Adding upstream version 115.8.0esr.upstream/115.8.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1467 insertions, 0 deletions

diff --git a/dom/media/gtest/TestVideoTrackEncoder.cpp b/dom/media/gtest/TestVideoTrackEncoder.cpp
new file mode 100644
index 0000000000..ee39213961
--- /dev/null
+++ b/dom/media/gtest/TestVideoTrackEncoder.cpp
@@ -0,0 +1,1467 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <algorithm>
+
+#include "DriftCompensation.h"
+#include "MediaTrackGraph.h"
+#include "MediaTrackListener.h"
+#include "VP8TrackEncoder.h"
+#include "WebMWriter.h"  // TODO: it's weird to include muxer header to get the class definition of VP8 METADATA
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "mozilla/ArrayUtils.h"
+#include "prtime.h"
+
+#include "YUVBufferGenerator.h"
+
+#define VIDEO_TRACK_RATE 90000
+
+using ::testing::_;
+using ::testing::Invoke;
+using ::testing::NiceMock;
+using ::testing::TestWithParam;
+using ::testing::Values;
+
+using namespace mozilla::layers;
+using namespace mozilla;
+
+struct InitParam {
+  bool mShouldSucceed;  // This parameter should cause success or fail result
+  int mWidth;           // frame width
+  int mHeight;          // frame height
+};
+
+class MockDriftCompensator : public DriftCompensator {
+ public:
+  MockDriftCompensator()
+      : DriftCompensator(GetCurrentSerialEventTarget(), VIDEO_TRACK_RATE) {
+    ON_CALL(*this, GetVideoTime(_, _))
+        .WillByDefault(Invoke([](TimeStamp, TimeStamp t) { return t; }));
+  }
+
+  MOCK_METHOD2(GetVideoTime, TimeStamp(TimeStamp, TimeStamp));
+};
+
+class TestVP8TrackEncoder : public VP8TrackEncoder {
+ public:
+  explicit TestVP8TrackEncoder(Maybe<float> aKeyFrameIntervalFactor = Nothing())
+      : VP8TrackEncoder(MakeRefPtr<NiceMock<MockDriftCompensator>>(),
+                        VIDEO_TRACK_RATE, mEncodedVideoQueue,
+                        FrameDroppingMode::DISALLOW, aKeyFrameIntervalFactor) {}
+
+  MockDriftCompensator* DriftCompensator() {
+    return static_cast<MockDriftCompensator*>(mDriftCompensator.get());
+  }
+
+  ::testing::AssertionResult TestInit(const InitParam& aParam) {
+    nsresult result =
+        Init(aParam.mWidth, aParam.mHeight, aParam.mWidth, aParam.mHeight, 30);
+
+    if (((NS_FAILED(result) && aParam.mShouldSucceed)) ||
+        (NS_SUCCEEDED(result) && !aParam.mShouldSucceed)) {
+      return ::testing::AssertionFailure()
+             << " width = " << aParam.mWidth << " height = " << aParam.mHeight;
+    }
+
+    return ::testing::AssertionSuccess();
+  }
+
+  MediaQueue<EncodedFrame> mEncodedVideoQueue;
+};
+
+// Init test
+TEST(VP8VideoTrackEncoder, Initialization)
+{
+  InitParam params[] = {
+      // Failure cases.
+      {false, 0, 0},  // Height/ width should be larger than 1.
+      {false, 0, 1},  // Height/ width should be larger than 1.
+      {false, 1, 0},  // Height/ width should be larger than 1.
+
+      // Success cases
+      {true, 640, 480},  // Standard VGA
+      {true, 800, 480},  // Standard WVGA
+      {true, 960, 540},  // Standard qHD
+      {true, 1280, 720}  // Standard HD
+  };
+
+  for (const InitParam& param : params) {
+    TestVP8TrackEncoder encoder;
+    EXPECT_TRUE(encoder.TestInit(param));
+  }
+}
+
+// Get MetaData test
+TEST(VP8VideoTrackEncoder, FetchMetaData)
+{
+  InitParam params[] = {
+      // Success cases
+      {true, 640, 480},  // Standard VGA
+      {true, 800, 480},  // Standard WVGA
+      {true, 960, 540},  // Standard qHD
+      {true, 1280, 720}  // Standard HD
+  };
+
+  for (const InitParam& param : params) {
+    TestVP8TrackEncoder encoder;
+    EXPECT_TRUE(encoder.TestInit(param));
+
+    RefPtr<TrackMetadataBase> meta = encoder.GetMetadata();
+    RefPtr<VP8Metadata> vp8Meta(static_cast<VP8Metadata*>(meta.get()));
+
+    // METADATA should be depend on how to initiate encoder.
+    EXPECT_EQ(vp8Meta->mWidth, param.mWidth);
+    EXPECT_EQ(vp8Meta->mHeight, param.mHeight);
+  }
+}
+
+// Encode test
+TEST(VP8VideoTrackEncoder, FrameEncode)
+{
+  TestVP8TrackEncoder encoder;
+  TimeStamp now = TimeStamp::Now();
+
+  // Create YUV images as source.
+  nsTArray<RefPtr<Image>> images;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+  images.AppendElement(generator.GenerateI420Image());
+  images.AppendElement(generator.GenerateNV12Image());
+  images.AppendElement(generator.GenerateNV21Image());
+
+  // Put generated YUV frame into video segment.
+  // Duration of each frame is 1 second.
+  VideoSegment segment;
+  for (nsTArray<RefPtr<Image>>::size_type i = 0; i < images.Length(); i++) {
+    RefPtr<Image> image = images[i];
+    segment.AppendFrame(image.forget(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false,
+                        now + TimeDuration::FromSeconds(i));
+  }
+
+  encoder.SetStartOffset(now);
+  encoder.AppendVideoSegment(std::move(segment));
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(images.Length()));
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+}
+
+// Test that encoding a single frame gives useful output.
+TEST(VP8VideoTrackEncoder, SingleFrameEncode)
+{
+  TestVP8TrackEncoder encoder;
+  TimeStamp now = TimeStamp::Now();
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+
+  // Pass a half-second frame to the encoder.
+  VideoSegment segment;
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false, now);
+
+  encoder.SetStartOffset(now);
+  encoder.AppendVideoSegment(std::move(segment));
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(0.5));
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  // Read out encoded data, and verify.
+  RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(EncodedFrame::VP8_I_FRAME, frame->mFrameType)
+      << "We only have one frame, so it should be a keyframe";
+
+  const uint64_t halfSecond = PR_USEC_PER_SEC / 2;
+  EXPECT_EQ(halfSecond, frame->mDuration);
+
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.AtEndOfStream());
+}
+
+// Test that encoding a couple of identical images gives useful output.
+TEST(VP8VideoTrackEncoder, SameFrameEncode)
+{
+  TestVP8TrackEncoder encoder;
+  TimeStamp now = TimeStamp::Now();
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+
+  // Pass 15 100ms frames to the encoder.
+  RefPtr<Image> image = generator.GenerateI420Image();
+  VideoSegment segment;
+  for (uint32_t i = 0; i < 15; ++i) {
+    segment.AppendFrame(do_AddRef(image), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false,
+                        now + TimeDuration::FromSeconds(i * 0.1));
+  }
+
+  encoder.SetStartOffset(now);
+  encoder.AppendVideoSegment(std::move(segment));
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(1.5));
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  // Verify total duration being 1.5s.
+  uint64_t totalDuration = 0;
+  while (RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront()) {
+    totalDuration += frame->mDuration;
+  }
+  const uint64_t oneAndAHalf = (PR_USEC_PER_SEC / 2) * 3;
+  EXPECT_EQ(oneAndAHalf, totalDuration);
+}
+
+// Test encoding a track that has to skip frames.
+TEST(VP8VideoTrackEncoder, SkippedFrames)
+{
+  TestVP8TrackEncoder encoder;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+  TimeStamp now = TimeStamp::Now();
+
+  // Pass 100 frames of the shortest possible duration where we don't get
+  // rounding errors between input/output rate.
+  VideoSegment segment;
+  for (uint32_t i = 0; i < 100; ++i) {
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false,
+                        now + TimeDuration::FromMilliseconds(i));
+  }
+
+  encoder.SetStartOffset(now);
+  encoder.AppendVideoSegment(std::move(segment));
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromMilliseconds(100));
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  // Verify total duration being 100 * 1ms = 100ms.
+  uint64_t totalDuration = 0;
+  while (RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront()) {
+    totalDuration += frame->mDuration;
+  }
+  const uint64_t hundredMillis = PR_USEC_PER_SEC / 10;
+  EXPECT_EQ(hundredMillis, totalDuration);
+}
+
+// Test encoding a track with frames subject to rounding errors.
+TEST(VP8VideoTrackEncoder, RoundingErrorFramesEncode)
+{
+  TestVP8TrackEncoder encoder;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+  TimeStamp now = TimeStamp::Now();
+
+  // Pass nine frames with timestamps not expressable in 90kHz sample rate,
+  // then one frame to make the total duration close to one second.
+  VideoSegment segment;
+  uint32_t usPerFrame = 99999;  // 99.999ms
+  for (uint32_t i = 0; i < 9; ++i) {
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false,
+                        now + TimeDuration::FromMicroseconds(i * usPerFrame));
+  }
+
+  // This last frame has timestamp start + 0.9s and duration 0.1s.
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false,
+                      now + TimeDuration::FromSeconds(0.9));
+
+  encoder.SetStartOffset(now);
+  encoder.AppendVideoSegment(std::move(segment));
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(1));
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  // Verify total duration being 1s.
+  uint64_t totalDuration = 0;
+  while (RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront()) {
+    totalDuration += frame->mDuration;
+  }
+  // Not exact, the stream is encoded in time base 90kHz.
+  const uint64_t oneSecond = PR_USEC_PER_SEC - 1;
+  EXPECT_EQ(oneSecond, totalDuration);
+}
+
+// Test that we're encoding timestamps rather than durations.
+TEST(VP8VideoTrackEncoder, TimestampFrameEncode)
+{
+  TestVP8TrackEncoder encoder;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+  TimeStamp now = TimeStamp::Now();
+
+  VideoSegment segment;
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false, now);
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false,
+                      now + TimeDuration::FromSeconds(0.05));
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false,
+                      now + TimeDuration::FromSeconds(0.2));
+
+  encoder.SetStartOffset(now);
+  encoder.AppendVideoSegment(std::move(segment));
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(0.3));
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  // Verify total duration being 0.3s and individual frames being [0.05s, 0.15s,
+  // 0.1s]
+  uint64_t expectedDurations[] = {(PR_USEC_PER_SEC / 10) / 2,
+                                  (PR_USEC_PER_SEC / 10) * 3 / 2,
+                                  (PR_USEC_PER_SEC / 10)};
+  uint64_t totalDuration = 0;
+  size_t i = 0;
+  while (RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront()) {
+    EXPECT_EQ(expectedDurations[i], frame->mDuration);
+    i++;
+    totalDuration += frame->mDuration;
+  }
+  const uint64_t pointThree = (PR_USEC_PER_SEC / 10) * 3;
+  EXPECT_EQ(pointThree, totalDuration);
+}
+
+// Test that we're compensating for drift when encoding.
+TEST(VP8VideoTrackEncoder, DriftingFrameEncode)
+{
+  TestVP8TrackEncoder encoder;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+  TimeStamp now = TimeStamp::Now();
+
+  // Set up major drift -- audio that goes twice as fast as video.
+  // This should make the given video durations double as they get encoded.
+  EXPECT_CALL(*encoder.DriftCompensator(), GetVideoTime(_, _))
+      .WillRepeatedly(Invoke(
+          [&](TimeStamp, TimeStamp aTime) { return now + (aTime - now) * 2; }));
+
+  VideoSegment segment;
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false, now);
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false,
+                      now + TimeDuration::FromSeconds(0.05));
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false,
+                      now + TimeDuration::FromSeconds(0.2));
+
+  encoder.SetStartOffset(now);
+  encoder.AppendVideoSegment(std::move(segment));
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(0.3));
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  // Verify total duration being 0.6s and individual frames being [0.1s, 0.3s,
+  // 0.2s]
+  uint64_t expectedDurations[] = {(PR_USEC_PER_SEC / 10),
+                                  (PR_USEC_PER_SEC / 10) * 3,
+                                  (PR_USEC_PER_SEC / 10) * 2};
+  uint64_t totalDuration = 0;
+  size_t i = 0;
+  while (RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront()) {
+    EXPECT_EQ(expectedDurations[i], frame->mDuration);
+    i++;
+    totalDuration += frame->mDuration;
+  }
+  const uint64_t pointSix = (PR_USEC_PER_SEC / 10) * 6;
+  EXPECT_EQ(pointSix, totalDuration);
+}
+
+// Test that suspending an encoding works.
+TEST(VP8VideoTrackEncoder, Suspended)
+{
+  TestVP8TrackEncoder encoder;
+  TimeStamp now = TimeStamp::Now();
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+
+  // Pass 3 frames with duration 0.1s. We suspend before and resume after the
+  // second frame.
+
+  {
+    VideoSegment segment;
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false, now);
+
+    encoder.SetStartOffset(now);
+    encoder.AppendVideoSegment(std::move(segment));
+    encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(0.1));
+  }
+
+  encoder.Suspend(now + TimeDuration::FromSeconds(0.1));
+
+  {
+    VideoSegment segment;
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false,
+                        now + TimeDuration::FromSeconds(0.1));
+    encoder.AppendVideoSegment(std::move(segment));
+    encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(0.2));
+  }
+
+  encoder.Resume(now + TimeDuration::FromSeconds(0.2));
+
+  {
+    VideoSegment segment;
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false,
+                        now + TimeDuration::FromSeconds(0.2));
+    encoder.AppendVideoSegment(std::move(segment));
+    encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(0.3));
+  }
+
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  // Verify that we have two encoded frames and a total duration of 0.2s.
+  uint64_t count = 0;
+  uint64_t totalDuration = 0;
+  while (RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront()) {
+    ++count;
+    totalDuration += frame->mDuration;
+  }
+  const uint64_t two = 2;
+  EXPECT_EQ(two, count);
+  const uint64_t pointTwo = (PR_USEC_PER_SEC / 10) * 2;
+  EXPECT_EQ(pointTwo, totalDuration);
+}
+
+// Test that ending a track while the video track encoder is suspended works.
+TEST(VP8VideoTrackEncoder, SuspendedUntilEnd)
+{
+  TestVP8TrackEncoder encoder;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+  TimeStamp now = TimeStamp::Now();
+
+  // Pass 2 frames with duration 0.1s. We suspend before the second frame.
+
+  {
+    VideoSegment segment;
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false, now);
+
+    encoder.SetStartOffset(now);
+    encoder.AppendVideoSegment(std::move(segment));
+    encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(0.1));
+  }
+
+  encoder.Suspend(now + TimeDuration::FromSeconds(0.1));
+
+  {
+    VideoSegment segment;
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false,
+                        now + TimeDuration::FromSeconds(0.1));
+    encoder.AppendVideoSegment(std::move(segment));
+    encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(0.2));
+  }
+
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  // Verify that we have one encoded frames and a total duration of 0.1s.
+  uint64_t count = 0;
+  uint64_t totalDuration = 0;
+  while (RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront()) {
+    ++count;
+    totalDuration += frame->mDuration;
+  }
+  const uint64_t one = 1;
+  EXPECT_EQ(one, count);
+  const uint64_t pointOne = PR_USEC_PER_SEC / 10;
+  EXPECT_EQ(pointOne, totalDuration);
+}
+
+// Test that ending a track that was always suspended works.
+TEST(VP8VideoTrackEncoder, AlwaysSuspended)
+{
+  TestVP8TrackEncoder encoder;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+  TimeStamp now = TimeStamp::Now();
+
+  // Suspend and then pass a frame with duration 2s.
+
+  encoder.Suspend(now);
+
+  VideoSegment segment;
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false, now);
+
+  encoder.SetStartOffset(now);
+  encoder.AppendVideoSegment(std::move(segment));
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(2));
+
+  encoder.NotifyEndOfStream();
+
+  // Verify that we have no encoded frames.
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.AtEndOfStream());
+}
+
+// Test that encoding a track that is suspended in the beginning works.
+TEST(VP8VideoTrackEncoder, SuspendedBeginning)
+{
+  TestVP8TrackEncoder encoder;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+  TimeStamp now = TimeStamp::Now();
+
+  // Suspend and pass a frame with duration 0.5s. Then resume and pass one more.
+  encoder.Suspend(now);
+
+  {
+    VideoSegment segment;
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false, now);
+
+    encoder.SetStartOffset(now);
+    encoder.AppendVideoSegment(std::move(segment));
+    encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(0.5));
+  }
+
+  encoder.Resume(now + TimeDuration::FromSeconds(0.5));
+
+  {
+    VideoSegment segment;
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false,
+                        now + TimeDuration::FromSeconds(0.5));
+    encoder.AppendVideoSegment(std::move(segment));
+    encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(1));
+  }
+
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  // Verify that we have one encoded frames and a total duration of 0.1s.
+  uint64_t count = 0;
+  uint64_t totalDuration = 0;
+  while (RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront()) {
+    ++count;
+    totalDuration += frame->mDuration;
+  }
+  const uint64_t one = 1;
+  EXPECT_EQ(one, count);
+  const uint64_t half = PR_USEC_PER_SEC / 2;
+  EXPECT_EQ(half, totalDuration);
+}
+
+// Test that suspending and resuming in the middle of already pushed data
+// works.
+TEST(VP8VideoTrackEncoder, SuspendedOverlap)
+{
+  TestVP8TrackEncoder encoder;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+  TimeStamp now = TimeStamp::Now();
+
+  {
+    // Pass a 1s frame and suspend after 0.5s.
+    VideoSegment segment;
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false, now);
+
+    encoder.SetStartOffset(now);
+    encoder.AppendVideoSegment(std::move(segment));
+  }
+
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(0.5));
+  encoder.Suspend(now + TimeDuration::FromSeconds(0.5));
+
+  {
+    // Pass another 1s frame and resume after 0.3 of this new frame.
+    VideoSegment segment;
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false,
+                        now + TimeDuration::FromSeconds(1));
+    encoder.AppendVideoSegment(std::move(segment));
+  }
+
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(1.3));
+  encoder.Resume(now + TimeDuration::FromSeconds(1.3));
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(2));
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  // Verify that we have two encoded frames and a total duration of 0.1s.
+  RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront();
+  const uint64_t pointFive = (PR_USEC_PER_SEC / 10) * 5;
+  EXPECT_EQ(pointFive, frame->mDuration);
+  frame = encoder.mEncodedVideoQueue.PopFront();
+  const uint64_t pointSeven = (PR_USEC_PER_SEC / 10) * 7;
+  EXPECT_EQ(pointSeven, frame->mDuration);
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.AtEndOfStream());
+}
+
+// Test that ending a track in the middle of already pushed data works.
+TEST(VP8VideoTrackEncoder, PrematureEnding)
+{
+  TestVP8TrackEncoder encoder;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+  TimeStamp now = TimeStamp::Now();
+
+  // Pass a 1s frame and end the track after 0.5s.
+  VideoSegment segment;
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false, now);
+
+  encoder.SetStartOffset(now);
+  encoder.AppendVideoSegment(std::move(segment));
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(0.5));
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  uint64_t totalDuration = 0;
+  while (RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront()) {
+    totalDuration += frame->mDuration;
+  }
+  const uint64_t half = PR_USEC_PER_SEC / 2;
+  EXPECT_EQ(half, totalDuration);
+}
+
+// Test that a track that starts at t > 0 works as expected.
+TEST(VP8VideoTrackEncoder, DelayedStart)
+{
+  TestVP8TrackEncoder encoder;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+  TimeStamp now = TimeStamp::Now();
+
+  // Pass a 2s frame, start (pass first CurrentTime) at 0.5s, end at 1s.
+  // Should result in a 0.5s encoding.
+  VideoSegment segment;
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false, now);
+
+  encoder.SetStartOffset(now + TimeDuration::FromSeconds(0.5));
+  encoder.AppendVideoSegment(std::move(segment));
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(1));
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  uint64_t totalDuration = 0;
+  while (RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront()) {
+    totalDuration += frame->mDuration;
+  }
+  const uint64_t half = PR_USEC_PER_SEC / 2;
+  EXPECT_EQ(half, totalDuration);
+}
+
+// Test that a track that starts at t > 0 works as expected, when
+// SetStartOffset comes after AppendVideoSegment.
+TEST(VP8VideoTrackEncoder, DelayedStartOtherEventOrder)
+{
+  TestVP8TrackEncoder encoder;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+  TimeStamp now = TimeStamp::Now();
+
+  // Pass a 2s frame, start (pass first CurrentTime) at 0.5s, end at 1s.
+  // Should result in a 0.5s encoding.
+  VideoSegment segment;
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false, now);
+
+  encoder.AppendVideoSegment(std::move(segment));
+  encoder.SetStartOffset(now + TimeDuration::FromSeconds(0.5));
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(1));
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  uint64_t totalDuration = 0;
+  while (RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront()) {
+    totalDuration += frame->mDuration;
+  }
+  const uint64_t half = PR_USEC_PER_SEC / 2;
+  EXPECT_EQ(half, totalDuration);
+}
+
+// Test that a track that starts at t >>> 0 works as expected.
+TEST(VP8VideoTrackEncoder, VeryDelayedStart)
+{
+  TestVP8TrackEncoder encoder;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+  TimeStamp now = TimeStamp::Now();
+
+  // Pass a 1s frame, start (pass first CurrentTime) at 10s, end at 10.5s.
+  // Should result in a 0.5s encoding.
+  VideoSegment segment;
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false, now);
+
+  encoder.SetStartOffset(now + TimeDuration::FromSeconds(10));
+  encoder.AppendVideoSegment(std::move(segment));
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(10.5));
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  uint64_t totalDuration = 0;
+  while (RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront()) {
+    totalDuration += frame->mDuration;
+  }
+  const uint64_t half = PR_USEC_PER_SEC / 2;
+  EXPECT_EQ(half, totalDuration);
+}
+
+// Test that a video frame that hangs around for a long time gets encoded
+// every second.
+TEST(VP8VideoTrackEncoder, LongFramesReEncoded)
+{
+  TestVP8TrackEncoder encoder;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+  TimeStamp now = TimeStamp::Now();
+
+  // Pass a frame at t=0 and start encoding.
+  // Advancing the current time by 6.5s should encode six 1s frames.
+  // Advancing the current time by another 5.5s should encode another five 1s
+  // frames.
+
+  VideoSegment segment;
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false, now);
+
+  encoder.SetStartOffset(now);
+  encoder.AppendVideoSegment(std::move(segment));
+
+  {
+    encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(6.5));
+
+    EXPECT_FALSE(encoder.IsEncodingComplete());
+    EXPECT_FALSE(encoder.mEncodedVideoQueue.IsFinished());
+
+    uint64_t count = 0;
+    uint64_t totalDuration = 0;
+    while (RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront()) {
+      ++count;
+      totalDuration += frame->mDuration;
+    }
+    const uint64_t sixSec = 6 * PR_USEC_PER_SEC;
+    EXPECT_EQ(sixSec, totalDuration);
+    EXPECT_EQ(6U, count);
+  }
+
+  {
+    encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(11));
+    encoder.NotifyEndOfStream();
+
+    EXPECT_TRUE(encoder.IsEncodingComplete());
+    EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+
+    uint64_t count = 0;
+    uint64_t totalDuration = 0;
+    while (RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront()) {
+      ++count;
+      totalDuration += frame->mDuration;
+    }
+    const uint64_t fiveSec = 5 * PR_USEC_PER_SEC;
+    EXPECT_EQ(fiveSec, totalDuration);
+    EXPECT_EQ(5U, count);
+  }
+}
+
+// Test that an encoding with no defined key frame interval encodes keyframes
+// as expected. Default interval should be 10s.
+TEST(VP8VideoTrackEncoder, DefaultKeyFrameInterval)
+{
+  // Set the factor high to only test the keyframe-forcing logic
+  TestVP8TrackEncoder encoder(Some(2.0));
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+  TimeStamp now = TimeStamp::Now();
+
+  // Pass a frame at t=0, and the frame-duplication logic will encode frames
+  // every second. Keyframes are expected at t=0, 10s and 20s.
+  VideoSegment segment;
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false, now);
+
+  encoder.SetStartOffset(now);
+  encoder.AppendVideoSegment(std::move(segment));
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromSeconds(21.5));
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  // Duplication logic ensures no frame duration is longer than 1 second.
+
+  // [0, 1000ms) - key-frame.
+  RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 1000UL, frame->mDuration);
+  EXPECT_EQ(EncodedFrame::VP8_I_FRAME, frame->mFrameType);
+
+  // [1000ms, 10000ms) - non-key-frames
+  for (int i = 0; i < 9; ++i) {
+    frame = encoder.mEncodedVideoQueue.PopFront();
+    EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 1000UL, frame->mDuration)
+        << "Start time: " << frame->mTime.ToMicroseconds() << "us";
+    EXPECT_EQ(EncodedFrame::VP8_P_FRAME, frame->mFrameType)
+        << "Start time: " << frame->mTime.ToMicroseconds() << "us";
+  }
+
+  // [10000ms, 11000ms) - key-frame
+  frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 1000UL, frame->mDuration);
+  EXPECT_EQ(EncodedFrame::VP8_I_FRAME, frame->mFrameType);
+
+  // [11000ms, 20000ms) - non-key-frames
+  for (int i = 0; i < 9; ++i) {
+    frame = encoder.mEncodedVideoQueue.PopFront();
+    EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 1000UL, frame->mDuration)
+        << "Start time: " << frame->mTime.ToMicroseconds() << "us";
+    EXPECT_EQ(EncodedFrame::VP8_P_FRAME, frame->mFrameType)
+        << "Start time: " << frame->mTime.ToMicroseconds() << "us";
+  }
+
+  // [20000ms, 21000ms) - key-frame
+  frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 1000UL, frame->mDuration);
+  EXPECT_EQ(EncodedFrame::VP8_I_FRAME, frame->mFrameType);
+
+  // [21000ms, 21500ms) - non-key-frame
+  frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 500UL, frame->mDuration);
+  EXPECT_EQ(EncodedFrame::VP8_P_FRAME, frame->mFrameType);
+
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.AtEndOfStream());
+}
+
+// Test that an encoding which is disabled on a frame timestamp encodes
+// frames as expected.
+TEST(VP8VideoTrackEncoder, DisableOnFrameTime)
+{
+  TestVP8TrackEncoder encoder;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+  TimeStamp now = TimeStamp::Now();
+
+  // Pass a frame in at t=0.
+  // Pass another frame in at t=100ms.
+  // Disable the track at t=100ms.
+  // Stop encoding at t=200ms.
+  // Should yield 2 frames, 1 real; 1 black.
+
+  VideoSegment segment;
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false, now);
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false,
+                      now + TimeDuration::FromMilliseconds(100));
+
+  encoder.SetStartOffset(now);
+  encoder.AppendVideoSegment(std::move(segment));
+
+  // Advancing 100ms, for simplicity.
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromMilliseconds(100));
+
+  encoder.Disable(now + TimeDuration::FromMilliseconds(100));
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromMilliseconds(200));
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  // [0, 100ms)
+  RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 100UL, frame->mDuration);
+
+  // [100ms, 200ms)
+  frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 100UL, frame->mDuration);
+
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.AtEndOfStream());
+}
+
+// Test that an encoding which is disabled between two frame timestamps
+// encodes frames as expected.
+TEST(VP8VideoTrackEncoder, DisableBetweenFrames)
+{
+  TestVP8TrackEncoder encoder;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+  TimeStamp now = TimeStamp::Now();
+
+  // Pass a frame in at t=0.
+  // Disable the track at t=50ms.
+  // Pass another frame in at t=100ms.
+  // Stop encoding at t=200ms.
+  // Should yield 3 frames, 1 real [0, 50); 2 black [50, 100) and [100, 200).
+
+  VideoSegment segment;
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false, now);
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false,
+                      now + TimeDuration::FromMilliseconds(100));
+
+  encoder.SetStartOffset(now);
+  encoder.AppendVideoSegment(std::move(segment));
+
+  encoder.Disable(now + TimeDuration::FromMilliseconds(50));
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromMilliseconds(200));
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  // [0, 50ms)
+  RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 50UL, frame->mDuration);
+
+  // [50ms, 100ms)
+  frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 50UL, frame->mDuration);
+
+  // [100ms, 200ms)
+  frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 100UL, frame->mDuration);
+
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.AtEndOfStream());
+}
+
+// Test that an encoding which is disabled before the first frame becomes
+// black immediately.
+TEST(VP8VideoTrackEncoder, DisableBeforeFirstFrame)
+{
+  TestVP8TrackEncoder encoder;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+  TimeStamp now = TimeStamp::Now();
+
+  // Disable the track at t=0.
+  // Pass a frame in at t=50ms.
+  // Enable the track at t=100ms.
+  // Stop encoding at t=200ms.
+  // Should yield 2 frames, 1 black [0, 100); 1 real [100, 200).
+
+  VideoSegment segment;
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false,
+                      now + TimeDuration::FromMilliseconds(50));
+
+  encoder.SetStartOffset(now);
+  encoder.Disable(now);
+  encoder.AppendVideoSegment(std::move(segment));
+
+  encoder.Enable(now + TimeDuration::FromMilliseconds(100));
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromMilliseconds(200));
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  // [0, 100ms)
+  RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 100UL, frame->mDuration);
+
+  // [100ms, 200ms)
+  frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 100UL, frame->mDuration);
+
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.AtEndOfStream());
+}
+
+// Test that an encoding which is enabled on a frame timestamp encodes
+// frames as expected.
+TEST(VP8VideoTrackEncoder, EnableOnFrameTime)
+{
+  TestVP8TrackEncoder encoder;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+  TimeStamp now = TimeStamp::Now();
+
+  // Disable the track at t=0.
+  // Pass a frame in at t=0.
+  // Pass another frame in at t=100ms.
+  // Enable the track at t=100ms.
+  // Stop encoding at t=200ms.
+  // Should yield 2 frames, 1 black; 1 real.
+
+  VideoSegment segment;
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false, now);
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false,
+                      now + TimeDuration::FromMilliseconds(100));
+
+  encoder.SetStartOffset(now);
+  encoder.Disable(now);
+  encoder.AppendVideoSegment(std::move(segment));
+
+  // Advancing 100ms, for simplicity.
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromMilliseconds(100));
+
+  encoder.Enable(now + TimeDuration::FromMilliseconds(100));
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromMilliseconds(200));
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  // [0, 100ms)
+  RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 100UL, frame->mDuration);
+
+  // [100ms, 200ms)
+  frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 100UL, frame->mDuration);
+
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.AtEndOfStream());
+}
+
+// Test that an encoding which is enabled between two frame timestamps encodes
+// frames as expected.
+TEST(VP8VideoTrackEncoder, EnableBetweenFrames)
+{
+  TestVP8TrackEncoder encoder;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+  TimeStamp now = TimeStamp::Now();
+
+  // Disable the track at t=0.
+  // Pass a frame in at t=0.
+  // Enable the track at t=50ms.
+  // Pass another frame in at t=100ms.
+  // Stop encoding at t=200ms.
+  // Should yield 3 frames, 1 black [0, 50); 2 real [50, 100) and [100, 200).
+
+  VideoSegment segment;
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false, now);
+  segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                      PRINCIPAL_HANDLE_NONE, false,
+                      now + TimeDuration::FromMilliseconds(100));
+
+  encoder.SetStartOffset(now);
+  encoder.Disable(now);
+  encoder.AppendVideoSegment(std::move(segment));
+
+  encoder.Enable(now + TimeDuration::FromMilliseconds(50));
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromMilliseconds(200));
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  // [0, 50ms)
+  RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 50UL, frame->mDuration);
+
+  // [50ms, 100ms)
+  frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 50UL, frame->mDuration);
+
+  // [100ms, 200ms)
+  frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 100UL, frame->mDuration);
+
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.AtEndOfStream());
+}
+
+// Test that making time go backwards removes any future frames in the
+// encoder.
+TEST(VP8VideoTrackEncoder, BackwardsTimeResets)
+{
+  TestVP8TrackEncoder encoder;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+  TimeStamp now = TimeStamp::Now();
+
+  encoder.SetStartOffset(now);
+
+  // Pass frames in at t=0, t=100ms, t=200ms, t=300ms.
+  // Advance time to t=125ms.
+  // Pass frames in at t=150ms, t=250ms, t=350ms.
+  // Stop encoding at t=300ms.
+  // Should yield 4 frames, at t=0, t=100ms, t=150ms, t=250ms.
+
+  {
+    VideoSegment segment;
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false, now);
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false,
+                        now + TimeDuration::FromMilliseconds(100));
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false,
+                        now + TimeDuration::FromMilliseconds(200));
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false,
+                        now + TimeDuration::FromMilliseconds(300));
+
+    encoder.AppendVideoSegment(std::move(segment));
+  }
+
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromMilliseconds(125));
+
+  {
+    VideoSegment segment;
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false,
+                        now + TimeDuration::FromMilliseconds(150));
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false,
+                        now + TimeDuration::FromMilliseconds(250));
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false,
+                        now + TimeDuration::FromMilliseconds(350));
+
+    encoder.AppendVideoSegment(std::move(segment));
+  }
+
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromMilliseconds(300));
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  // [0, 100ms)
+  RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 100UL, frame->mDuration);
+
+  // [100ms, 150ms)
+  frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 50UL, frame->mDuration);
+
+  // [150ms, 250ms)
+  frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 100UL, frame->mDuration);
+
+  // [250ms, 300ms)
+  frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 50UL, frame->mDuration);
+
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.AtEndOfStream());
+}
+
+// Test that trying to encode a null image removes any future frames in the
+// encoder.
+TEST(VP8VideoTrackEncoder, NullImageResets)
+{
+  TestVP8TrackEncoder encoder;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(640, 480));
+  TimeStamp now = TimeStamp::Now();
+
+  encoder.SetStartOffset(now);
+
+  // Pass frames in at t=0, t=100ms, t=200ms, t=300ms.
+  // Advance time to t=125ms.
+  // Pass in a null image at t=125ms.
+  // Pass frames in at t=250ms, t=350ms.
+  // Stop encoding at t=300ms.
+  // Should yield 3 frames, at t=0, t=100ms, t=250ms.
+
+  {
+    VideoSegment segment;
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false, now);
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false,
+                        now + TimeDuration::FromMilliseconds(100));
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false,
+                        now + TimeDuration::FromMilliseconds(200));
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false,
+                        now + TimeDuration::FromMilliseconds(300));
+
+    encoder.AppendVideoSegment(std::move(segment));
+  }
+
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromMilliseconds(125));
+
+  {
+    VideoSegment segment;
+    segment.AppendFrame(nullptr, generator.GetSize(), PRINCIPAL_HANDLE_NONE,
+                        false, now + TimeDuration::FromMilliseconds(125));
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false,
+                        now + TimeDuration::FromMilliseconds(250));
+    segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                        PRINCIPAL_HANDLE_NONE, false,
+                        now + TimeDuration::FromMilliseconds(350));
+
+    encoder.AppendVideoSegment(std::move(segment));
+  }
+
+  encoder.AdvanceCurrentTime(now + TimeDuration::FromMilliseconds(300));
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  // [0, 100ms)
+  RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 100UL, frame->mDuration);
+
+  // [100ms, 250ms)
+  frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 150UL, frame->mDuration);
+
+  // [250ms, 300ms)
+  frame = encoder.mEncodedVideoQueue.PopFront();
+  EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 50UL, frame->mDuration);
+
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.AtEndOfStream());
+}
+
+TEST(VP8VideoTrackEncoder, MaxKeyFrameDistanceLowFramerate)
+{
+  TestVP8TrackEncoder encoder;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(240, 180));
+  TimeStamp now = TimeStamp::Now();
+
+  encoder.SetStartOffset(now);
+
+  // Pass 10s worth of frames at 2 fps and verify that the key frame interval
+  // is ~7.5s.
+  const TimeDuration duration = TimeDuration::FromSeconds(10);
+  const uint32_t numFrames = 10 * 2;
+  const TimeDuration frameDuration = duration / static_cast<int64_t>(numFrames);
+
+  {
+    VideoSegment segment;
+    for (uint32_t i = 0; i < numFrames; ++i) {
+      segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                          PRINCIPAL_HANDLE_NONE, false,
+                          now + frameDuration * i);
+    }
+    encoder.AppendVideoSegment(std::move(segment));
+  }
+
+  encoder.AdvanceCurrentTime(now + duration);
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  for (uint32_t i = 0; i < numFrames; ++i) {
+    const RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront();
+    EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 500UL, frame->mDuration)
+        << "Frame " << i << ", with start: " << frame->mTime.ToMicroseconds()
+        << "us";
+    // 7.5s key frame interval at 2 fps becomes the 15th frame.
+    EXPECT_EQ(
+        i % 15 == 0 ? EncodedFrame::VP8_I_FRAME : EncodedFrame::VP8_P_FRAME,
+        frame->mFrameType)
+        << "Frame " << i << ", with start: " << frame->mTime.ToMicroseconds()
+        << "us";
+  }
+
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.AtEndOfStream());
+}
+
+// This is "High" framerate, as in higher than the test for "Low" framerate.
+// We don't make it too high because the test takes considerably longer to
+// run.
+TEST(VP8VideoTrackEncoder, MaxKeyFrameDistanceHighFramerate)
+{
+  TestVP8TrackEncoder encoder;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(240, 180));
+  TimeStamp now = TimeStamp::Now();
+
+  encoder.SetStartOffset(now);
+
+  // Pass 10s worth of frames at 8 fps and verify that the key frame interval
+  // is ~7.5s.
+  const TimeDuration duration = TimeDuration::FromSeconds(10);
+  const uint32_t numFrames = 10 * 8;
+  const TimeDuration frameDuration = duration / static_cast<int64_t>(numFrames);
+
+  {
+    VideoSegment segment;
+    for (uint32_t i = 0; i < numFrames; ++i) {
+      segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                          PRINCIPAL_HANDLE_NONE, false,
+                          now + frameDuration * i);
+    }
+    encoder.AppendVideoSegment(std::move(segment));
+  }
+
+  encoder.AdvanceCurrentTime(now + duration);
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  for (uint32_t i = 0; i < numFrames; ++i) {
+    const RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront();
+    EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 125UL, frame->mDuration)
+        << "Frame " << i << ", with start: " << frame->mTime.ToMicroseconds()
+        << "us";
+    // 7.5s key frame interval at 8 fps becomes the 60th frame.
+    EXPECT_EQ(
+        i % 60 == 0 ? EncodedFrame::VP8_I_FRAME : EncodedFrame::VP8_P_FRAME,
+        frame->mFrameType)
+        << "Frame " << i << ", with start: " << frame->mTime.ToMicroseconds()
+        << "us";
+  }
+
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.AtEndOfStream());
+}
+
+TEST(VP8VideoTrackEncoder, MaxKeyFrameDistanceAdaptiveFramerate)
+{
+  TestVP8TrackEncoder encoder;
+  YUVBufferGenerator generator;
+  generator.Init(mozilla::gfx::IntSize(240, 180));
+  TimeStamp now = TimeStamp::Now();
+
+  encoder.SetStartOffset(now);
+
+  // Pass 11s worth of frames at 2 fps and verify that there is a key frame
+  // at 7.5s. Then pass 14s worth of frames at 10 fps and verify that there is
+  // a key frame at 15s (due to re-init) and then one at 22.5s.
+
+  const TimeDuration firstDuration = TimeDuration::FromSeconds(11);
+  const uint32_t firstNumFrames = 11 * 2;
+  const TimeDuration firstFrameDuration =
+      firstDuration / static_cast<int64_t>(firstNumFrames);
+  {
+    VideoSegment segment;
+    for (uint32_t i = 0; i < firstNumFrames; ++i) {
+      segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                          PRINCIPAL_HANDLE_NONE, false,
+                          now + firstFrameDuration * i);
+    }
+    encoder.AppendVideoSegment(std::move(segment));
+  }
+  encoder.AdvanceCurrentTime(now + firstDuration);
+
+  const TimeDuration secondDuration = TimeDuration::FromSeconds(14);
+  const uint32_t secondNumFrames = 14 * 10;
+  const TimeDuration secondFrameDuration =
+      secondDuration / static_cast<int64_t>(secondNumFrames);
+  {
+    VideoSegment segment;
+    for (uint32_t i = 0; i < secondNumFrames; ++i) {
+      segment.AppendFrame(generator.GenerateI420Image(), generator.GetSize(),
+                          PRINCIPAL_HANDLE_NONE, false,
+                          now + firstDuration + secondFrameDuration * i);
+    }
+    encoder.AppendVideoSegment(std::move(segment));
+  }
+  encoder.AdvanceCurrentTime(now + firstDuration + secondDuration);
+
+  encoder.NotifyEndOfStream();
+
+  EXPECT_TRUE(encoder.IsEncodingComplete());
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+  EXPECT_FALSE(encoder.mEncodedVideoQueue.AtEndOfStream());
+
+  // [0, 11s) - keyframe distance is now 7.5s@2fps = 15.
+  for (uint32_t i = 0; i < 22; ++i) {
+    const RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront();
+    EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 500UL, frame->mDuration)
+        << "Frame " << i << ", with start: " << frame->mTime.ToMicroseconds()
+        << "us";
+    // 7.5s key frame interval at 2 fps becomes the 15th frame.
+    EXPECT_EQ(
+        i % 15 == 0 ? EncodedFrame::VP8_I_FRAME : EncodedFrame::VP8_P_FRAME,
+        frame->mFrameType)
+        << "Frame " << i << ", with start: " << frame->mTime.ToMicroseconds()
+        << "us";
+  }
+
+  // Input framerate is now 10fps.
+  // Framerate re-evaluation every 5s, so the keyframe distance changed at
+  // 15s.
+  for (uint32_t i = 22; i < 162; ++i) {
+    const RefPtr<EncodedFrame> frame = encoder.mEncodedVideoQueue.PopFront();
+    EXPECT_EQ(PR_USEC_PER_SEC / 1000 * 100UL, frame->mDuration)
+        << "Frame " << i << ", with start: " << frame->mTime.ToMicroseconds()
+        << "us";
+    if (i < 22 + 40) {
+      // [11s, 15s) - 40 frames at 10fps but with the 2fps keyframe distance.
+      EXPECT_EQ(
+          i % 15 == 0 ? EncodedFrame::VP8_I_FRAME : EncodedFrame::VP8_P_FRAME,
+          frame->mFrameType)
+          << "Frame " << i << ", with start: " << frame->mTime.ToMicroseconds()
+          << "us";
+    } else {
+      // [15s, 25s) - 100 frames at 10fps. Keyframe distance 75. Starts with
+      // keyframe due to re-init.
+      EXPECT_EQ((i - 22 - 40) % 75 == 0 ? EncodedFrame::VP8_I_FRAME
+                                        : EncodedFrame::VP8_P_FRAME,
+                frame->mFrameType)
+          << "Frame " << i << ", with start: " << frame->mTime.ToMicroseconds()
+          << "us";
+    }
+  }
+
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.AtEndOfStream());
+}
+
+// EOS test
+TEST(VP8VideoTrackEncoder, EncodeComplete)
+{
+  TestVP8TrackEncoder encoder;
+
+  // NotifyEndOfStream should wrap up the encoding immediately.
+  encoder.NotifyEndOfStream();
+  EXPECT_TRUE(encoder.mEncodedVideoQueue.IsFinished());
+}