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uvg266/src/transform.c
Arttu Ylä-Outinen 5fb7afe8c4 Add --implicit-rdpcm command line parameter. 
Makes it possible to use lossless coding without implicit residual DPCM.
2016-10-03 20:01:55 +09:00

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/*****************************************************************************
* 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 <http://www.gnu.org/licenses/>.
****************************************************************************/
#include "transform.h"
#include "image.h"
#include "kvazaar.h"
#include "rdo.h"
#include "strategies/strategies-dct.h"
#include "strategies/strategies-quant.h"
#include "tables.h"
/**
* \brief RDPCM direction.
*/
typedef enum rdpcm_dir {
RDPCM_VER = 0, // vertical
RDPCM_HOR = 1, // horizontal
} rdpcm_dir;
//////////////////////////////////////////////////////////////////////////
// INITIALIZATIONS
//
const uint8_t kvz_g_chroma_scale[58]=
{
0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,16,
17,18,19,20,21,22,23,24,25,26,27,28,29,29,30,31,32,
33,33,34,34,35,35,36,36,37,37,38,39,40,41,42,43,44,
45,46,47,48,49,50,51
};
//////////////////////////////////////////////////////////////////////////
// FUNCTIONS
//
/**
* \brief Bypass transform and quantization.
*
* Copies the reference pixels directly to reconstruction and the residual
* directly to coefficients. Used when cu_transquant_bypass_flag is set.
* Parameters pred_in and rec_out may be aliased.
*
* \param width Transform width.
* \param in_stride Stride for ref_in and pred_in
* \param out_stride Stride for rec_out and coeff_out.
* \param ref_in Reference pixels.
* \param pred_in Predicted pixels.
* \param rec_out Returns the reconstructed pixels.
* \param coeff_out Returns the coefficients used for reconstruction of rec_out.
*
* \returns Whether coeff_out contains any non-zero coefficients.
*/
static bool bypass_transquant(const int width,
const int in_stride,
const int out_stride,
const kvz_pixel *const ref_in,
const kvz_pixel *const pred_in,
kvz_pixel *rec_out,
coeff_t *coeff_out)
{
bool nonzero_coeffs = false;
for (int y = 0; y < width; ++y) {
for (int x = 0; x < width; ++x) {
int32_t in_idx = x + y * in_stride;
int32_t out_idx = x + y * out_stride;
// The residual must be computed before writing to rec_out because
// pred_in and rec_out may point to the same array.
coeff_t coeff = (coeff_t)(ref_in[in_idx] - pred_in[in_idx]);
coeff_out[out_idx] = coeff;
rec_out[out_idx] = ref_in[in_idx];
nonzero_coeffs |= (coeff != 0);
}
}
return nonzero_coeffs;
}
/**
* Apply DPCM to residual.
*
* \param width width of the block
* \param stride stride of coeff array
* \param dir RDPCM direction
* \param coeff coefficients (residual) to filter
*/
static void rdpcm(const int width,
const int stride,
const rdpcm_dir dir,
coeff_t *coeff)
{
const int offset = (dir == RDPCM_HOR) ? 1 : stride;
const int min_x = (dir == RDPCM_HOR) ? 1 : 0;
const int min_y = (dir == RDPCM_HOR) ? 0 : 1;
for (int y = width - 1; y >= min_y; y--) {
for (int x = width - 1; x >= min_x; x--) {
const int index = x + y * stride;
coeff[index] -= coeff[index - offset];
}
}
}
/**
* \brief Get scaled QP used in quantization
*
*/
int32_t kvz_get_scaled_qp(int8_t type, int8_t qp, int8_t qp_offset)
{
int32_t qp_scaled = 0;
if(type == 0) {
qp_scaled = qp + qp_offset;
} else {
qp_scaled = CLIP(-qp_offset, 57, qp);
if(qp_scaled < 0) {
qp_scaled = qp_scaled + qp_offset;
} else {
qp_scaled = kvz_g_chroma_scale[qp_scaled] + qp_offset;
}
}
return qp_scaled;
}
/**
* \brief NxN inverse transform (2D)
* \param coeff input data (transform coefficients)
* \param block output data (residual)
* \param block_size input data (width of transform)
*/
void kvz_transformskip(const encoder_control_t * const encoder, int16_t *block,int16_t *coeff, int8_t block_size)
{
uint32_t log2_tr_size = kvz_g_convert_to_bit[block_size] + 2;
int32_t shift = MAX_TR_DYNAMIC_RANGE - encoder->bitdepth - log2_tr_size;
int32_t j,k;
for (j = 0; j < block_size; j++) {
for(k = 0; k < block_size; k ++) {
coeff[j * block_size + k] = block[j * block_size + k] << shift;
}
}
}
/**
* \brief inverse transform skip
* \param coeff input data (transform coefficients)
* \param block output data (residual)
* \param block_size width of transform
*/
void kvz_itransformskip(const encoder_control_t * const encoder, int16_t *block,int16_t *coeff, int8_t block_size)
{
uint32_t log2_tr_size = kvz_g_convert_to_bit[block_size] + 2;
int32_t shift = MAX_TR_DYNAMIC_RANGE - encoder->bitdepth - log2_tr_size;
int32_t j,k;
int32_t offset;
offset = (1 << (shift -1)); // For rounding
for ( j = 0; j < block_size; j++ ) {
for(k = 0; k < block_size; k ++) {
block[j * block_size + k] = (coeff[j * block_size + k] + offset) >> shift;
}
}
}
/**
* \brief forward transform (2D)
* \param block input residual
* \param coeff transform coefficients
* \param block_size width of transform
*/
void kvz_transform2d(const encoder_control_t * const encoder, int16_t *block, int16_t *coeff, int8_t block_size, int32_t mode)
{
dct_func *dct_func = kvz_get_dct_func(block_size, mode);
dct_func(encoder->bitdepth, block, coeff);
}
void kvz_itransform2d(const encoder_control_t * const encoder, int16_t *block, int16_t *coeff, int8_t block_size, int32_t mode)
{
dct_func *idct_func = kvz_get_idct_func(block_size, mode);
idct_func(encoder->bitdepth, coeff, block);
}
/**
* \brief Like kvz_quantize_residual except that this uses trskip if that is better.
*
* Using this function saves one step of quantization and inverse quantization
* compared to doing the decision separately from the actual operation.
*
* \param width Transform width.
* \param color Color.
* \param scan_order Coefficient scan order.
* \param trskip_out Whether transform skip is used.
* \param stride Stride for ref_in, pred_in rec_out and coeff_out.
* \param ref_in Reference pixels.
* \param pred_in Predicted pixels.
* \param rec_out Reconstructed pixels.
* \param coeff_out Coefficients used for reconstruction of rec_out.
*
* \returns Whether coeff_out contains any non-zero coefficients.
*/
int kvz_quantize_residual_trskip(
encoder_state_t *const state,
const cu_info_t *const cur_cu, const int width, const color_t color,
const coeff_scan_order_t scan_order, int8_t *trskip_out,
const int in_stride, const int out_stride,
const kvz_pixel *const ref_in, const kvz_pixel *const pred_in,
kvz_pixel *rec_out, coeff_t *coeff_out)
{
struct {
kvz_pixel rec[4*4];
coeff_t coeff[4*4];
uint32_t cost;
int has_coeffs;
} skip, noskip, *best;
const int bit_cost = (int)(state->frame->cur_lambda_cost+0.5);
noskip.has_coeffs = kvz_quantize_residual(
state, cur_cu, width, color, scan_order,
0, in_stride, 4,
ref_in, pred_in, noskip.rec, noskip.coeff);
noskip.cost = kvz_pixels_calc_ssd(ref_in, noskip.rec, in_stride, 4, 4);
noskip.cost += kvz_get_coeff_cost(state, noskip.coeff, 4, 0, scan_order) * bit_cost;
skip.has_coeffs = kvz_quantize_residual(
state, cur_cu, width, color, scan_order,
1, in_stride, 4,
ref_in, pred_in, skip.rec, skip.coeff);
skip.cost = kvz_pixels_calc_ssd(ref_in, skip.rec, in_stride, 4, 4);
skip.cost += kvz_get_coeff_cost(state, skip.coeff, 4, 0, scan_order) * bit_cost;
if (noskip.cost <= skip.cost) {
*trskip_out = 0;
best = &noskip;
} else {
*trskip_out = 1;
best = &skip;
}
if (best->has_coeffs || rec_out != pred_in) {
// If there is no residual and reconstruction is already in rec_out,
// we can skip this.
kvz_pixels_blit(best->rec, rec_out, width, width, 4, out_stride);
}
kvz_coefficients_blit(best->coeff, coeff_out, width, width, 4, out_stride);
return best->has_coeffs;
}
/**
* This function calculates the residual coefficients for a region of the LCU
* (defined by x, y and depth) and updates the reconstruction with the
* kvantized residual.
*
* It handles recursion for transform split, but that is currently only work
* for 64x64 inter to 32x32 transform blocks.
*
* Inputs are:
* - lcu->rec pixels after prediction for the area
* - lcu->ref reference pixels for the area
* - lcu->cu for the area
*
* Outputs are:
* - lcu->rec reconstruction after quantized residual
* - lcu->coeff quantized coefficients for the area
* - lcu->cbf coded block flags for the area
* - lcu->cu.intra[].tr_skip for the area
*/
void kvz_quantize_lcu_luma_residual(encoder_state_t * const state, int32_t x, int32_t y, const uint8_t depth, cu_info_t *cur_pu, lcu_t* lcu)
{
// we have 64>>depth transform size
const vector2d_t lcu_px = { SUB_SCU(x), SUB_SCU(y) };
if (cur_pu == NULL) {
cur_pu = LCU_GET_CU_AT_PX(lcu, lcu_px.x, lcu_px.y);
}
const int8_t width = LCU_WIDTH>>depth;
// Tell clang-analyzer what is up. For some reason it can't figure out from
// asserting just depth.
assert(width == 4 || width == 8 || width == 16 || width == 32 || width == 64);
// Split transform and increase depth
if (depth == 0 || cur_pu->tr_depth > depth) {
int offset = width / 2;
kvz_quantize_lcu_luma_residual(state, x, y, depth+1, NULL, lcu);
kvz_quantize_lcu_luma_residual(state, x + offset, y, depth+1, NULL, lcu);
kvz_quantize_lcu_luma_residual(state, x, y + offset, depth+1, NULL, lcu);
kvz_quantize_lcu_luma_residual(state, x + offset, y + offset, depth+1, NULL, lcu);
// Propagate coded block flags from child CUs to parent CU.
if (depth <= MAX_DEPTH) {
uint16_t child_cbfs[3] = {
LCU_GET_CU_AT_PX(lcu, lcu_px.x + offset, lcu_px.y )->cbf,
LCU_GET_CU_AT_PX(lcu, lcu_px.x, lcu_px.y + offset)->cbf,
LCU_GET_CU_AT_PX(lcu, lcu_px.x + offset, lcu_px.y + offset)->cbf,
};
cbf_set_conditionally(&cur_pu->cbf, child_cbfs, depth, COLOR_Y);
}
return;
}
{
const int luma_offset = lcu_px.x + lcu_px.y * LCU_WIDTH;
// Pointers to current location in arrays with prediction.
kvz_pixel *recbase_y = &lcu->rec.y[luma_offset];
// Pointers to current location in arrays with reference.
const kvz_pixel *base_y = &lcu->ref.y[luma_offset];
// Pointers to current location in arrays with kvantized coefficients.
coeff_t *orig_coeff_y = &lcu->coeff.y[luma_offset];
coeff_scan_order_t scan_idx_luma = kvz_get_scan_order(cur_pu->type, cur_pu->intra.mode, depth);
#if OPTIMIZATION_SKIP_RESIDUAL_ON_THRESHOLD
uint32_t residual_sum = 0;
#endif
// Clear coded block flag structures for depths lower than current depth.
// This should ensure that the CBF data doesn't get corrupted if this function
// is called more than once.
cbf_clear(&cur_pu->cbf, depth, COLOR_Y);
if (state->encoder_control->cfg->lossless) {
if (bypass_transquant(width,
LCU_WIDTH, LCU_WIDTH,
base_y, recbase_y,
recbase_y, orig_coeff_y)) {
cbf_set(&cur_pu->cbf, depth, COLOR_Y);
}
if (state->encoder_control->cfg->implicit_rdpcm && cur_pu->type == CU_INTRA) {
// implicit rdpcm for horizontal and vertical intra modes
if (cur_pu->intra.mode == 10) {
rdpcm(width, LCU_WIDTH, RDPCM_HOR, orig_coeff_y);
} else if (cur_pu->intra.mode == 26) {
rdpcm(width, LCU_WIDTH, RDPCM_VER, orig_coeff_y);
}
}
} else if (width == 4 && state->encoder_control->trskip_enable) {
// Try quantization with trskip and use it if it's better.
int has_coeffs = kvz_quantize_residual_trskip(
state, cur_pu, width, COLOR_Y, scan_idx_luma,
&cur_pu->intra.tr_skip,
LCU_WIDTH, LCU_WIDTH,
base_y, recbase_y, recbase_y, orig_coeff_y
);
if (has_coeffs) {
cbf_set(&cur_pu->cbf, depth, COLOR_Y);
}
} else {
int has_coeffs = kvz_quantize_residual(
state, cur_pu, width, COLOR_Y, scan_idx_luma,
0,
LCU_WIDTH, LCU_WIDTH,
base_y, recbase_y, recbase_y, orig_coeff_y
);
if (has_coeffs) {
cbf_set(&cur_pu->cbf, depth, COLOR_Y);
}
}
}
}
void kvz_quantize_lcu_chroma_residual(encoder_state_t * const state, int32_t x, int32_t y, const uint8_t depth, cu_info_t *cur_cu, lcu_t* lcu)
{
// we have 64>>depth transform size
const vector2d_t lcu_px = { SUB_SCU(x), SUB_SCU(y) };
const int8_t width = LCU_WIDTH>>depth;
if (cur_cu == NULL) {
cur_cu = LCU_GET_CU_AT_PX(lcu, lcu_px.x, lcu_px.y);
}
// Tell clang-analyzer what is up. For some reason it can't figure out from
// asserting just depth.
assert(width == 4 || width == 8 || width == 16 || width == 32 || width == 64);
// Split transform and increase depth
if (depth == 0 || cur_cu->tr_depth > depth) {
int offset = width / 2;
kvz_quantize_lcu_chroma_residual(state, x, y, depth+1, NULL, lcu);
kvz_quantize_lcu_chroma_residual(state, x + offset, y, depth+1, NULL, lcu);
kvz_quantize_lcu_chroma_residual(state, x, y + offset, depth+1, NULL, lcu);
kvz_quantize_lcu_chroma_residual(state, x + offset, y + offset, depth+1, NULL, lcu);
// Propagate coded block flags from child CUs to parent CU.
if (depth < MAX_DEPTH) {
uint16_t child_cbfs[3] = {
LCU_GET_CU_AT_PX(lcu, lcu_px.x + offset, lcu_px.y )->cbf,
LCU_GET_CU_AT_PX(lcu, lcu_px.x, lcu_px.y + offset)->cbf,
LCU_GET_CU_AT_PX(lcu, lcu_px.x + offset, lcu_px.y + offset)->cbf,
};
cbf_set_conditionally(&cur_cu->cbf, child_cbfs, depth, COLOR_U);
cbf_set_conditionally(&cur_cu->cbf, child_cbfs, depth, COLOR_V);
}
return;
}
// If luma is 4x4, do chroma for the 8x8 luma area when handling the top
// left PU because the coordinates are correct.
if (depth <= MAX_DEPTH || (lcu_px.x % 8 == 0 && lcu_px.y % 8 == 0)) {
cbf_clear(&cur_cu->cbf, depth, COLOR_U);
cbf_clear(&cur_cu->cbf, depth, COLOR_V);
const int chroma_offset = lcu_px.x / 2 + lcu_px.y / 2 * LCU_WIDTH_C;
kvz_pixel *recbase_u = &lcu->rec.u[chroma_offset];
kvz_pixel *recbase_v = &lcu->rec.v[chroma_offset];
const kvz_pixel *base_u = &lcu->ref.u[chroma_offset];
const kvz_pixel *base_v = &lcu->ref.v[chroma_offset];
coeff_t *orig_coeff_u = &lcu->coeff.u[chroma_offset];
coeff_t *orig_coeff_v = &lcu->coeff.v[chroma_offset];
coeff_scan_order_t scan_idx_chroma;
int tr_skip = 0;
int chroma_depth = (depth == MAX_PU_DEPTH ? depth - 1 : depth);
int chroma_width = LCU_WIDTH_C >> chroma_depth;
scan_idx_chroma = kvz_get_scan_order(cur_cu->type, cur_cu->intra.mode_chroma, depth);
if (state->encoder_control->cfg->lossless) {
if (bypass_transquant(chroma_width,
LCU_WIDTH_C, LCU_WIDTH_C,
base_u, recbase_u,
recbase_u, orig_coeff_u)) {
cbf_set(&cur_cu->cbf, depth, COLOR_U);
}
if (bypass_transquant(chroma_width,
LCU_WIDTH_C, LCU_WIDTH_C,
base_v, recbase_v,
recbase_v, orig_coeff_v)) {
cbf_set(&cur_cu->cbf, depth, COLOR_V);
}
if (state->encoder_control->cfg->implicit_rdpcm && cur_cu->type == CU_INTRA) {
// implicit rdpcm for horizontal and vertical intra modes
if (cur_cu->intra.mode_chroma == 10) {
rdpcm(chroma_width, LCU_WIDTH_C, RDPCM_HOR, orig_coeff_u);
rdpcm(chroma_width, LCU_WIDTH_C, RDPCM_HOR, orig_coeff_v);
} else if (cur_cu->intra.mode_chroma == 26) {
rdpcm(chroma_width, LCU_WIDTH_C, RDPCM_VER, orig_coeff_u);
rdpcm(chroma_width, LCU_WIDTH_C, RDPCM_VER, orig_coeff_v);
}
}
} else {
if (kvz_quantize_residual(state, cur_cu, chroma_width, COLOR_U, scan_idx_chroma, tr_skip, LCU_WIDTH_C, LCU_WIDTH_C, base_u, recbase_u, recbase_u, orig_coeff_u)) {
cbf_set(&cur_cu->cbf, depth, COLOR_U);
}
if (kvz_quantize_residual(state, cur_cu, chroma_width, COLOR_V, scan_idx_chroma, tr_skip, LCU_WIDTH_C, LCU_WIDTH_C, base_v, recbase_v, recbase_v, orig_coeff_v)) {
cbf_set(&cur_cu->cbf, depth, COLOR_V);
}
}
}
}
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