries/LibVideo/VP9/Decoder.h
View file

@ -77,17 +77,17 @@ private:
u16 dc_q(u8 bit_depth, u8 b);
u16 ac_q(u8 bit_depth, u8 b);
// Returns the quantizer index for the current block
u8 get_qindex();
u8 get_base_quantizer_index(BlockContext const&);
// Returns the quantizer value for the dc coefficient for a particular plane
u16 get_dc_quant(u8 bit_depth, u8 plane);
u16 get_dc_quantizer(BlockContext const&, u8 plane);
// Returns the quantizer value for the ac coefficient for a particular plane
u16 get_ac_quant(u8 bit_depth, u8 plane);
u16 get_ac_quantizer(BlockContext const&, u8 plane);
// (8.6.2) Reconstruct process
DecoderErrorOr<void> reconstruct(u8 plane, BlockContext const&, u32 transform_block_x, u32 transform_block_y, TXSize transform_block_size);
// (8.7) Inverse transform process
DecoderErrorOr<void> inverse_transform_2d(u8 bit_depth, Span<Intermediate> dequantized, u8 log2_of_block_size);
DecoderErrorOr<void> inverse_transform_2d(BlockContext const&, Span<Intermediate> dequantized, u8 log2_of_block_size);
// (8.7.1) 1D Transforms
// (8.7.1.1) Butterfly functions

21
Userland/Libraries/LibVideo/VP9/Parser.cpp
View file

@ -261,7 +261,7 @@ DecoderErrorOr<FrameContext> Parser::uncompressed_header()
frame_context.probability_context_index = probability_context_index;
TRY(loop_filter_params(frame_context));
TRY(quantization_params());
TRY(quantization_params(frame_context));
TRY(segmentation_params());
TRY(tile_info(frame_context));
@ -418,13 +418,12 @@ DecoderErrorOr<void> Parser::loop_filter_params(FrameContext& frame_context)
return {};
}
DecoderErrorOr<void> Parser::quantization_params()
DecoderErrorOr<void> Parser::quantization_params(FrameContext& frame_context)
{
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;
frame_context.base_quantizer_index = TRY_READ(m_bit_stream->read_f8());
frame_context.y_dc_quantizer_index_delta = TRY(read_delta_q());
frame_context.uv_dc_quantizer_index_delta = TRY(read_delta_q());
frame_context.uv_ac_quantizer_index_delta = TRY(read_delta_q());
return {};
}
@ -538,7 +537,7 @@ void Parser::setup_past_independence()
DecoderErrorOr<void> Parser::compressed_header(FrameContext& frame_context)
{
TRY(read_tx_mode());
TRY(read_tx_mode(frame_context));
if (m_tx_mode == TXModeSelect)
TRY(tx_mode_probs());
TRY(read_coef_probs());
@ -557,9 +556,9 @@ DecoderErrorOr<void> Parser::compressed_header(FrameContext& frame_context)
return {};
}
DecoderErrorOr<void> Parser::read_tx_mode()
DecoderErrorOr<void> Parser::read_tx_mode(FrameContext const& frame_context)
{
if (m_lossless) {
if (frame_context.is_lossless()) {
m_tx_mode = Only_4x4;
} else {
auto tx_mode = TRY_READ(m_bit_stream->read_literal(2));
@ -1429,7 +1428,7 @@ u32 const* Parser::get_scan(BlockContext const& block_context, size_t plane, TXS
if (plane > 0 || tx_size == TX_32x32) {
m_tx_type = DCT_DCT;
} else if (tx_size == TX_4x4) {
if (m_lossless || m_is_inter)
if (block_context.frame_context.is_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)];

9
Userland/Libraries/LibVideo/VP9/Parser.h
View file

@ -65,7 +65,7 @@ private:
DecoderErrorOr<void> compute_image_size(FrameContext&);
DecoderErrorOr<InterpolationFilter> read_interpolation_filter();
DecoderErrorOr<void> loop_filter_params(FrameContext&);
DecoderErrorOr<void> quantization_params();
DecoderErrorOr<void> quantization_params(FrameContext&);
DecoderErrorOr<i8> read_delta_q();
DecoderErrorOr<void> segmentation_params();
DecoderErrorOr<u8> read_prob();
@ -76,7 +76,7 @@ private:
/* (6.3) Compressed Header Syntax */
DecoderErrorOr<void> compressed_header(FrameContext&);
DecoderErrorOr<void> read_tx_mode();
DecoderErrorOr<void> read_tx_mode(FrameContext const&);
DecoderErrorOr<void> tx_mode_probs();
DecoderErrorOr<u8> diff_update_prob(u8 prob);
DecoderErrorOr<u8> decode_term_subexp();
@ -148,11 +148,6 @@ private:
FrameType m_previous_frame_type { FrameType::KeyFrame };
Array<i8, MAX_REF_FRAMES> m_previous_loop_filter_ref_deltas;
Array<i8, 2> m_previous_loop_filter_mode_deltas;
u8 m_base_q_idx { 0 };
i8 m_delta_q_y_dc { 0 };
i8 m_delta_q_uv_dc { 0 };
i8 m_delta_q_uv_ac { 0 };
bool m_lossless { false };
u8 m_segmentation_tree_probs[7];
u8 m_segmentation_pred_prob[3];
bool m_feature_enabled[8][4];