RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-28 11:47:34 +00:00
Code Issues Activity Actions

LibVideo/VP9: Drop the decoder intermediate bounds checks

Browse source 
Checking the bounds of the intermediate values was only implemented to
help debug the decoder. However, it is non-fatal to have the values
exceed the spec-defined bounds, and causes a measurable performance
reduction.

Additionally, the checks were implemented as an assertion, which is
easily broken by bad input files.

I see about a 4-5% decrease in decoding times in the `webm_in_vp9` test
in TestVP9Decode.
This commit is contained in:
Zaggy1024 2023-02-10 11:44:30 -06:00 • committed by Andreas Kling
parent 7c607462a4
commit 33ff3427eb
2 changed files with 50 additions and 82 deletions
Download patch file Download diff file Expand all files Collapse all files

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

@ -89,9 +89,9 @@ private:
inline i32 cos64(u8 angle);
inline i32 sin64(u8 angle);
// The function B( a, b, angle, 0 ) performs a butterfly rotation.
inline void butterfly_rotation_in_place(u8 bit_depth, Span<Intermediate> data, size_t index_a, size_t index_b, u8 angle, bool flip);
inline void butterfly_rotation_in_place(Span<Intermediate> data, size_t index_a, size_t index_b, u8 angle, bool flip);
// The function H( a, b, 0 ) performs a Hadamard rotation.
inline void hadamard_rotation_in_place(u8 bit_depth, Span<Intermediate> data, size_t index_a, size_t index_b, bool flip);
inline void hadamard_rotation_in_place(Span<Intermediate> data, size_t index_a, size_t index_b, bool flip);
// The function SB( a, b, angle, 0 ) performs a butterfly rotation.
// Spec defines the source as array T, and the destination array as S.
template<typename S, typename D>
@ -104,16 +104,13 @@ private:
template<typename T>
inline i32 round_2(T value, u8 bits);
// Checks whether the value is representable by a signed integer with (8 + bit_depth) bits.
inline bool check_intermediate_bounds(u8 bit_depth, Intermediate value);
// (8.7.1.10) This process does an in-place Walsh-Hadamard transform of the array T (of length 4).
inline DecoderErrorOr<void> inverse_walsh_hadamard_transform(Span<Intermediate> data, u8 log2_of_block_size, u8 shift);
// (8.7.1.2) Inverse DCT array permutation process
inline DecoderErrorOr<void> inverse_discrete_cosine_transform_array_permutation(Span<Intermediate> data, u8 log2_of_block_size);
// (8.7.1.3) Inverse DCT process
inline DecoderErrorOr<void> inverse_discrete_cosine_transform(u8 bit_depth, Span<Intermediate> data, u8 log2_of_block_size);
inline DecoderErrorOr<void> inverse_discrete_cosine_transform(Span<Intermediate> data, u8 log2_of_block_size);
// (8.7.1.4) This process performs the in-place permutation of the array T of length 2 n which is required as the first step of
// the inverse ADST.
@ -123,15 +120,15 @@ private:
inline void inverse_asymmetric_discrete_sine_transform_output_array_permutation(Span<Intermediate> data, u8 log2_of_block_size);
// (8.7.1.6) This process does an in-place transform of the array T to perform an inverse ADST.
inline void inverse_asymmetric_discrete_sine_transform_4(u8 bit_depth, Span<Intermediate> data);
inline void inverse_asymmetric_discrete_sine_transform_4(Span<Intermediate> data);
// (8.7.1.7) This process does an in-place transform of the array T using a higher precision array S for intermediate
// results.
inline DecoderErrorOr<void> inverse_asymmetric_discrete_sine_transform_8(u8 bit_depth, Span<Intermediate> data);
inline DecoderErrorOr<void> inverse_asymmetric_discrete_sine_transform_8(Span<Intermediate> data);
// (8.7.1.8) This process does an in-place transform of the array T using a higher precision array S for intermediate
// results.
inline DecoderErrorOr<void> inverse_asymmetric_discrete_sine_transform_16(u8 bit_depth, Span<Intermediate> data);
inline DecoderErrorOr<void> inverse_asymmetric_discrete_sine_transform_16(Span<Intermediate> data);
// (8.7.1.9) This process performs an in-place inverse ADST process on the array T of size 2 n for 2 ≤ n ≤ 4.
inline DecoderErrorOr<void> inverse_asymmetric_discrete_sine_transform(u8 bit_depth, Span<Intermediate> data, u8 log2_of_block_size);
inline DecoderErrorOr<void> inverse_asymmetric_discrete_sine_transform(Span<Intermediate> data, u8 log2_of_block_size);
/* (8.10) Reference Frame Update Process */
DecoderErrorOr<void> update_reference_frames(FrameContext const&);