modules/video_processing: refactor interface->include + more.

Moved/renamed:
webrtc/modules/video_processing/main/interface -> webrtc/modules/video_processing/include
webrtc/modules/video_processing/main/source/* -> webrtc/modules/video_processing
webrtc/modules/video_processing/main/test/unit_test -> webrtc/modules/video_processing/test

No downstream code seems to use this module.

BUG=webrtc:5095
TESTED=git cl try -c --bot=android_compile_rel --bot=linux_compile_rel --bot=win_compile_rel --bot=mac_compile_rel --bot=ios_rel --bot=linux_gn_rel --bot=win_x64_gn_rel --bot=mac_x64_gn_rel --bot=android_gn_rel -m tryserver.webrtc
R=pbos@webrtc.org, stefan@webrtc.org

Review URL: https://codereview.webrtc.org/1410663004 .

Cr-Commit-Position: refs/heads/master@{#10697}

webrtc/modules/video_processing/brightness_detection.cc

@@ -0,0 +1,133 @@
+/*
+ *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/video_processing/include/video_processing.h"
+#include "webrtc/modules/video_processing/brightness_detection.h"
+
+#include <math.h>
+
+namespace webrtc {
+
+VPMBrightnessDetection::VPMBrightnessDetection() {
+  Reset();
+}
+
+VPMBrightnessDetection::~VPMBrightnessDetection() {}
+
+void VPMBrightnessDetection::Reset() {
+  frame_cnt_bright_ = 0;
+  frame_cnt_dark_ = 0;
+}
+
+int32_t VPMBrightnessDetection::ProcessFrame(
+    const VideoFrame& frame,
+    const VideoProcessingModule::FrameStats& stats) {
+  if (frame.IsZeroSize()) {
+    return VPM_PARAMETER_ERROR;
+  }
+  int width = frame.width();
+  int height = frame.height();
+
+  if (!VideoProcessingModule::ValidFrameStats(stats)) {
+    return VPM_PARAMETER_ERROR;
+  }
+
+  const uint8_t frame_cnt_alarm = 2;
+
+  // Get proportion in lowest bins.
+  uint8_t low_th = 20;
+  float prop_low = 0;
+  for (uint32_t i = 0; i < low_th; i++) {
+    prop_low += stats.hist[i];
+  }
+  prop_low /= stats.num_pixels;
+
+  // Get proportion in highest bins.
+  unsigned char high_th = 230;
+  float prop_high = 0;
+  for (uint32_t i = high_th; i < 256; i++) {
+    prop_high += stats.hist[i];
+  }
+  prop_high /= stats.num_pixels;
+
+  if (prop_high < 0.4) {
+    if (stats.mean < 90 || stats.mean > 170) {
+      // Standard deviation of Y
+      const uint8_t* buffer = frame.buffer(kYPlane);
+      float std_y = 0;
+      for (int h = 0; h < height; h += (1 << stats.subSamplHeight)) {
+        int row = h*width;
+        for (int w = 0; w < width; w += (1 << stats.subSamplWidth)) {
+          std_y += (buffer[w + row] - stats.mean) * (buffer[w + row] -
+              stats.mean);
+        }
+      }
+      std_y = sqrt(std_y / stats.num_pixels);
+
+      // Get percentiles.
+      uint32_t sum = 0;
+      uint32_t median_y = 140;
+      uint32_t perc05 = 0;
+      uint32_t perc95 = 255;
+      float pos_perc05 = stats.num_pixels * 0.05f;
+      float pos_median = stats.num_pixels * 0.5f;
+      float posPerc95 = stats.num_pixels * 0.95f;
+      for (uint32_t i = 0; i < 256; i++) {
+        sum += stats.hist[i];
+        if (sum < pos_perc05) perc05 = i;     // 5th perc.
+        if (sum < pos_median) median_y = i;    // 50th perc.
+        if (sum < posPerc95)
+          perc95 = i;     // 95th perc.
+        else
+          break;
+      }
+
+        // Check if image is too dark
+        if ((std_y < 55) && (perc05 < 50))  {
+          if (median_y < 60 || stats.mean < 80 ||  perc95 < 130 ||
+              prop_low > 0.20) {
+            frame_cnt_dark_++;
+          } else {
+            frame_cnt_dark_ = 0;
+          }
+        } else {
+          frame_cnt_dark_ = 0;
+        }
+
+        // Check if image is too bright
+        if ((std_y < 52) && (perc95 > 200) && (median_y > 160)) {
+          if (median_y > 185 || stats.mean > 185 || perc05 > 140 ||
+              prop_high > 0.25) {
+            frame_cnt_bright_++;
+          } else {
+            frame_cnt_bright_ = 0;
+          }
+        } else {
+          frame_cnt_bright_ = 0;
+        }
+    } else {
+      frame_cnt_dark_ = 0;
+      frame_cnt_bright_ = 0;
+    }
+  } else {
+    frame_cnt_bright_++;
+    frame_cnt_dark_ = 0;
+  }
+
+  if (frame_cnt_dark_ > frame_cnt_alarm) {
+    return VideoProcessingModule::kDarkWarning;
+  } else if (frame_cnt_bright_ > frame_cnt_alarm) {
+    return VideoProcessingModule::kBrightWarning;
+  } else {
+    return VideoProcessingModule::kNoWarning;
+  }
+}
+
+}  // namespace webrtc