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uvg266/src/intra.c
Ari Koivula 09b742796f Simplify intra reference border construction. 
Doesn't change anything but makes the control flow more clear.
2014-02-10 16:19:17 +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
* \brief Functions for handling intra frames.
*/
#include "intra.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "config.h"
#include "encoder.h"
const uint8_t intra_hor_ver_dist_thres[5] = {0,7,1,0,0};
/**
* \brief Set intrablock mode (and init typedata)
* \param pic picture to use
* \param xCtb x CU position (smallest CU)
* \param yCtb y CU position (smallest CU)
* \param depth current CU depth
* \param mode mode to set
* \returns Void
*/
void intra_set_block_mode(picture *pic,uint32_t x_cu, uint32_t y_cu, uint8_t depth, uint8_t mode, uint8_t part_mode)
{
uint32_t x, y;
int width_in_scu = pic->width_in_lcu<<MAX_DEPTH; //!< Width in smallest CU
int block_scu_width = (LCU_WIDTH>>depth)/(LCU_WIDTH>>MAX_DEPTH);
if (part_mode == SIZE_NxN) {
cu_info *cur_cu = &pic->cu_array[MAX_DEPTH][x_cu + y_cu * width_in_scu];
// Modes are already set.
cur_cu->depth = depth;
cur_cu->type = CU_INTRA;
cur_cu->tr_depth = depth + 1;
return;
}
// Loop through all the blocks in the area of cur_cu
for (y = y_cu; y < y_cu + block_scu_width; y++) {
for (x = x_cu; x < x_cu + block_scu_width; x++) {
cu_info *cur_cu = &pic->cu_array[MAX_DEPTH][x + y * width_in_scu];
cur_cu->depth = depth;
cur_cu->type = CU_INTRA;
cur_cu->intra[0].mode = mode;
cur_cu->intra[1].mode = mode;
cur_cu->intra[2].mode = mode;
cur_cu->intra[3].mode = mode;
cur_cu->part_size = part_mode;
cur_cu->tr_depth = depth;
}
}
}
/**
* \brief get intrablock mode
* \param pic picture to use
* \param xCtb x CU position (smallest CU)
* \param yCtb y CU position (smallest CU)
* \param depth current CU depth
* \returns mode if it's present, otherwise -1
*/
int8_t intra_get_block_mode(picture *pic, uint32_t x_cu, uint32_t y_cu, uint8_t depth)
{
int width_in_scu = pic->width_in_lcu<<MAX_DEPTH; //!< width in smallest CU
int cu_pos = y_cu * width_in_scu + x_cu;
if (pic->cu_array[MAX_DEPTH][cu_pos].type == CU_INTRA) {
return pic->cu_array[MAX_DEPTH][cu_pos].intra[0].mode;
}
return -1;
}
/**
* \brief get intrablock mode
* \param pic picture data to use
* \param picwidth width of the picture data
* \param xpos x-position
* \param ypos y-position
* \param width block width
* \returns DC prediction
*/
int16_t intra_get_dc_pred(pixel *pic, uint16_t picwidth, uint32_t xpos, uint32_t ypos, uint8_t width)
{
int32_t i, sum = 0;
// pixels on top and left
for (i = -picwidth; i < width - picwidth; i++) {
sum += pic[i];
}
for (i = -1; i < width * picwidth - 1; i += picwidth) {
sum += pic[i];
}
// return the average
return (sum + width) / (width + width);
}
#define PU_INDEX(x_pu, y_pu) (((x_pu) % 2) + 2 * (y_pu % 2))
/**
* \brief Function for deriving intra luma predictions
* \param pic picture to use
* \param x_cu x CU position (smallest CU)
* \param y_cu y CU position (smallest CU)
* \param depth current CU depth
* \param preds output buffer for 3 predictions
* \returns (predictions are found)?1:0
*/
int8_t intra_get_dir_luma_predictor(picture* pic, uint32_t x_pu, uint32_t y_pu, uint8_t depth, int8_t* preds)
{
int x_cu = x_pu / 2;
int y_cu = y_pu / 2;
// The default mode if block is not coded yet is INTRA_DC.
int32_t left_intra_dir = 1;
int32_t above_intra_dir = 1;
int width_in_scu = pic->width_in_lcu<<MAX_DEPTH;
int32_t cu_pos = y_cu * width_in_scu + x_cu;
cu_info* cur_cu = &pic->cu_array[MAX_DEPTH][cu_pos];
cu_info* left_cu = 0;
cu_info* above_cu = 0;
if (x_cu > 0) {
left_cu = &pic->cu_array[MAX_DEPTH][cu_pos - 1];
}
// Don't take the above CU across the LCU boundary.
if (y_cu > 0 &&
((y_cu * (LCU_WIDTH>>MAX_DEPTH)) % LCU_WIDTH) != 0)
{
above_cu = &pic->cu_array[MAX_DEPTH][cu_pos - width_in_scu];
}
if (cur_cu->part_size == SIZE_NxN && x_pu % 2 == 1) {
// If current CU is NxN and PU is on the right half, take mode from the
// left half of the same CU.
left_intra_dir = cur_cu->intra[PU_INDEX(0, y_pu)].mode;
} else if (left_cu && left_cu->type == CU_INTRA) {
// Otherwise take the mode from the right side of the CU on the left.
left_intra_dir = left_cu->intra[PU_INDEX(1, y_pu)].mode;
}
if (cur_cu->part_size == SIZE_NxN && y_pu % 2 == 1) {
// If current CU is NxN and PU is on the bottom half, take mode from the
// top half of the same CU.
above_intra_dir = cur_cu->intra[PU_INDEX(x_pu, 0)].mode;
} else if (above_cu && above_cu->type == CU_INTRA &&
(y_cu * (LCU_WIDTH>>MAX_DEPTH)) % LCU_WIDTH != 0)
{
// Otherwise take the mode from the bottom half of the CU above.
above_intra_dir = above_cu->intra[PU_INDEX(x_pu, 1)].mode;
}
// Left PU predictor
/*if(x_cu && pic->cu_array[MAX_DEPTH][cu_pos - 1].type == CU_INTRA && pic->cu_array[MAX_DEPTH][cu_pos - 1].coded) {
left_intra_dir = pic->cu_array[MAX_DEPTH][cu_pos - 1].intra[0].mode;
}
// Top PU predictor
if(y_cu && ((y_cu * (LCU_WIDTH>>MAX_DEPTH)) % LCU_WIDTH) != 0
&& pic->cu_array[MAX_DEPTH][cu_pos - width_in_scu].type == CU_INTRA && pic->cu_array[MAX_DEPTH][cu_pos - width_in_scu].coded) {
above_intra_dir = pic->cu_array[MAX_DEPTH][cu_pos - width_in_scu].intra[0].mode;
}*/
// If the predictions are the same, add new predictions
if (left_intra_dir == above_intra_dir) {
if (left_intra_dir > 1) { // angular modes
preds[0] = left_intra_dir;
preds[1] = ((left_intra_dir + 29) % 32) + 2;
preds[2] = ((left_intra_dir - 1 ) % 32) + 2;
} else { //non-angular
preds[0] = 0;//PLANAR_IDX;
preds[1] = 1;//DC_IDX;
preds[2] = 26;//VER_IDX;
}
} else { // If we have two distinct predictions
preds[0] = left_intra_dir;
preds[1] = above_intra_dir;
// add planar mode if it's not yet present
if (left_intra_dir && above_intra_dir ) {
preds[2] = 0; // PLANAR_IDX;
} else { // else we add 26 or 1
preds[2] = (left_intra_dir+above_intra_dir)<2? 26 : 1;
}
}
return 1;
}
/**
* \brief Intra filtering of the border samples
* \param ref reference picture data
* \param x_cu x CU position (smallest CU)
* \param y_cu y CU position (smallest CU)
* \param depth current CU depth
* \param preds output buffer for 3 predictions
* \returns (predictions are found)?1:0
*/
void intra_filter(pixel *ref, int32_t stride,int32_t width, int8_t mode)
{
#define FWIDTH (LCU_WIDTH*2+1)
pixel filtered[FWIDTH * FWIDTH]; //!< temporary buffer for filtered samples
pixel *filteredShift = &filtered[FWIDTH+1]; //!< pointer to temporary buffer with offset (1,1)
int x,y;
if (!mode) {
// pF[ -1 ][ -1 ] = ( p[ -1 ][ 0 ] + 2*p[ -1 ][ -1 ] + p[ 0 ][ -1 ] + 2 ) >> 2 (8 35)
filteredShift[-FWIDTH-1] = (ref[-1] + 2*ref[-(int32_t)stride-1] + ref[-(int32_t)stride] + 2) >> 2;
// pF[ -1 ][ y ] = ( p[ -1 ][ y + 1 ] + 2*p[ -1 ][ y ] + p[ -1 ][ y - 1 ] + 2 ) >> 2 for y = 0..nTbS * 2 - 2 (8 36)
for (y = 0; y < (int32_t)width * 2 - 1; y++) {
filteredShift[y*FWIDTH-1] = (ref[(y + 1) * stride - 1] + 2*ref[y * stride - 1] + ref[(y - 1) * stride - 1] + 2) >> 2;
}
// pF[ -1 ][ nTbS * 2 - 1 ] = p[ -1 ][ nTbS * 2 - 1 ] (8 37)
filteredShift[(width * 2 - 1) * FWIDTH - 1] = ref[(width * 2 - 1) * stride - 1];
// pF[ x ][ -1 ] = ( p[ x - 1 ][ -1 ] + 2*p[ x ][ -1 ] + p[ x + 1 ][ -1 ] + 2 ) >> 2 for x = 0..nTbS * 2 - 2 (8 38)
for(x = 0; x < (int32_t)width*2-1; x++) {
filteredShift[x - FWIDTH] = (ref[x - 1 - stride] + 2*ref[x - stride] + ref[x + 1 - stride] + 2) >> 2;
}
// pF[ nTbS * 2 - 1 ][ -1 ] = p[ nTbS * 2 - 1 ][ -1 ]
filteredShift[(width * 2 - 1) - FWIDTH] = ref[(width * 2 - 1) - stride];
// Copy filtered samples to the input array
for (x = -1; x < (int32_t)width * 2; x++) {
ref[x - stride] = filtered[x + 1];
}
for(y = 0; y < (int32_t)width * 2; y++) {
ref[y * stride - 1] = filtered[(y + 1) * FWIDTH];
}
} else {
printf("UNHANDLED: %s: %d\r\n", __FILE__, __LINE__);
exit(1);
}
#undef FWIDTH
}
/**
* \brief Function to test best intra prediction mode
* \param orig original picture data
* \param origstride original picture stride
* \param rec reconstructed picture data
* \param recstride reconstructed picture stride
* \param xpos source x-position
* \param ypos source y-position
* \param width block size to predict
* \param dst destination buffer for best prediction
* \param dststride destination width
* \param sad_out sad value of best mode
* \returns best intra mode
This function derives the prediction samples for planar mode (intra coding).
*/
int16_t intra_prediction(pixel *orig, int32_t origstride, pixel *rec, int32_t recstride, uint32_t xpos,
uint32_t ypos, uint32_t width, pixel *dst, int32_t dststride, uint32_t *sad_out)
{
uint32_t best_sad = 0xffffffff;
uint32_t sad = 0;
int16_t best_mode = 1;
int32_t x,y,i;
cost_16bit_nxn_func cost_func = get_sad_16bit_nxn_func(width);
// Temporary block arrays
// TODO: alloc with alignment
pixel pred[LCU_WIDTH * LCU_WIDTH + 1];
pixel orig_block[LCU_WIDTH * LCU_WIDTH + 1];
pixel rec_filtered_temp[(LCU_WIDTH * 2 + 8) * (LCU_WIDTH * 2 + 8) + 1];
pixel* rec_filtered = &rec_filtered_temp[recstride + 1]; //!< pointer to rec_filtered_temp with offset of (1,1)
pixel *orig_shift = &orig[xpos + ypos*origstride]; //!< pointer to orig with offset of (1,1)
int8_t filter = (width<32); // TODO: chroma support
uint8_t threshold = intra_hor_ver_dist_thres[g_to_bits[width]]; //!< Intra filtering threshold
#define COPY_PRED_TO_DST() for (y = 0; y < (int32_t)width; y++) { for (x = 0; x < (int32_t)width; x++) { dst[x + y*dststride] = pred[x + y*width]; } }
#define CHECK_FOR_BEST(mode, additional_sad) sad = cost_func(pred, orig_block); \
sad += additional_sad;\
if(sad < best_sad)\
{\
best_sad = sad;\
best_mode = mode;\
COPY_PRED_TO_DST();\
}
// Store original block for SAD computation
i = 0;
for(y = 0; y < (int32_t)width; y++) {
for(x = 0; x < (int32_t)width; x++) {
orig_block[i++] = orig_shift[x + y*origstride];
}
}
// Filtered only needs the borders
for (y = -1; y < (int32_t)recstride; y++) {
rec_filtered[y*recstride - 1] = rec[y*recstride - 1];
}
for (x = 0; x < (int32_t)recstride; x++) {
rec_filtered[x - recstride] = rec[x - recstride];
}
// Apply filter
intra_filter(rec_filtered,recstride,width,0);
// Test DC mode (never filtered)
x = intra_get_dc_pred(rec, recstride, xpos, ypos, width);
for (i = 0; i < (int32_t)(width*width); i++) {
pred[i] = x;
}
CHECK_FOR_BEST(1,0);
// Check angular not requiring filtering
for (i = 2; i < 35; i++) {
int distance = MIN(abs(i - 26),abs(i - 10)); //!< Distance from top and left predictions
if(distance <= threshold) {
intra_get_angular_pred(rec, recstride, pred, width, width, width, i, xpos?1:0, ypos?1:0, filter);
CHECK_FOR_BEST(i,0);
}
}
// FROM THIS POINT FORWARD, USING FILTERED PREDICTION
// Test planar mode (always filtered)
intra_get_planar_pred(rec_filtered, recstride, xpos, ypos, width, pred, width);
CHECK_FOR_BEST(0,0);
// Check angular predictions which require filtered samples
// TODO: add conditions to skip some modes on borders
// chroma can use only 26 and 10 (if not using luma-prediction)
for (i = 2; i < 35; i++) {
int distance = MIN(abs(i-26),abs(i-10)); //!< Distance from top and left predictions
if(distance > threshold) {
intra_get_angular_pred(rec_filtered, recstride, pred, width, width, width, i, xpos?1:0, ypos?1:0, filter);
CHECK_FOR_BEST(i,0);
}
}
// assign final sad to output
*sad_out = best_sad;
#undef COPY_PRED_TO_DST
#undef CHECK_FOR_BEST
return best_mode;
}
/**
* \brief Reconstruct intra block according to prediction
* \param rec reconstructed picture data
* \param recstride reconstructed picture stride
* \param xpos source x-position
* \param ypos source y-position
* \param width block size to predict
* \param dst destination buffer for best prediction
* \param dststride destination width
* \param mode intra mode to use
* \param chroma chroma-block flag
*/
void intra_recon(pixel* rec,uint32_t recstride, uint32_t xpos, uint32_t ypos,uint32_t width, pixel* dst,int32_t dststride, int8_t mode, int8_t chroma)
{
int32_t x,y,i;
pixel pred[LCU_WIDTH * LCU_WIDTH];
int8_t filter = !chroma && width < 32;
// Filtering apply if luma and not DC
if (!chroma && mode != 1 && width > 4) {
uint8_t threshold = intra_hor_ver_dist_thres[g_to_bits[width]];
if(MIN(abs(mode-26),abs(mode-10)) > threshold) {
intra_filter(rec,recstride,width,0);
}
}
// planar
if (mode == 0) {
intra_get_planar_pred(rec, recstride, xpos, ypos, width, pred, width);
} else if (mode == 1) { // DC
i = intra_get_dc_pred(rec, recstride, xpos, ypos, width);
for (y = 0; y < (int32_t)width; y++) {
for (x = 0; x < (int32_t)width; x++) {
dst[x + y*dststride] = i;
}
}
// Assigned value directly to output, no need to stay here
return;
} else { // directional predictions
intra_get_angular_pred(rec, recstride,pred, width, width, width, mode, xpos?1:0, ypos?1:0, filter);
}
for(y = 0; y < (int32_t)width; y++) {
for(x = 0; x < (int32_t)width; x++) {
dst[x+y*dststride] = pred[x+y*width];
}
}
}
/**
* \brief Build top and left borders for a reference block.
* \param pic picture to use as a source
* \param outwidth width of the prediction block
* \param chroma signaling if chroma is used, 0 = luma, 1 = U and 2 = V
*
* The end result is 2*width+8 x 2*width+8 array, with only the top and left
* edge pixels filled with the reconstructed pixels.
*/
void intra_build_reference_border(picture *pic, const pixel *src, int32_t x_luma, int32_t y_luma, int16_t outwidth,
pixel *dst, int32_t dststride, int8_t chroma)
{
// Some other function might make use of the arrays num_ref_pixels_top and
// num_ref_pixels_left in the future, but until that happens lets leave
// them here.
/**
* \brief Table for looking up the number of intra reference pixels based on
* prediction units coordinate within an LCU.
*
* This table was generated by "tools/generate_ref_pixel_tables.py".
*/
static const uint8_t num_ref_pixels_top[16][16] = {
{ 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64 },
{ 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4 },
{ 16, 12, 8, 4, 16, 12, 8, 4, 16, 12, 8, 4, 16, 12, 8, 4 },
{ 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4 },
{ 32, 28, 24, 20, 16, 12, 8, 4, 32, 28, 24, 20, 16, 12, 8, 4 },
{ 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4 },
{ 16, 12, 8, 4, 16, 12, 8, 4, 16, 12, 8, 4, 16, 12, 8, 4 },
{ 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4 },
{ 64, 60, 56, 52, 48, 44, 40, 36, 32, 28, 24, 20, 16, 12, 8, 4 },
{ 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4 },
{ 16, 12, 8, 4, 16, 12, 8, 4, 16, 12, 8, 4, 16, 12, 8, 4 },
{ 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4 },
{ 32, 28, 24, 20, 16, 12, 8, 4, 32, 28, 24, 20, 16, 12, 8, 4 },
{ 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4 },
{ 16, 12, 8, 4, 16, 12, 8, 4, 16, 12, 8, 4, 16, 12, 8, 4 },
{ 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4 }
};
/**
* \brief Table for looking up the number of intra reference pixels based on
* prediction units coordinate within an LCU.
*
* This table was generated by "tools/generate_ref_pixel_tables.py".
*/
static const uint8_t num_ref_pixels_left[16][16] = {
{ 64, 4, 8, 4, 16, 4, 8, 4, 32, 4, 8, 4, 16, 4, 8, 4 },
{ 64, 4, 4, 4, 12, 4, 4, 4, 28, 4, 4, 4, 12, 4, 4, 4 },
{ 64, 4, 8, 4, 8, 4, 8, 4, 24, 4, 8, 4, 8, 4, 8, 4 },
{ 64, 4, 4, 4, 4, 4, 4, 4, 20, 4, 4, 4, 4, 4, 4, 4 },
{ 64, 4, 8, 4, 16, 4, 8, 4, 16, 4, 8, 4, 16, 4, 8, 4 },
{ 64, 4, 4, 4, 12, 4, 4, 4, 12, 4, 4, 4, 12, 4, 4, 4 },
{ 64, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4 },
{ 64, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4 },
{ 64, 4, 8, 4, 16, 4, 8, 4, 32, 4, 8, 4, 16, 4, 8, 4 },
{ 64, 4, 4, 4, 12, 4, 4, 4, 28, 4, 4, 4, 12, 4, 4, 4 },
{ 64, 4, 8, 4, 8, 4, 8, 4, 24, 4, 8, 4, 8, 4, 8, 4 },
{ 64, 4, 4, 4, 4, 4, 4, 4, 20, 4, 4, 4, 4, 4, 4, 4 },
{ 64, 4, 8, 4, 16, 4, 8, 4, 16, 4, 8, 4, 16, 4, 8, 4 },
{ 64, 4, 4, 4, 12, 4, 4, 4, 12, 4, 4, 4, 12, 4, 4, 4 },
{ 64, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4 },
{ 64, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4 }
};
const pixel dc_val = 1 << (g_bitdepth - 1);
const int is_chroma = chroma ? 1 : 0;
const int src_width = pic->width >> is_chroma;
const int src_height = pic->height >> is_chroma;
// input picture pointer
//const pixel * const src = (!chroma) ? pic->y_recdata : ((chroma == 1) ? pic->u_recdata : pic->v_recdata);
// Convert luma coordinates to chroma coordinates for chroma.
const int x = chroma ? x_luma / 2 : x_luma;
const int y = chroma ? y_luma / 2 : y_luma;
// input picture pointer shifted to start from the left-top corner of the current block
const pixel *const src_shifted = &src[x + y * src_width];
const int y_in_lcu = y_luma % LCU_WIDTH;
const int x_in_lcu = x_luma % LCU_WIDTH;
// Copy pixels for left edge.
if (x > 0) {
// Get the number of reference pixels based on the PU coordinate within the LCU.
int num_ref_pixels = num_ref_pixels_left[y_in_lcu / 4][x_in_lcu / 4] >> is_chroma;
int i;
pixel nearest_pixel;
// Max pixel we can copy from src is yy + outwidth - 1 because the dst
// extends one pixel to the left.
num_ref_pixels = MIN(num_ref_pixels, outwidth - 1);
// There are no coded pixels below the frame.
num_ref_pixels = MIN(num_ref_pixels, src_height - y);
// There are no coded pixels below the bottom of the LCU due to raster
// scan order.
num_ref_pixels = MIN(num_ref_pixels, (LCU_WIDTH - y_in_lcu) >> is_chroma);
// Copy pixels from coded CUs.
for (i = 0; i < num_ref_pixels; ++i) {
dst[(i + 1) * dststride] = src_shifted[i*src_width - 1];
}
// Extend the last pixel for the rest of the reference values.
nearest_pixel = dst[i * dststride];
for (i = num_ref_pixels; i < outwidth - 1; ++i) {
dst[i * dststride] = nearest_pixel;
}
} else {
// If we are on the left edge, extend the first pixel of the top row.
pixel nearest_pixel = y > 0 ? src_shifted[-src_width] : dc_val;
int i;
for (i = 1; i < outwidth - 1; i++) {
dst[i * dststride] = nearest_pixel;
}
}
// Copy pixels for top edge.
if (y > 0) {
// Get the number of reference pixels based on the PU coordinate within the LCU.
int num_ref_pixels = num_ref_pixels_top[y_in_lcu / 4][x_in_lcu / 4] >> is_chroma;
int i;
pixel nearest_pixel;
// Max pixel we can copy from src is yy + outwidth - 1 because the dst
// extends one pixel to the left.
num_ref_pixels = MIN(num_ref_pixels, outwidth - 1);
// All LCUs in the row above have been coded.
num_ref_pixels = MIN(num_ref_pixels, src_width - x);
// Copy pixels from coded CUs.
for (i = 0; i < num_ref_pixels; ++i) {
dst[i + 1] = src_shifted[i - src_width];
}
// Extend the last pixel for the rest of the reference values.
nearest_pixel = src_shifted[num_ref_pixels - src_width - 1];
for (; i < outwidth - 1; ++i) {
dst[i + 1] = nearest_pixel;
}
} else {
// Extend nearest pixel.
pixel nearest_pixel = x > 0 ? src_shifted[-1] : dc_val;
int i;
for(i = 1; i < outwidth; i++)
{
dst[i] = nearest_pixel;
}
}
// If top-left corner sample doesn't exist, use the sample from below.
// Unavailable samples on the left boundary are copied from below if
// available. This is the only place they are available because we don't
// support constrained intra prediction.
dst[0] = (x > 0 && y > 0) ? src_shifted[-src_width - 1] : dst[dststride];
}
const int32_t ang_table[9] = {0, 2, 5, 9, 13, 17, 21, 26, 32};
const int32_t inv_ang_table[9] = {0, 4096, 1638, 910, 630, 482, 390, 315, 256}; // (256 * 32) / Angle
/**
* \brief this functions constructs the angular intra prediction from border samples
*
*/
void intra_get_angular_pred(pixel* src, int32_t src_stride, pixel* dst, int32_t dst_stride, int32_t width,
int32_t height, int32_t dir_mode, int8_t left_avail,int8_t top_avail, int8_t filter)
{
int32_t k,l;
int32_t blk_size = width;
// Map the mode index to main prediction direction and angle
int8_t mode_hor = dir_mode < 18;
int8_t mode_ver = !mode_hor;
int32_t intra_pred_angle = mode_ver ? (int32_t)dir_mode - 26 : mode_hor ? -((int32_t)dir_mode - 10) : 0;
int32_t abs_ang = abs(intra_pred_angle);
int32_t sign_ang = intra_pred_angle < 0 ? -1 : 1;
// Set bitshifts and scale the angle parameter to block size
int32_t inv_angle = inv_ang_table[abs_ang];
// Do angular predictions
pixel *ref_main;
pixel *ref_side;
pixel ref_above[2 * LCU_WIDTH + 1];
pixel ref_left[2 * LCU_WIDTH + 1];
abs_ang = ang_table[abs_ang];
intra_pred_angle = sign_ang * abs_ang;
// Initialise the Main and Left reference array.
if (intra_pred_angle < 0) {
int32_t invAngleSum = 128; // rounding for (shift by 8)
for (k = 0; k < blk_size + 1; k++) {
ref_above[k + blk_size - 1] = src[k - src_stride - 1];
ref_left[k + blk_size - 1] = src[(k - 1) * src_stride - 1];
}
ref_main = (mode_ver ? ref_above : ref_left) + (blk_size - 1);
ref_side = (mode_ver ? ref_left : ref_above) + (blk_size - 1);
// Extend the Main reference to the left.
for (k =- 1; k > blk_size * intra_pred_angle>>5; k--) {
invAngleSum += inv_angle;
ref_main[k] = ref_side[invAngleSum>>8];
}
} else {
for (k = 0; k < 2 * blk_size + 1; k++) {
ref_above[k] = src[k - src_stride - 1];
ref_left[k] = src[(k - 1) * src_stride - 1];
}
ref_main = mode_ver ? ref_above : ref_left;
ref_side = mode_ver ? ref_left : ref_above;
}
if (intra_pred_angle == 0) {
for (k = 0; k < blk_size; k++) {
for (l = 0; l < blk_size; l++) {
dst[k * dst_stride + l] = ref_main[l + 1];
}
}
if (filter) {
for (k=0;k<blk_size;k++) {
dst[k * dst_stride] = CLIP(0, (1<<g_bitdepth) - 1, dst[k * dst_stride] + (( ref_side[k + 1] - ref_side[0]) >> 1));
}
}
} else {
int32_t delta_pos=0;
int32_t delta_int;
int32_t delta_fract;
int32_t minus_delta_fract;
int32_t ref_main_index;
for (k = 0; k < blk_size; k++) {
delta_pos += intra_pred_angle;
delta_int = delta_pos >> 5;
delta_fract = delta_pos & (32 - 1);
if (delta_fract) {
minus_delta_fract = (32 - delta_fract);
// Do linear filtering
for (l = 0; l < blk_size; l++) {
ref_main_index = l + delta_int + 1;
dst[k * dst_stride + l] = (pixel) ( (minus_delta_fract * ref_main[ref_main_index]
+ delta_fract * ref_main[ref_main_index + 1] + 16) >> 5);
}
} else {
// Just copy the integer samples
for (l = 0; l < blk_size; l++) {
dst[k * dst_stride + l] = ref_main[l + delta_int + 1];
}
}
}
}
// Flip the block if this is the horizontal mode
if (mode_hor) {
pixel tmp;
for (k=0;k<blk_size-1;k++) {
for (l=k+1;l<blk_size;l++) {
tmp = dst[k * dst_stride + l];
dst[k * dst_stride + l] = dst[l * dst_stride + k];
dst[l * dst_stride + k] = tmp;
}
}
}
}
void intra_dc_pred_filtering(pixel *src, int32_t src_stride, pixel *dst, int32_t dst_stride, int32_t width, int32_t height )
{
int32_t x, y, dst_stride2, src_stride2;
// boundary pixels processing
dst[0] = ((src[-src_stride] + src[-1] + 2 * dst[0] + 2) >> 2);
for (x = 1; x < width; x++) {
dst[x] = ((src[x - src_stride] + 3 * dst[x] + 2) >> 2);
}
for ( y = 1, dst_stride2 = dst_stride, src_stride2 = src_stride-1;
y < height; y++, dst_stride2+=dst_stride, src_stride2+=src_stride ) {
dst[dst_stride2] = ((src[src_stride2] + 3 * dst[dst_stride2] + 2) >> 2);
}
return;
}
/**
* \brief Function for deriving planar intra prediction.
* \param src source pixel array
* \param srcstride source width
* \param xpos source x-position
* \param ypos source y-position
* \param width block size to predict
* \param dst destination buffer for prediction
* \param dststride destination width
This function derives the prediction samples for planar mode (intra coding).
*/
void intra_get_planar_pred(pixel* src,int32_t srcstride, uint32_t xpos, uint32_t ypos,uint32_t width, pixel* dst,int32_t dststride)
{
int32_t k, l, bottom_left, top_right;
int32_t hor_pred;
int32_t left_column[LCU_WIDTH+1], top_row[LCU_WIDTH+1], bottom_row[LCU_WIDTH+1], right_column[LCU_WIDTH+1];
uint32_t blk_size = width;
uint32_t offset_2d = width;
uint32_t shift_1d = g_convert_to_bit[ width ] + 2;
uint32_t shift_2d = shift_1d + 1;
// Get left and above reference column and row
for (k = 0; k < (int32_t)blk_size + 1; k++) {
top_row[k] = src[k - srcstride];
left_column[k] = src[k * srcstride - 1];
}
// Prepare intermediate variables used in interpolation
bottom_left = left_column[blk_size];
top_right = top_row[blk_size];
for (k = 0; k < (int32_t)blk_size; k++) {
bottom_row[k] = bottom_left - top_row[k];
right_column[k] = top_right - left_column[k];
top_row[k] <<= shift_1d;
left_column[k] <<= shift_1d;
}
// Generate prediction signal
for (k = 0; k < (int32_t)blk_size; k++) {
hor_pred = left_column[k] + offset_2d;
for (l = 0; l < (int32_t)blk_size; l++) {
hor_pred += right_column[k];
top_row[l] += bottom_row[l];
dst[k * dststride + l] = ( (hor_pred + top_row[l]) >> shift_2d );
}
}
}
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