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LibVideo: Implement inter prediction

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This enables the second frame of the test video to be decoded.

It appears that the test video uses a superframe (group of multiple
frames) for the first chunk of the file, but we haven't implemented
superframe parsing.

We also ignore the show_frame flag, so for now, this
means that the second frame read out is shown when it should not be. To
fix this, another error type needs to be implemented that is "thrown" to
decoder's client so they know to send another sample buffer.
This commit is contained in:
Zaggy1024 2022-09-21 20:16:40 -05:00 • committed by Andrew Kaster
parent 50d4217dbc
commit b0187dfc27
6 changed files with 487 additions and 51 deletions
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22
Userland/Libraries/LibVideo/VP9/Decoder.h
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@ -50,10 +50,19 @@ private:
DecoderErrorOr<void> predict_intra(u8 plane, u32 x, u32 y, bool have_left, bool have_above, bool not_on_right, TXSize tx_size, u32 block_index);
// (8.5.1) Inter prediction process
DecoderErrorOr<void> predict_inter(u8 plane, u32 x, u32 y, u32 w, u32 h, u32 block_index);
DecoderErrorOr<void> predict_inter(u8 plane, u32 x, u32 y, u32 width, u32 height, u32 block_index);
// (8.5.2.1) Motion vector selection process
MotionVector select_motion_vector(u8 plane, u8 ref_list, u32 block_index);
// (8.5.2.2) Motion vector clamping process
MotionVector clamp_motion_vector(u8 plane, MotionVector vector);
// (8.5.2.3) Motion vector scaling process
DecoderErrorOr<MotionVector> scale_motion_vector(u8 plane, u8 ref_list, u32 x, u32 y, MotionVector vector);
// From (8.5.1) Inter prediction process, steps 2-5
DecoderErrorOr<void> predict_inter_block(u8 plane, u8 ref_list, u32 x, u32 y, u32 width, u32 height, u32 block_index, Vector<u16>& buffer);
/* (8.6) Reconstruction and Dequantization */
// FIXME: These should be inline or constexpr
u16 dc_q(u8 b);
u16 ac_q(u8 b);
// Returns the quantizer index for the current block
@ -126,6 +135,12 @@ private:
struct {
// FIXME: We may be able to consolidate some of these to reduce memory consumption.
// FIXME: Create a new struct to store these buffers, specifying size and providing
// helper functions to get values at coordinates. All *_at(row, column)
// functions in Decoder.cpp and functions returning row * width + column
// should be replaced if possible.
Vector<Intermediate> dequantized;
Vector<Intermediate> row_or_column;
@ -138,6 +153,11 @@ private:
Vector<Intermediate> transform_temp;
Vector<i64> adst_temp;
// predict_inter
Vector<u16> inter_horizontal;
Vector<u16> inter_predicted;
Vector<u16> inter_predicted_compound;
Vector<Intermediate> intermediate[3];
Vector<u16> output[3];
} m_buffers;