Move kMinPixelsPerFrame constant in VideoStreamEncoder to VideoEncoder::ScalingSettings.

webrtc/media/engine/videoencodersoftwarefallbackwrapper.h

 /*
  *  Copyright (c) 2016 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 34 matching lines @@
   bool SupportsNativeHandle() const override;
   ScalingSettings GetScalingSettings() const override;
   const char *ImplementationName() const override;
 
  private:
   bool InitFallbackEncoder();
 
   // If |forced_fallback_possible_| is true:
   // The forced fallback is requested if the target bitrate is below |low_kbps|
   // for more than |min_low_ms| and the input video resolution is not larger
-  // than |kMaxPixels|.
-  // If the bitrate is above |high_kbps|, the forced fallback is requested to
-  // immediately be stopped.
+  // than |kMaxPixelsStart|.
+  // If the bitrate is above |high_kbps| and the resolution is not smaller than
+  // |kMinPixelsStop|, the forced fallback is requested to immediately be
+  // stopped.
   class ForcedFallbackParams {
    public:
     bool ShouldStart(uint32_t bitrate_kbps, const VideoCodec& codec);
-    bool ShouldStop(uint32_t bitrate_kbps) const;
+    bool ShouldStop(uint32_t bitrate_kbps, const VideoCodec& codec) const;
     void Reset() { start_ms.reset(); }
     bool IsValid(const VideoCodec& codec) const {
-      return codec.width * codec.height <= kMaxPixels;
+      return codec.width * codec.height <= kMaxPixelsStart;
     }
     rtc::Optional<int64_t> start_ms;  // Set when bitrate is below |low_kbps|.
     uint32_t low_kbps = 100;
     uint32_t high_kbps = 150;
     int64_t min_low_ms = 10000;
-    const int kMaxPixels = 320 * 240;
+    const int kMaxPixelsStart = 320 * 240;
+    const int kMinPixelsStop = 320 * 180;
   };
 
   bool RequestForcedFallback();
   bool TryReleaseForcedFallbackEncoder();
   bool TryReInitForcedFallbackEncoder();
   void ValidateSettingsForForcedFallback();
   bool IsForcedFallbackActive() const;
 
   // Settings used in the last InitEncode call and used if a dynamic fallback to
   // software is required.
@@ skipping 18 matching lines @@
   std::string fallback_implementation_name_;
   EncodedImageCallback* callback_;
 
   bool forced_fallback_possible_;
   ForcedFallbackParams forced_fallback_;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MEDIA_ENGINE_VIDEOENCODERSOFTWAREFALLBACKWRAPPER_H_