Tune QP-based quality thresholds.

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;
-static const int kMeasureSecondsDownscale = 3;
 // 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;
 }  // namespace
 
 QualityScaler::QualityScaler()
     : low_qp_threshold_(-1), framerate_down_(false) {}
@@ skipping 147 matching lines @@
     downscale_shift_ = 0;
   if (!up) {
     // Hit first downscale, start using a slower threshold for going up.
     measure_seconds_upscale_ = kMeasureSecondsUpscale;
     UpdateSampleCounts();
   }
   ClearSamples();
 }
 
 }  // namespace webrtc