diff --git a/modules/video_coding/generic_encoder.cc b/modules/video_coding/generic_encoder.cc
index ec4795254f..fd642fd24a 100644
--- a/modules/video_coding/generic_encoder.cc
+++ b/modules/video_coding/generic_encoder.cc
@@ -49,6 +49,7 @@ int32_t VCMGenericEncoder::InitEncode(const VideoCodec* settings,
   RTC_DCHECK_RUNS_SERIALIZED(&race_checker_);
   TRACE_EVENT0("webrtc", "VCMGenericEncoder::InitEncode");
   streams_or_svc_num_ = settings->numberOfSimulcastStreams;
+  codec_type_ = settings->codecType;
   if (settings->codecType == kVideoCodecVP9) {
     streams_or_svc_num_ = settings->VP9().numberOfSpatialLayers;
   }
@@ -122,9 +123,16 @@ void VCMGenericEncoder::SetEncoderParameters(const EncoderParameters& params) {
       size_t layer_bitrate_bytes_per_sec =
           params.target_bitrate.GetSpatialLayerSum(i) / 8;
       // VP9 rate control is not yet moved out of VP9Impl. Due to that rates
-      // are not split among spatial layers.
-      if (layer_bitrate_bytes_per_sec == 0)
-        layer_bitrate_bytes_per_sec = params.target_bitrate.get_sum_bps() / 8;
+      // are not split among spatial layers. Use default 1:2:4 bitrate
+      // distribution.
+      // TODO(ilnik): move bitrate per spatial layer calculations out of
+      // vp9_impl.cc and drop the check below.
+      if (codec_type_ == kVideoCodecVP9) {
+        int scaling_factor_num = 1 << i;                          // 1, 2 or 4
+        int scaling_factor_den = (1 << streams_or_svc_num_) - 1;  // 1 + 2 + 4
+        layer_bitrate_bytes_per_sec = params.target_bitrate.get_sum_bps() / 8 *
+                                      scaling_factor_num / scaling_factor_den;
+      }
       vcm_encoded_frame_callback_->OnTargetBitrateChanged(
           layer_bitrate_bytes_per_sec, i);
     }
@@ -223,6 +231,10 @@ void VCMEncodedFrameCallback::OnEncodeStarted(int64_t capture_time_ms,
       rtc::TimeDiff(capture_time_ms, timing_frames_info_[simulcast_svc_idx]
                                          .encode_start_list.back()
                                          .capture_time_ms) >= 0);
+  // If stream is disabled due to low bandwidth OnEncodeStarted still will be
+  // called and have to be ignored.
+  if (timing_frames_info_[simulcast_svc_idx].target_bitrate_bytes_per_sec == 0)
+    return;
   if (timing_frames_info_[simulcast_svc_idx].encode_start_list.size() ==
       kMaxEncodeStartTimeListSize) {
     RTC_LOG(LS_WARNING) << "Too many frames in the encode_start_list."
@@ -279,6 +291,9 @@ EncodedImageCallback::Result VCMEncodedFrameCallback::OnEncodedImage(
         encode_start_ms.emplace(
             encode_start_list->front().encode_start_time_ms);
         encode_start_list->pop_front();
+      } else {
+        LOG(LS_WARNING) << "Frame with no encode started time recordings. "
+                           "Encoder may be reordering frames.";
       }
 
       size_t target_bitrate =
diff --git a/modules/video_coding/generic_encoder.h b/modules/video_coding/generic_encoder.h
index 878588dd4c..dc94e4aae5 100644
--- a/modules/video_coding/generic_encoder.h
+++ b/modules/video_coding/generic_encoder.h
@@ -135,7 +135,8 @@ class VCMGenericEncoder {
   const bool internal_source_;
   rtc::CriticalSection params_lock_;
   EncoderParameters encoder_params_ RTC_GUARDED_BY(params_lock_);
-  size_t streams_or_svc_num_;
+  size_t streams_or_svc_num_ RTC_GUARDED_BY(race_checker_);
+  VideoCodecType codec_type_ RTC_GUARDED_BY(race_checker_);
 };
 
 }  // namespace webrtc
diff --git a/modules/video_coding/generic_encoder_unittest.cc b/modules/video_coding/generic_encoder_unittest.cc
index caada6e720..48c152f32a 100644
--- a/modules/video_coding/generic_encoder_unittest.cc
+++ b/modules/video_coding/generic_encoder_unittest.cc
@@ -185,6 +185,7 @@ TEST(TestVCMEncodedFrameCallback, NoTimingFrameIfNoEncodeStartTime) {
   VideoCodec::TimingFrameTriggerThresholds thresholds;
   thresholds.delay_ms = 1;  // Make all frames timing frames.
   callback.SetTimingFramesThresholds(thresholds);
+  callback.OnTargetBitrateChanged(500, 0);
 
   // Verify a single frame works with encode start time set.
   callback.OnEncodeStarted(timestamp, 0);
@@ -208,6 +209,8 @@ TEST(TestVCMEncodedFrameCallback, NotifiesAboutDroppedFrames) {
   codec_specific.codecSpecific.generic.simulcast_idx = 0;
   FakeEncodedImageCallback sink;
   VCMEncodedFrameCallback callback(&sink, nullptr);
+  // Any non-zero bitrate needed to be set before the first frame.
+  callback.OnTargetBitrateChanged(500, 0);
   callback.OnEncodeStarted(timestamp1, 0);
   EXPECT_EQ(0u, sink.GetNumFramesDropped());
   image.capture_time_ms_ = timestamp1;