Move kMinPixelsPerFrame constant in VideoStreamEncoder to VideoEncoder::ScalingSettings.

webrtc/modules/video_coding/codecs/vp8/vp8_impl.cc

Index: webrtc/modules/video_coding/codecs/vp8/vp8_impl.cc
diff --git a/webrtc/modules/video_coding/codecs/vp8/vp8_impl.cc b/webrtc/modules/video_coding/codecs/vp8/vp8_impl.cc
index 3f9f879befcf75e8f4f682a3997853653a013401..5933073a3fe68739040ca0f0e13a9ee7edb246a5 100644
--- a/webrtc/modules/video_coding/codecs/vp8/vp8_impl.cc
+++ b/webrtc/modules/video_coding/codecs/vp8/vp8_impl.cc
@@ -42,6 +42,8 @@ namespace {
 
 const char kVp8PostProcArmFieldTrial[] = "WebRTC-VP8-Postproc-Arm";
 const char kVp8GfBoostFieldTrial[] = "WebRTC-VP8-GfBoost";
+const char kVp8ForceFallbackEncoderFieldTrial[] =
+    "WebRTC-VP8-Forced-Fallback-Encoder";
 
 const int kTokenPartitions = VP8_ONE_TOKENPARTITION;
 enum { kVp8ErrorPropagationTh = 30 };
@@ -110,6 +112,31 @@ int NumStreamsDisabled(const std::vector<bool>& streams) {
   return num_disabled;
 }
 
+rtc::Optional<int> GetForcedFallbackMinPixelsFromFieldTrialGroup() {
+  if (!webrtc::field_trial::IsEnabled(kVp8ForceFallbackEncoderFieldTrial))
+    return rtc::Optional<int>();
+
+  std::string group =
+      webrtc::field_trial::FindFullName(kVp8ForceFallbackEncoderFieldTrial);
+  if (group.empty())
+    return rtc::Optional<int>();
+
+  int low_kbps;
+  int high_kbps;
+  int min_low_ms;
+  int min_pixels;
+  if (sscanf(group.c_str(), "Enabled-%d,%d,%d,%d", &low_kbps, &high_kbps,
+             &min_low_ms, &min_pixels) != 4) {
+    return rtc::Optional<int>();
+  }
+
+  if (min_low_ms <= 0 || min_pixels <= 0 || low_kbps <= 0 ||
+      high_kbps <= low_kbps) {
+    return rtc::Optional<int>();
+  }
+  return rtc::Optional<int>(min_pixels);
+}
+
 bool GetGfBoostPercentageFromFieldTrialGroup(int* boost_percentage) {
   std::string group = webrtc::field_trial::FindFullName(kVp8GfBoostFieldTrial);
   if (group.empty())
@@ -181,6 +208,7 @@ vpx_enc_frame_flags_t VP8EncoderImpl::EncodeFlags(
 
 VP8EncoderImpl::VP8EncoderImpl()
     : use_gf_boost_(webrtc::field_trial::IsEnabled(kVp8GfBoostFieldTrial)),
+      min_pixels_per_frame_(GetForcedFallbackMinPixelsFromFieldTrialGroup()),
       encoded_complete_callback_(nullptr),
       inited_(false),
       timestamp_(0),
@@ -935,6 +963,10 @@ VideoEncoder::ScalingSettings VP8EncoderImpl::GetScalingSettings() const {
   const bool enable_scaling = encoders_.size() == 1 &&
                               configurations_[0].rc_dropframe_thresh > 0 &&
                               codec_.VP8().automaticResizeOn;
+  if (enable_scaling && min_pixels_per_frame_) {
+    return VideoEncoder::ScalingSettings(enable_scaling,
+                                         *min_pixels_per_frame_);
+  }
   return VideoEncoder::ScalingSettings(enable_scaling);
 }