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uvg266/src/search.c
Marko Viitanen 28aa20df12 Basic search for multiple reference frames
2014-02-17 09:58:10 +02:00

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/*****************************************************************************
* This file is part of Kvazaar HEVC encoder.
*
* Copyright (C) 2013-2014 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 General Public License version 2 as published
* by the Free Software Foundation.
*
* 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Kvazaar. If not, see <http://www.gnu.org/licenses/>.
****************************************************************************/
/*
* \file
*/
#include "search.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "config.h"
#include "bitstream.h"
#include "picture.h"
#include "intra.h"
#include "inter.h"
#include "filter.h"
// Temporarily for debugging.
#define USE_INTRA_IN_P 1
//#define RENDER_CU encoder->frame==2
#define RENDER_CU 0
#define SEARCH_MV_FULL_RADIUS 0
#define IN_FRAME(x, y, width, height, block_width, block_height) \
((x) >= 0 && (y) >= 0 \
&& (x) + (block_width) <= (width) \
&& (y) + (block_height) <= (height))
/**
* This is used in the hexagon_search to select 3 points to search.
*
* The start of the hexagonal pattern has been repeated at the end so that
* the indices between 1-6 can be used as the start of a 3-point list of new
* points to search.
*
* 6 o-o 1 / 7
* / \
* 5 o 0 o 2 / 8
* \ /
* 4 o-o 3
*/
const vector2d large_hexbs[10] = {
{ 0, 0 },
{ 1, -2 }, { 2, 0 }, { 1, 2 }, { -1, 2 }, { -2, 0 }, { -1, -2 },
{ 1, -2 }, { 2, 0 }
};
/**
* This is used as the last step of the hexagon search.
*/
const vector2d small_hexbs[5] = {
{ 0, 0 },
{ -1, -1 }, { -1, 0 }, { 1, 0 }, { 1, 1 }
};
int calc_mvd_cost(int x, int y, const vector2d *pred)
{
int cost = 0;
// Get the absolute difference vector and count the bits.
x = abs(abs(x) - abs(pred->x));
y = abs(abs(y) - abs(pred->y));
while (x >>= 1) {
++cost;
}
while (y >>= 1) {
++cost;
}
// I don't know what is a good cost function for this. It probably doesn't
// have to aproximate the actual cost of encoding the vector, but it's a
// place to start.
// Add two for quarter pixel resolution and multiply by two for Exp-Golomb.
return (cost ? (cost + 2) << 1 : 0);
}
/**
* \brief Do motion search using the HEXBS algorithm.
*
* \param depth log2 depth of the search
* \param pic Picture motion vector is searched for.
* \param ref Picture motion vector is searched from.
* \param orig Top left corner of the searched for block.
* \param mv_in_out Predicted mv in and best out. Quarter pixel precision.
*
* \returns Cost of the motion vector.
*
* Motion vector is searched by first searching iteratively with the large
* hexagon pattern until the best match is at the center of the hexagon.
* As a final step a smaller hexagon is used to check the adjacent pixels.
*
* If a non 0,0 predicted motion vector predictor is given as mv_in_out,
* the 0,0 vector is also tried. This is hoped to help in the case where
* the predicted motion vector is way off. In the future even more additional
* points like 0,0 might be used, such as vectors from top or left.
*/
unsigned hexagon_search(unsigned depth,
const picture *pic, const picture *ref,
const vector2d *orig, vector2d *mv_in_out)
{
vector2d mv = { mv_in_out->x >> 2, mv_in_out->y >> 2 };
int block_width = CU_WIDTH_FROM_DEPTH(depth);
unsigned best_cost = UINT32_MAX;
unsigned i;
unsigned best_index = 0; // Index of large_hexbs or finally small_hexbs.
// Search the initial 7 points of the hexagon.
for (i = 0; i < 7; ++i) {
const vector2d *pattern = &large_hexbs[i];
unsigned cost = calc_sad(pic, ref, orig->x, orig->y,
orig->x + mv.x + pattern->x, orig->y + mv.y + pattern->y,
block_width, block_width);
cost += calc_mvd_cost(mv.x + pattern->x, mv.y + pattern->y, mv_in_out);
if (cost < best_cost) {
best_cost = cost;
best_index = i;
}
}
// Try the 0,0 vector.
if (!(mv.x == 0 && mv.y == 0)) {
unsigned cost = calc_sad(pic, ref, orig->x, orig->y,
orig->x, orig->y,
block_width, block_width);
cost += calc_mvd_cost(0, 0, mv_in_out);
// If the 0,0 is better, redo the hexagon around that point.
if (cost < best_cost) {
best_cost = cost;
best_index = 0;
mv.x = 0;
mv.y = 0;
for (i = 1; i < 7; ++i) {
const vector2d *pattern = &large_hexbs[i];
unsigned cost = calc_sad(pic, ref, orig->x, orig->y,
orig->x + pattern->x,
orig->y + pattern->y,
block_width, block_width);
cost += calc_mvd_cost(pattern->x, pattern->y, mv_in_out);
if (cost < best_cost) {
best_cost = cost;
best_index = i;
}
}
}
}
// Iteratively search the 3 new points around the best match, until the best
// match is in the center.
while (best_index != 0) {
unsigned start; // Starting point of the 3 offsets to be searched.
if (best_index == 1) {
start = 6;
} else if (best_index == 8) {
start = 1;
} else {
start = best_index - 1;
}
// Move the center to the best match.
mv.x += large_hexbs[best_index].x;
mv.y += large_hexbs[best_index].y;
best_index = 0;
// Iterate through the next 3 points.
for (i = 0; i < 3; ++i) {
const vector2d *offset = &large_hexbs[start + i];
unsigned cost = calc_sad(pic, ref, orig->x, orig->y,
orig->x + mv.x + offset->x,
orig->y + mv.y + offset->y,
block_width, block_width);
cost += calc_mvd_cost(mv.x + offset->x, mv.y + offset->y, mv_in_out);
if (cost < best_cost) {
best_cost = cost;
best_index = start + i;
}
++offset;
}
}
// Move the center to the best match.
mv.x += large_hexbs[best_index].x;
mv.y += large_hexbs[best_index].y;
best_index = 0;
// Do the final step of the search with a small pattern.
for (i = 1; i < 5; ++i) {
const vector2d *offset = &small_hexbs[i];
unsigned cost = calc_sad(pic, ref, orig->x, orig->y,
orig->x + mv.x + offset->x,
orig->y + mv.y + offset->y,
block_width, block_width);
cost += calc_mvd_cost(mv.x + offset->x, mv.y + offset->y, mv_in_out);
if (cost > 0 && cost < best_cost) {
best_cost = cost;
best_index = i;
}
}
// Adjust the movement vector according to the final best match.
mv.x += small_hexbs[best_index].x;
mv.y += small_hexbs[best_index].y;
// Return final movement vector in quarter-pixel precision.
mv_in_out->x = mv.x << 2;
mv_in_out->y = mv.y << 2;
return best_cost;
}
unsigned search_mv_full(unsigned depth,
const picture *pic, const picture *ref,
const vector2d *orig, vector2d *mv_in_out)
{
vector2d mv = { mv_in_out->x >> 2, mv_in_out->y >> 2 };
int block_width = CU_WIDTH_FROM_DEPTH(depth);
unsigned best_cost = UINT32_MAX;
int x, y;
vector2d min_mv, max_mv;
/*if (abs(mv.x) > SEARCH_MV_FULL_RADIUS || abs(mv.y) > SEARCH_MV_FULL_RADIUS) {
best_cost = calc_sad(pic, ref, orig->x, orig->y,
orig->x, orig->y,
block_width, block_width);
mv.x = 0;
mv.y = 0;
}*/
min_mv.x = mv.x - SEARCH_MV_FULL_RADIUS;
min_mv.y = mv.y - SEARCH_MV_FULL_RADIUS;
max_mv.x = mv.x + SEARCH_MV_FULL_RADIUS;
max_mv.y = mv.y + SEARCH_MV_FULL_RADIUS;
for (y = min_mv.y; y < max_mv.y; ++y) {
for (x = min_mv.x; x < max_mv.x; ++x) {
unsigned cost = calc_sad(pic, ref, orig->x, orig->y,
orig->x + x,
orig->y + y,
block_width, block_width);
cost += calc_mvd_cost(x, y, mv_in_out);
if (cost < best_cost) {
best_cost = cost;
mv.x = x;
mv.y = y;
}
}
}
mv_in_out->x = mv.x << 2;
mv_in_out->y = mv.y << 2;
return best_cost;
}
void search_inter(encoder_control *encoder, uint16_t x_ctb, uint16_t y_ctb, uint8_t depth) {
picture *cur_pic = encoder->in.cur_pic;
int ref_idx = 0;
cu_info *cur_cu = &cur_pic->cu_array[depth][x_ctb + y_ctb * (encoder->in.width_in_lcu << MAX_DEPTH)];
cur_cu->inter.cost = UINT_MAX;
for (ref_idx = 0; ref_idx < encoder->ref->used_size; ref_idx++) {
picture *ref_pic = encoder->ref->pics[ref_idx];
unsigned width_in_scu = NO_SCU_IN_LCU(ref_pic->width_in_lcu);
cu_info *ref_cu = &ref_pic->cu_array[MAX_DEPTH][y_ctb * width_in_scu + x_ctb];
uint32_t temp_cost;
vector2d orig, mv;
orig.x = x_ctb * CU_MIN_SIZE_PIXELS;
orig.y = y_ctb * CU_MIN_SIZE_PIXELS;
mv.x = 0;
mv.y = 0;
if (ref_cu->type == CU_INTER) {
mv.x = ref_cu->inter.mv[0];
mv.y = ref_cu->inter.mv[1];
}
#if SEARCH_MV_FULL_RADIUS
cur_cu->inter.cost = search_mv_full(depth, cur_pic, ref_pic, &orig, &mv);
#else
temp_cost = hexagon_search(depth, cur_pic, ref_pic, &orig, &mv);
#endif
if(temp_cost < cur_cu->inter.cost) {
cur_cu->inter.mv_ref = ref_idx;
cur_cu->inter.mv_dir = 1;
cur_cu->inter.mv[0] = (int16_t)mv.x;
cur_cu->inter.mv[1] = (int16_t)mv.y;
cur_cu->inter.cost = temp_cost;
}
}
}
void search_intra(encoder_control *encoder, uint16_t x_ctb, uint16_t y_ctb, uint8_t depth)
{
int16_t x = x_ctb * (LCU_WIDTH >> MAX_DEPTH);
int16_t y = y_ctb * (LCU_WIDTH >> MAX_DEPTH);
picture *cur_pic = encoder->in.cur_pic;
uint8_t width = LCU_WIDTH >> depth;
cu_info *cur_cu = &cur_pic->cu_array[depth][x_ctb + y_ctb * (encoder->in.width_in_lcu << MAX_DEPTH)];
// INTRAPREDICTION
pixel pred[LCU_WIDTH * LCU_WIDTH + 1];
pixel rec[(LCU_WIDTH * 2 + 1) * (LCU_WIDTH * 2 + 1)];
pixel *recShift = &rec[(LCU_WIDTH >> (depth)) * 2 + 8 + 1];
// Build reconstructed block to use in prediction with extrapolated borders
intra_build_reference_border(cur_pic, cur_pic->y_data,
x, y,
(int16_t)width * 2 + 8, rec, (int16_t)width * 2 + 8, 0);
cur_cu->intra[0].mode = (int8_t)intra_prediction(encoder->in.cur_pic->y_data,
encoder->in.width, recShift, width * 2 + 8, x, y,
width, pred, width, &cur_cu->intra[0].cost);
cur_cu->part_size = SIZE_2Nx2N;
// Do search for NxN split.
if (depth == MAX_DEPTH) {
// Save 2Nx2N information to compare with NxN.
int nn_cost = cur_cu->intra[0].cost;
int8_t nn_mode = cur_cu->intra[0].mode;
int i;
int cost = (int)(g_lambda_cost[encoder->QP] * 4.5); // round to nearest
static vector2d offsets[4] = {{0,0},{1,0},{0,1},{1,1}};
width = 4;
recShift = &rec[width * 2 + 8 + 1];
for (i = 0; i < 4; ++i) {
int x_pos = x + offsets[i].x * width;
int y_pos = y + offsets[i].y * width;
intra_build_reference_border(cur_pic, cur_pic->y_data,
x_pos, y_pos,
(int16_t)width * 2 + 8, rec, (int16_t)width * 2 + 8, 0);
cur_cu->intra[i].mode = (int8_t)intra_prediction(encoder->in.cur_pic->y_data,
encoder->in.width, recShift, width * 2 + 8, (int16_t)x_pos, (int16_t)y_pos,
width, pred, width, &cur_cu->intra[i].cost);
cost += cur_cu->intra[i].cost;
}
// Choose between 2Nx2N and NxN.
if (nn_cost <= cost) {
cur_cu->intra[0].cost = nn_cost;
cur_cu->intra[0].mode = nn_mode;
} else {
cur_cu->intra[0].cost = cost;
cur_cu->part_size = SIZE_NxN;
}
}
}
/**
* \brief Search best modes at each depth for the whole picture.
*
* This function fills the cur_pic->cu_array of the current picture
* with the best mode and it's cost for each CU at each depth for the whole
* frame.
*/
void search_tree(encoder_control *encoder,
int x, int y, uint8_t depth)
{
int cu_width = LCU_WIDTH >> depth;
uint16_t x_ctb = (uint16_t)x / (LCU_WIDTH >> MAX_DEPTH);
uint16_t y_ctb = (uint16_t)y / (LCU_WIDTH >> MAX_DEPTH);
// Stop recursion if the CU is completely outside the frame.
if (x >= encoder->in.width || y >= encoder->in.height) {
return;
}
// If the CU is partially outside the frame, split.
if (x + cu_width > encoder->in.width ||
y + cu_width > encoder->in.height)
{
int half_cu = cu_width / 2;
search_tree(encoder, x, y, depth + 1);
search_tree(encoder, x + half_cu, y, depth + 1);
search_tree(encoder, x, y + half_cu, depth + 1);
search_tree(encoder, x + half_cu, y + half_cu, depth + 1);
return;
}
// CU is completely inside the frame, so search for best prediction mode at
// this depth.
{
picture *cur_pic = encoder->in.cur_pic;
if (cur_pic->slicetype != SLICE_I &&
depth >= MIN_INTER_SEARCH_DEPTH &&
depth <= MAX_INTER_SEARCH_DEPTH)
{
search_inter(encoder, x_ctb, y_ctb, depth);
}
if (depth >= MIN_INTRA_SEARCH_DEPTH &&
depth <= MAX_INTRA_SEARCH_DEPTH)
{
search_intra(encoder, x_ctb, y_ctb, depth);
}
}
// Recurse to max search depth.
if (depth < MAX_INTRA_SEARCH_DEPTH && depth < MAX_INTER_SEARCH_DEPTH) {
int half_cu = cu_width / 2;;
search_tree(encoder, x, y, depth + 1);
search_tree(encoder, x + half_cu, y, depth + 1);
search_tree(encoder, x, y + half_cu, depth + 1);
search_tree(encoder, x + half_cu, y + half_cu, depth + 1);
}
}
/**
* \brief
*/
uint32_t search_best_mode(encoder_control *encoder,
uint16_t x_ctb, uint16_t y_ctb, uint8_t depth)
{
cu_info *cur_cu = &encoder->in.cur_pic->cu_array[depth]
[x_ctb + y_ctb * (encoder->in.width_in_lcu << MAX_DEPTH)];
uint32_t best_intra_cost = cur_cu->intra[0].cost;
uint32_t best_inter_cost = cur_cu->inter.cost;
uint32_t lambda_cost = (int)(4.5 * g_lambda_cost[encoder->QP]); //TODO: Correct cost calculation
if (depth < MAX_INTRA_SEARCH_DEPTH && depth < MAX_INTER_SEARCH_DEPTH) {
uint32_t cost = lambda_cost;
uint8_t change = 1 << (MAX_DEPTH - 1 - depth);
cost += search_best_mode(encoder, x_ctb, y_ctb, depth + 1);
cost += search_best_mode(encoder, x_ctb + change, y_ctb, depth + 1);
cost += search_best_mode(encoder, x_ctb, y_ctb + change, depth + 1);
cost += search_best_mode(encoder, x_ctb + change, y_ctb + change, depth + 1);
if (cost < best_intra_cost && cost < best_inter_cost)
{
// Better value was found at a lower level.
return cost;
}
}
// If search hasn't been peformed at all for this block, the cost will be
// max value, so it is safe to just compare costs. It just has to be made
// sure that no value overflows.
if (best_inter_cost <= best_intra_cost) {
inter_set_block(encoder->in.cur_pic, x_ctb, y_ctb, depth, cur_cu);
return best_inter_cost;
} else {
intra_set_block_mode(encoder->in.cur_pic, x_ctb, y_ctb, depth,
cur_cu->intra[0].mode, cur_cu->part_size);
return best_intra_cost;
}
}
/**
* \brief
*/
void search_slice_data(encoder_control *encoder)
{
int16_t x_lcu, y_lcu;
// Initialize the costs in the cu-array used for searching.
{
int d, x_cu, y_cu;
for (y_cu = 0; y_cu < encoder->in.height / CU_MIN_SIZE_PIXELS; ++y_cu) {
for (x_cu = 0; x_cu < encoder->in.width / CU_MIN_SIZE_PIXELS; ++x_cu) {
for (d = 0; d <= MAX_DEPTH; ++d) {
picture *cur_pic = encoder->in.cur_pic;
cu_info *cur_cu = &cur_pic->cu_array[d][x_cu + y_cu * (encoder->in.width_in_lcu << MAX_DEPTH)];
cur_cu->intra[0].cost = UINT32_MAX;
cur_cu->inter.cost = UINT32_MAX;
}
}
}
}
// Loop through every LCU in the slice
for (y_lcu = 0; y_lcu < encoder->in.height_in_lcu; y_lcu++) {
for (x_lcu = 0; x_lcu < encoder->in.width_in_lcu; x_lcu++) {
uint8_t depth = 0;
// Recursive function for looping through all the sub-blocks
search_tree(encoder, x_lcu * LCU_WIDTH, y_lcu * LCU_WIDTH, depth);
// Decide actual coding modes
search_best_mode(encoder, x_lcu << MAX_DEPTH, y_lcu << MAX_DEPTH, depth);
encode_block_residual(encoder, x_lcu << MAX_DEPTH, y_lcu << MAX_DEPTH, depth);
}
}
}
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