tor-browser

aq_variance.c (11525B)

---

/*
* Copyright (c) 2016, Alliance for Open Media. All rights reserved.
*
* This source code is subject to the terms of the BSD 2 Clause License and
* the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
* was not distributed with this source code in the LICENSE file, you can
* obtain it at www.aomedia.org/license/software. If the Alliance for Open
* Media Patent License 1.0 was not distributed with this source code in the
* PATENTS file, you can obtain it at www.aomedia.org/license/patent.
*/

#include <math.h>
#include <stdlib.h>

#include "aom_dsp/aom_dsp_common.h"
#include "aom_ports/mem.h"

#include "av1/encoder/aq_variance.h"
#include "av1/common/seg_common.h"
#include "av1/encoder/encodeframe.h"
#include "av1/encoder/ratectrl.h"
#include "av1/encoder/rd.h"
#include "av1/encoder/segmentation.h"
#include "av1/encoder/dwt.h"
#include "config/aom_config.h"

#if !CONFIG_REALTIME_ONLY
static const double rate_ratio[MAX_SEGMENTS] = { 2.2, 1.7, 1.3, 1.0,
                                                0.9, .8,  .7,  .6 };

static const double deltaq_rate_ratio[MAX_SEGMENTS] = { 2.5,  2.0, 1.5, 1.0,
                                                       0.75, 1.0, 1.0, 1.0 };
#define ENERGY_MIN (-4)
#define ENERGY_MAX (1)
#define ENERGY_SPAN (ENERGY_MAX - ENERGY_MIN + 1)
#define ENERGY_IN_BOUNDS(energy) \
 assert((energy) >= ENERGY_MIN && (energy) <= ENERGY_MAX)

static const int segment_id[ENERGY_SPAN] = { 0, 1, 1, 2, 3, 4 };

#define SEGMENT_ID(i) segment_id[(i) - ENERGY_MIN]

void av1_vaq_frame_setup(AV1_COMP *cpi) {
 AV1_COMMON *cm = &cpi->common;
 const RefreshFrameInfo *const refresh_frame = &cpi->refresh_frame;
 const int base_qindex = cm->quant_params.base_qindex;
 struct segmentation *seg = &cm->seg;
 int i;

 int resolution_change =
     cm->prev_frame && (cm->width != cm->prev_frame->width ||
                        cm->height != cm->prev_frame->height);
 int avg_energy = (int)(cpi->twopass_frame.mb_av_energy - 2);
 double avg_ratio;
 if (avg_energy > 7) avg_energy = 7;
 if (avg_energy < 0) avg_energy = 0;
 avg_ratio = rate_ratio[avg_energy];

 if (resolution_change) {
   memset(cpi->enc_seg.map, 0, cm->mi_params.mi_rows * cm->mi_params.mi_cols);
   av1_clearall_segfeatures(seg);
   av1_disable_segmentation(seg);
   return;
 }
 if (frame_is_intra_only(cm) || cm->features.error_resilient_mode ||
     refresh_frame->alt_ref_frame ||
     (refresh_frame->golden_frame && !cpi->rc.is_src_frame_alt_ref)) {
   cpi->vaq_refresh = 1;

   av1_enable_segmentation(seg);
   av1_clearall_segfeatures(seg);

   for (i = 0; i < MAX_SEGMENTS; ++i) {
     // Set up avg segment id to be 1.0 and adjust the other segments around
     // it.
     int qindex_delta =
         av1_compute_qdelta_by_rate(cpi, cm->current_frame.frame_type,
                                    base_qindex, rate_ratio[i] / avg_ratio);

     // We don't allow qindex 0 in a segment if the base value is not 0.
     // Q index 0 (lossless) implies 4x4 encoding only and in AQ mode a segment
     // Q delta is sometimes applied without going back around the rd loop.
     // This could lead to an illegal combination of partition size and q.
     if ((base_qindex != 0) && ((base_qindex + qindex_delta) == 0)) {
       qindex_delta = -base_qindex + 1;
     }

     av1_set_segdata(seg, i, SEG_LVL_ALT_Q, qindex_delta);
     av1_enable_segfeature(seg, i, SEG_LVL_ALT_Q);
   }
 }
}

int av1_log_block_avg(const AV1_COMP *cpi, const MACROBLOCK *x, BLOCK_SIZE bs,
                     int mi_row, int mi_col) {
 // This functions returns the block average of luma block
 unsigned int sum, avg, num_pix;
 int r, c;
 const int pic_w = cpi->common.width;
 const int pic_h = cpi->common.height;
 const int bw = MI_SIZE * mi_size_wide[bs];
 const int bh = MI_SIZE * mi_size_high[bs];
 const uint16_t *x16 = CONVERT_TO_SHORTPTR(x->plane[0].src.buf);

 sum = 0;
 num_pix = 0;
 avg = 0;
 int row = mi_row << MI_SIZE_LOG2;
 int col = mi_col << MI_SIZE_LOG2;
 for (r = row; (r < (row + bh)) && (r < pic_h); r++) {
   for (c = col; (c < (col + bw)) && (c < pic_w); c++) {
     sum += *(x16 + r * x->plane[0].src.stride + c);
     num_pix++;
   }
 }
 if (num_pix != 0) {
   avg = sum / num_pix;
 }
 return avg;
}

#define DEFAULT_E_MIDPOINT 10.0

static unsigned int haar_ac_energy(const MACROBLOCK *x, BLOCK_SIZE bs) {
 const MACROBLOCKD *xd = &x->e_mbd;
 int stride = x->plane[0].src.stride;
 const uint8_t *buf = x->plane[0].src.buf;
 const int num_8x8_cols = block_size_wide[bs] / 8;
 const int num_8x8_rows = block_size_high[bs] / 8;
 const int hbd = is_cur_buf_hbd(xd);

 int64_t var = av1_haar_ac_sad_mxn_uint8_input(buf, stride, hbd, num_8x8_rows,
                                               num_8x8_cols);

 return (unsigned int)((uint64_t)var * 256) >> num_pels_log2_lookup[bs];
}

static double log_block_wavelet_energy(const MACROBLOCK *x, BLOCK_SIZE bs) {
 unsigned int haar_sad = haar_ac_energy(x, bs);
 return log1p(haar_sad);
}

int av1_block_wavelet_energy_level(const AV1_COMP *cpi, const MACROBLOCK *x,
                                  BLOCK_SIZE bs) {
 double energy, energy_midpoint;
 energy_midpoint = (is_stat_consumption_stage_twopass(cpi))
                       ? cpi->twopass_frame.frame_avg_haar_energy
                       : DEFAULT_E_MIDPOINT;
 energy = log_block_wavelet_energy(x, bs) - energy_midpoint;
 return clamp((int)round(energy), ENERGY_MIN, ENERGY_MAX);
}

int av1_compute_q_from_energy_level_deltaq_mode(const AV1_COMP *const cpi,
                                               int block_var_level) {
 int rate_level;
 const AV1_COMMON *const cm = &cpi->common;

 if (DELTA_Q_PERCEPTUAL_MODULATION == 1) {
   ENERGY_IN_BOUNDS(block_var_level);
   rate_level = SEGMENT_ID(block_var_level);
 } else {
   rate_level = block_var_level;
 }
 const int base_qindex = cm->quant_params.base_qindex;
 int qindex_delta =
     av1_compute_qdelta_by_rate(cpi, cm->current_frame.frame_type, base_qindex,
                                deltaq_rate_ratio[rate_level]);

 if ((base_qindex != 0) && ((base_qindex + qindex_delta) == 0)) {
   qindex_delta = -base_qindex + 1;
 }
 return base_qindex + qindex_delta;
}

// Comparer used by qsort() to order an array of unsigned int from smallest to
// largest.
static int comp_unsigned_int(const void *a, const void *b) {
 unsigned int arg1 = *(const unsigned int *)a;
 unsigned int arg2 = *(const unsigned int *)b;

 return (arg1 > arg2) - (arg1 < arg2);
}

unsigned int av1_get_variance_boost_block_variance(const AV1_COMP *cpi,
                                                  const MACROBLOCK *x) {
#define SUPERBLOCK_SIZE 64
#define SUBBLOCK_SIZE 8
#define SUBBLOCKS_IN_SB_DIM (SUPERBLOCK_SIZE / SUBBLOCK_SIZE)
#define SUBBLOCKS_IN_SB (SUBBLOCKS_IN_SB_DIM * SUBBLOCKS_IN_SB_DIM)
#define SUBBLOCKS_IN_OCTILE (SUBBLOCKS_IN_SB / 8)
 DECLARE_ALIGNED(16, static const uint16_t,
                 av1_highbd_all_zeros[SUBBLOCK_SIZE]) = { 0 };
 DECLARE_ALIGNED(16, static const uint8_t,
                 av1_all_zeros[SUBBLOCK_SIZE]) = { 0 };

 const MACROBLOCKD *xd = &x->e_mbd;
 unsigned int sse;
 // Octile is currently hard-coded and optimized for still pictures. In the
 // future, we might want to expose this as a parameter that can be fine-tuned
 // by the caller.
 // An octile of 5 was chosen because it was found to strike the best balance
 // between quality and consistency. Lower octiles tend to score lower in
 // SSIMU2, while higher octiles tend to harm subjective quality consistency,
 // especially in <1 MP images.
 const int octile = 5;
 const uint8_t *all_zeros = is_cur_buf_hbd(xd)
                                ? CONVERT_TO_BYTEPTR(av1_highbd_all_zeros)
                                : av1_all_zeros;
 unsigned int variances[SUBBLOCKS_IN_SB];

 // Calculate subblock variances.
 aom_variance_fn_t vf = cpi->ppi->fn_ptr[BLOCK_8X8].vf;
 for (int subb_i = 0; subb_i < SUBBLOCKS_IN_SB_DIM; subb_i++) {
   int i = subb_i * SUBBLOCK_SIZE;
   for (int subb_j = 0; subb_j < SUBBLOCKS_IN_SB_DIM; subb_j++) {
     int j = subb_j * SUBBLOCK_SIZE;
     // Truncating values to integers (i.e. the 64 term) was found to perform
     // better than rounding, or returning them as doubles.
     variances[subb_i * SUBBLOCKS_IN_SB_DIM + subb_j] =
         vf(x->plane[0].src.buf + i * x->plane[0].src.stride + j,
            x->plane[0].src.stride, all_zeros, 0, &sse) /
         64;
   }
 }

 // Order the 8x8 SB values from smallest to largest variance.
 qsort(variances, SUBBLOCKS_IN_SB, sizeof(unsigned int), comp_unsigned_int);

 // Sample three 8x8 variance values: at the specified octile, previous octile,
 // and next octile. Make sure we use the last subblock in each octile as the
 // representative of the octile.
 assert(octile >= 1 && octile <= 8);
 const int middle_index = octile * SUBBLOCKS_IN_OCTILE - 1;
 const int lower_index =
     AOMMAX(SUBBLOCKS_IN_OCTILE - 1, middle_index - SUBBLOCKS_IN_OCTILE);
 const int upper_index =
     AOMMIN(SUBBLOCKS_IN_SB - 1, middle_index + SUBBLOCKS_IN_OCTILE);

 // Weigh the three variances in a 1:2:1 ratio, with rounding (the +2 term).
 // This allows for smoother delta-q transitions among superblocks with
 // mixed-variance features.
 const unsigned int variance =
     (variances[lower_index] + (variances[middle_index] * 2) +
      variances[upper_index] + 2) /
     4;

 return variance;
}
#endif  // !CONFIG_REALTIME_ONLY

int av1_log_block_var(const AV1_COMP *cpi, const MACROBLOCK *x, BLOCK_SIZE bs) {
 DECLARE_ALIGNED(16, static const uint16_t,
                 av1_highbd_all_zeros[MAX_SB_SIZE]) = { 0 };
 DECLARE_ALIGNED(16, static const uint8_t, av1_all_zeros[MAX_SB_SIZE]) = { 0 };

 // This function returns a score for the blocks local variance as calculated
 // by: sum of the log of the (4x4 variances) of each subblock to the current
 // block (x,bs)
 // * 32 / number of pixels in the block_size.
 // This is used for segmentation because to avoid situations in which a large
 // block with a gentle gradient gets marked high variance even though each
 // subblock has a low variance.   This allows us to assign the same segment
 // number for the same sorts of area regardless of how the partitioning goes.

 const MACROBLOCKD *xd = &x->e_mbd;
 double var = 0;
 unsigned int sse;
 int i, j;

 int right_overflow =
     (xd->mb_to_right_edge < 0) ? ((-xd->mb_to_right_edge) >> 3) : 0;
 int bottom_overflow =
     (xd->mb_to_bottom_edge < 0) ? ((-xd->mb_to_bottom_edge) >> 3) : 0;

 const int bw = MI_SIZE * mi_size_wide[bs] - right_overflow;
 const int bh = MI_SIZE * mi_size_high[bs] - bottom_overflow;

 aom_variance_fn_t vf = cpi->ppi->fn_ptr[BLOCK_4X4].vf;
 for (i = 0; i < bh; i += 4) {
   for (j = 0; j < bw; j += 4) {
     if (is_cur_buf_hbd(xd)) {
       var += log1p(vf(x->plane[0].src.buf + i * x->plane[0].src.stride + j,
                       x->plane[0].src.stride,
                       CONVERT_TO_BYTEPTR(av1_highbd_all_zeros), 0, &sse) /
                    16.0);
     } else {
       var += log1p(vf(x->plane[0].src.buf + i * x->plane[0].src.stride + j,
                       x->plane[0].src.stride, av1_all_zeros, 0, &sse) /
                    16.0);
     }
   }
 }
 // Use average of 4x4 log variance. The range for 8 bit 0 - 9.704121561.
 var /= (bw / 4 * bh / 4);
 if (var > 7) var = 7;

 return (int)(var);
}