Make prior H264 QP adjustments iOS specific.

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.
  */
 
@@ skipping 20 matching lines @@
 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;
 
+#if defined(WEBRTC_IOS)
 const int QualityScaler::kLowH264QpThreshold = 32;
 const int QualityScaler::kBadH264QpThreshold = 42;
+#else
+const int QualityScaler::kLowH264QpThreshold = 22;
+const int QualityScaler::kBadH264QpThreshold = 35;
+#endif
 
 QualityScaler::QualityScaler() : low_qp_threshold_(-1) {}
 
 void QualityScaler::Init(int low_qp_threshold,
                          int high_qp_threshold,
                          int initial_bitrate_kbps,
                          int width,
                          int height,
                          int fps) {
   ClearSamples();
@@ skipping 124 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