/*****************************************************************************
* This file is part of Kvazaar HEVC encoder.
*
* Copyright (C) 2013-2015 Tampere University of Technology and others (see
* COPYING file).
*
* Kvazaar is free software: you can redistribute it and/or modify it under
* the terms of the GNU Lesser General Public License as published by the
* Free Software Foundation; either version 2.1 of the License, or (at your
* option) any later version.
*
* Kvazaar is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with Kvazaar. If not, see .
****************************************************************************/
#include "inter.h"
#include
#include
#include
#include "encoder.h"
#include "imagelist.h"
#include "strategies/generic/picture-generic.h"
#include "strategies/strategies-ipol.h"
#include "videoframe.h"
#include "strategies/strategies-picture.h"
typedef struct {
const cu_info_t *a[2];
const cu_info_t *b[3];
const cu_info_t *c3;
const cu_info_t *h;
} merge_candidates_t;
static void inter_recon_frac_luma(const encoder_state_t * const state,
const kvz_picture * const ref,
int32_t xpos,
int32_t ypos,
int32_t block_width,
int32_t block_height,
const int16_t mv_param[2],
lcu_t *lcu)
{
int mv_frac_x = (mv_param[0] & 3);
int mv_frac_y = (mv_param[1] & 3);
#define FILTER_SIZE_Y 8 //Luma filter size
// Fractional luma 1/4-pel
kvz_extended_block src = {0, 0, 0, 0};
// Fractional luma
kvz_get_extended_block(xpos,
ypos,
mv_param[0] >> 2,
mv_param[1] >> 2,
state->tile->offset_x,
state->tile->offset_y,
ref->y,
ref->width,
ref->height,
FILTER_SIZE_Y,
block_width,
block_height,
&src);
kvz_sample_quarterpel_luma(state->encoder_control,
src.orig_topleft,
src.stride,
block_width,
block_height,
lcu->rec.y + (ypos%LCU_WIDTH)*LCU_WIDTH + (xpos%LCU_WIDTH),
LCU_WIDTH,
mv_frac_x,
mv_frac_y,
mv_param);
if (src.malloc_used) free(src.buffer);
}
static void inter_recon_14bit_frac_luma(const encoder_state_t * const state,
const kvz_picture * const ref,
int32_t xpos,
int32_t ypos,
int32_t block_width,
int32_t block_height,
const int16_t mv_param[2],
hi_prec_buf_t *hi_prec_out)
{
int mv_frac_x = (mv_param[0] & 3);
int mv_frac_y = (mv_param[1] & 3);
#define FILTER_SIZE_Y 8 //Luma filter size
// Fractional luma 1/4-pel
kvz_extended_block src = { 0, 0, 0, 0 };
// Fractional luma
kvz_get_extended_block(xpos,
ypos,
mv_param[0] >> 2,
mv_param[1] >> 2,
state->tile->offset_x,
state->tile->offset_y,
ref->y,
ref->width,
ref->height,
FILTER_SIZE_Y,
block_width,
block_height,
&src);
kvz_sample_14bit_quarterpel_luma(state->encoder_control,
src.orig_topleft,
src.stride,
block_width,
block_height,
hi_prec_out->y + (ypos%LCU_WIDTH)*LCU_WIDTH + (xpos%LCU_WIDTH),
LCU_WIDTH,
mv_frac_x,
mv_frac_y,
mv_param);
if (src.malloc_used) free(src.buffer);
}
static void inter_recon_frac_chroma(const encoder_state_t * const state,
const kvz_picture * const ref,
int32_t xpos,
int32_t ypos,
int32_t block_width,
int32_t block_height,
const int16_t mv_param[2],
lcu_t *lcu)
{
int mv_frac_x = (mv_param[0] & 7);
int mv_frac_y = (mv_param[1] & 7);
// Translate to chroma
xpos >>= 1;
ypos >>= 1;
block_width >>= 1;
block_height >>= 1;
#define FILTER_SIZE_C 4 //Chroma filter size
// Fractional chroma 1/8-pel
kvz_extended_block src_u = { 0, 0, 0, 0 };
kvz_extended_block src_v = { 0, 0, 0, 0 };
//Fractional chroma U
kvz_get_extended_block(xpos, ypos,
(mv_param[0] >> 2) >> 1,
(mv_param[1] >> 2) >> 1,
state->tile->offset_x >> 1,
state->tile->offset_y >> 1,
ref->u,
ref->width >> 1,
ref->height >> 1,
FILTER_SIZE_C,
block_width,
block_height,
&src_u);
kvz_sample_octpel_chroma(state->encoder_control, src_u.orig_topleft, src_u.stride, block_width,
block_height, lcu->rec.u + (ypos % LCU_WIDTH_C)*LCU_WIDTH_C + (xpos % LCU_WIDTH_C), LCU_WIDTH_C, mv_frac_x, mv_frac_y, mv_param);
//Fractional chroma V
kvz_get_extended_block(xpos, ypos,
(mv_param[0] >> 2) >> 1,
(mv_param[1] >> 2) >> 1,
state->tile->offset_x >> 1,
state->tile->offset_y >> 1,
ref->v,
ref->width >> 1,
ref->height >> 1,
FILTER_SIZE_C,
block_width,
block_height,
&src_v);
kvz_sample_octpel_chroma(state->encoder_control, src_v.orig_topleft, src_v.stride, block_width,
block_height, lcu->rec.v + (ypos % LCU_WIDTH_C)*LCU_WIDTH_C + (xpos % LCU_WIDTH_C), LCU_WIDTH_C, mv_frac_x, mv_frac_y, mv_param);
if (src_u.malloc_used) free(src_u.buffer);
if (src_v.malloc_used) free(src_v.buffer);
}
static void inter_recon_14bit_frac_chroma(const encoder_state_t * const state,
const kvz_picture * const ref,
int32_t xpos,
int32_t ypos,
int32_t block_width,
int32_t block_height,
const int16_t mv_param[2],
hi_prec_buf_t *hi_prec_out)
{
int mv_frac_x = (mv_param[0] & 7);
int mv_frac_y = (mv_param[1] & 7);
// Translate to chroma
xpos >>= 1;
ypos >>= 1;
block_width >>= 1;
block_height >>= 1;
#define FILTER_SIZE_C 4 //Chroma filter size
// Fractional chroma 1/8-pel
kvz_extended_block src_u = { 0, 0, 0, 0 };
kvz_extended_block src_v = { 0, 0, 0, 0 };
//Fractional chroma U
kvz_get_extended_block(xpos,
ypos,
(mv_param[0] >> 2) >> 1,
(mv_param[1] >> 2) >> 1,
state->tile->offset_x >> 1,
state->tile->offset_y >> 1,
ref->u,
ref->width >> 1,
ref->height >> 1,
FILTER_SIZE_C,
block_width,
block_height,
&src_u);
kvz_sample_14bit_octpel_chroma(state->encoder_control,
src_u.orig_topleft,
src_u.stride,
block_width,
block_height,
hi_prec_out->u + (ypos % LCU_WIDTH_C)*LCU_WIDTH_C + (xpos % LCU_WIDTH_C),
LCU_WIDTH_C,
mv_frac_x,
mv_frac_y,
mv_param);
//Fractional chroma V
kvz_get_extended_block(xpos,
ypos,
(mv_param[0] >> 2) >> 1,
(mv_param[1] >> 2) >> 1,
state->tile->offset_x >> 1,
state->tile->offset_y >> 1,
ref->v,
ref->width >> 1,
ref->height >> 1,
FILTER_SIZE_C,
block_width,
block_height,
&src_v);
kvz_sample_14bit_octpel_chroma(state->encoder_control,
src_v.orig_topleft,
src_v.stride,
block_width,
block_height,
hi_prec_out->v + (ypos % LCU_WIDTH_C)*LCU_WIDTH_C + (xpos % LCU_WIDTH_C),
LCU_WIDTH_C,
mv_frac_x,
mv_frac_y,
mv_param);
if (src_u.malloc_used) free(src_u.buffer);
if (src_v.malloc_used) free(src_v.buffer);
}
/**
* \brief Copy from frame with extended border.
*
* \param ref_buf pointer to the start of ref buffer
* \param ref_stride stride of ref buffer
* \param ref_width width of frame
* \param ref_height height of frame
* \param rec_buf pointer to the start of pu in rec buffer
* \param rec_stride stride of rec buffer
* \param width width of copied block
* \param height height of copied block
* \param mv_in_frame coordinates of copied block in frame coordinates
*/
static void inter_cp_with_ext_border(const kvz_pixel *ref_buf, int ref_stride,
int ref_width, int ref_height,
kvz_pixel *rec_buf, int rec_stride,
int width, int height,
const vector2d_t *mv_in_frame)
{
for (int y = mv_in_frame->y; y < mv_in_frame->y + height; ++y) {
for (int x = mv_in_frame->x; x < mv_in_frame->x + width; ++x) {
vector2d_t in_frame = {
CLIP(0, ref_width - 1, x),
CLIP(0, ref_height - 1, y),
};
vector2d_t in_pu = {
x - mv_in_frame->x,
y - mv_in_frame->y,
};
int pu_index = in_pu.y * rec_stride + in_pu.x;
int frame_index = in_frame.y * ref_stride + in_frame.x;
rec_buf[pu_index] = ref_buf[frame_index];
}
}
}
/**
* \brief Reconstruct an inter PU using uniprediction.
*
* \param state encoder state
* \param ref picture to copy the data from
* \param xpos PU x position
* \param ypos PU y position
* \param width PU width
* \param height PU height
* \param mv_param motion vector
* \param lcu destination lcu
* \param hi_prec_out destination of high precision output, or NULL if not needed
*/
static void inter_recon_unipred(const encoder_state_t * const state,
const kvz_picture * const ref,
int32_t xpos,
int32_t ypos,
int32_t width,
int32_t height,
const int16_t mv_param[2],
lcu_t *lcu,
hi_prec_buf_t *hi_prec_out)
{
const vector2d_t pu_in_tile = { xpos, ypos };
const vector2d_t pu_in_lcu = { xpos % LCU_WIDTH, ypos % LCU_WIDTH };
const vector2d_t mv_in_pu = { mv_param[0] >> 2, mv_param[1] >> 2 };
const vector2d_t mv_in_frame = {
mv_in_pu.x + pu_in_tile.x + state->tile->offset_x,
mv_in_pu.y + pu_in_tile.y + state->tile->offset_y
};
const bool mv_is_outside_frame = mv_in_frame.x < 0 ||
mv_in_frame.y < 0 ||
mv_in_frame.x + width > ref->width ||
mv_in_frame.y + height > ref->height;
// With 420, odd coordinates need interpolation.
const int8_t fractional_chroma = (mv_in_pu.x & 1) || (mv_in_pu.y & 1);
const int8_t fractional_luma = ((mv_param[0] & 3) || (mv_param[1] & 3));
// Generate prediction for luma.
if (fractional_luma) {
// With a fractional MV, do interpolation.
if (state->encoder_control->cfg.bipred && hi_prec_out) {
inter_recon_14bit_frac_luma(state, ref,
pu_in_tile.x, pu_in_tile.y,
width, height,
mv_param, hi_prec_out);
} else {
inter_recon_frac_luma(state, ref,
pu_in_tile.x, pu_in_tile.y,
width, height,
mv_param, lcu);
}
} else {
// With an integer MV, copy pixels directly from the reference.
const int lcu_pu_index = pu_in_lcu.y * LCU_WIDTH + pu_in_lcu.x;
if (mv_is_outside_frame) {
inter_cp_with_ext_border(ref->y, ref->width,
ref->width, ref->height,
&lcu->rec.y[lcu_pu_index], LCU_WIDTH,
width, height,
&mv_in_frame);
} else {
const int frame_mv_index = mv_in_frame.y * ref->width + mv_in_frame.x;
kvz_pixels_blit(&ref->y[frame_mv_index],
&lcu->rec.y[lcu_pu_index],
width, height,
ref->width, LCU_WIDTH);
}
}
if (state->encoder_control->chroma_format == KVZ_CSP_400) {
return;
}
// Generate prediction for chroma.
if (fractional_luma || fractional_chroma) {
// With a fractional MV, do interpolation.
if (state->encoder_control->cfg.bipred && hi_prec_out) {
inter_recon_14bit_frac_chroma(state, ref,
pu_in_tile.x, pu_in_tile.y,
width, height,
mv_param, hi_prec_out);
} else {
inter_recon_frac_chroma(state, ref,
pu_in_tile.x, pu_in_tile.y,
width, height,
mv_param, lcu);
}
} else {
// With an integer MV, copy pixels directly from the reference.
const int lcu_pu_index_c = pu_in_lcu.y / 2 * LCU_WIDTH_C + pu_in_lcu.x / 2;
const vector2d_t mv_in_frame_c = { mv_in_frame.x / 2, mv_in_frame.y / 2 };
if (mv_is_outside_frame) {
inter_cp_with_ext_border(ref->u, ref->width / 2,
ref->width / 2, ref->height / 2,
&lcu->rec.u[lcu_pu_index_c], LCU_WIDTH_C,
width / 2, height / 2,
&mv_in_frame_c);
inter_cp_with_ext_border(ref->v, ref->width / 2,
ref->width / 2, ref->height / 2,
&lcu->rec.v[lcu_pu_index_c], LCU_WIDTH_C,
width / 2, height / 2,
&mv_in_frame_c);
} else {
const int frame_mv_index = mv_in_frame_c.y * ref->width / 2 + mv_in_frame_c.x;
kvz_pixels_blit(&ref->u[frame_mv_index],
&lcu->rec.u[lcu_pu_index_c],
width / 2, height / 2,
ref->width / 2, LCU_WIDTH_C);
kvz_pixels_blit(&ref->v[frame_mv_index],
&lcu->rec.v[lcu_pu_index_c],
width / 2, height / 2,
ref->width / 2, LCU_WIDTH_C);
}
}
}
/**
* \brief Reconstruct bi-pred inter PU
*
* \param state encoder state
* \param ref1 reference picture to copy the data from
* \param ref2 other reference picture to copy the data from
* \param xpos PU x position
* \param ypos PU y position
* \param width PU width
* \param height PU height
* \param mv_param motion vectors
* \param lcu destination lcu
*/
void kvz_inter_recon_bipred(const encoder_state_t * const state,
const kvz_picture * ref1,
const kvz_picture * ref2,
int32_t xpos,
int32_t ypos,
int32_t width,
int32_t height,
int16_t mv_param[2][2],
lcu_t* lcu)
{
kvz_pixel temp_lcu_y[LCU_WIDTH*LCU_WIDTH];
kvz_pixel temp_lcu_u[LCU_WIDTH_C*LCU_WIDTH_C];
kvz_pixel temp_lcu_v[LCU_WIDTH_C*LCU_WIDTH_C];
const int hi_prec_luma_rec0 = mv_param[0][0] & 3 || mv_param[0][1] & 3;
const int hi_prec_luma_rec1 = mv_param[1][0] & 3 || mv_param[1][1] & 3;
const int hi_prec_chroma_rec0 = mv_param[0][0] & 7 || mv_param[0][1] & 7;
const int hi_prec_chroma_rec1 = mv_param[1][0] & 7 || mv_param[1][1] & 7;
hi_prec_buf_t* high_precision_rec0 = 0;
hi_prec_buf_t* high_precision_rec1 = 0;
if (hi_prec_chroma_rec0) high_precision_rec0 = kvz_hi_prec_buf_t_alloc(LCU_WIDTH*LCU_WIDTH);
if (hi_prec_chroma_rec1) high_precision_rec1 = kvz_hi_prec_buf_t_alloc(LCU_WIDTH*LCU_WIDTH);
//Reconstruct both predictors
inter_recon_unipred(state, ref1, xpos, ypos, width, height, mv_param[0], lcu, high_precision_rec0);
if (!hi_prec_luma_rec0){
memcpy(temp_lcu_y, lcu->rec.y, sizeof(kvz_pixel) * 64 * 64);
}
if (!hi_prec_chroma_rec0){
memcpy(temp_lcu_u, lcu->rec.u, sizeof(kvz_pixel) * 32 * 32);
memcpy(temp_lcu_v, lcu->rec.v, sizeof(kvz_pixel) * 32 * 32);
}
inter_recon_unipred(state, ref2, xpos, ypos, width, height, mv_param[1], lcu, high_precision_rec1);
kvz_inter_recon_bipred_test(hi_prec_luma_rec0, hi_prec_luma_rec1, hi_prec_chroma_rec0, hi_prec_chroma_rec1, height, width, ypos, xpos, high_precision_rec0, high_precision_rec1, lcu);
/*
// After reconstruction, merge the predictors by taking an average of each pixel
for (temp_y = 0; temp_y < height; ++temp_y) {
int y_in_lcu = ((ypos + temp_y) & ((LCU_WIDTH)-1));
for (temp_x = 0; temp_x < width; ++temp_x) {
int x_in_lcu = ((xpos + temp_x) & ((LCU_WIDTH)-1));
int16_t sample0_y = (hi_prec_luma_rec0 ? high_precision_rec0->y[y_in_lcu * LCU_WIDTH + x_in_lcu] : (temp_lcu_y[y_in_lcu * LCU_WIDTH + x_in_lcu] << (14 - KVZ_BIT_DEPTH)));
int16_t sample1_y = (hi_prec_luma_rec1 ? high_precision_rec1->y[y_in_lcu * LCU_WIDTH + x_in_lcu] : (lcu->rec.y[y_in_lcu * LCU_WIDTH + x_in_lcu] << (14 - KVZ_BIT_DEPTH)));
lcu->rec.y[y_in_lcu * LCU_WIDTH + x_in_lcu] = (kvz_pixel)kvz_fast_clip_32bit_to_pixel((sample0_y + sample1_y + offset) >> shift);
}
}
for (temp_y = 0; temp_y < height >> 1; ++temp_y) {
int y_in_lcu = (((ypos >> 1) + temp_y) & (LCU_WIDTH_C - 1));
for (temp_x = 0; temp_x < width >> 1; ++temp_x) {
int x_in_lcu = (((xpos >> 1) + temp_x) & (LCU_WIDTH_C - 1));
int16_t sample0_u = (hi_prec_chroma_rec0 ? high_precision_rec0->u[y_in_lcu * LCU_WIDTH_C + x_in_lcu] : (temp_lcu_u[y_in_lcu * LCU_WIDTH_C + x_in_lcu] << (14 - KVZ_BIT_DEPTH)));
int16_t sample1_u = (hi_prec_chroma_rec1 ? high_precision_rec1->u[y_in_lcu * LCU_WIDTH_C + x_in_lcu] : (lcu->rec.u[y_in_lcu * LCU_WIDTH_C + x_in_lcu] << (14 - KVZ_BIT_DEPTH)));
lcu->rec.u[y_in_lcu * LCU_WIDTH_C + x_in_lcu] = (kvz_pixel)kvz_fast_clip_32bit_to_pixel((sample0_u + sample1_u + offset) >> shift);
int16_t sample0_v = (hi_prec_chroma_rec0 ? high_precision_rec0->v[y_in_lcu * LCU_WIDTH_C + x_in_lcu] : (temp_lcu_v[y_in_lcu * LCU_WIDTH_C + x_in_lcu] << (14 - KVZ_BIT_DEPTH)));
int16_t sample1_v = (hi_prec_chroma_rec1 ? high_precision_rec1->v[y_in_lcu * LCU_WIDTH_C + x_in_lcu] : (lcu->rec.v[y_in_lcu * LCU_WIDTH_C + x_in_lcu] << (14 - KVZ_BIT_DEPTH)));
lcu->rec.v[y_in_lcu * LCU_WIDTH_C + x_in_lcu] = (kvz_pixel)kvz_fast_clip_32bit_to_pixel((sample0_v + sample1_v + offset) >> shift);
}
}
*/
if (high_precision_rec0 != 0) kvz_hi_prec_buf_t_free(high_precision_rec0);
if (high_precision_rec1 != 0) kvz_hi_prec_buf_t_free(high_precision_rec1);
}
/**
* Reconstruct a single CU.
*
* The CU may consist of multiple PUs, each of which can use either
* uniprediction or biprediction.
*
* \param state encoder state
* \param lcu containing LCU
* \param x x-coordinate of the CU in pixels
* \param y y-coordinate of the CU in pixels
* \param width CU width
*/
void kvz_inter_recon_cu(const encoder_state_t * const state,
lcu_t *lcu,
int32_t x,
int32_t y,
int32_t width)
{
cu_info_t *cu = LCU_GET_CU_AT_PX(lcu, SUB_SCU(x), SUB_SCU(y));
const int num_pu = kvz_part_mode_num_parts[cu->part_size];
for (int i = 0; i < num_pu; ++i) {
const int pu_x = PU_GET_X(cu->part_size, width, x, i);
const int pu_y = PU_GET_Y(cu->part_size, width, y, i);
const int pu_w = PU_GET_W(cu->part_size, width, i);
const int pu_h = PU_GET_H(cu->part_size, width, i);
cu_info_t *pu = LCU_GET_CU_AT_PX(lcu, SUB_SCU(pu_x), SUB_SCU(pu_y));
if (pu->inter.mv_dir == 3) {
const kvz_picture *const refs[2] = {
state->frame->ref->images[
state->frame->ref_LX[0][
pu->inter.mv_ref[0]]],
state->frame->ref->images[
state->frame->ref_LX[1][
pu->inter.mv_ref[1]]],
};
kvz_inter_recon_bipred(state,
refs[0], refs[1],
pu_x, pu_y,
pu_w, pu_h,
pu->inter.mv,
lcu);
} else {
const int mv_idx = pu->inter.mv_dir - 1;
const kvz_picture *const ref =
state->frame->ref->images[
state->frame->ref_LX[mv_idx][
pu->inter.mv_ref[mv_idx]]];
inter_recon_unipred(state,
ref,
pu_x, pu_y,
pu_w, pu_h,
pu->inter.mv[mv_idx],
lcu,
NULL);
}
}
}
/**
* \brief Clear unused L0/L1 motion vectors and reference
* \param cu coding unit to clear
*/
static void inter_clear_cu_unused(cu_info_t* cu)
{
for (unsigned i = 0; i < 2; ++i) {
if (cu->inter.mv_dir & (1 << i)) continue;
cu->inter.mv[i][0] = 0;
cu->inter.mv[i][1] = 0;
cu->inter.mv_ref[i] = 255;
}
}
/**
* \brief Check whether a0 mv cand block is coded before the current block.
* \param x x-coordinate of the current block (in pixels)
* \param y y-coordinate of the current block (in pixels)
* \param width width of the current block (in pixels)
* \param height height of the current block (in pixels)
* \return True, if the a0 mv candidate block is coded before the
* current block. Otherwise false.
*/
static bool is_a0_cand_coded(int x, int y, int width, int height)
{
int size = MIN(width & ~(width - 1), height & ~(height - 1));
if (height != size) {
// For SMP and AMP blocks the situation is equivalent to a square block
// at the lower left corner of the PU.
y = y + height - size;
}
while (size < LCU_WIDTH) {
const int parent_size = 2 * size;
const int cu_index = (x % parent_size != 0) + 2 * (y % parent_size != 0);
switch (cu_index) {
case 0:
// A0 is in the CU directly left of the parent CU so it has been
// coded already.
// +---+---+
// | X | |
// |---+---+
// A0 | | |
// +---+---+
return true;
case 1:
// A0 is in the CU that will be coded after the current CU.
// +---+---+
// | | X |
// |---+---+
// |A0 | |
// +---+---+
return false;
case 2:
// +---+---+
// | | |
// |---+---+
// | X | |
// +---+---+
// A0
// Move to the parent block.
y -= size;
size = parent_size;
break;
case 3:
// A0 is in the CU directly down of the parent CU so is has not
// been coded yet.
// +---+---+
// | | |
// |---+---+
// | | X |
// +---+---+
// A0
return false;
}
}
// For 64x64 blocks A0 candidate is located outside the LCU.
return false;
}
/**
* \brief Check whether b0 mv cand block is coded before the current block.
* \param x x-coordinate of the current block (in pixels)
* \param y y-coordinate of the current block (in pixels)
* \param width width of the current block (in pixels)
* \param height height of the current block (in pixels)
* \return True, if the b0 mv candidate block is coded before the
* current block. Otherwise false.
*/
static bool is_b0_cand_coded(int x, int y, int width, int height)
{
int size = MIN(width & ~(width - 1), height & ~(height - 1));
if (width != size) {
// For SMP and AMP blocks the situation is equivalent to a square block
// at the upper right corner of the PU.
x = x + width - size;
}
while (size < LCU_WIDTH) {
const int parent_size = 2 * size;
const int cu_index = (x % parent_size != 0) + 2 * (y % parent_size != 0);
switch (cu_index) {
case 0:
// B0 is in the CU directly above the parent CU so it has been
// coded already.
// B0
// +---+---+
// | X | |
// |---+---+
// | | |
// +---+---+
return true;
case 1:
// B0
// +---+---+
// | | X |
// |---+---+
// | | |
// +---+---+
// Move to the parent block.
x -= size;
size = parent_size;
break;
case 2:
// +---+---+
// | |B0 |
// |---+---+
// | X | |
// +---+---+
return true;
case 3:
// B0 is in the CU directly right of the parent CU so is has not
// been coded yet.
// +---+---+
// | | | B0
// |---+---+
// | | X |
// +---+---+
return false;
}
}
// The LCU to the right and up of the current LCU has been coded already.
return true;
}
/**
* \brief Get merge candidates for current block
*
* \param state encoder control state to use
* \param x block x position in SCU
* \param y block y position in SCU
* \param width current block width
* \param height current block height
* \param ref_list which reference list, L0 is 1 and L1 is 2
* \param ref_idx index in the reference list
* \param cand_out will be filled with C3 and H candidates
*/
static void get_temporal_merge_candidates(const encoder_state_t * const state,
int32_t x,
int32_t y,
int32_t width,
int32_t height,
uint8_t ref_list,
uint8_t ref_idx,
merge_candidates_t *cand_out)
{
/*
Predictor block locations
_________
|CurrentPU|
| |C0|__ |
| |C3| |
|_________|_
|H|
*/
cand_out->c3 = cand_out->h = NULL;
// Find temporal reference
if (state->frame->ref->used_size) {
uint32_t colocated_ref;
// Select L0/L1 ref_idx reference
if (state->frame->ref_LX_size[ref_list-1] > ref_idx) {
colocated_ref = state->frame->ref_LX[ref_list - 1][ref_idx];
} else {
// not found
return;
}
cu_array_t *ref_cu_array = state->frame->ref->cu_arrays[colocated_ref];
int cu_per_width = ref_cu_array->width / SCU_WIDTH;
uint32_t xColBr = x + width;
uint32_t yColBr = y + height;
// H must be available
if (xColBr < state->encoder_control->in.width &&
yColBr < state->encoder_control->in.height) {
int32_t H_offset = -1;
// Y inside the current CTU / LCU
if (yColBr % LCU_WIDTH != 0) {
H_offset = ((xColBr >> 4) << 4) / SCU_WIDTH +
(((yColBr >> 4) << 4) / SCU_WIDTH) * cu_per_width;
}
if (H_offset >= 0) {
// Only use when it's inter block
if (ref_cu_array->data[H_offset].type == CU_INTER) {
cand_out->h = &ref_cu_array->data[H_offset];
}
}
}
uint32_t xColCtr = x + (width / 2);
uint32_t yColCtr = y + (height / 2);
// C3 must be inside the LCU, in the center position of current CU
if (xColCtr < state->encoder_control->in.width && yColCtr < state->encoder_control->in.height) {
uint32_t C3_offset = ((xColCtr >> 4) << 4) / SCU_WIDTH + ((((yColCtr >> 4) << 4) / SCU_WIDTH) * cu_per_width);
if (ref_cu_array->data[C3_offset].type == CU_INTER) {
cand_out->c3 = &ref_cu_array->data[C3_offset];
}
}
}
}
/**
* \brief Get merge candidates for current block.
*
* The output parameters b0, b1, b2, a0, a1 are pointed to the
* corresponding cu_info_t struct in lcu->cu, or set to NULL, if the
* candidate is not available.
*
* \param x block x position in pixels
* \param y block y position in pixels
* \param width block width in pixels
* \param height block height in pixels
* \param picture_width tile width in pixels
* \param picture_height tile height in pixels
* \param lcu current LCU
* \param cand_out will be filled with A and B candidates
*/
static void get_spatial_merge_candidates(int32_t x,
int32_t y,
int32_t width,
int32_t height,
int32_t picture_width,
int32_t picture_height,
lcu_t *lcu,
merge_candidates_t *cand_out)
{
/*
Predictor block locations
____ _______
|B2|______|B1|B0|
| |
| Cur CU |
__| |
|A1|_________|
|A0|
*/
int32_t x_local = SUB_SCU(x); //!< coordinates from top-left of this LCU
int32_t y_local = SUB_SCU(y);
// A0 and A1 availability testing
if (x != 0) {
cu_info_t *a1 = LCU_GET_CU_AT_PX(lcu, x_local - 1, y_local + height - 1);
// Do not check a1->coded because the block above is always coded before
// the current one and the flag is not set when searching an SMP block.
if (a1->type == CU_INTER) {
inter_clear_cu_unused(a1);
cand_out->a[1] = a1;
}
if (y_local + height < LCU_WIDTH && y + height < picture_height) {
cu_info_t *a0 = LCU_GET_CU_AT_PX(lcu, x_local - 1, y_local + height);
if (a0->type == CU_INTER && is_a0_cand_coded(x, y, width, height)) {
inter_clear_cu_unused(a0);
cand_out->a[0] = a0;
}
}
}
// B0, B1 and B2 availability testing
if (y != 0) {
cu_info_t *b0 = NULL;
if (x + width < picture_width) {
if (x_local + width < LCU_WIDTH) {
b0 = LCU_GET_CU_AT_PX(lcu, x_local + width, y_local - 1);
} else if (y_local == 0) {
// Special case, top-right CU
b0 = LCU_GET_TOP_RIGHT_CU(lcu);
}
}
if (b0 && b0->type == CU_INTER && is_b0_cand_coded(x, y, width, height)) {
inter_clear_cu_unused(b0);
cand_out->b[0] = b0;
}
cu_info_t *b1 = LCU_GET_CU_AT_PX(lcu, x_local + width - 1, y_local - 1);
// Do not check b1->coded because the block to the left is always coded
// before the current one and the flag is not set when searching an SMP
// block.
if (b1->type == CU_INTER) {
inter_clear_cu_unused(b1);
cand_out->b[1] = b1;
}
if (x != 0) {
cu_info_t *b2 = LCU_GET_CU_AT_PX(lcu, x_local - 1, y_local - 1);
// Do not check b2->coded because the block above and to the left is
// always coded before the current one.
if (b2->type == CU_INTER) {
inter_clear_cu_unused(b2);
cand_out->b[2] = b2;
}
}
}
}
/**
* \brief Get merge candidates for current block.
*
* The output parameters b0, b1, b2, a0, a1 are pointed to the
* corresponding cu_info_t struct in lcu->cu, or set to NULL, if the
* candidate is not available.
*
* \param cua cu information
* \param x block x position in pixels
* \param y block y position in pixels
* \param width block width in pixels
* \param height block height in pixels
* \param picture_width tile width in pixels
* \param picture_height tile height in pixels
* \param cand_out will be filled with A and B candidates
*/
static void get_spatial_merge_candidates_cua(const cu_array_t *cua,
int32_t x,
int32_t y,
int32_t width,
int32_t height,
int32_t picture_width,
int32_t picture_height,
merge_candidates_t *cand_out)
{
/*
Predictor block locations
____ _______
|B2|______|B1|B0|
| |
| Cur CU |
__| |
|A1|_________|
|A0|
*/
int32_t x_local = SUB_SCU(x); //!< coordinates from top-left of this LCU
int32_t y_local = SUB_SCU(y);
// A0 and A1 availability testing
if (x != 0) {
const cu_info_t *a1 = kvz_cu_array_at_const(cua, x - 1, y + height - 1);
// The block above is always coded before the current one.
if (a1->type == CU_INTER) {
cand_out->a[1] = a1;
}
if (y_local + height < LCU_WIDTH && y + height < picture_height) {
const cu_info_t *a0 = kvz_cu_array_at_const(cua, x - 1, y + height);
if (a0->type == CU_INTER && is_a0_cand_coded(x, y, width, height)) {
cand_out->a[0] = a0;
}
}
}
// B0, B1 and B2 availability testing
if (y != 0) {
if (x + width < picture_width && (x_local + width < LCU_WIDTH || y_local == 0)) {
const cu_info_t *b0 = kvz_cu_array_at_const(cua, x + width, y - 1);
if (b0->type == CU_INTER && is_b0_cand_coded(x, y, width, height)) {
cand_out->b[0] = b0;
}
}
const cu_info_t *b1 = kvz_cu_array_at_const(cua, x + width - 1, y - 1);
// The block to the left is always coded before the current one.
if (b1->type == CU_INTER) {
cand_out->b[1] = b1;
}
if (x != 0) {
const cu_info_t *b2 = kvz_cu_array_at_const(cua, x - 1, y - 1);
// The block above and to the left is always coded before the current
// one.
if (b2->type == CU_INTER) {
cand_out->b[2] = b2;
}
}
}
}
static INLINE int16_t get_scaled_mv(int16_t mv, int scale)
{
int32_t scaled = scale * mv;
return CLIP(-32768, 32767, (scaled + 127 + (scaled < 0)) >> 8);
}
static void apply_mv_scaling_pocs(int32_t current_poc,
int32_t current_ref_poc,
int32_t neighbor_poc,
int32_t neighbor_ref_poc,
int16_t mv_cand[2])
{
int32_t diff_current = current_poc - current_ref_poc;
int32_t diff_neighbor = neighbor_poc - neighbor_ref_poc;
if (diff_current == diff_neighbor) return;
diff_current = CLIP(-128, 127, diff_current);
diff_neighbor = CLIP(-128, 127, diff_neighbor);
int scale = CLIP(-4096, 4095,
(diff_current * ((0x4000 + (abs(diff_neighbor) >> 1)) / diff_neighbor) + 32) >> 6);
mv_cand[0] = get_scaled_mv(mv_cand[0], scale);
mv_cand[1] = get_scaled_mv(mv_cand[1], scale);
}
static INLINE void apply_mv_scaling(const encoder_state_t *state,
const cu_info_t *current_cu,
const cu_info_t *neighbor_cu,
int8_t current_reflist,
int8_t neighbor_reflist,
int16_t mv_cand[2])
{
apply_mv_scaling_pocs(state->frame->poc,
state->frame->ref->pocs[
state->frame->ref_LX[current_reflist][
current_cu->inter.mv_ref[current_reflist]]],
state->frame->poc,
state->frame->ref->pocs[
state->frame->ref_LX[neighbor_reflist][
neighbor_cu->inter.mv_ref[neighbor_reflist]]],
mv_cand);
}
/**
* \brief Try to add a temporal MVP or merge candidate.
*
* \param state encoder state
* \param current_ref index of the picture referenced by the current CU
* \param colocated colocated CU
* \param reflist either 0 (for L0) or 1 (for L1)
* \param[out] mv_out Returns the motion vector
*
* \return Whether a temporal candidate was added or not.
*/
static bool add_temporal_candidate(const encoder_state_t *state,
uint8_t current_ref,
const cu_info_t *colocated,
int32_t reflist,
int16_t mv_out[2])
{
if (!colocated) return false;
int colocated_ref;
if (state->frame->ref_LX_size[0] > 0) {
// get the first reference from L0 if it exists
colocated_ref = state->frame->ref_LX[0][0];
} else {
// otherwise no candidate added
return false;
}
// When there are reference pictures from the future (POC > current POC)
// in L0 or L1, the primary list for the colocated PU is the inverse of
// collocated_from_l0_flag. Otherwise it is equal to reflist.
//
// Kvazaar always sets collocated_from_l0_flag so the list is L1 when
// there are future references.
int col_list = reflist;
for (int i = 0; i < state->frame->ref->used_size; i++) {
if (state->frame->ref->pocs[i] > state->frame->poc) {
col_list = 1;
break;
}
}
if ((colocated->inter.mv_dir & (col_list + 1)) == 0) {
// Use the other list if the colocated PU does not have a MV for the
// primary list.
col_list = 1 - col_list;
}
mv_out[0] = colocated->inter.mv[col_list][0];
mv_out[1] = colocated->inter.mv[col_list][1];
apply_mv_scaling_pocs(
state->frame->poc,
state->frame->ref->pocs[current_ref],
state->frame->ref->pocs[colocated_ref],
state->frame->ref->images[colocated_ref]->ref_pocs[
state->frame->ref->ref_LXs[colocated_ref]
[col_list][colocated->inter.mv_ref[col_list]]],
mv_out
);
return true;
}
static INLINE bool add_mvp_candidate(const encoder_state_t *state,
const cu_info_t *cur_cu,
const cu_info_t *cand,
int8_t reflist,
bool scaling,
int16_t mv_cand_out[2])
{
if (!cand) return false;
assert(cand->inter.mv_dir != 0);
for (int i = 0; i < 2; i++) {
const int cand_list = i == 0 ? reflist : !reflist;
if ((cand->inter.mv_dir & (1 << cand_list)) == 0) continue;
if (scaling) {
mv_cand_out[0] = cand->inter.mv[cand_list][0];
mv_cand_out[1] = cand->inter.mv[cand_list][1];
apply_mv_scaling(state, cur_cu, cand, reflist, cand_list, mv_cand_out);
return true;
}
if (cand->inter.mv_dir & (1 << cand_list) &&
state->frame->ref_LX[cand_list][cand->inter.mv_ref[cand_list]] ==
state->frame->ref_LX[reflist][cur_cu->inter.mv_ref[reflist]])
{
mv_cand_out[0] = cand->inter.mv[cand_list][0];
mv_cand_out[1] = cand->inter.mv[cand_list][1];
return true;
}
}
return false;
}
/**
* \brief Pick two mv candidates from the spatial and temporal candidates.
*/
static void get_mv_cand_from_candidates(const encoder_state_t * const state,
int32_t x,
int32_t y,
int32_t width,
int32_t height,
const merge_candidates_t *merge_cand,
const cu_info_t *cur_cu,
int8_t reflist,
int16_t mv_cand[2][2])
{
const cu_info_t *const *a = merge_cand->a;
const cu_info_t *const *b = merge_cand->b;
const cu_info_t *c3 = merge_cand->c3;
const cu_info_t *h = merge_cand->h;
uint8_t candidates = 0;
uint8_t b_candidates = 0;
// Left predictors without scaling
for (int i = 0; i < 2; i++) {
if (add_mvp_candidate(state, cur_cu, a[i], reflist, false, mv_cand[candidates])) {
candidates++;
break;
}
}
// Left predictors with scaling
if (candidates == 0) {
for (int i = 0; i < 2; i++) {
if (add_mvp_candidate(state, cur_cu, a[i], reflist, true, mv_cand[candidates])) {
candidates++;
break;
}
}
}
// Top predictors without scaling
for (int i = 0; i < 3; i++) {
if (add_mvp_candidate(state, cur_cu, b[i], reflist, false, mv_cand[candidates])) {
b_candidates++;
break;
}
}
candidates += b_candidates;
// When a1 or a0 is available, we dont check for secondary B candidates.
if (a[0] || a[1]) {
b_candidates = 1;
} else if (candidates != 2) {
b_candidates = 0;
}
if (!b_candidates) {
// Top predictors with scaling
for (int i = 0; i < 3; i++) {
if (add_mvp_candidate(state, cur_cu, b[i], reflist, true, mv_cand[candidates])) {
candidates++;
break;
}
}
}
// Remove identical candidate
if (candidates == 2 && mv_cand[0][0] == mv_cand[1][0] && mv_cand[0][1] == mv_cand[1][1]) {
candidates = 1;
}
// Use Temporal Motion Vector Prediction when enabled.
// TMVP required at least two sequential P/B-frames.
bool can_use_tmvp =
state->encoder_control->cfg.tmvp_enable &&
state->frame->poc > 1 &&
state->frame->ref->used_size &&
candidates < AMVP_MAX_NUM_CANDS &&
(h != NULL || c3 != NULL);
if (can_use_tmvp && add_temporal_candidate(state,
state->frame->ref_LX[reflist][cur_cu->inter.mv_ref[reflist]],
(h != NULL) ? h : c3,
reflist,
mv_cand[candidates]))
{
candidates++;
}
// Fill with (0,0)
while (candidates < AMVP_MAX_NUM_CANDS) {
mv_cand[candidates][0] = 0;
mv_cand[candidates][1] = 0;
candidates++;
}
}
/**
* \brief Get MV prediction for current block.
*
* \param state encoder state
* \param x block x position in pixels
* \param y block y position in pixels
* \param width block width in pixels
* \param height block height in pixels
* \param mv_cand Return the motion vector candidates.
* \param cur_cu current CU
* \param lcu current LCU
* \param reflist reflist index (either 0 or 1)
*/
void kvz_inter_get_mv_cand(const encoder_state_t * const state,
int32_t x,
int32_t y,
int32_t width,
int32_t height,
int16_t mv_cand[2][2],
cu_info_t* cur_cu,
lcu_t *lcu,
int8_t reflist)
{
merge_candidates_t merge_cand = { {0, 0}, {0, 0, 0}, 0, 0 };
get_spatial_merge_candidates(x, y, width, height,
state->tile->frame->width,
state->tile->frame->height,
lcu,
&merge_cand);
get_temporal_merge_candidates(state, x, y, width, height, 1, 0, &merge_cand);
get_mv_cand_from_candidates(state, x, y, width, height, &merge_cand, cur_cu, reflist, mv_cand);
}
/**
* \brief Get MV prediction for current block using state->tile->frame->cu_array.
*
* \param state encoder state
* \param x block x position in pixels
* \param y block y position in pixels
* \param width block width in pixels
* \param height block height in pixels
* \param mv_cand Return the motion vector candidates.
* \param cur_cu current CU
* \param reflist reflist index (either 0 or 1)
*/
void kvz_inter_get_mv_cand_cua(const encoder_state_t * const state,
int32_t x,
int32_t y,
int32_t width,
int32_t height,
int16_t mv_cand[2][2],
const cu_info_t* cur_cu,
int8_t reflist)
{
merge_candidates_t merge_cand = { {0, 0}, {0, 0, 0}, 0, 0 };
const cu_array_t *cua = state->tile->frame->cu_array;
get_spatial_merge_candidates_cua(cua,
x, y, width, height,
state->tile->frame->width, state->tile->frame->height,
&merge_cand);
get_temporal_merge_candidates(state, x, y, width, height, 1, 0, &merge_cand);
get_mv_cand_from_candidates(state, x, y, width, height, &merge_cand, cur_cu, reflist, mv_cand);
}
static bool is_duplicate_candidate(const cu_info_t* cu1, const cu_info_t* cu2)
{
if (!cu2) return false;
if (cu1->inter.mv_dir != cu2->inter.mv_dir) return false;
for (int reflist = 0; reflist < 2; reflist++) {
if (cu1->inter.mv_dir & (1 << reflist)) {
if (cu1->inter.mv[reflist][0] != cu2->inter.mv[reflist][0] ||
cu1->inter.mv[reflist][1] != cu2->inter.mv[reflist][1] ||
cu1->inter.mv_ref[reflist] != cu2->inter.mv_ref[reflist]) {
return false;
}
}
}
return true;
}
static bool add_merge_candidate(const cu_info_t *cand,
const cu_info_t *possible_duplicate1,
const cu_info_t *possible_duplicate2,
inter_merge_cand_t *merge_cand_out)
{
if (!cand ||
is_duplicate_candidate(cand, possible_duplicate1) ||
is_duplicate_candidate(cand, possible_duplicate2)) {
return false;
}
merge_cand_out->mv[0][0] = cand->inter.mv[0][0];
merge_cand_out->mv[0][1] = cand->inter.mv[0][1];
merge_cand_out->mv[1][0] = cand->inter.mv[1][0];
merge_cand_out->mv[1][1] = cand->inter.mv[1][1];
merge_cand_out->ref[0] = cand->inter.mv_ref[0]; // L0/L1 references
merge_cand_out->ref[1] = cand->inter.mv_ref[1];
merge_cand_out->dir = cand->inter.mv_dir;
return true;
}
/**
* \brief Get merge predictions for current block
* \param state the encoder state
* \param x block x position in SCU
* \param y block y position in SCU
* \param width block width
* \param height block height
* \param use_a1 true, if candidate a1 can be used
* \param use_b1 true, if candidate b1 can be used
* \param mv_cand Returns the merge candidates.
* \param lcu lcu containing the block
* \return number of merge candidates
*/
uint8_t kvz_inter_get_merge_cand(const encoder_state_t * const state,
int32_t x, int32_t y,
int32_t width, int32_t height,
bool use_a1, bool use_b1,
inter_merge_cand_t mv_cand[MRG_MAX_NUM_CANDS],
lcu_t *lcu)
{
uint8_t candidates = 0;
int8_t zero_idx = 0;
merge_candidates_t merge_cand = { {0, 0}, {0, 0, 0}, 0, 0 };
get_spatial_merge_candidates(x, y, width, height,
state->tile->frame->width,
state->tile->frame->height,
lcu,
&merge_cand);
const cu_info_t **a = merge_cand.a;
const cu_info_t **b = merge_cand.b;
if (!use_a1) a[1] = NULL;
if (!use_b1) b[1] = NULL;
if (add_merge_candidate(a[1], NULL, NULL, &mv_cand[candidates])) candidates++;
if (add_merge_candidate(b[1], a[1], NULL, &mv_cand[candidates])) candidates++;
if (add_merge_candidate(b[0], b[1], NULL, &mv_cand[candidates])) candidates++;
if (add_merge_candidate(a[0], a[1], NULL, &mv_cand[candidates])) candidates++;
if (candidates < 4 &&
add_merge_candidate(b[2], a[1], b[1], &mv_cand[candidates])) candidates++;
bool can_use_tmvp =
state->encoder_control->cfg.tmvp_enable &&
candidates < MRG_MAX_NUM_CANDS &&
state->frame->ref->used_size;
if (can_use_tmvp) {
mv_cand[candidates].dir = 0;
const int max_reflist = (state->frame->slicetype == KVZ_SLICE_B ? 1 : 0);
for (int reflist = 0; reflist <= max_reflist; reflist++) {
// Fetch temporal candidates for the current CU
get_temporal_merge_candidates(state, x, y, width, height, 1, 0, &merge_cand);
// TODO: enable L1 TMVP candidate
// get_temporal_merge_candidates(state, x, y, width, height, 2, 0, &merge_cand);
const cu_info_t *temporal_cand =
(merge_cand.h != NULL) ? merge_cand.h : merge_cand.c3;
if (add_temporal_candidate(state,
// Reference index 0 is always used for
// the temporal merge candidate.
state->frame->ref_LX[reflist][0],
temporal_cand,
reflist,
mv_cand[candidates].mv[reflist])) {
mv_cand[candidates].ref[reflist] = 0;
mv_cand[candidates].dir |= (1 << reflist);
}
}
if (mv_cand[candidates].dir != 0) candidates++;
}
if (candidates < MRG_MAX_NUM_CANDS && state->frame->slicetype == KVZ_SLICE_B) {
#define NUM_PRIORITY_LIST 12;
static const uint8_t priorityList0[] = { 0, 1, 0, 2, 1, 2, 0, 3, 1, 3, 2, 3 };
static const uint8_t priorityList1[] = { 1, 0, 2, 0, 2, 1, 3, 0, 3, 1, 3, 2 };
uint8_t cutoff = candidates;
for (int32_t idx = 0; idx= candidates || j >= candidates) break;
// Find one L0 and L1 candidate according to the priority list
if ((mv_cand[i].dir & 0x1) && (mv_cand[j].dir & 0x2)) {
mv_cand[candidates].dir = 3;
// get Mv from cand[i] and cand[j]
mv_cand[candidates].mv[0][0] = mv_cand[i].mv[0][0];
mv_cand[candidates].mv[0][1] = mv_cand[i].mv[0][1];
mv_cand[candidates].mv[1][0] = mv_cand[j].mv[1][0];
mv_cand[candidates].mv[1][1] = mv_cand[j].mv[1][1];
mv_cand[candidates].ref[0] = mv_cand[i].ref[0];
mv_cand[candidates].ref[1] = mv_cand[j].ref[1];
if (state->frame->ref_LX[0][mv_cand[i].ref[0]] ==
state->frame->ref_LX[1][mv_cand[j].ref[1]]
&&
mv_cand[i].mv[0][0] == mv_cand[j].mv[1][0] &&
mv_cand[i].mv[0][1] == mv_cand[j].mv[1][1]) {
// Not a candidate
} else {
candidates++;
}
}
}
}
int num_ref = state->frame->ref->used_size;
if (candidates < MRG_MAX_NUM_CANDS && state->frame->slicetype == KVZ_SLICE_B) {
int j;
int ref_negative = 0;
int ref_positive = 0;
for (j = 0; j < state->frame->ref->used_size; j++) {
if (state->frame->ref->pocs[j] < state->frame->poc) {
ref_negative++;
} else {
ref_positive++;
}
}
num_ref = MIN(ref_negative, ref_positive);
}
// Add (0,0) prediction
while (candidates != MRG_MAX_NUM_CANDS) {
mv_cand[candidates].mv[0][0] = 0;
mv_cand[candidates].mv[0][1] = 0;
mv_cand[candidates].ref[0] = (zero_idx >= num_ref - 1) ? 0 : zero_idx;
mv_cand[candidates].ref[1] = mv_cand[candidates].ref[0];
mv_cand[candidates].dir = 1;
if (state->frame->slicetype == KVZ_SLICE_B) {
mv_cand[candidates].mv[1][0] = 0;
mv_cand[candidates].mv[1][1] = 0;
mv_cand[candidates].dir = 3;
}
zero_idx++;
candidates++;
}
return candidates;
}