1 files changed, 126 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/video_coding/chain_diff_calculator_unittest.cc b/third_party/libwebrtc/modules/video_coding/chain_diff_calculator_unittest.cc
new file mode 100644
index 0000000000..efd09bd888
--- /dev/null
+++ b/third_party/libwebrtc/modules/video_coding/chain_diff_calculator_unittest.cc
@@ -0,0 +1,126 @@
+/*
+ *  Copyright (c) 2020 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "modules/video_coding/chain_diff_calculator.h"
+
+#include "test/gmock.h"
+#include "test/gtest.h"
+
+namespace webrtc {
+namespace {
+
+using ::testing::ElementsAre;
+using ::testing::SizeIs;
+
+TEST(ChainDiffCalculatorTest, SingleChain) {
+  // Simulate  a stream with 2 temporal layer where chain
+  // protects temporal layer 0.
+  ChainDiffCalculator calculator;
+  // Key frame.
+  calculator.Reset({true});
+  EXPECT_THAT(calculator.From(1, {true}), ElementsAre(0));
+  // T1 delta frame.
+  EXPECT_THAT(calculator.From(2, {false}), ElementsAre(1));
+  // T0 delta frame.
+  EXPECT_THAT(calculator.From(3, {true}), ElementsAre(2));
+}
+
+TEST(ChainDiffCalculatorTest, TwoChainsFullSvc) {
+  // Simulate a full svc stream with 2 spatial and 2 temporal layers.
+  // chains are protecting temporal layers 0.
+  ChainDiffCalculator calculator;
+  // S0 Key frame.
+  calculator.Reset({true, true});
+  EXPECT_THAT(calculator.From(1, {true, true}), ElementsAre(0, 0));
+  // S1 Key frame.
+  EXPECT_THAT(calculator.From(2, {false, true}), ElementsAre(1, 1));
+  // S0T1 delta frame.
+  EXPECT_THAT(calculator.From(3, {false, false}), ElementsAre(2, 1));
+  // S1T1 delta frame.
+  EXPECT_THAT(calculator.From(4, {false, false}), ElementsAre(3, 2));
+  // S0T0 delta frame.
+  EXPECT_THAT(calculator.From(5, {true, true}), ElementsAre(4, 3));
+  // S1T0 delta frame.
+  EXPECT_THAT(calculator.From(6, {false, true}), ElementsAre(1, 1));
+}
+
+TEST(ChainDiffCalculatorTest, TwoChainsKSvc) {
+  // Simulate a k-svc stream with 2 spatial and 2 temporal layers.
+  // chains are protecting temporal layers 0.
+  ChainDiffCalculator calculator;
+  // S0 Key frame.
+  calculator.Reset({true, true});
+  EXPECT_THAT(calculator.From(1, {true, true}), ElementsAre(0, 0));
+  // S1 Key frame.
+  EXPECT_THAT(calculator.From(2, {false, true}), ElementsAre(1, 1));
+  // S0T1 delta frame.
+  EXPECT_THAT(calculator.From(3, {false, false}), ElementsAre(2, 1));
+  // S1T1 delta frame.
+  EXPECT_THAT(calculator.From(4, {false, false}), ElementsAre(3, 2));
+  // S0T0 delta frame.
+  EXPECT_THAT(calculator.From(5, {true, false}), ElementsAre(4, 3));
+  // S1T0 delta frame.
+  EXPECT_THAT(calculator.From(6, {false, true}), ElementsAre(1, 4));
+}
+
+TEST(ChainDiffCalculatorTest, TwoChainsSimulcast) {
+  // Simulate a k-svc stream with 2 spatial and 2 temporal layers.
+  // chains are protecting temporal layers 0.
+  ChainDiffCalculator calculator;
+  // S0 Key frame.
+  calculator.Reset({true, false});
+  EXPECT_THAT(calculator.From(1, {true, false}), ElementsAre(0, 0));
+  // S1 Key frame.
+  calculator.Reset({false, true});
+  EXPECT_THAT(calculator.From(2, {false, true}), ElementsAre(1, 0));
+  // S0T1 delta frame.
+  EXPECT_THAT(calculator.From(3, {false, false}), ElementsAre(2, 1));
+  // S1T1 delta frame.
+  EXPECT_THAT(calculator.From(4, {false, false}), ElementsAre(3, 2));
+  // S0T0 delta frame.
+  EXPECT_THAT(calculator.From(5, {true, false}), ElementsAre(4, 3));
+  // S1T0 delta frame.
+  EXPECT_THAT(calculator.From(6, {false, true}), ElementsAre(1, 4));
+}
+
+TEST(ChainDiffCalculatorTest, ResilentToAbsentChainConfig) {
+  ChainDiffCalculator calculator;
+  // Key frame.
+  calculator.Reset({true, false});
+  EXPECT_THAT(calculator.From(1, {true, false}), ElementsAre(0, 0));
+  // Forgot to set chains. should still return 2 chain_diffs.
+  EXPECT_THAT(calculator.From(2, {}), ElementsAre(1, 0));
+  // chain diffs for next frame(s) are undefined, but still there should be
+  // correct number of them.
+  EXPECT_THAT(calculator.From(3, {true, false}), SizeIs(2));
+  EXPECT_THAT(calculator.From(4, {false, true}), SizeIs(2));
+  // Since previous two frames updated all the chains, can expect what
+  // chain_diffs would be.
+  EXPECT_THAT(calculator.From(5, {false, false}), ElementsAre(2, 1));
+}
+
+TEST(ChainDiffCalculatorTest, ResilentToTooMainChains) {
+  ChainDiffCalculator calculator;
+  // Key frame.
+  calculator.Reset({true, false});
+  EXPECT_THAT(calculator.From(1, {true, false}), ElementsAre(0, 0));
+  // Set wrong number of chains. Expect number of chain_diffs is not changed.
+  EXPECT_THAT(calculator.From(2, {true, true, true}), ElementsAre(1, 0));
+  // chain diffs for next frame(s) are undefined, but still there should be
+  // correct number of them.
+  EXPECT_THAT(calculator.From(3, {true, false}), SizeIs(2));
+  EXPECT_THAT(calculator.From(4, {false, true}), SizeIs(2));
+  // Since previous two frames updated all the chains, can expect what
+  // chain_diffs would be.
+  EXPECT_THAT(calculator.From(5, {false, false}), ElementsAre(2, 1));
+}
+
+}  // namespace
+}  // namespace webrtc