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LibVideo/VP9: Use a bitwise enum for motion vector joint selection

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The motion vector joints enum is set up so that the first bit indicates
that a vector should have a non-zero value in the column, and the
second bit indicates a non-zero value for the row. Taking advantage of
this makes the code a bit more legible.
This commit is contained in:
Zaggy1024 2022-11-25 04:19:35 -06:00 • committed by Andreas Kling
parent f4761dab09
commit d82dc14bd9
3 changed files with 13 additions and 14 deletions
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7
Userland/Libraries/LibVideo/VP9/Enums.h
View file

@ -113,10 +113,9 @@ enum class PredictionMode : u8 {
};
enum MvJoint : u8 {
MvJointZero = 0,
MvJointHnzvz = 1,
MvJointHzvnz = 2,
MvJointHnzvnz = 3,
MotionVectorAllZero = 0,
MotionVectorNonZeroColumn = 1,
MotionVectorNonZeroRow = 2,
};
enum MvClass : u8 {

6
Userland/Libraries/LibVideo/VP9/LookupTables.h
View file

@ -142,9 +142,9 @@ static constexpr int interp_filter_tree[4] = {
-EightTapSmooth, -EightTapSharp
};
static constexpr int mv_joint_tree[6] = {
-MvJointZero, 2,
-MvJointHnzvz, 4,
-MvJointHzvnz, -MvJointHnzvnz
-MotionVectorAllZero, 2,
-MotionVectorNonZeroColumn, 4,
-MotionVectorNonZeroRow, -(MotionVectorNonZeroColumn | MotionVectorNonZeroRow)
};
static constexpr int mv_class_tree[20] = {
-MvClass0, 2,

14
Userland/Libraries/LibVideo/VP9/Parser.cpp
View file

@ -1276,14 +1276,14 @@ static bool should_use_high_precision_motion_vector(MotionVector const& delta_ve
DecoderErrorOr<MotionVector> Parser::read_motion_vector(BlockContext const& block_context, BlockMotionVectorCandidates const& candidates, ReferenceIndex reference_index)
{
m_use_hp = block_context.frame_context.high_precision_motion_vectors_allowed && should_use_high_precision_motion_vector(candidates[reference_index].best_vector);
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_single_motion_vector_component(0)));
if (mv_joint == MvJointHnzvz || mv_joint == MvJointHnzvnz)
diff_mv.set_column(TRY(read_single_motion_vector_component(1)));
MotionVector delta_vector;
auto joint = TRY_READ(TreeParser::parse_motion_vector_joint(*m_bit_stream, *m_probability_tables, *m_syntax_element_counter));
if ((joint & MotionVectorNonZeroRow) != 0)
delta_vector.set_row(TRY(read_single_motion_vector_component(0)));
if ((joint & MotionVectorNonZeroColumn) != 0)
delta_vector.set_column(TRY(read_single_motion_vector_component(1)));
return candidates[reference_index].best_vector + diff_mv;
return candidates[reference_index].best_vector + delta_vector;
}
// read_mv_component( comp ) in the spec.