Extract common simulcast logic from VP8 wrapper and simulcast adapter

webrtc/modules/video_coding/utility/simulcast_state_unittest.cc

Index: webrtc/modules/video_coding/utility/simulcast_state_unittest.cc
diff --git a/webrtc/modules/video_coding/utility/simulcast_state_unittest.cc b/webrtc/modules/video_coding/utility/simulcast_state_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..aecdd74341e3b58e42a6c06ccb47ba150c6e53e6
--- /dev/null
+++ b/webrtc/modules/video_coding/utility/simulcast_state_unittest.cc
@@ -0,0 +1,304 @@
+/*
+ *  Copyright (c) 2016 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 "webrtc/modules/video_coding/utility/simulcast_state.h"
+
+#include <algorithm>
+#include <memory>
+#include <vector>
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace webrtc {
+namespace {
+const int kMaxStreams = kMaxSimulcastStreams;
+}  // namespace
+
+class SimulcastStateTest : public ::testing::Test {
+ public:
+  SimulcastStateTest() {}
+  virtual ~SimulcastStateTest() {}
+
+  void SetUp() override {
+    memset(&codec_, 0, sizeof(VideoCodec));
+    codec_.codecType = kVideoCodecVP8;
+    codec_.numberOfSimulcastStreams = 0;
+    codec_.minBitrate = 60;
+    codec_.targetBitrate = 600;
+    codec_.maxBitrate = 2400;
+    codec_.startBitrate = 300;
+  }
+
+  void ExpectState(
+      const std::vector<SimulcastState::Stream>& expected_streams) {
+    const std::vector<SimulcastState::Stream>& actual_streams =
+        simulcast_state_->Streams();
+    ASSERT_EQ(expected_streams.size(), actual_streams.size());
+    const int num_streams = expected_streams.size();
+    ASSERT_LE(num_streams, kMaxStreams);
+    for (int i = 0; i < num_streams; ++i) {
+      const SimulcastState::Stream& expected = expected_streams[i];
+      const SimulcastState::Stream& actual = actual_streams[i];
+      EXPECT_EQ(i, expected.idx);
+      EXPECT_EQ(i, actual.idx);
+      EXPECT_EQ(expected.allocated_rate_bps, actual.allocated_rate_bps);
+      EXPECT_EQ(expected.sending, actual.sending);
+      EXPECT_EQ(expected.keyframe_request, actual.keyframe_request);
+    }
+  }
+
+  void TestRateAllocation() {
+    int spillover_bps = 0;
+    int margin_bps = 0;
+    std::vector<SimulcastState::Stream> expected_streams;
+    for (int i = 0; i < codec_.numberOfSimulcastStreams; ++i) {
+      SimulcastState::Stream stream(i, &codec_, 0);
+      stream.sending = i == 0;
+      stream.keyframe_request = stream.sending;
+      stream.allocated_rate_bps =
+          stream.sending ? stream.config.minBitrate * 1000 : 0;
+      expected_streams.push_back(stream);
+    }
+
+    simulcast_state_.reset(new SimulcastState(codec_));
+    simulcast_state_->AllocateBitrate(0);
+    EXPECT_TRUE(simulcast_state_->GetAndResetKeyFrameRequest(0));
+    expected_streams[0].keyframe_request = false;
+
+    int top_layer = 0;
+    for (uint32_t i = 1; i < codec_.maxBitrate; ++i) {
+      simulcast_state_->AllocateBitrate(i * 1000);
+      ExpectState(expected_streams);
+
+      // Always allocate enough bitrate for the lowest stream.
+      if (top_layer == 0 && i < codec_.simulcastStream[0].minBitrate) {
+        expected_streams[0].allocated_rate_bps =
+            codec_.simulcastStream[0].minBitrate * 1000;
+        continue;
+      }
+
+      const int min_bitrate =
+          expected_streams[top_layer].config.minBitrate * 1000;
+      const int target_bitrate =
+          expected_streams[top_layer].config.targetBitrate * 1000;
+      const int max_bitrate =
+          expected_streams[top_layer].config.maxBitrate * 1000;
+
+      if (top_layer > 0 &&
+          expected_streams[top_layer].allocated_rate_bps == min_bitrate) {
+        // Update and reset key frame status on first updater after enabling
+        // layer.
+        EXPECT_TRUE(simulcast_state_->GetAndResetKeyFrameRequest(top_layer));
+        expected_streams[top_layer].keyframe_request = false;
+      }
+
+      // First fill up the top layer until target_bitrate.
+      if (expected_streams[top_layer].allocated_rate_bps < target_bitrate) {
+        expected_streams[top_layer].allocated_rate_bps += 1000;
+        continue;
+      }
+
+      // We have allocated up to the target bitrate. Anything above this may
+      // be reallocated to a higher layer once it has enough bitrate to reach
+      // its min_bitrate.
+      margin_bps += 1000;
+      if (expected_streams[top_layer].allocated_rate_bps < max_bitrate) {
+        expected_streams[top_layer].allocated_rate_bps += 1000;
+      } else {
+        // TODO(sprang): When we enable allocating extra bits to layers other
+        // than the top one, traverse down and do that here.
+        spillover_bps += 1000;
+      }
+
+      // Check if there is enough bitrate to enable the next layer.
+      if (top_layer + 1 < codec_.numberOfSimulcastStreams &&
+          margin_bps >= static_cast<int>(
+                            expected_streams[top_layer + 1].config.minBitrate) *
+                            1000) {
+        ++top_layer;
+        expected_streams[top_layer].sending = true;
+        expected_streams[top_layer].keyframe_request = true;
+
+        // Steal margin bits from the lower layers.
+        // TODO(sprang): Loop over j when we enable allocating extra bits to
+        // layers other than the top one.
+        int j = top_layer - 1;
+        int available_margin =
+            expected_streams[j].allocated_rate_bps -
+            (expected_streams[j].config.targetBitrate * 1000);
+        int consumed_margin = std::min(available_margin, margin_bps);
+        expected_streams[j].allocated_rate_bps -= consumed_margin;
+        margin_bps -= consumed_margin;
+
+        if (margin_bps > 0 && spillover_bps > 0) {
+          // The rest of the needed margin is in allocated spillover.
+          EXPECT_EQ(margin_bps, spillover_bps);
+          spillover_bps = 0;
+          margin_bps = 0;
+        } else {
+          EXPECT_EQ(0, margin_bps);
+        }
+
+        expected_streams[top_layer].allocated_rate_bps =
+            expected_streams[top_layer].config.minBitrate * 1000;
+      }
+    }
+  }
+
+  VideoCodec codec_;
+  std::unique_ptr<SimulcastState> simulcast_state_;
+};
+
+TEST_F(SimulcastStateTest, NoSimulcast) {
+  simulcast_state_.reset(new SimulcastState(codec_));
+
+  SimulcastState::Stream expected_stream(0, &codec_,
+                                         codec_.startBitrate * 1000);
+  std::vector<SimulcastState::Stream> expected_streams;
+  expected_streams.push_back(expected_stream);
+
+  ExpectState(expected_streams);
+
+  for (uint32_t i = 0; i < codec_.maxBitrate + 1; ++i) {
+    simulcast_state_->AllocateBitrate(i * 1000);
+    if (i < codec_.minBitrate) {
+      expected_streams[0].allocated_rate_bps = codec_.minBitrate * 1000;
+    } else if (i > codec_.maxBitrate) {
+      expected_streams[0].allocated_rate_bps = codec_.maxBitrate * 1000;
+    } else {
+      expected_streams[0].allocated_rate_bps = i * 1000;
+    }
+    ExpectState(expected_streams);
+  }
+}
+
+TEST_F(SimulcastStateTest, MultipleStreamsRates) {
+  for (int num_streams = 1; num_streams < kMaxStreams; ++num_streams) {
+    codec_.numberOfSimulcastStreams = num_streams;
+    codec_.startBitrate = 0;
+
+    for (int i = 0; i < num_streams; ++i) {
+      codec_.simulcastStream[i].minBitrate =
+          ((i + 1) * codec_.minBitrate) / kMaxStreams;
+      codec_.simulcastStream[i].targetBitrate =
+          ((i + 1) * codec_.targetBitrate) / kMaxStreams;
+      codec_.simulcastStream[i].maxBitrate =
+          ((i + 1) * codec_.maxBitrate) / kMaxStreams;
+    }
+
+    TestRateAllocation();
+  }
+}
+
+TEST_F(SimulcastStateTest, NextMinLargerThanMax) {
+  codec_.startBitrate = 0;
+  codec_.numberOfSimulcastStreams = 2;
+  codec_.simulcastStream[0].minBitrate = 10;
+  codec_.simulcastStream[0].targetBitrate = 100;
+  codec_.simulcastStream[0].maxBitrate = 200;
+  codec_.simulcastStream[1].minBitrate = 300;
+  codec_.simulcastStream[1].targetBitrate = 400;
+  codec_.simulcastStream[1].maxBitrate = 500;
+
+  TestRateAllocation();
+}
+
+TEST_F(SimulcastStateTest, LargerMinButLowerMax) {
+  codec_.startBitrate = 0;
+  codec_.numberOfSimulcastStreams = 3;
+  codec_.simulcastStream[0].minBitrate = 100;
+  codec_.simulcastStream[0].targetBitrate = 200;
+  codec_.simulcastStream[0].maxBitrate = 600;
+  codec_.simulcastStream[1].minBitrate = 200;
+  codec_.simulcastStream[1].targetBitrate = 300;
+  codec_.simulcastStream[1].maxBitrate = 400;
+  codec_.simulcastStream[2].minBitrate = 300;
+  codec_.simulcastStream[2].targetBitrate = 600;
+  codec_.simulcastStream[2].maxBitrate = 800;
+
+  TestRateAllocation();
+}
+
+TEST_F(SimulcastStateTest, SetsSendingAndKeyframeStates) {
+  codec_.startBitrate = 0;
+  codec_.numberOfSimulcastStreams = 3;
+
+  codec_.simulcastStream[0].minBitrate = 100;
+  codec_.simulcastStream[0].targetBitrate = 200;
+  codec_.simulcastStream[0].maxBitrate = 600;
+  const int kFirstCutoff = codec_.simulcastStream[0].minBitrate * 1000;
+
+  codec_.simulcastStream[1].minBitrate = 300;
+  codec_.simulcastStream[1].targetBitrate = 600;
+  codec_.simulcastStream[1].maxBitrate = 1200;
+  const int kSecondCutoff = (codec_.simulcastStream[0].targetBitrate +
+                             codec_.simulcastStream[1].minBitrate) *
+                            1000;
+
+  codec_.simulcastStream[2].minBitrate = 500;
+  codec_.simulcastStream[2].targetBitrate = 800;
+  codec_.simulcastStream[2].maxBitrate = 1500;
+  const int kThirdCutoff = (codec_.simulcastStream[0].targetBitrate +
+                            codec_.simulcastStream[1].targetBitrate +
+                            codec_.simulcastStream[2].minBitrate) *
+                           1000;
+
+  simulcast_state_.reset(new SimulcastState(codec_));
+
+  simulcast_state_->AllocateBitrate(kFirstCutoff);
+  EXPECT_TRUE(simulcast_state_->GetAndResetKeyFrameRequest(0));
+  EXPECT_TRUE(simulcast_state_->IsSending(0));
+  EXPECT_FALSE(simulcast_state_->GetAndResetKeyFrameRequest(1));
+  EXPECT_FALSE(simulcast_state_->IsSending(1));
+  EXPECT_FALSE(simulcast_state_->GetAndResetKeyFrameRequest(2));
+  EXPECT_FALSE(simulcast_state_->IsSending(2));
+
+  simulcast_state_->AllocateBitrate(kSecondCutoff);
+  EXPECT_FALSE(simulcast_state_->GetAndResetKeyFrameRequest(0));
+  EXPECT_TRUE(simulcast_state_->IsSending(0));
+  EXPECT_TRUE(simulcast_state_->GetAndResetKeyFrameRequest(1));
+  EXPECT_TRUE(simulcast_state_->IsSending(1));
+  EXPECT_FALSE(simulcast_state_->GetAndResetKeyFrameRequest(2));
+  EXPECT_FALSE(simulcast_state_->IsSending(2));
+
+  simulcast_state_->AllocateBitrate(kThirdCutoff);
+  EXPECT_FALSE(simulcast_state_->GetAndResetKeyFrameRequest(0));
+  EXPECT_TRUE(simulcast_state_->IsSending(0));
+  EXPECT_FALSE(simulcast_state_->GetAndResetKeyFrameRequest(1));
+  EXPECT_TRUE(simulcast_state_->IsSending(1));
+  EXPECT_TRUE(simulcast_state_->GetAndResetKeyFrameRequest(2));
+  EXPECT_TRUE(simulcast_state_->IsSending(2));
+
+  simulcast_state_->AllocateBitrate(kSecondCutoff);
+  EXPECT_FALSE(simulcast_state_->GetAndResetKeyFrameRequest(0));
+  EXPECT_TRUE(simulcast_state_->IsSending(0));
+  EXPECT_FALSE(simulcast_state_->GetAndResetKeyFrameRequest(1));
+  EXPECT_TRUE(simulcast_state_->IsSending(1));
+  EXPECT_FALSE(simulcast_state_->GetAndResetKeyFrameRequest(2));
+  EXPECT_FALSE(simulcast_state_->IsSending(2));
+
+  simulcast_state_->AllocateBitrate(kFirstCutoff);
+  EXPECT_FALSE(simulcast_state_->GetAndResetKeyFrameRequest(0));
+  EXPECT_TRUE(simulcast_state_->IsSending(0));
+  EXPECT_FALSE(simulcast_state_->GetAndResetKeyFrameRequest(1));
+  EXPECT_FALSE(simulcast_state_->IsSending(1));
+  EXPECT_FALSE(simulcast_state_->GetAndResetKeyFrameRequest(2));
+  EXPECT_FALSE(simulcast_state_->IsSending(2));
+
+  simulcast_state_->AllocateBitrate(kThirdCutoff);
+  EXPECT_FALSE(simulcast_state_->GetAndResetKeyFrameRequest(0));
+  EXPECT_TRUE(simulcast_state_->IsSending(0));
+  EXPECT_TRUE(simulcast_state_->GetAndResetKeyFrameRequest(1));
+  EXPECT_TRUE(simulcast_state_->IsSending(1));
+  EXPECT_TRUE(simulcast_state_->GetAndResetKeyFrameRequest(2));
+  EXPECT_TRUE(simulcast_state_->IsSending(2));
+}
+
+}  // namespace webrtc