Fix bug in SvcRateAllocator capping to VideoCodec.maxBitrate
When allocating bitrate, some parts of the coded directly uses the bitrate parameter, while others lets it be capped by VideoCodec.maxBitrate. This may result in an inconsistency between expected and actual number of temporal layers, causing a crash.
Even better would be to update VideoCodecInitializer to not create
VideoCodec instances where there's not enough maxBitrate to activate
all spatial layers - but that's a much more complex issue.
Bug: chromium:1423365
Change-Id: Ic74b68261ea6043f1795accdd9864319ab535435
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/298041
Commit-Queue: Erik Språng <sprang@webrtc.org>
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#39593}
diff --git a/modules/video_coding/svc/svc_rate_allocator.cc b/modules/video_coding/svc/svc_rate_allocator.cc
index b6ae0d7..f3514a1 100644
--- a/modules/video_coding/svc/svc_rate_allocator.cc
+++ b/modules/video_coding/svc/svc_rate_allocator.cc
@@ -253,8 +253,7 @@
hysteresis_factor = experiment_settings_.GetVideoHysteresisFactor();
}
- DataRate stable_rate =
- std::min(parameters.total_bitrate, parameters.stable_bitrate);
+ DataRate stable_rate = std::min(total_bitrate, parameters.stable_bitrate);
// First check if bitrate has grown large enough to enable new layers.
size_t num_enabled_with_hysteresis =
FindNumEnabledLayers(stable_rate / hysteresis_factor);
@@ -266,7 +265,7 @@
std::min(last_active_layer_count_, FindNumEnabledLayers(stable_rate));
}
} else {
- num_spatial_layers = FindNumEnabledLayers(parameters.total_bitrate);
+ num_spatial_layers = FindNumEnabledLayers(total_bitrate);
}
last_active_layer_count_ = num_spatial_layers;
diff --git a/modules/video_coding/svc/svc_rate_allocator_unittest.cc b/modules/video_coding/svc/svc_rate_allocator_unittest.cc
index b3a365d..44d1eae 100644
--- a/modules/video_coding/svc/svc_rate_allocator_unittest.cc
+++ b/modules/video_coding/svc/svc_rate_allocator_unittest.cc
@@ -361,6 +361,21 @@
EXPECT_EQ(allocation.GetSpatialLayerSum(2), 0u);
}
+TEST(SvcRateAllocatorTest, CapsAllocationToMaxBitrate) {
+ VideoCodec codec = Configure(1280, 720, 3, 3, false);
+ codec.maxBitrate = 70; // Cap the overall max bitrate to 70kbps.
+ SvcRateAllocator allocator = SvcRateAllocator(codec);
+
+ // Allocate 3Mbps which should be enough for all layers.
+ VideoBitrateAllocation allocation =
+ allocator.Allocate(VideoBitrateAllocationParameters(3'000'000, 30));
+
+ // The 3Mbps should be capped to 70kbps, so only first layer is active.
+ EXPECT_EQ(allocation.GetSpatialLayerSum(0), 70'000u);
+ EXPECT_EQ(allocation.GetSpatialLayerSum(1), 0u);
+ EXPECT_EQ(allocation.GetSpatialLayerSum(2), 0u);
+}
+
class SvcRateAllocatorTestParametrizedContentType
: public ::testing::Test,
public ::testing::WithParamInterface<bool> {
