Move the QP scaling thresholds to the relevant encoders

webrtc/modules/video_coding/codecs/h264/h264_video_toolbox_encoder.mm

 /*
  *  Copyright (c) 2015 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 15 matching lines @@
 #include "webrtc/base/logging.h"
 #include "webrtc/modules/video_coding/codecs/h264/h264_video_toolbox_nalu.h"
 #include "webrtc/system_wrappers/include/clock.h"
 
 namespace internal {
 
 // The ratio between kVTCompressionPropertyKey_DataRateLimits and
 // kVTCompressionPropertyKey_AverageBitRate. The data rate limit is set higher
 // than the average bit rate to avoid undershooting the target.
 const float kLimitToAverageBitRateFactor = 1.5f;
+// These thresholds deviate from the default h264 QP thresholds, as they
+// have been found to work better on devices that support VideoToolbox
+const int kLowH264QpThreshold = 28;
+const int kHighH264QpThreshold = 39;
 
 // Convenience function for creating a dictionary.
 inline CFDictionaryRef CreateCFDictionary(CFTypeRef* keys,
                                           CFTypeRef* values,
                                           size_t size) {
   return CFDictionaryCreate(kCFAllocatorDefault, keys, values, size,
                             &kCFTypeDictionaryKeyCallBacks,
                             &kCFTypeDictionaryValueCallBacks);
 }
 
@@ skipping 179 matching lines @@
   DestroyCompressionSession();
 }
 
 int H264VideoToolboxEncoder::InitEncode(const VideoCodec* codec_settings,
                                         int number_of_cores,
                                         size_t max_payload_size) {
   RTC_DCHECK(codec_settings);
   RTC_DCHECK_EQ(codec_settings->codecType, kVideoCodecH264);
   {
     rtc::CritScope lock(&quality_scaler_crit_);
-    quality_scaler_.Init(QualityScaler::kLowH264QpThreshold,
-                         QualityScaler::kBadH264QpThreshold,
+    quality_scaler_.Init(internal::kLowH264QpThreshold,
+                         internal::kHighH264QpThreshold,
                          codec_settings->startBitrate, codec_settings->width,
                          codec_settings->height, codec_settings->maxFramerate);
     QualityScaler::Resolution res = quality_scaler_.GetScaledResolution();
     // TODO(tkchin): We may need to enforce width/height dimension restrictions
     // to match what the encoder supports.
     width_ = res.width;
     height_ = res.height;
   }
   // We can only set average bitrate on the HW encoder.
   target_bitrate_bps_ = codec_settings->startBitrate;
@@ skipping 380 matching lines @@
   if (result != 0) {
     LOG(LS_ERROR) << "Encode callback failed: " << result;
     return;
   }
   bitrate_adjuster_.Update(frame._size);
 }
 
 }  // namespace webrtc
 
 #endif  // defined(WEBRTC_VIDEO_TOOLBOX_SUPPORTED)