diff --git a/logging/rtc_event_log/rtc_event_log_parser.cc b/logging/rtc_event_log/rtc_event_log_parser.cc
index 5a3d1aee01..5b7c00de40 100644
--- a/logging/rtc_event_log/rtc_event_log_parser.cc
+++ b/logging/rtc_event_log/rtc_event_log_parser.cc
@@ -57,10 +57,18 @@ constexpr size_t kStunOverhead = 4;
 constexpr uint16_t kDefaultOverhead =
     kUdpOverhead + kSrtpOverhead + kIpv4Overhead;
 
+// Starting at a multiple of common audio sample rate (48000) and video tick
+// rate (90000) to make a tick count of 0 to correspond to something without
+// decimals in base 10. Starting at 0 is not safe as it would cause negative
+// wraparound if the first timestamps are out of order.
+constexpr uint64_t kStartingCaptureTimeTicks = 90 * 48 * 1000;
+
 struct MediaStreamInfo {
-  MediaStreamInfo() = default;
+  MediaStreamInfo() : unwrap_capture_ticks(kStartingCaptureTimeTicks) {}
   MediaStreamInfo(LoggedMediaType media_type, bool rtx)
-      : media_type(media_type), rtx(rtx) {}
+      : media_type(media_type),
+        rtx(rtx),
+        unwrap_capture_ticks(kStartingCaptureTimeTicks) {}
   LoggedMediaType media_type = LoggedMediaType::kUnknown;
   bool rtx = false;
   SeqNumUnwrapper<uint32_t> unwrap_capture_ticks;
@@ -1945,12 +1953,7 @@ std::vector<LoggedPacketInfo> ParsedRtcEventLog::GetPacketInfos(
       // RTX copy the timestamp of the retransmitted packets. This means that
       // RTX streams don't have a unique clock offset and frequency, so
       // the RTP timstamps can't be unwrapped.
-
-      // Add an offset to avoid |capture_ticks| to become negative in the case
-      // of reordering.
-      constexpr int64_t kStartingCaptureTimeTicks = 90 * 48 * 1000;
-      int64_t capture_ticks =
-          kStartingCaptureTimeTicks +
+      uint64_t capture_ticks =
           stream->unwrap_capture_ticks.Unwrap(rtp.header.timestamp);
       // TODO(srte): Use logged sample rate when it is added to the format.
       capture_time = Timestamp::seconds(
diff --git a/modules/video_coding/frame_buffer2.cc b/modules/video_coding/frame_buffer2.cc
index d382b2e8e0..e4def869d2 100644
--- a/modules/video_coding/frame_buffer2.cc
+++ b/modules/video_coding/frame_buffer2.cc
@@ -328,8 +328,11 @@ void FrameBuffer::UpdateRtt(int64_t rtt_ms) {
 }
 
 bool FrameBuffer::ValidReferences(const EncodedFrame& frame) const {
+  if (frame.id.picture_id < 0)
+    return false;
+
   for (size_t i = 0; i < frame.num_references; ++i) {
-    if (frame.references[i] >= frame.id.picture_id)
+    if (frame.references[i] < 0 || frame.references[i] >= frame.id.picture_id)
       return false;
 
     for (size_t j = i + 1; j < frame.num_references; ++j) {
diff --git a/modules/video_coding/loss_notification_controller.cc b/modules/video_coding/loss_notification_controller.cc
index 44cca34abd..6e07bd11be 100644
--- a/modules/video_coding/loss_notification_controller.cc
+++ b/modules/video_coding/loss_notification_controller.cc
@@ -69,7 +69,7 @@ void LossNotificationController::OnReceivedPacket(const VCMPacket& packet) {
 
   if (packet.generic_descriptor->FirstPacketInSubFrame()) {
     const uint16_t frame_id = packet.generic_descriptor->FrameId();
-    const int64_t unwrapped_frame_id = frame_id_unwrapper_.Unwrap(frame_id);
+    const uint64_t unwrapped_frame_id = frame_id_unwrapper_.Unwrap(frame_id);
 
     // Ignore repeated or reordered frames.
     // TODO(TODO(bugs.webrtc.org/10336): Handle frame reordering.
@@ -124,7 +124,7 @@ void LossNotificationController::OnAssembledFrame(
     return;
   }
 
-  const int64_t unwrapped_frame_id = frame_id_unwrapper_.Unwrap(frame_id);
+  const uint64_t unwrapped_frame_id = frame_id_unwrapper_.Unwrap(frame_id);
   if (!AllDependenciesDecodable(unwrapped_frame_id, frame_dependency_diffs)) {
     return;
   }
@@ -142,7 +142,7 @@ void LossNotificationController::DiscardOldInformation() {
 }
 
 bool LossNotificationController::AllDependenciesDecodable(
-    int64_t unwrapped_frame_id,
+    uint64_t unwrapped_frame_id,
     rtc::ArrayView<const uint16_t> frame_dependency_diffs) const {
   RTC_DCHECK_CALLED_SEQUENTIALLY(&sequenced_task_checker_);
 
@@ -154,7 +154,8 @@ bool LossNotificationController::AllDependenciesDecodable(
   // One possibility that is ignored, is that the packet may be corrupt.
 
   for (uint16_t frame_dependency_diff : frame_dependency_diffs) {
-    const int64_t unwrapped_ref_frame_id =
+    RTC_DCHECK_GT(unwrapped_frame_id, frame_dependency_diff);
+    const uint64_t unwrapped_ref_frame_id =
         unwrapped_frame_id - frame_dependency_diff;
 
     const auto ref_frame_it =
diff --git a/modules/video_coding/loss_notification_controller.h b/modules/video_coding/loss_notification_controller.h
index 4cdfbb80f9..a2d640fe23 100644
--- a/modules/video_coding/loss_notification_controller.h
+++ b/modules/video_coding/loss_notification_controller.h
@@ -41,7 +41,7 @@ class LossNotificationController {
   void DiscardOldInformation();
 
   bool AllDependenciesDecodable(
-      int64_t unwrapped_frame_id,
+      uint64_t unwrapped_frame_id,
       rtc::ArrayView<const uint16_t> frame_dependency_diffs) const;
 
   // When the loss of a packet or the non-decodability of a frame is detected,
@@ -70,7 +70,7 @@ class LossNotificationController {
       RTC_GUARDED_BY(sequenced_task_checker_);
 
   // Tracked to avoid processing repeated frames (buggy/malicious remote).
-  absl::optional<int64_t> last_received_unwrapped_frame_id_
+  absl::optional<uint64_t> last_received_unwrapped_frame_id_
       RTC_GUARDED_BY(sequenced_task_checker_);
 
   // Tracked to avoid processing repeated packets.
@@ -97,7 +97,7 @@ class LossNotificationController {
   // Track which frames are decodable. Later frames are also decodable if
   // all of their dependencies can be found in this container.
   // (Naturally, later frames must also be assemblable to be decodable.)
-  std::set<int64_t> decodable_unwrapped_frame_ids_
+  std::set<uint64_t> decodable_unwrapped_frame_ids_
       RTC_GUARDED_BY(sequenced_task_checker_);
 
   rtc::SequencedTaskChecker sequenced_task_checker_;
diff --git a/modules/video_coding/rtp_frame_reference_finder_unittest.cc b/modules/video_coding/rtp_frame_reference_finder_unittest.cc
index 5d8f6f1fcc..1f5016154a 100644
--- a/modules/video_coding/rtp_frame_reference_finder_unittest.cc
+++ b/modules/video_coding/rtp_frame_reference_finder_unittest.cc
@@ -54,6 +54,8 @@ class FakePacketBuffer : public PacketBuffer {
 class TestRtpFrameReferenceFinder : public ::testing::Test,
                                     public OnCompleteFrameCallback {
  protected:
+  static constexpr uint64_t kUnwrappedSequenceStart = 1000000000000000000UL;
+
   TestRtpFrameReferenceFinder()
       : rand_(0x8739211),
         ref_packet_buffer_(new FakePacketBuffer()),
@@ -216,7 +218,7 @@ class TestRtpFrameReferenceFinder : public ::testing::Test,
   void CheckReferences(int64_t picture_id_offset,
                        uint16_t sidx,
                        T... refs) const {
-    int64_t pid = picture_id_offset;
+    int64_t pid = kUnwrappedSequenceStart + picture_id_offset;
     auto frame_it = frames_from_callback_.find(std::make_pair(pid, sidx));
     if (frame_it == frames_from_callback_.end()) {
       ADD_FAILURE() << "Could not find frame with (pid:sidx): (" << pid << ":"
@@ -251,7 +253,7 @@ class TestRtpFrameReferenceFinder : public ::testing::Test,
 
   template <typename... T>
   void RefsToSet(std::set<int64_t>* m, int64_t ref, T... refs) const {
-    m->insert(ref);
+    m->insert(ref + kUnwrappedSequenceStart);
     RefsToSet(m, refs...);
   }
 
@@ -292,8 +294,8 @@ TEST_F(TestRtpFrameReferenceFinder, PaddingPacketsReordered) {
   InsertGeneric(sn + 2, sn + 3, false);
 
   EXPECT_EQ(2UL, frames_from_callback_.size());
-  CheckReferencesGeneric(sn);
-  CheckReferencesGeneric(sn + 3, sn + 0);
+  CheckReferencesGeneric(0);
+  CheckReferencesGeneric(3, 0);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, PaddingPacketsReorderedMultipleKeyframes) {
@@ -375,16 +377,16 @@ TEST_F(TestRtpFrameReferenceFinder, Vp8NoPictureId) {
   InsertVp8(sn + 21, sn + 21, false);
 
   ASSERT_EQ(10UL, frames_from_callback_.size());
-  CheckReferencesVp8(sn + 2);
-  CheckReferencesVp8(sn + 4, sn + 2);
-  CheckReferencesVp8(sn + 8, sn + 4);
-  CheckReferencesVp8(sn + 9, sn + 8);
-  CheckReferencesVp8(sn + 11, sn + 9);
-  CheckReferencesVp8(sn + 12);
-  CheckReferencesVp8(sn + 17, sn + 12);
-  CheckReferencesVp8(sn + 18, sn + 17);
-  CheckReferencesVp8(sn + 20, sn + 18);
-  CheckReferencesVp8(sn + 21, sn + 20);
+  CheckReferencesVp8(0);
+  CheckReferencesVp8(2, 0);
+  CheckReferencesVp8(6, 2);
+  CheckReferencesVp8(7, 6);
+  CheckReferencesVp8(9, 7);
+  CheckReferencesVp8(10);
+  CheckReferencesVp8(15, 10);
+  CheckReferencesVp8(16, 15);
+  CheckReferencesVp8(18, 16);
+  CheckReferencesVp8(19, 18);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp8NoPictureIdReordered) {
@@ -402,16 +404,16 @@ TEST_F(TestRtpFrameReferenceFinder, Vp8NoPictureIdReordered) {
   InsertVp8(sn + 21, sn + 21, false);
 
   ASSERT_EQ(10UL, frames_from_callback_.size());
-  CheckReferencesVp8(sn + 2);
-  CheckReferencesVp8(sn + 4, sn + 2);
-  CheckReferencesVp8(sn + 8, sn + 4);
-  CheckReferencesVp8(sn + 9, sn + 8);
-  CheckReferencesVp8(sn + 11, sn + 9);
-  CheckReferencesVp8(sn + 12);
-  CheckReferencesVp8(sn + 17, sn + 12);
-  CheckReferencesVp8(sn + 18, sn + 17);
-  CheckReferencesVp8(sn + 20, sn + 18);
-  CheckReferencesVp8(sn + 21, sn + 20);
+  CheckReferencesVp8(0);
+  CheckReferencesVp8(2, 0);
+  CheckReferencesVp8(6, 2);
+  CheckReferencesVp8(7, 6);
+  CheckReferencesVp8(9, 7);
+  CheckReferencesVp8(10);
+  CheckReferencesVp8(15, 10);
+  CheckReferencesVp8(16, 15);
+  CheckReferencesVp8(18, 16);
+  CheckReferencesVp8(19, 18);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp8KeyFrameReferences) {
@@ -419,7 +421,7 @@ TEST_F(TestRtpFrameReferenceFinder, Vp8KeyFrameReferences) {
   InsertVp8(sn, sn, true);
 
   ASSERT_EQ(1UL, frames_from_callback_.size());
-  CheckReferencesVp8(sn);
+  CheckReferencesVp8(0);
 }
 
 // Test with 1 temporal layer.
@@ -433,10 +435,10 @@ TEST_F(TestRtpFrameReferenceFinder, Vp8TemporalLayers_0) {
   InsertVp8(sn + 3, sn + 3, false, pid + 3, 0, 4);
 
   ASSERT_EQ(4UL, frames_from_callback_.size());
-  CheckReferencesVp8(pid);
-  CheckReferencesVp8(pid + 1, pid);
-  CheckReferencesVp8(pid + 2, pid + 1);
-  CheckReferencesVp8(pid + 3, pid + 2);
+  CheckReferencesVp8(0);
+  CheckReferencesVp8(1, 0);
+  CheckReferencesVp8(2, 1);
+  CheckReferencesVp8(3, 2);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp8DuplicateTl1Frames) {
@@ -452,12 +454,12 @@ TEST_F(TestRtpFrameReferenceFinder, Vp8DuplicateTl1Frames) {
   InsertVp8(sn + 5, sn + 5, false, pid + 5, 1, 2);
 
   ASSERT_EQ(6UL, frames_from_callback_.size());
-  CheckReferencesVp8(pid);
-  CheckReferencesVp8(pid + 1, pid);
-  CheckReferencesVp8(pid + 2, pid);
-  CheckReferencesVp8(pid + 3, pid + 1, pid + 2);
-  CheckReferencesVp8(pid + 4, pid + 2);
-  CheckReferencesVp8(pid + 5, pid + 3, pid + 4);
+  CheckReferencesVp8(0);
+  CheckReferencesVp8(1, 0);
+  CheckReferencesVp8(2, 0);
+  CheckReferencesVp8(3, 1, 2);
+  CheckReferencesVp8(4, 2);
+  CheckReferencesVp8(5, 3, 4);
 }
 
 // Test with 1 temporal layer.
@@ -474,13 +476,13 @@ TEST_F(TestRtpFrameReferenceFinder, Vp8TemporalLayersReordering_0) {
   InsertVp8(sn + 4, sn + 4, false, pid + 4, 0, 5);
 
   ASSERT_EQ(7UL, frames_from_callback_.size());
-  CheckReferencesVp8(pid);
-  CheckReferencesVp8(pid + 1, pid);
-  CheckReferencesVp8(pid + 2, pid + 1);
-  CheckReferencesVp8(pid + 3, pid + 2);
-  CheckReferencesVp8(pid + 4, pid + 3);
-  CheckReferencesVp8(pid + 5, pid + 4);
-  CheckReferencesVp8(pid + 6, pid + 5);
+  CheckReferencesVp8(0);
+  CheckReferencesVp8(1, 0);
+  CheckReferencesVp8(2, 1);
+  CheckReferencesVp8(3, 2);
+  CheckReferencesVp8(4, 3);
+  CheckReferencesVp8(5, 4);
+  CheckReferencesVp8(6, 5);
 }
 
 // Test with 2 temporal layers in a 01 pattern.
@@ -494,10 +496,10 @@ TEST_F(TestRtpFrameReferenceFinder, Vp8TemporalLayers_01) {
   InsertVp8(sn + 3, sn + 3, false, pid + 3, 1, 0);
 
   ASSERT_EQ(4UL, frames_from_callback_.size());
-  CheckReferencesVp8(pid);
-  CheckReferencesVp8(pid + 1, pid);
-  CheckReferencesVp8(pid + 2, pid);
-  CheckReferencesVp8(pid + 3, pid + 1, pid + 2);
+  CheckReferencesVp8(0);
+  CheckReferencesVp8(1, 0);
+  CheckReferencesVp8(2, 0);
+  CheckReferencesVp8(3, 1, 2);
 }
 
 // Test with 2 temporal layers in a 01 pattern.
@@ -515,14 +517,14 @@ TEST_F(TestRtpFrameReferenceFinder, Vp8TemporalLayersReordering_01) {
   InsertVp8(sn + 7, sn + 7, false, pid + 7, 1, 2);
 
   ASSERT_EQ(8UL, frames_from_callback_.size());
-  CheckReferencesVp8(pid);
-  CheckReferencesVp8(pid + 1, pid);
-  CheckReferencesVp8(pid + 2, pid);
-  CheckReferencesVp8(pid + 3, pid + 1, pid + 2);
-  CheckReferencesVp8(pid + 4, pid + 2);
-  CheckReferencesVp8(pid + 5, pid + 3, pid + 4);
-  CheckReferencesVp8(pid + 6, pid + 4);
-  CheckReferencesVp8(pid + 7, pid + 5, pid + 6);
+  CheckReferencesVp8(0);
+  CheckReferencesVp8(1, 0);
+  CheckReferencesVp8(2, 0);
+  CheckReferencesVp8(3, 1, 2);
+  CheckReferencesVp8(4, 2);
+  CheckReferencesVp8(5, 3, 4);
+  CheckReferencesVp8(6, 4);
+  CheckReferencesVp8(7, 5, 6);
 }
 
 // Test with 3 temporal layers in a 0212 pattern.
@@ -544,18 +546,18 @@ TEST_F(TestRtpFrameReferenceFinder, Vp8TemporalLayers_0212) {
   InsertVp8(sn + 11, sn + 11, false, pid + 11, 2, 57);
 
   ASSERT_EQ(12UL, frames_from_callback_.size());
-  CheckReferencesVp8(pid);
-  CheckReferencesVp8(pid + 1, pid);
-  CheckReferencesVp8(pid + 2, pid);
-  CheckReferencesVp8(pid + 3, pid, pid + 1, pid + 2);
-  CheckReferencesVp8(pid + 4, pid);
-  CheckReferencesVp8(pid + 5, pid + 2, pid + 3, pid + 4);
-  CheckReferencesVp8(pid + 6, pid + 2, pid + 4);
-  CheckReferencesVp8(pid + 7, pid + 4, pid + 5, pid + 6);
-  CheckReferencesVp8(pid + 8, pid + 4);
-  CheckReferencesVp8(pid + 9, pid + 8);
-  CheckReferencesVp8(pid + 10, pid + 8);
-  CheckReferencesVp8(pid + 11, pid + 8, pid + 9, pid + 10);
+  CheckReferencesVp8(0);
+  CheckReferencesVp8(1, 0);
+  CheckReferencesVp8(2, 0);
+  CheckReferencesVp8(3, 0, 1, 2);
+  CheckReferencesVp8(4, 0);
+  CheckReferencesVp8(5, 2, 3, 4);
+  CheckReferencesVp8(6, 2, 4);
+  CheckReferencesVp8(7, 4, 5, 6);
+  CheckReferencesVp8(8, 4);
+  CheckReferencesVp8(9, 8);
+  CheckReferencesVp8(10, 8);
+  CheckReferencesVp8(11, 8, 9, 10);
 }
 
 // Test with 3 temporal layers in a 0212 pattern.
@@ -568,8 +570,8 @@ TEST_F(TestRtpFrameReferenceFinder, Vp8TemporalLayersMissingFrame_0212) {
   InsertVp8(sn + 3, sn + 3, false, pid + 3, 2, 55, false);
 
   ASSERT_EQ(2UL, frames_from_callback_.size());
-  CheckReferencesVp8(pid);
-  CheckReferencesVp8(pid + 2, pid);
+  CheckReferencesVp8(0);
+  CheckReferencesVp8(2, 0);
 }
 
 // Test with 3 temporal layers in a 0212 pattern.
@@ -591,18 +593,18 @@ TEST_F(TestRtpFrameReferenceFinder, Vp8TemporalLayersReordering_0212) {
   InsertVp8(sn + 10, sn + 10, false, pid + 10, 1, 57, true);
 
   ASSERT_EQ(12UL, frames_from_callback_.size());
-  CheckReferencesVp8(pid);
-  CheckReferencesVp8(pid + 1, pid);
-  CheckReferencesVp8(pid + 2, pid);
-  CheckReferencesVp8(pid + 3, pid, pid + 1, pid + 2);
-  CheckReferencesVp8(pid + 4, pid);
-  CheckReferencesVp8(pid + 5, pid + 2, pid + 3, pid + 4);
-  CheckReferencesVp8(pid + 6, pid + 2, pid + 4);
-  CheckReferencesVp8(pid + 7, pid + 4, pid + 5, pid + 6);
-  CheckReferencesVp8(pid + 8, pid + 4);
-  CheckReferencesVp8(pid + 9, pid + 8);
-  CheckReferencesVp8(pid + 10, pid + 8);
-  CheckReferencesVp8(pid + 11, pid + 8, pid + 9, pid + 10);
+  CheckReferencesVp8(0);
+  CheckReferencesVp8(1, 0);
+  CheckReferencesVp8(2, 0);
+  CheckReferencesVp8(3, 0, 1, 2);
+  CheckReferencesVp8(4, 0);
+  CheckReferencesVp8(5, 2, 3, 4);
+  CheckReferencesVp8(6, 2, 4);
+  CheckReferencesVp8(7, 4, 5, 6);
+  CheckReferencesVp8(8, 4);
+  CheckReferencesVp8(9, 8);
+  CheckReferencesVp8(10, 8);
+  CheckReferencesVp8(11, 8, 9, 10);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp8InsertManyFrames_0212) {
@@ -611,6 +613,7 @@ TEST_F(TestRtpFrameReferenceFinder, Vp8InsertManyFrames_0212) {
 
   const int keyframes_to_insert = 50;
   const int frames_per_keyframe = 120;  // Should be a multiple of 4.
+  int64_t offset = 0;
   uint8_t tl0 = 128;
 
   for (int k = 0; k < keyframes_to_insert; ++k) {
@@ -618,29 +621,31 @@ TEST_F(TestRtpFrameReferenceFinder, Vp8InsertManyFrames_0212) {
     InsertVp8(sn + 1, sn + 1, false, pid + 1, 2, tl0, true);
     InsertVp8(sn + 2, sn + 2, false, pid + 2, 1, tl0, true);
     InsertVp8(sn + 3, sn + 3, false, pid + 3, 2, tl0, false);
-    CheckReferencesVp8(pid);
-    CheckReferencesVp8(pid + 1, pid);
-    CheckReferencesVp8(pid + 2, pid);
-    CheckReferencesVp8(pid + 3, pid, pid + 1, pid + 2);
+    CheckReferencesVp8(offset);
+    CheckReferencesVp8(offset + 1, offset);
+    CheckReferencesVp8(offset + 2, offset);
+    CheckReferencesVp8(offset + 3, offset, offset + 1, offset + 2);
     frames_from_callback_.clear();
     ++tl0;
 
     for (int f = 4; f < frames_per_keyframe; f += 4) {
       uint16_t sf = sn + f;
-      int64_t pidf = pid + f;
+      uint16_t pidf = pid + f;
+      int64_t offsetf = offset + f;
 
       InsertVp8(sf, sf, false, pidf, 0, tl0, false);
       InsertVp8(sf + 1, sf + 1, false, pidf + 1, 2, tl0, false);
       InsertVp8(sf + 2, sf + 2, false, pidf + 2, 1, tl0, false);
       InsertVp8(sf + 3, sf + 3, false, pidf + 3, 2, tl0, false);
-      CheckReferencesVp8(pidf, pidf - 4);
-      CheckReferencesVp8(pidf + 1, pidf, pidf - 1, pidf - 2);
-      CheckReferencesVp8(pidf + 2, pidf, pidf - 2);
-      CheckReferencesVp8(pidf + 3, pidf, pidf + 1, pidf + 2);
+      CheckReferencesVp8(offsetf, offsetf - 4);
+      CheckReferencesVp8(offsetf + 1, offsetf, offsetf - 1, offsetf - 2);
+      CheckReferencesVp8(offsetf + 2, offsetf, offsetf - 2);
+      CheckReferencesVp8(offsetf + 3, offsetf, offsetf + 1, offsetf + 2);
       frames_from_callback_.clear();
       ++tl0;
     }
 
+    offset += frames_per_keyframe;
     pid += frames_per_keyframe;
     sn += frames_per_keyframe;
   }
@@ -661,13 +666,13 @@ TEST_F(TestRtpFrameReferenceFinder, Vp8LayerSync) {
   InsertVp8(sn + 7, sn + 7, false, pid + 7, 1, 3, false);
 
   ASSERT_EQ(7UL, frames_from_callback_.size());
-  CheckReferencesVp8(pid);
-  CheckReferencesVp8(pid + 1, pid);
-  CheckReferencesVp8(pid + 2, pid);
-  CheckReferencesVp8(pid + 4, pid + 2);
-  CheckReferencesVp8(pid + 5, pid + 4);
-  CheckReferencesVp8(pid + 6, pid + 4);
-  CheckReferencesVp8(pid + 7, pid + 6, pid + 5);
+  CheckReferencesVp8(0);
+  CheckReferencesVp8(1, 0);
+  CheckReferencesVp8(2, 0);
+  CheckReferencesVp8(4, 2);
+  CheckReferencesVp8(5, 4);
+  CheckReferencesVp8(6, 4);
+  CheckReferencesVp8(7, 6, 5);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp8Tl1SyncFrameAfterTl1Frame) {
@@ -677,9 +682,9 @@ TEST_F(TestRtpFrameReferenceFinder, Vp8Tl1SyncFrameAfterTl1Frame) {
   InsertVp8(1003, 1003, false, 5, 1, 248, true);   // due to this frame.
 
   ASSERT_EQ(3UL, frames_from_callback_.size());
-  CheckReferencesVp8(1);
-  CheckReferencesVp8(3, 1);
-  CheckReferencesVp8(5, 3);
+  CheckReferencesVp8(0);
+  CheckReferencesVp8(2, 0);
+  CheckReferencesVp8(4, 2);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp8DetectMissingFrame_0212) {
@@ -696,15 +701,15 @@ TEST_F(TestRtpFrameReferenceFinder, Vp8DetectMissingFrame_0212) {
   InsertVp8(5, 5, false, 5, 0, 2, false);
   ASSERT_EQ(8UL, frames_from_callback_.size());
 
-  CheckReferencesVp8(1);
-  CheckReferencesVp8(2, 1);
-  CheckReferencesVp8(3, 1);
-  CheckReferencesVp8(4, 3, 2, 1);
+  CheckReferencesVp8(0);
+  CheckReferencesVp8(1, 0);
+  CheckReferencesVp8(2, 0);
+  CheckReferencesVp8(3, 2, 1, 0);
 
-  CheckReferencesVp8(5, 1);
-  CheckReferencesVp8(6, 5, 4, 3);
-  CheckReferencesVp8(7, 5, 3);
-  CheckReferencesVp8(8, 7, 6, 5);
+  CheckReferencesVp8(4, 0);
+  CheckReferencesVp8(5, 4, 3, 2);
+  CheckReferencesVp8(6, 4, 2);
+  CheckReferencesVp8(7, 6, 5, 4);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp9GofInsertOneFrame) {
@@ -715,7 +720,7 @@ TEST_F(TestRtpFrameReferenceFinder, Vp9GofInsertOneFrame) {
 
   InsertVp9Gof(sn, sn, true, pid, 0, 0, 0, false, false, &ss);
 
-  CheckReferencesVp9(pid, 0);
+  CheckReferencesVp9(0, 0);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp9NoPictureIdReordered) {
@@ -733,16 +738,16 @@ TEST_F(TestRtpFrameReferenceFinder, Vp9NoPictureIdReordered) {
   InsertVp9Gof(sn + 18, sn + 18, false);
 
   ASSERT_EQ(10UL, frames_from_callback_.size());
-  CheckReferencesVp9(sn + 2, 0);
-  CheckReferencesVp9(sn + 4, 0, sn + 2);
-  CheckReferencesVp9(sn + 8, 0, sn + 4);
-  CheckReferencesVp9(sn + 9, 0, sn + 8);
-  CheckReferencesVp9(sn + 11, 0, sn + 9);
-  CheckReferencesVp9(sn + 12, 0);
-  CheckReferencesVp9(sn + 17, 0, sn + 12);
-  CheckReferencesVp9(sn + 18, 0, sn + 17);
-  CheckReferencesVp9(sn + 20, 0, sn + 18);
-  CheckReferencesVp9(sn + 21, 0, sn + 20);
+  CheckReferencesVp9(0, 0);
+  CheckReferencesVp9(2, 0, 0);
+  CheckReferencesVp9(6, 0, 2);
+  CheckReferencesVp9(7, 0, 6);
+  CheckReferencesVp9(9, 0, 7);
+  CheckReferencesVp9(10, 0);
+  CheckReferencesVp9(15, 0, 10);
+  CheckReferencesVp9(16, 0, 15);
+  CheckReferencesVp9(18, 0, 16);
+  CheckReferencesVp9(19, 0, 18);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp9GofTemporalLayers_0) {
@@ -773,26 +778,26 @@ TEST_F(TestRtpFrameReferenceFinder, Vp9GofTemporalLayers_0) {
   InsertVp9Gof(sn + 19, sn + 19, false, pid + 19, 0, 0, 19, false);
 
   ASSERT_EQ(20UL, frames_from_callback_.size());
-  CheckReferencesVp9(pid, 0);
-  CheckReferencesVp9(pid + 1, 0, pid);
-  CheckReferencesVp9(pid + 2, 0, pid + 1);
-  CheckReferencesVp9(pid + 3, 0, pid + 2);
-  CheckReferencesVp9(pid + 4, 0, pid + 3);
-  CheckReferencesVp9(pid + 5, 0, pid + 4);
-  CheckReferencesVp9(pid + 6, 0, pid + 5);
-  CheckReferencesVp9(pid + 7, 0, pid + 6);
-  CheckReferencesVp9(pid + 8, 0, pid + 7);
-  CheckReferencesVp9(pid + 9, 0, pid + 8);
-  CheckReferencesVp9(pid + 10, 0, pid + 9);
-  CheckReferencesVp9(pid + 11, 0, pid + 10);
-  CheckReferencesVp9(pid + 12, 0, pid + 11);
-  CheckReferencesVp9(pid + 13, 0, pid + 12);
-  CheckReferencesVp9(pid + 14, 0, pid + 13);
-  CheckReferencesVp9(pid + 15, 0, pid + 14);
-  CheckReferencesVp9(pid + 16, 0, pid + 15);
-  CheckReferencesVp9(pid + 17, 0, pid + 16);
-  CheckReferencesVp9(pid + 18, 0, pid + 17);
-  CheckReferencesVp9(pid + 19, 0, pid + 18);
+  CheckReferencesVp9(0, 0);
+  CheckReferencesVp9(1, 0, 0);
+  CheckReferencesVp9(2, 0, 1);
+  CheckReferencesVp9(3, 0, 2);
+  CheckReferencesVp9(4, 0, 3);
+  CheckReferencesVp9(5, 0, 4);
+  CheckReferencesVp9(6, 0, 5);
+  CheckReferencesVp9(7, 0, 6);
+  CheckReferencesVp9(8, 0, 7);
+  CheckReferencesVp9(9, 0, 8);
+  CheckReferencesVp9(10, 0, 9);
+  CheckReferencesVp9(11, 0, 10);
+  CheckReferencesVp9(12, 0, 11);
+  CheckReferencesVp9(13, 0, 12);
+  CheckReferencesVp9(14, 0, 13);
+  CheckReferencesVp9(15, 0, 14);
+  CheckReferencesVp9(16, 0, 15);
+  CheckReferencesVp9(17, 0, 16);
+  CheckReferencesVp9(18, 0, 17);
+  CheckReferencesVp9(19, 0, 18);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp9GofSpatialLayers_2) {
@@ -809,11 +814,11 @@ TEST_F(TestRtpFrameReferenceFinder, Vp9GofSpatialLayers_2) {
   InsertVp9Gof(sn + 4, sn + 4, false, pid + 2, 1, 0, 1, false, true);
 
   ASSERT_EQ(5UL, frames_from_callback_.size());
-  CheckReferencesVp9(pid, 0);
-  CheckReferencesVp9(pid + 1, 0, pid);
-  CheckReferencesVp9(pid + 1, 1);
-  CheckReferencesVp9(pid + 2, 0, pid + 1);
-  CheckReferencesVp9(pid + 2, 1, pid + 1);
+  CheckReferencesVp9(0, 0);
+  CheckReferencesVp9(1, 0, 0);
+  CheckReferencesVp9(1, 1);
+  CheckReferencesVp9(2, 0, 1);
+  CheckReferencesVp9(2, 1, 1);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp9GofTemporalLayersReordered_0) {
@@ -844,26 +849,26 @@ TEST_F(TestRtpFrameReferenceFinder, Vp9GofTemporalLayersReordered_0) {
   InsertVp9Gof(sn + 18, sn + 18, false, pid + 18, 0, 0, 18, false);
 
   ASSERT_EQ(20UL, frames_from_callback_.size());
-  CheckReferencesVp9(pid, 0);
-  CheckReferencesVp9(pid + 1, 0, pid);
-  CheckReferencesVp9(pid + 2, 0, pid + 1);
-  CheckReferencesVp9(pid + 3, 0, pid + 2);
-  CheckReferencesVp9(pid + 4, 0, pid + 3);
-  CheckReferencesVp9(pid + 5, 0, pid + 4);
-  CheckReferencesVp9(pid + 6, 0, pid + 5);
-  CheckReferencesVp9(pid + 7, 0, pid + 6);
-  CheckReferencesVp9(pid + 8, 0, pid + 7);
-  CheckReferencesVp9(pid + 9, 0, pid + 8);
-  CheckReferencesVp9(pid + 10, 0, pid + 9);
-  CheckReferencesVp9(pid + 11, 0, pid + 10);
-  CheckReferencesVp9(pid + 12, 0, pid + 11);
-  CheckReferencesVp9(pid + 13, 0, pid + 12);
-  CheckReferencesVp9(pid + 14, 0, pid + 13);
-  CheckReferencesVp9(pid + 15, 0, pid + 14);
-  CheckReferencesVp9(pid + 16, 0, pid + 15);
-  CheckReferencesVp9(pid + 17, 0, pid + 16);
-  CheckReferencesVp9(pid + 18, 0, pid + 17);
-  CheckReferencesVp9(pid + 19, 0, pid + 18);
+  CheckReferencesVp9(0, 0);
+  CheckReferencesVp9(1, 0, 0);
+  CheckReferencesVp9(2, 0, 1);
+  CheckReferencesVp9(3, 0, 2);
+  CheckReferencesVp9(4, 0, 3);
+  CheckReferencesVp9(5, 0, 4);
+  CheckReferencesVp9(6, 0, 5);
+  CheckReferencesVp9(7, 0, 6);
+  CheckReferencesVp9(8, 0, 7);
+  CheckReferencesVp9(9, 0, 8);
+  CheckReferencesVp9(10, 0, 9);
+  CheckReferencesVp9(11, 0, 10);
+  CheckReferencesVp9(12, 0, 11);
+  CheckReferencesVp9(13, 0, 12);
+  CheckReferencesVp9(14, 0, 13);
+  CheckReferencesVp9(15, 0, 14);
+  CheckReferencesVp9(16, 0, 15);
+  CheckReferencesVp9(17, 0, 16);
+  CheckReferencesVp9(18, 0, 17);
+  CheckReferencesVp9(19, 0, 18);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp9GofSkipFramesTemporalLayers_01) {
@@ -883,12 +888,12 @@ TEST_F(TestRtpFrameReferenceFinder, Vp9GofSkipFramesTemporalLayers_01) {
   InsertVp9Gof(sn + 11, sn + 11, false, pid + 11, 0, 1, 5, false);
 
   ASSERT_EQ(6UL, frames_from_callback_.size());
-  CheckReferencesVp9(pid, 0);
-  CheckReferencesVp9(pid + 1, 0, pid);
-  CheckReferencesVp9(pid + 4, 0);
-  CheckReferencesVp9(pid + 5, 0, pid + 4);
-  CheckReferencesVp9(pid + 10, 0, pid + 8);
-  CheckReferencesVp9(pid + 11, 0, pid + 10);
+  CheckReferencesVp9(0, 0);
+  CheckReferencesVp9(1, 0, 0);
+  CheckReferencesVp9(4, 0);
+  CheckReferencesVp9(5, 0, 4);
+  CheckReferencesVp9(10, 0, 8);
+  CheckReferencesVp9(11, 0, 10);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp9GofSkipFramesTemporalLayers_0212) {
@@ -903,10 +908,10 @@ TEST_F(TestRtpFrameReferenceFinder, Vp9GofSkipFramesTemporalLayers_0212) {
   InsertVp9Gof(sn + 3, sn + 3, false, pid + 3, 0, 2, 0, false);
 
   ASSERT_EQ(4UL, frames_from_callback_.size());
-  CheckReferencesVp9(pid, 0);
-  CheckReferencesVp9(pid + 1, 0, pid);
-  CheckReferencesVp9(pid + 2, 0, pid);
-  CheckReferencesVp9(pid + 3, 0, pid + 2);
+  CheckReferencesVp9(0, 0);
+  CheckReferencesVp9(1, 0, 0);
+  CheckReferencesVp9(2, 0, 0);
+  CheckReferencesVp9(3, 0, 2);
 
   // Skip frames with tl0 = 1
 
@@ -916,26 +921,26 @@ TEST_F(TestRtpFrameReferenceFinder, Vp9GofSkipFramesTemporalLayers_0212) {
   InsertVp9Gof(sn + 11, sn + 11, false, pid + 11, 0, 2, 2, false);
 
   ASSERT_EQ(8UL, frames_from_callback_.size());
-  CheckReferencesVp9(pid + 8, 0);
-  CheckReferencesVp9(pid + 9, 0, pid + 8);
-  CheckReferencesVp9(pid + 10, 0, pid + 8);
-  CheckReferencesVp9(pid + 11, 0, pid + 10);
+  CheckReferencesVp9(8, 0);
+  CheckReferencesVp9(9, 0, 8);
+  CheckReferencesVp9(10, 0, 8);
+  CheckReferencesVp9(11, 0, 10);
 
   // Now insert frames with tl0 = 1
   InsertVp9Gof(sn + 4, sn + 4, true, pid + 4, 0, 0, 1, false, true, &ss);
   InsertVp9Gof(sn + 7, sn + 7, false, pid + 7, 0, 2, 1, false);
 
   ASSERT_EQ(9UL, frames_from_callback_.size());
-  CheckReferencesVp9(pid + 4, 0);
+  CheckReferencesVp9(4, 0);
 
   // Rest of frames belonging to tl0 = 1
   InsertVp9Gof(sn + 5, sn + 5, false, pid + 5, 0, 2, 1, false);
   InsertVp9Gof(sn + 6, sn + 6, false, pid + 6, 0, 1, 1, true);  // up-switch
 
   ASSERT_EQ(12UL, frames_from_callback_.size());
-  CheckReferencesVp9(pid + 5, 0, pid + 4);
-  CheckReferencesVp9(pid + 6, 0, pid + 4);
-  CheckReferencesVp9(pid + 7, 0, pid + 6);
+  CheckReferencesVp9(5, 0, 4);
+  CheckReferencesVp9(6, 0, 4);
+  CheckReferencesVp9(7, 0, 6);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp9GofTemporalLayers_01) {
@@ -966,26 +971,26 @@ TEST_F(TestRtpFrameReferenceFinder, Vp9GofTemporalLayers_01) {
   InsertVp9Gof(sn + 19, sn + 19, false, pid + 19, 0, 1, 9, false);
 
   ASSERT_EQ(20UL, frames_from_callback_.size());
-  CheckReferencesVp9(pid, 0);
-  CheckReferencesVp9(pid + 1, 0, pid);
-  CheckReferencesVp9(pid + 2, 0, pid);
-  CheckReferencesVp9(pid + 3, 0, pid + 2);
-  CheckReferencesVp9(pid + 4, 0, pid + 2);
-  CheckReferencesVp9(pid + 5, 0, pid + 4);
-  CheckReferencesVp9(pid + 6, 0, pid + 4);
-  CheckReferencesVp9(pid + 7, 0, pid + 6);
-  CheckReferencesVp9(pid + 8, 0, pid + 6);
-  CheckReferencesVp9(pid + 9, 0, pid + 8);
-  CheckReferencesVp9(pid + 10, 0, pid + 8);
-  CheckReferencesVp9(pid + 11, 0, pid + 10);
-  CheckReferencesVp9(pid + 12, 0, pid + 10);
-  CheckReferencesVp9(pid + 13, 0, pid + 12);
-  CheckReferencesVp9(pid + 14, 0, pid + 12);
-  CheckReferencesVp9(pid + 15, 0, pid + 14);
-  CheckReferencesVp9(pid + 16, 0, pid + 14);
-  CheckReferencesVp9(pid + 17, 0, pid + 16);
-  CheckReferencesVp9(pid + 18, 0, pid + 16);
-  CheckReferencesVp9(pid + 19, 0, pid + 18);
+  CheckReferencesVp9(0, 0);
+  CheckReferencesVp9(1, 0, 0);
+  CheckReferencesVp9(2, 0, 0);
+  CheckReferencesVp9(3, 0, 2);
+  CheckReferencesVp9(4, 0, 2);
+  CheckReferencesVp9(5, 0, 4);
+  CheckReferencesVp9(6, 0, 4);
+  CheckReferencesVp9(7, 0, 6);
+  CheckReferencesVp9(8, 0, 6);
+  CheckReferencesVp9(9, 0, 8);
+  CheckReferencesVp9(10, 0, 8);
+  CheckReferencesVp9(11, 0, 10);
+  CheckReferencesVp9(12, 0, 10);
+  CheckReferencesVp9(13, 0, 12);
+  CheckReferencesVp9(14, 0, 12);
+  CheckReferencesVp9(15, 0, 14);
+  CheckReferencesVp9(16, 0, 14);
+  CheckReferencesVp9(17, 0, 16);
+  CheckReferencesVp9(18, 0, 16);
+  CheckReferencesVp9(19, 0, 18);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp9GofTemporalLayersReordered_01) {
@@ -1016,26 +1021,26 @@ TEST_F(TestRtpFrameReferenceFinder, Vp9GofTemporalLayersReordered_01) {
   InsertVp9Gof(sn + 18, sn + 18, false, pid + 18, 0, 0, 9, false);
 
   ASSERT_EQ(20UL, frames_from_callback_.size());
-  CheckReferencesVp9(pid, 0);
-  CheckReferencesVp9(pid + 1, 0, pid);
-  CheckReferencesVp9(pid + 2, 0, pid);
-  CheckReferencesVp9(pid + 3, 0, pid + 2);
-  CheckReferencesVp9(pid + 4, 0, pid + 2);
-  CheckReferencesVp9(pid + 5, 0, pid + 4);
-  CheckReferencesVp9(pid + 6, 0, pid + 4);
-  CheckReferencesVp9(pid + 7, 0, pid + 6);
-  CheckReferencesVp9(pid + 8, 0, pid + 6);
-  CheckReferencesVp9(pid + 9, 0, pid + 8);
-  CheckReferencesVp9(pid + 10, 0, pid + 8);
-  CheckReferencesVp9(pid + 11, 0, pid + 10);
-  CheckReferencesVp9(pid + 12, 0, pid + 10);
-  CheckReferencesVp9(pid + 13, 0, pid + 12);
-  CheckReferencesVp9(pid + 14, 0, pid + 12);
-  CheckReferencesVp9(pid + 15, 0, pid + 14);
-  CheckReferencesVp9(pid + 16, 0, pid + 14);
-  CheckReferencesVp9(pid + 17, 0, pid + 16);
-  CheckReferencesVp9(pid + 18, 0, pid + 16);
-  CheckReferencesVp9(pid + 19, 0, pid + 18);
+  CheckReferencesVp9(0, 0);
+  CheckReferencesVp9(1, 0, 0);
+  CheckReferencesVp9(2, 0, 0);
+  CheckReferencesVp9(3, 0, 2);
+  CheckReferencesVp9(4, 0, 2);
+  CheckReferencesVp9(5, 0, 4);
+  CheckReferencesVp9(6, 0, 4);
+  CheckReferencesVp9(7, 0, 6);
+  CheckReferencesVp9(8, 0, 6);
+  CheckReferencesVp9(9, 0, 8);
+  CheckReferencesVp9(10, 0, 8);
+  CheckReferencesVp9(11, 0, 10);
+  CheckReferencesVp9(12, 0, 10);
+  CheckReferencesVp9(13, 0, 12);
+  CheckReferencesVp9(14, 0, 12);
+  CheckReferencesVp9(15, 0, 14);
+  CheckReferencesVp9(16, 0, 14);
+  CheckReferencesVp9(17, 0, 16);
+  CheckReferencesVp9(18, 0, 16);
+  CheckReferencesVp9(19, 0, 18);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp9GofTemporalLayers_0212) {
@@ -1066,26 +1071,26 @@ TEST_F(TestRtpFrameReferenceFinder, Vp9GofTemporalLayers_0212) {
   InsertVp9Gof(sn + 19, sn + 19, false, pid + 19, 0, 2, 4, false);
 
   ASSERT_EQ(20UL, frames_from_callback_.size());
-  CheckReferencesVp9(pid, 0);
-  CheckReferencesVp9(pid + 1, 0, pid);
-  CheckReferencesVp9(pid + 2, 0, pid);
-  CheckReferencesVp9(pid + 3, 0, pid + 2);
-  CheckReferencesVp9(pid + 4, 0, pid);
-  CheckReferencesVp9(pid + 5, 0, pid + 4);
-  CheckReferencesVp9(pid + 6, 0, pid + 4);
-  CheckReferencesVp9(pid + 7, 0, pid + 6);
-  CheckReferencesVp9(pid + 8, 0, pid + 4);
-  CheckReferencesVp9(pid + 9, 0, pid + 8);
-  CheckReferencesVp9(pid + 10, 0, pid + 8);
-  CheckReferencesVp9(pid + 11, 0, pid + 10);
-  CheckReferencesVp9(pid + 12, 0, pid + 8);
-  CheckReferencesVp9(pid + 13, 0, pid + 12);
-  CheckReferencesVp9(pid + 14, 0, pid + 12);
-  CheckReferencesVp9(pid + 15, 0, pid + 14);
-  CheckReferencesVp9(pid + 16, 0, pid + 12);
-  CheckReferencesVp9(pid + 17, 0, pid + 16);
-  CheckReferencesVp9(pid + 18, 0, pid + 16);
-  CheckReferencesVp9(pid + 19, 0, pid + 18);
+  CheckReferencesVp9(0, 0);
+  CheckReferencesVp9(1, 0, 0);
+  CheckReferencesVp9(2, 0, 0);
+  CheckReferencesVp9(3, 0, 2);
+  CheckReferencesVp9(4, 0, 0);
+  CheckReferencesVp9(5, 0, 4);
+  CheckReferencesVp9(6, 0, 4);
+  CheckReferencesVp9(7, 0, 6);
+  CheckReferencesVp9(8, 0, 4);
+  CheckReferencesVp9(9, 0, 8);
+  CheckReferencesVp9(10, 0, 8);
+  CheckReferencesVp9(11, 0, 10);
+  CheckReferencesVp9(12, 0, 8);
+  CheckReferencesVp9(13, 0, 12);
+  CheckReferencesVp9(14, 0, 12);
+  CheckReferencesVp9(15, 0, 14);
+  CheckReferencesVp9(16, 0, 12);
+  CheckReferencesVp9(17, 0, 16);
+  CheckReferencesVp9(18, 0, 16);
+  CheckReferencesVp9(19, 0, 18);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp9GofTemporalLayersReordered_0212) {
@@ -1116,26 +1121,26 @@ TEST_F(TestRtpFrameReferenceFinder, Vp9GofTemporalLayersReordered_0212) {
   InsertVp9Gof(sn + 18, sn + 18, false, pid + 18, 0, 1, 4, false);
 
   ASSERT_EQ(20UL, frames_from_callback_.size());
-  CheckReferencesVp9(pid, 0);
-  CheckReferencesVp9(pid + 1, 0, pid);
-  CheckReferencesVp9(pid + 2, 0, pid);
-  CheckReferencesVp9(pid + 3, 0, pid + 2);
-  CheckReferencesVp9(pid + 4, 0, pid);
-  CheckReferencesVp9(pid + 5, 0, pid + 4);
-  CheckReferencesVp9(pid + 6, 0, pid + 4);
-  CheckReferencesVp9(pid + 7, 0, pid + 6);
-  CheckReferencesVp9(pid + 8, 0, pid + 4);
-  CheckReferencesVp9(pid + 9, 0, pid + 8);
-  CheckReferencesVp9(pid + 10, 0, pid + 8);
-  CheckReferencesVp9(pid + 11, 0, pid + 10);
-  CheckReferencesVp9(pid + 12, 0, pid + 8);
-  CheckReferencesVp9(pid + 13, 0, pid + 12);
-  CheckReferencesVp9(pid + 14, 0, pid + 12);
-  CheckReferencesVp9(pid + 15, 0, pid + 14);
-  CheckReferencesVp9(pid + 16, 0, pid + 12);
-  CheckReferencesVp9(pid + 17, 0, pid + 16);
-  CheckReferencesVp9(pid + 18, 0, pid + 16);
-  CheckReferencesVp9(pid + 19, 0, pid + 18);
+  CheckReferencesVp9(0, 0);
+  CheckReferencesVp9(1, 0, 0);
+  CheckReferencesVp9(2, 0, 0);
+  CheckReferencesVp9(3, 0, 2);
+  CheckReferencesVp9(4, 0, 0);
+  CheckReferencesVp9(5, 0, 4);
+  CheckReferencesVp9(6, 0, 4);
+  CheckReferencesVp9(7, 0, 6);
+  CheckReferencesVp9(8, 0, 4);
+  CheckReferencesVp9(9, 0, 8);
+  CheckReferencesVp9(10, 0, 8);
+  CheckReferencesVp9(11, 0, 10);
+  CheckReferencesVp9(12, 0, 8);
+  CheckReferencesVp9(13, 0, 12);
+  CheckReferencesVp9(14, 0, 12);
+  CheckReferencesVp9(15, 0, 14);
+  CheckReferencesVp9(16, 0, 12);
+  CheckReferencesVp9(17, 0, 16);
+  CheckReferencesVp9(18, 0, 16);
+  CheckReferencesVp9(19, 0, 18);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp9GofTemporalLayersUpSwitch_02120212) {
@@ -1162,22 +1167,22 @@ TEST_F(TestRtpFrameReferenceFinder, Vp9GofTemporalLayersUpSwitch_02120212) {
   InsertVp9Gof(sn + 15, sn + 15, false, pid + 15, 0, 2, 3, false);
 
   ASSERT_EQ(16UL, frames_from_callback_.size());
-  CheckReferencesVp9(pid, 0);
-  CheckReferencesVp9(pid + 1, 0, pid);
-  CheckReferencesVp9(pid + 2, 0, pid);
-  CheckReferencesVp9(pid + 3, 0, pid + 1, pid + 2);
-  CheckReferencesVp9(pid + 4, 0, pid);
-  CheckReferencesVp9(pid + 5, 0, pid + 3, pid + 4);
-  CheckReferencesVp9(pid + 6, 0, pid + 2, pid + 4);
-  CheckReferencesVp9(pid + 7, 0, pid + 6);
-  CheckReferencesVp9(pid + 8, 0, pid + 4);
-  CheckReferencesVp9(pid + 9, 0, pid + 8);
-  CheckReferencesVp9(pid + 10, 0, pid + 8);
-  CheckReferencesVp9(pid + 11, 0, pid + 9, pid + 10);
-  CheckReferencesVp9(pid + 12, 0, pid + 8);
-  CheckReferencesVp9(pid + 13, 0, pid + 11, pid + 12);
-  CheckReferencesVp9(pid + 14, 0, pid + 10, pid + 12);
-  CheckReferencesVp9(pid + 15, 0, pid + 13, pid + 14);
+  CheckReferencesVp9(0, 0);
+  CheckReferencesVp9(1, 0, 0);
+  CheckReferencesVp9(2, 0, 0);
+  CheckReferencesVp9(3, 0, 1, 2);
+  CheckReferencesVp9(4, 0, 0);
+  CheckReferencesVp9(5, 0, 3, 4);
+  CheckReferencesVp9(6, 0, 2, 4);
+  CheckReferencesVp9(7, 0, 6);
+  CheckReferencesVp9(8, 0, 4);
+  CheckReferencesVp9(9, 0, 8);
+  CheckReferencesVp9(10, 0, 8);
+  CheckReferencesVp9(11, 0, 9, 10);
+  CheckReferencesVp9(12, 0, 8);
+  CheckReferencesVp9(13, 0, 11, 12);
+  CheckReferencesVp9(14, 0, 10, 12);
+  CheckReferencesVp9(15, 0, 13, 14);
 }
 
 TEST_F(TestRtpFrameReferenceFinder,
@@ -1205,22 +1210,22 @@ TEST_F(TestRtpFrameReferenceFinder,
   InsertVp9Gof(sn + 14, sn + 14, false, pid + 14, 0, 1, 3, false);
 
   ASSERT_EQ(16UL, frames_from_callback_.size());
-  CheckReferencesVp9(pid, 0);
-  CheckReferencesVp9(pid + 1, 0, pid);
-  CheckReferencesVp9(pid + 2, 0, pid);
-  CheckReferencesVp9(pid + 3, 0, pid + 1, pid + 2);
-  CheckReferencesVp9(pid + 4, 0, pid);
-  CheckReferencesVp9(pid + 5, 0, pid + 3, pid + 4);
-  CheckReferencesVp9(pid + 6, 0, pid + 2, pid + 4);
-  CheckReferencesVp9(pid + 7, 0, pid + 6);
-  CheckReferencesVp9(pid + 8, 0, pid + 4);
-  CheckReferencesVp9(pid + 9, 0, pid + 8);
-  CheckReferencesVp9(pid + 10, 0, pid + 8);
-  CheckReferencesVp9(pid + 11, 0, pid + 9, pid + 10);
-  CheckReferencesVp9(pid + 12, 0, pid + 8);
-  CheckReferencesVp9(pid + 13, 0, pid + 11, pid + 12);
-  CheckReferencesVp9(pid + 14, 0, pid + 10, pid + 12);
-  CheckReferencesVp9(pid + 15, 0, pid + 13, pid + 14);
+  CheckReferencesVp9(0, 0);
+  CheckReferencesVp9(1, 0, 0);
+  CheckReferencesVp9(2, 0, 0);
+  CheckReferencesVp9(3, 0, 1, 2);
+  CheckReferencesVp9(4, 0, 0);
+  CheckReferencesVp9(5, 0, 3, 4);
+  CheckReferencesVp9(6, 0, 2, 4);
+  CheckReferencesVp9(7, 0, 6);
+  CheckReferencesVp9(8, 0, 4);
+  CheckReferencesVp9(9, 0, 8);
+  CheckReferencesVp9(10, 0, 8);
+  CheckReferencesVp9(11, 0, 9, 10);
+  CheckReferencesVp9(12, 0, 8);
+  CheckReferencesVp9(13, 0, 11, 12);
+  CheckReferencesVp9(14, 0, 10, 12);
+  CheckReferencesVp9(15, 0, 13, 14);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp9GofTemporalLayersReordered_01_0212) {
@@ -1244,18 +1249,18 @@ TEST_F(TestRtpFrameReferenceFinder, Vp9GofTemporalLayersReordered_01_0212) {
   InsertVp9Gof(sn + 9, sn + 9, false, pid + 9, 0, 2, 3, false);
 
   ASSERT_EQ(12UL, frames_from_callback_.size());
-  CheckReferencesVp9(pid, 0);
-  CheckReferencesVp9(pid + 1, 0, pid);
-  CheckReferencesVp9(pid + 2, 0, pid);
-  CheckReferencesVp9(pid + 3, 0, pid + 2);
-  CheckReferencesVp9(pid + 4, 0, pid);
-  CheckReferencesVp9(pid + 5, 0, pid + 4);
-  CheckReferencesVp9(pid + 6, 0, pid + 4);
-  CheckReferencesVp9(pid + 7, 0, pid + 6);
-  CheckReferencesVp9(pid + 8, 0, pid + 4);
-  CheckReferencesVp9(pid + 9, 0, pid + 8);
-  CheckReferencesVp9(pid + 10, 0, pid + 8);
-  CheckReferencesVp9(pid + 11, 0, pid + 10);
+  CheckReferencesVp9(0, 0);
+  CheckReferencesVp9(1, 0, 0);
+  CheckReferencesVp9(2, 0, 0);
+  CheckReferencesVp9(3, 0, 2);
+  CheckReferencesVp9(4, 0, 0);
+  CheckReferencesVp9(5, 0, 4);
+  CheckReferencesVp9(6, 0, 4);
+  CheckReferencesVp9(7, 0, 6);
+  CheckReferencesVp9(8, 0, 4);
+  CheckReferencesVp9(9, 0, 8);
+  CheckReferencesVp9(10, 0, 8);
+  CheckReferencesVp9(11, 0, 10);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp9FlexibleModeOneFrame) {
@@ -1265,7 +1270,7 @@ TEST_F(TestRtpFrameReferenceFinder, Vp9FlexibleModeOneFrame) {
   InsertVp9Flex(sn, sn, true, pid, 0, 0, false);
 
   ASSERT_EQ(1UL, frames_from_callback_.size());
-  CheckReferencesVp9(pid, 0);
+  CheckReferencesVp9(0, 0);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp9FlexibleModeTwoSpatialLayers) {
@@ -1288,20 +1293,20 @@ TEST_F(TestRtpFrameReferenceFinder, Vp9FlexibleModeTwoSpatialLayers) {
   InsertVp9Flex(sn + 13, sn + 13, false, pid + 8, 1, 0, false, {1});
 
   ASSERT_EQ(14UL, frames_from_callback_.size());
-  CheckReferencesVp9(pid, 0);
-  CheckReferencesVp9(pid, 1);
-  CheckReferencesVp9(pid + 1, 1, pid);
-  CheckReferencesVp9(pid + 2, 0, pid);
-  CheckReferencesVp9(pid + 2, 1, pid + 1);
-  CheckReferencesVp9(pid + 3, 1, pid + 2);
-  CheckReferencesVp9(pid + 4, 0, pid + 2);
-  CheckReferencesVp9(pid + 4, 1, pid + 3);
-  CheckReferencesVp9(pid + 5, 1, pid + 4);
-  CheckReferencesVp9(pid + 6, 0, pid + 4);
-  CheckReferencesVp9(pid + 6, 1, pid + 5);
-  CheckReferencesVp9(pid + 7, 1, pid + 6);
-  CheckReferencesVp9(pid + 8, 0, pid + 6);
-  CheckReferencesVp9(pid + 8, 1, pid + 7);
+  CheckReferencesVp9(0, 0);
+  CheckReferencesVp9(0, 1);
+  CheckReferencesVp9(1, 1, 0);
+  CheckReferencesVp9(2, 0, 0);
+  CheckReferencesVp9(2, 1, 1);
+  CheckReferencesVp9(3, 1, 2);
+  CheckReferencesVp9(4, 0, 2);
+  CheckReferencesVp9(4, 1, 3);
+  CheckReferencesVp9(5, 1, 4);
+  CheckReferencesVp9(6, 0, 4);
+  CheckReferencesVp9(6, 1, 5);
+  CheckReferencesVp9(7, 1, 6);
+  CheckReferencesVp9(8, 0, 6);
+  CheckReferencesVp9(8, 1, 7);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp9FlexibleModeTwoSpatialLayersReordered) {
@@ -1324,28 +1329,27 @@ TEST_F(TestRtpFrameReferenceFinder, Vp9FlexibleModeTwoSpatialLayersReordered) {
   InsertVp9Flex(sn + 12, sn + 12, false, pid + 8, 0, 0, false, {2});
 
   ASSERT_EQ(14UL, frames_from_callback_.size());
-  CheckReferencesVp9(pid, 0);
-  CheckReferencesVp9(pid, 1);
-  CheckReferencesVp9(pid + 1, 1, pid);
-  CheckReferencesVp9(pid + 2, 0, pid);
-  CheckReferencesVp9(pid + 2, 1, pid + 1);
-  CheckReferencesVp9(pid + 3, 1, pid + 2);
-  CheckReferencesVp9(pid + 4, 0, pid + 2);
-  CheckReferencesVp9(pid + 4, 1, pid + 3);
-  CheckReferencesVp9(pid + 5, 1, pid + 4);
-  CheckReferencesVp9(pid + 6, 0, pid + 4);
-  CheckReferencesVp9(pid + 6, 1, pid + 5);
-  CheckReferencesVp9(pid + 7, 1, pid + 6);
-  CheckReferencesVp9(pid + 8, 0, pid + 6);
-  CheckReferencesVp9(pid + 8, 1, pid + 7);
+  CheckReferencesVp9(0, 0);
+  CheckReferencesVp9(0, 1);
+  CheckReferencesVp9(1, 1, 0);
+  CheckReferencesVp9(2, 0, 0);
+  CheckReferencesVp9(2, 1, 1);
+  CheckReferencesVp9(3, 1, 2);
+  CheckReferencesVp9(4, 0, 2);
+  CheckReferencesVp9(4, 1, 3);
+  CheckReferencesVp9(5, 1, 4);
+  CheckReferencesVp9(6, 0, 4);
+  CheckReferencesVp9(6, 1, 5);
+  CheckReferencesVp9(7, 1, 6);
+  CheckReferencesVp9(8, 0, 6);
+  CheckReferencesVp9(8, 1, 7);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, WrappingFlexReference) {
   InsertVp9Flex(0, 0, false, 0, 0, 0, false, {1});
 
   ASSERT_EQ(1UL, frames_from_callback_.size());
-  const EncodedFrame& frame = *frames_from_callback_.begin()->second;
-  ASSERT_EQ(frame.id.picture_id - frame.references[0], 1);
+  CheckReferencesVp9(1, 0, 0);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp9GofPidJump) {
@@ -1364,7 +1368,7 @@ TEST_F(TestRtpFrameReferenceFinder, Vp9GofTl0Jump) {
   GofInfoVP9 ss;
   ss.SetGofInfoVP9(kTemporalStructureMode3);
 
-  InsertVp9Gof(sn, sn, true, pid, 0, 0, 125, true, false, &ss);
+  InsertVp9Gof(sn, sn, true, pid + 0, 0, 0, 125, true, false, &ss);
   InsertVp9Gof(sn + 1, sn + 1, false, pid + 1, 0, 0, 0, false, true, &ss);
 }
 
@@ -1381,7 +1385,7 @@ TEST_F(TestRtpFrameReferenceFinder, Vp9GofTidTooHigh) {
   InsertVp9Gof(sn + 1, sn + 1, false, pid + 1, 0, 0, 1);
 
   ASSERT_EQ(1UL, frames_from_callback_.size());
-  CheckReferencesVp9(pid, 0);
+  CheckReferencesVp9(0, 0);
 }
 
 TEST_F(TestRtpFrameReferenceFinder, Vp9GofZeroFrames) {
@@ -1394,8 +1398,8 @@ TEST_F(TestRtpFrameReferenceFinder, Vp9GofZeroFrames) {
   InsertVp9Gof(sn + 1, sn + 1, false, pid + 1, 0, 0, 1);
 
   ASSERT_EQ(2UL, frames_from_callback_.size());
-  CheckReferencesVp9(pid, 0);
-  CheckReferencesVp9(pid + 1, 0, pid);
+  CheckReferencesVp9(0, 0);
+  CheckReferencesVp9(1, 0, 0);
 }
 
 }  // namespace video_coding
diff --git a/modules/video_coding/video_packet_buffer_unittest.cc b/modules/video_coding/video_packet_buffer_unittest.cc
index 9d8a3b0a33..3ef562406b 100644
--- a/modules/video_coding/video_packet_buffer_unittest.cc
+++ b/modules/video_coding/video_packet_buffer_unittest.cc
@@ -501,7 +501,7 @@ TEST_F(TestPacketBuffer, InsertPacketAfterOldFrameObjectIsRemoved) {
   uint16_t seq_num = kFirstSeqNum;
 
   // Loop until seq_num wraps around.
-  SeqNumUnwrapper<uint16_t> unwrapper;
+  SeqNumUnwrapper<uint16_t> unwrapper(0);
   while (unwrapper.Unwrap(seq_num) < std::numeric_limits<uint16_t>::max()) {
     Insert(seq_num++, kKeyFrame, kFirst, kNotLast, 0, nullptr, timestamp);
     for (int i = 0; i < 5; ++i) {
diff --git a/rtc_base/numerics/sequence_number_util.h b/rtc_base/numerics/sequence_number_util.h
index 57efb5128d..9a7361d353 100644
--- a/rtc_base/numerics/sequence_number_util.h
+++ b/rtc_base/numerics/sequence_number_util.h
@@ -81,35 +81,46 @@ struct DescendingSeqNumComp {
   bool operator()(T a, T b) const { return AheadOf<T, M>(b, a); }
 };
 
-// A sequence number unwrapper where the first unwrapped value equals the
-// first value being unwrapped.
+// A sequencer number unwrapper where the start value of the unwrapped sequence
+// can be set. The unwrapped value is not allowed to wrap.
 template <typename T, T M = 0>
 class SeqNumUnwrapper {
+  // Use '<' instead of rtc::SafeLt to avoid crbug.com/753488
   static_assert(
       std::is_unsigned<T>::value &&
-          std::numeric_limits<T>::max() < std::numeric_limits<int64_t>::max(),
-      "Type unwrapped must be an unsigned integer smaller than int64_t.");
+          std::numeric_limits<T>::max() < std::numeric_limits<uint64_t>::max(),
+      "Type unwrapped must be an unsigned integer smaller than uint64_t.");
 
  public:
-  int64_t Unwrap(T value) {
-    if (!last_value_) {
-      last_unwrapped_ = {value};
-    } else {
-      last_unwrapped_ += ForwardDiff<T, M>(*last_value_, value);
+  // We want a default value that is close to 2^62 for a two reasons. Firstly,
+  // we can unwrap wrapping numbers in either direction, and secondly, the
+  // unwrapped numbers can be stored in either int64_t or uint64_t. We also want
+  // the default value to be human readable, which makes a power of 10 suitable.
+  static constexpr uint64_t kDefaultStartValue = 1000000000000000000UL;
 
-      if (!AheadOrAt<T, M>(value, *last_value_)) {
-        constexpr int64_t kBackwardAdjustment =
-            M == 0 ? int64_t{std::numeric_limits<T>::max()} + 1 : M;
-        last_unwrapped_ -= kBackwardAdjustment;
-      }
+  SeqNumUnwrapper() : last_unwrapped_(kDefaultStartValue) {}
+  explicit SeqNumUnwrapper(uint64_t start_at) : last_unwrapped_(start_at) {}
+
+  uint64_t Unwrap(T value) {
+    if (!last_value_)
+      last_value_.emplace(value);
+
+    uint64_t unwrapped = 0;
+    if (AheadOrAt<T, M>(value, *last_value_)) {
+      unwrapped = last_unwrapped_ + ForwardDiff<T, M>(*last_value_, value);
+      RTC_CHECK_GE(unwrapped, last_unwrapped_);
+    } else {
+      unwrapped = last_unwrapped_ - ReverseDiff<T, M>(*last_value_, value);
+      RTC_CHECK_LT(unwrapped, last_unwrapped_);
     }
 
-    last_value_ = value;
+    *last_value_ = value;
+    last_unwrapped_ = unwrapped;
     return last_unwrapped_;
   }
 
  private:
-  int64_t last_unwrapped_ = 0;
+  uint64_t last_unwrapped_;
   absl::optional<T> last_value_;
 };
 
diff --git a/rtc_base/numerics/sequence_number_util_unittest.cc b/rtc_base/numerics/sequence_number_util_unittest.cc
index 09a4514238..881e0177dd 100644
--- a/rtc_base/numerics/sequence_number_util_unittest.cc
+++ b/rtc_base/numerics/sequence_number_util_unittest.cc
@@ -211,65 +211,82 @@ TEST_F(TestSeqNumUtil, SeqNumComparatorWithDivisor) {
   }
 }
 
-TEST(SeqNumUnwrapper, PreserveStartValue) {
-  SeqNumUnwrapper<uint8_t> unwrapper;
-  EXPECT_EQ(123, unwrapper.Unwrap(123));
+#if GTEST_HAS_DEATH_TEST
+#if !defined(WEBRTC_ANDROID)
+TEST(SeqNumUnwrapper, NoBackWardWrap) {
+  SeqNumUnwrapper<uint8_t> unwrapper(0);
+  EXPECT_EQ(0U, unwrapper.Unwrap(0));
+
+  // The unwrapped sequence is not allowed to wrap, if that happens the
+  // SeqNumUnwrapper should have been constructed with a higher start value.
+  EXPECT_DEATH(unwrapper.Unwrap(255), "");
 }
 
+TEST(SeqNumUnwrapper, NoForwardWrap) {
+  SeqNumUnwrapper<uint32_t> unwrapper(std::numeric_limits<uint64_t>::max());
+  EXPECT_EQ(std::numeric_limits<uint64_t>::max(), unwrapper.Unwrap(0));
+
+  // The unwrapped sequence is not allowed to wrap, if that happens the
+  // SeqNumUnwrapper should have been constructed with a lower start value.
+  EXPECT_DEATH(unwrapper.Unwrap(1), "");
+}
+#endif
+#endif
+
 TEST(SeqNumUnwrapper, ForwardWrap) {
-  SeqNumUnwrapper<uint8_t> unwrapper;
-  EXPECT_EQ(255, unwrapper.Unwrap(255));
-  EXPECT_EQ(256, unwrapper.Unwrap(0));
+  SeqNumUnwrapper<uint8_t> unwrapper(0);
+  EXPECT_EQ(0U, unwrapper.Unwrap(255));
+  EXPECT_EQ(1U, unwrapper.Unwrap(0));
 }
 
 TEST(SeqNumUnwrapper, ForwardWrapWithDivisor) {
-  SeqNumUnwrapper<uint8_t, 33> unwrapper;
-  EXPECT_EQ(30, unwrapper.Unwrap(30));
-  EXPECT_EQ(36, unwrapper.Unwrap(3));
+  SeqNumUnwrapper<uint8_t, 33> unwrapper(0);
+  EXPECT_EQ(0U, unwrapper.Unwrap(30));
+  EXPECT_EQ(6U, unwrapper.Unwrap(3));
 }
 
 TEST(SeqNumUnwrapper, BackWardWrap) {
-  SeqNumUnwrapper<uint8_t> unwrapper;
-  EXPECT_EQ(0, unwrapper.Unwrap(0));
-  EXPECT_EQ(-2, unwrapper.Unwrap(254));
+  SeqNumUnwrapper<uint8_t> unwrapper(10);
+  EXPECT_EQ(10U, unwrapper.Unwrap(0));
+  EXPECT_EQ(8U, unwrapper.Unwrap(254));
 }
 
 TEST(SeqNumUnwrapper, BackWardWrapWithDivisor) {
-  SeqNumUnwrapper<uint8_t, 33> unwrapper;
-  EXPECT_EQ(0, unwrapper.Unwrap(0));
-  EXPECT_EQ(-2, unwrapper.Unwrap(31));
+  SeqNumUnwrapper<uint8_t, 33> unwrapper(10);
+  EXPECT_EQ(10U, unwrapper.Unwrap(0));
+  EXPECT_EQ(8U, unwrapper.Unwrap(31));
 }
 
 TEST(SeqNumUnwrapper, Unwrap) {
-  SeqNumUnwrapper<uint16_t> unwrapper;
+  SeqNumUnwrapper<uint16_t> unwrapper(0);
   const uint16_t kMax = std::numeric_limits<uint16_t>::max();
   const uint16_t kMaxDist = kMax / 2 + 1;
 
-  EXPECT_EQ(0, unwrapper.Unwrap(0));
+  EXPECT_EQ(0U, unwrapper.Unwrap(0));
   EXPECT_EQ(kMaxDist, unwrapper.Unwrap(kMaxDist));
-  EXPECT_EQ(0, unwrapper.Unwrap(0));
+  EXPECT_EQ(0U, unwrapper.Unwrap(0));
 
   EXPECT_EQ(kMaxDist, unwrapper.Unwrap(kMaxDist));
   EXPECT_EQ(kMax, unwrapper.Unwrap(kMax));
-  EXPECT_EQ(kMax + 1, unwrapper.Unwrap(0));
+  EXPECT_EQ(kMax + 1U, unwrapper.Unwrap(0));
   EXPECT_EQ(kMax, unwrapper.Unwrap(kMax));
   EXPECT_EQ(kMaxDist, unwrapper.Unwrap(kMaxDist));
-  EXPECT_EQ(0, unwrapper.Unwrap(0));
+  EXPECT_EQ(0U, unwrapper.Unwrap(0));
 }
 
 TEST(SeqNumUnwrapper, UnwrapOddDivisor) {
-  SeqNumUnwrapper<uint8_t, 11> unwrapper;
+  SeqNumUnwrapper<uint8_t, 11> unwrapper(10);
 
-  EXPECT_EQ(10, unwrapper.Unwrap(10));
-  EXPECT_EQ(11, unwrapper.Unwrap(0));
-  EXPECT_EQ(16, unwrapper.Unwrap(5));
-  EXPECT_EQ(21, unwrapper.Unwrap(10));
-  EXPECT_EQ(22, unwrapper.Unwrap(0));
-  EXPECT_EQ(17, unwrapper.Unwrap(6));
-  EXPECT_EQ(12, unwrapper.Unwrap(1));
-  EXPECT_EQ(7, unwrapper.Unwrap(7));
-  EXPECT_EQ(2, unwrapper.Unwrap(2));
-  EXPECT_EQ(0, unwrapper.Unwrap(0));
+  EXPECT_EQ(10U, unwrapper.Unwrap(10));
+  EXPECT_EQ(11U, unwrapper.Unwrap(0));
+  EXPECT_EQ(16U, unwrapper.Unwrap(5));
+  EXPECT_EQ(21U, unwrapper.Unwrap(10));
+  EXPECT_EQ(22U, unwrapper.Unwrap(0));
+  EXPECT_EQ(17U, unwrapper.Unwrap(6));
+  EXPECT_EQ(12U, unwrapper.Unwrap(1));
+  EXPECT_EQ(7U, unwrapper.Unwrap(7));
+  EXPECT_EQ(2U, unwrapper.Unwrap(2));
+  EXPECT_EQ(0U, unwrapper.Unwrap(0));
 }
 
 TEST(SeqNumUnwrapper, ManyForwardWraps) {
@@ -279,7 +296,7 @@ TEST(SeqNumUnwrapper, ManyForwardWraps) {
   SeqNumUnwrapper<uint16_t, kLargeNumber> unwrapper;
 
   uint16_t next_unwrap = 0;
-  int64_t expected = 0;
+  uint64_t expected = decltype(unwrapper)::kDefaultStartValue;
   for (int i = 0; i < kNumWraps * 2 + 1; ++i) {
     EXPECT_EQ(expected, unwrapper.Unwrap(next_unwrap));
     expected += kMaxStep;
@@ -291,10 +308,10 @@ TEST(SeqNumUnwrapper, ManyBackwardWraps) {
   const int kLargeNumber = 4711;
   const int kMaxStep = kLargeNumber / 2;
   const int kNumWraps = 100;
-  SeqNumUnwrapper<uint16_t, kLargeNumber> unwrapper;
+  SeqNumUnwrapper<uint16_t, kLargeNumber> unwrapper(kLargeNumber * kNumWraps);
 
   uint16_t next_unwrap = 0;
-  int64_t expected = 0;
+  uint64_t expected = kLargeNumber * kNumWraps;
   for (uint16_t i = 0; i < kNumWraps * 2 + 1; ++i) {
     EXPECT_EQ(expected, unwrapper.Unwrap(next_unwrap));
     expected -= kMaxStep;
diff --git a/rtc_tools/event_log_visualizer/analyzer.cc b/rtc_tools/event_log_visualizer/analyzer.cc
index 2023336235..7f07329f25 100644
--- a/rtc_tools/event_log_visualizer/analyzer.cc
+++ b/rtc_tools/event_log_visualizer/analyzer.cc
@@ -140,10 +140,10 @@ absl::optional<uint32_t> EstimateRtpClockFrequency(
     int64_t end_time_us) {
   RTC_CHECK(packets.size() >= 2);
   SeqNumUnwrapper<uint32_t> unwrapper;
-  int64_t first_rtp_timestamp =
+  uint64_t first_rtp_timestamp =
       unwrapper.Unwrap(packets[0].rtp.header.timestamp);
   int64_t first_log_timestamp = packets[0].log_time_us();
-  int64_t last_rtp_timestamp = first_rtp_timestamp;
+  uint64_t last_rtp_timestamp = first_rtp_timestamp;
   int64_t last_log_timestamp = first_log_timestamp;
   for (size_t i = 1; i < packets.size(); i++) {
     if (packets[i].log_time_us() > end_time_us)