Revert "Add QVGA to thresholds for initial quality."

webrtc/modules/video_coding/utility/quality_scaler.cc

 /*
  *  Copyright (c) 2014 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_coding/utility/quality_scaler.h"
 
 namespace webrtc {
 
 namespace {
 static const int kMinFps = 5;
 // Threshold constant used until first downscale (to permit fast rampup).
 static const int kMeasureSecondsFastUpscale = 2;
 static const int kMeasureSecondsUpscale = 5;
 static const int kMeasureSecondsDownscale = 5;
 static const int kFramedropPercentThreshold = 60;
+static const int kHdResolutionThreshold = 700 * 500;
+static const int kHdBitrateThresholdKbps = 500;
 // Min width/height to downscale to, set to not go below QVGA, but with some
 // margin to permit "almost-QVGA" resolutions, such as QCIF.
 static const int kMinDownscaleDimension = 140;
-// Initial resolutions corresponding to a bitrate. Aa bit above their actual
-// values to permit near-VGA and near-QVGA resolutions to use the same
-// mechanism.
-static const int kVgaBitrateThresholdKbps = 500;
-static const int kVgaNumPixels = 700 * 500;  // 640x480
-static const int kQvgaBitrateThresholdKbps = 250;
-static const int kQvgaNumPixels = 400 * 300;  // 320x240
 }  // namespace
 
 // QP thresholds are chosen to be high enough to be hit in practice when quality
 // is good, but also low enough to not cause a flip-flop behavior (e.g. going up
 // in resolution shouldn't give so bad quality that we should go back down).
 
 const int QualityScaler::kLowVp8QpThreshold = 29;
 const int QualityScaler::kBadVp8QpThreshold = 95;
 
 const int QualityScaler::kLowH264QpThreshold = 22;
@@ skipping 10 matching lines @@
   ClearSamples();
   low_qp_threshold_ = low_qp_threshold;
   high_qp_threshold_ = high_qp_threshold;
   downscale_shift_ = 0;
   // Use a faster window for upscaling initially (but be more graceful later).
   // This enables faster initial rampups without risking strong up-down
   // behavior later.
   measure_seconds_upscale_ = kMeasureSecondsFastUpscale;
   const int init_width = width;
   const int init_height = height;
-  if (initial_bitrate_kbps > 0) {
-    int init_num_pixels = width * height;
-    if (initial_bitrate_kbps < kVgaBitrateThresholdKbps)
-      init_num_pixels = kVgaNumPixels;
-    if (initial_bitrate_kbps < kQvgaBitrateThresholdKbps)
-      init_num_pixels = kQvgaNumPixels;
-    while (width * height > init_num_pixels) {
+  // TODO(glaznev): Investigate using thresholds for other resolutions
+  // or threshold tables.
+  if (initial_bitrate_kbps > 0 &&
+      initial_bitrate_kbps < kHdBitrateThresholdKbps) {
+    // Start scaling to roughly VGA.
+    while (width * height > kHdResolutionThreshold) {
       ++downscale_shift_;
       width /= 2;
       height /= 2;
     }
   }
 
   // Zero out width/height so they can be checked against inside
   // UpdateTargetResolution.
   res_.width = res_.height = 0;
   UpdateTargetResolution(init_width, init_height);
@@ skipping 98 matching lines @@
   if (downscale_shift_ < 0)
     downscale_shift_ = 0;
   if (!up) {
     // First downscale hit, start using a slower threshold for going up.
     measure_seconds_upscale_ = kMeasureSecondsUpscale;
     UpdateSampleCounts();
   }
 }
 
 }  // namespace webrtc