[VP9 SVC] Round spatial layers dimensions to ensure integer scaling factors are used

Bug: webrtc:11652
Change-Id: Id3642d607f62b72a567d521d9874b8588c2ce429
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/176517
Reviewed-by: Erik Språng <sprang@webrtc.org>
Commit-Queue: Ilya Nikolaevskiy <ilnik@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31465}

modules/video_coding/codecs/vp9/svc_config.cc

@@ -79,6 +79,11 @@ std::vector<SpatialLayer> ConfigureSvcNormalVideo(size_t input_width,
   // First active layer must be configured.
   num_spatial_layers = std::max(num_spatial_layers, first_active_layer + 1);
 
+  // Ensure top layer is even enough.
+  int required_divisiblity = 1 << num_spatial_layers;
+  input_width = input_width - input_width % required_divisiblity;
+  input_height = input_height - input_height % required_divisiblity;
+
   for (size_t sl_idx = first_active_layer; sl_idx < num_spatial_layers;
        ++sl_idx) {
     SpatialLayer spatial_layer = {0};

modules/video_coding/video_codec_initializer.cc

@@ -219,6 +219,14 @@ VideoCodec VideoCodecInitializer::VideoEncoderConfigToVideoCodec(
         video_codec.spatialLayers[i] = spatial_layers[i];
       }
 
+      // The top spatial layer dimensions may not be equal to the input
+      // resolution because of the rounding or explicit configuration.
+      // This difference must be propagated to the stream configuration.
+      video_codec.width = spatial_layers.back().width;
+      video_codec.height = spatial_layers.back().height;
+      video_codec.simulcastStream[0].width = spatial_layers.back().width;
+      video_codec.simulcastStream[0].height = spatial_layers.back().height;
+
       // Update layering settings.
       video_codec.VP9()->numberOfSpatialLayers =
           static_cast<unsigned char>(spatial_layers.size());

video/video_stream_encoder.cc

@@ -588,6 +588,13 @@ void VideoStreamEncoder::ReconfigureEncoder() {
     RTC_LOG(LS_ERROR) << "Failed to create encoder configuration.";
   }
 
+  if (encoder_config_.codec_type == kVideoCodecVP9) {
+    // Spatial layers configuration might impose some parity restrictions,
+    // thus some cropping might be needed.
+    crop_width_ = last_frame_info_->width - codec.width;
+    crop_height_ = last_frame_info_->height - codec.height;
+  }
+
   char log_stream_buf[4 * 1024];
   rtc::SimpleStringBuilder log_stream(log_stream_buf);
   log_stream << "ReconfigureEncoder:\n";

video/video_stream_encoder_unittest.cc

@@ -5917,4 +5917,34 @@ TEST_F(VideoStreamEncoderTest, AutomaticAnimationDetection) {
   video_stream_encoder_->Stop();
 }
 
+TEST_F(VideoStreamEncoderTest, ConfiguresVp9SvcAtOddResolutions) {
+  const int kWidth = 720;  // 540p adapted down.
+  const int kHeight = 405;
+  const int kNumFrames = 3;
+  // Works on screenshare mode.
+  ResetEncoder("VP9", /*num_streams=*/1, /*num_temporal_layers=*/1,
+               /*num_spatial_layers=*/2, /*screenshare=*/true);
+
+  video_source_.set_adaptation_enabled(true);
+
+  video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
+      DataRate::BitsPerSec(kTargetBitrateBps),
+      DataRate::BitsPerSec(kTargetBitrateBps),
+      DataRate::BitsPerSec(kTargetBitrateBps), 0, 0, 0);
+
+  VideoFrame frame = CreateFrame(1, kWidth, kHeight);
+
+  // Pass enough frames with the full update to trigger animation detection.
+  for (int i = 0; i < kNumFrames; ++i) {
+    int64_t timestamp_ms =
+        fake_clock_.TimeNanos() / rtc::kNumNanosecsPerMillisec;
+    frame.set_ntp_time_ms(timestamp_ms);
+    frame.set_timestamp_us(timestamp_ms * 1000);
+    video_source_.IncomingCapturedFrame(frame);
+    WaitForEncodedFrame(timestamp_ms);
+  }
+
+  video_stream_encoder_->Stop();
+}
+
 }  // namespace webrtc