1/*
2 *  Copyright (c) 2011 The WebRTC 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 "webrtc/modules/video_processing/main/interface/video_processing.h"
12#include "webrtc/modules/video_processing/main/source/brightness_detection.h"
13
14#include <math.h>
15
16namespace webrtc {
17
18VPMBrightnessDetection::VPMBrightnessDetection() :
19    id_(0) {
20  Reset();
21}
22
23VPMBrightnessDetection::~VPMBrightnessDetection() {}
24
25int32_t VPMBrightnessDetection::ChangeUniqueId(const int32_t id) {
26  id_ = id;
27  return VPM_OK;
28}
29
30void VPMBrightnessDetection::Reset() {
31  frame_cnt_bright_ = 0;
32  frame_cnt_dark_ = 0;
33}
34
35int32_t VPMBrightnessDetection::ProcessFrame(
36    const I420VideoFrame& frame,
37    const VideoProcessingModule::FrameStats& stats) {
38  if (frame.IsZeroSize()) {
39    return VPM_PARAMETER_ERROR;
40  }
41  int width = frame.width();
42  int height = frame.height();
43
44  if (!VideoProcessingModule::ValidFrameStats(stats)) {
45    return VPM_PARAMETER_ERROR;
46  }
47
48  const uint8_t frame_cnt_alarm = 2;
49
50  // Get proportion in lowest bins.
51  uint8_t low_th = 20;
52  float prop_low = 0;
53  for (uint32_t i = 0; i < low_th; i++) {
54    prop_low += stats.hist[i];
55  }
56  prop_low /= stats.num_pixels;
57
58  // Get proportion in highest bins.
59  unsigned char high_th = 230;
60  float prop_high = 0;
61  for (uint32_t i = high_th; i < 256; i++) {
62    prop_high += stats.hist[i];
63  }
64  prop_high /= stats.num_pixels;
65
66  if (prop_high < 0.4) {
67    if (stats.mean < 90 || stats.mean > 170) {
68      // Standard deviation of Y
69      const uint8_t* buffer = frame.buffer(kYPlane);
70      float std_y = 0;
71      for (int h = 0; h < height; h += (1 << stats.subSamplHeight)) {
72        int row = h*width;
73        for (int w = 0; w < width; w += (1 << stats.subSamplWidth)) {
74          std_y += (buffer[w + row] - stats.mean) * (buffer[w + row] -
75              stats.mean);
76        }
77      }
78      std_y = sqrt(std_y / stats.num_pixels);
79
80      // Get percentiles.
81      uint32_t sum = 0;
82      uint32_t median_y = 140;
83      uint32_t perc05 = 0;
84      uint32_t perc95 = 255;
85      float pos_perc05 = stats.num_pixels * 0.05f;
86      float pos_median = stats.num_pixels * 0.5f;
87      float posPerc95 = stats.num_pixels * 0.95f;
88      for (uint32_t i = 0; i < 256; i++) {
89        sum += stats.hist[i];
90        if (sum < pos_perc05) perc05 = i;     // 5th perc.
91        if (sum < pos_median) median_y = i;    // 50th perc.
92        if (sum < posPerc95)
93          perc95 = i;     // 95th perc.
94        else
95          break;
96      }
97
98        // Check if image is too dark
99        if ((std_y < 55) && (perc05 < 50))  {
100          if (median_y < 60 || stats.mean < 80 ||  perc95 < 130 ||
101              prop_low > 0.20) {
102            frame_cnt_dark_++;
103          } else {
104            frame_cnt_dark_ = 0;
105          }
106        } else {
107          frame_cnt_dark_ = 0;
108        }
109
110        // Check if image is too bright
111        if ((std_y < 52) && (perc95 > 200) && (median_y > 160)) {
112          if (median_y > 185 || stats.mean > 185 || perc05 > 140 ||
113              prop_high > 0.25) {
114            frame_cnt_bright_++;
115          } else {
116            frame_cnt_bright_ = 0;
117          }
118        } else {
119          frame_cnt_bright_ = 0;
120        }
121    } else {
122      frame_cnt_dark_ = 0;
123      frame_cnt_bright_ = 0;
124    }
125  } else {
126    frame_cnt_bright_++;
127    frame_cnt_dark_ = 0;
128  }
129
130  if (frame_cnt_dark_ > frame_cnt_alarm) {
131    return VideoProcessingModule::kDarkWarning;
132  } else if (frame_cnt_bright_ > frame_cnt_alarm) {
133    return VideoProcessingModule::kBrightWarning;
134  } else {
135    return VideoProcessingModule::kNoWarning;
136  }
137}
138
139}  // namespace webrtc
140