1/*
2 *  Copyright (c) 2014 The WebM project authors. All Rights Reserved.
3 *
4 *  Use of this source code is governed by a BSD-style license
5 *  that can be found in the LICENSE file in the root of the source
6 *  tree. An additional intellectual property rights grant can be found
7 *  in the file PATENTS.  All contributing project authors may
8 *  be found in the AUTHORS file in the root of the source tree.
9 */
10
11#include <limits.h>
12#include <math.h>
13
14#include "vp9/common/vp9_seg_common.h"
15
16#include "vp9/encoder/vp9_segmentation.h"
17
18static const double in_frame_q_adj_ratio[MAX_SEGMENTS] =
19  {1.0, 2.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0};
20
21void vp9_setup_in_frame_q_adj(VP9_COMP *cpi) {
22  VP9_COMMON *const cm = &cpi->common;
23  struct segmentation *const seg = &cm->seg;
24
25  // Make SURE use of floating point in this function is safe.
26  vp9_clear_system_state();
27
28  if (cm->frame_type == KEY_FRAME ||
29      cpi->refresh_alt_ref_frame ||
30      (cpi->refresh_golden_frame && !cpi->rc.is_src_frame_alt_ref)) {
31    int segment;
32
33    // Clear down the segment map.
34    vpx_memset(cpi->segmentation_map, 0, cm->mi_rows * cm->mi_cols);
35
36    // Clear down the complexity map used for rd.
37    vpx_memset(cpi->complexity_map, 0, cm->mi_rows * cm->mi_cols);
38
39    vp9_enable_segmentation(seg);
40    vp9_clearall_segfeatures(seg);
41
42    // Select delta coding method.
43    seg->abs_delta = SEGMENT_DELTADATA;
44
45    // Segment 0 "Q" feature is disabled so it defaults to the baseline Q.
46    vp9_disable_segfeature(seg, 0, SEG_LVL_ALT_Q);
47
48    // Use some of the segments for in frame Q adjustment.
49    for (segment = 1; segment < 2; segment++) {
50      const int qindex_delta =
51          vp9_compute_qdelta_by_rate(&cpi->rc, cm->frame_type, cm->base_qindex,
52                                     in_frame_q_adj_ratio[segment]);
53      vp9_enable_segfeature(seg, segment, SEG_LVL_ALT_Q);
54      vp9_set_segdata(seg, segment, SEG_LVL_ALT_Q, qindex_delta);
55    }
56  }
57}
58
59// Select a segment for the current SB64
60void vp9_select_in_frame_q_segment(VP9_COMP *cpi,
61                                      int mi_row, int mi_col,
62                                      int output_enabled, int projected_rate) {
63  VP9_COMMON *const cm = &cpi->common;
64
65  const int mi_offset = mi_row * cm->mi_cols + mi_col;
66  const int bw = num_8x8_blocks_wide_lookup[BLOCK_64X64];
67  const int bh = num_8x8_blocks_high_lookup[BLOCK_64X64];
68  const int xmis = MIN(cm->mi_cols - mi_col, bw);
69  const int ymis = MIN(cm->mi_rows - mi_row, bh);
70  int complexity_metric = 64;
71  int x, y;
72
73  unsigned char segment;
74
75  if (!output_enabled) {
76    segment = 0;
77  } else {
78    // Rate depends on fraction of a SB64 in frame (xmis * ymis / bw * bh).
79    // It is converted to bits * 256 units.
80    const int target_rate = (cpi->rc.sb64_target_rate * xmis * ymis * 256) /
81                            (bw * bh);
82
83    if (projected_rate < (target_rate / 4)) {
84      segment = 1;
85    } else {
86      segment = 0;
87    }
88
89    if (target_rate > 0) {
90      complexity_metric =
91        clamp((int)((projected_rate * 64) / target_rate), 16, 255);
92    }
93  }
94
95  // Fill in the entires in the segment map corresponding to this SB64.
96  for (y = 0; y < ymis; y++) {
97    for (x = 0; x < xmis; x++) {
98      cpi->segmentation_map[mi_offset + y * cm->mi_cols + x] = segment;
99      cpi->complexity_map[mi_offset + y * cm->mi_cols + x] =
100        (unsigned char)complexity_metric;
101    }
102  }
103}
104