Drop frames until specified bitrate is achieved.

webrtc/video/video_quality_test.cc

Index: webrtc/video/video_quality_test.cc
diff --git a/webrtc/video/video_quality_test.cc b/webrtc/video/video_quality_test.cc
index c438274fcaac472a2c7ba64cc45bde8ef21231b0..989892dc8b6990c01f49911f8228189d7ec6045c 100644
--- a/webrtc/video/video_quality_test.cc
+++ b/webrtc/video/video_quality_test.cc
@@ -241,6 +241,7 @@ class VideoAnalyzer : public PacketReceiver,
   void PreEncodeOnFrame(const VideoFrame& video_frame) {
     rtc::CritScope lock(&crit_);
     if (!first_send_timestamp_ && rtp_timestamp_delta_ == 0) {
+      printf("pre-encode: setting first_send_timestamp\n");
       while (frames_.front().timestamp() != video_frame.timestamp()) {
         ++dropped_frames_before_first_encode_;
         frames_.pop_front();
@@ -264,6 +265,7 @@ class VideoAnalyzer : public PacketReceiver,
       rtc::CritScope lock(&crit_);
 
       if (rtp_timestamp_delta_ == 0) {
+        printf("Now setting delta\n");
         rtp_timestamp_delta_ = header.timestamp - *first_send_timestamp_;
         first_send_timestamp_ = rtc::Optional<uint32_t>();
       }
@@ -307,16 +309,18 @@ class VideoAnalyzer : public PacketReceiver,
         // No previous frame rendered, this one was dropped after sending but
         // before rendering.
         ++dropped_frames_before_rendering_;
-        frames_.pop_front();
-        RTC_CHECK(!frames_.empty());
-        continue;
+      } else {
+        AddFrameComparison(frames_.front(), *last_rendered_frame_, true,
+                           render_time_ms);
       }
-      AddFrameComparison(frames_.front(), *last_rendered_frame_, true,
-                         render_time_ms);
       frames_.pop_front();
       RTC_DCHECK(!frames_.empty());
     }
 
+    printf("send_timestamp: %ld\n", send_timestamp);
+    printf("frame_timestamp: %ld\n",
+           wrap_handler_.Unwrap(frames_.front().timestamp()));
+
     VideoFrame reference_frame = frames_.front();
     frames_.pop_front();
     int64_t reference_timestamp =
@@ -326,6 +330,7 @@ class VideoAnalyzer : public PacketReceiver,
       // Look at RTPSender::BuildRTPHeader.
       ++send_timestamp;
     }
+    printf("diff: %ld\n", reference_timestamp - send_timestamp);
     ASSERT_EQ(reference_timestamp, send_timestamp);
 
     AddFrameComparison(reference_frame, video_frame, false, render_time_ms);
@@ -1156,6 +1161,8 @@ void VideoQualityTest::SetupScreenshare() {
 
   // Fill out codec settings.
   video_encoder_config_.content_type = VideoEncoderConfig::ContentType::kScreen;
+  degradation_preference_ =
+      VideoSendStream::DegradationPreference::kMaintainResolution;
   if (params_.video.codec == "VP8") {
     VideoCodecVP8 vp8_settings = VideoEncoder::GetDefaultVp8Settings();
     vp8_settings.denoisingOn = false;
@@ -1309,9 +1316,8 @@ void VideoQualityTest::RunWithAnalyzer(const Params& params) {
   CreateFlexfecStreams();
   CreateVideoStreams();
   analyzer.SetSendStream(video_send_stream_);
-  video_send_stream_->SetSource(
-      analyzer.OutputInterface(),
-      VideoSendStream::DegradationPreference::kBalanced);
+  video_send_stream_->SetSource(analyzer.OutputInterface(),
+                                degradation_preference_);
 
   CreateCapturer();
   rtc::VideoSinkWants wants;
@@ -1453,9 +1459,8 @@ void VideoQualityTest::RunWithRenderers(const Params& params) {
     video_receive_stream = call->CreateVideoReceiveStream(
         video_receive_configs_[stream_id].Copy());
     CreateCapturer();
-    video_send_stream_->SetSource(
-        video_capturer_.get(),
-        VideoSendStream::DegradationPreference::kBalanced);
+    video_send_stream_->SetSource(video_capturer_.get(),
+                                  degradation_preference_);
   }
 
   AudioReceiveStream* audio_receive_stream = nullptr;