diff --git a/call/rampup_tests.cc b/call/rampup_tests.cc
index 91788b097a..5917a6bc45 100644
--- a/call/rampup_tests.cc
+++ b/call/rampup_tests.cc
@@ -441,7 +441,7 @@ void RampUpDownUpTester::PollStats() {
     bool suspended = false;
     if (num_video_streams_ > 0) {
       webrtc::VideoSendStream::Stats stats = send_stream_->GetStats();
-      for (auto it : stats.substreams) {
+      for (const auto& it : stats.substreams) {
         transmit_bitrate_bps += it.second.total_bitrate_bps;
       }
       suspended = stats.suspended;
diff --git a/logging/rtc_event_log/encoder/rtc_event_log_encoder_new_format.cc b/logging/rtc_event_log/encoder/rtc_event_log_encoder_new_format.cc
index 6116d8d1e2..b9e222d2d6 100644
--- a/logging/rtc_event_log/encoder/rtc_event_log_encoder_new_format.cc
+++ b/logging/rtc_event_log/encoder/rtc_event_log_encoder_new_format.cc
@@ -1295,7 +1295,7 @@ void RtcEventLogEncoderNewFormat::EncodeRtpPacketIncoming(
     const std::map<uint32_t, std::vector<const RtcEventRtpPacketIncoming*>>&
         batch,
     rtclog2::EventStream* event_stream) {
-  for (auto it : batch) {
+  for (const auto& it : batch) {
     RTC_DCHECK(!it.second.empty());
     EncodeRtpPacket(it.second, event_stream->add_incoming_rtp_packets());
   }
@@ -1305,7 +1305,7 @@ void RtcEventLogEncoderNewFormat::EncodeRtpPacketOutgoing(
     const std::map<uint32_t, std::vector<const RtcEventRtpPacketOutgoing*>>&
         batch,
     rtclog2::EventStream* event_stream) {
-  for (auto it : batch) {
+  for (const auto& it : batch) {
     RTC_DCHECK(!it.second.empty());
     EncodeRtpPacket(it.second, event_stream->add_outgoing_rtp_packets());
   }
diff --git a/media/engine/webrtc_voice_engine_unittest.cc b/media/engine/webrtc_voice_engine_unittest.cc
index d05feb5625..663dd8caba 100644
--- a/media/engine/webrtc_voice_engine_unittest.cc
+++ b/media/engine/webrtc_voice_engine_unittest.cc
@@ -801,7 +801,7 @@ TEST_F(WebRtcVoiceEngineTestFake, CreateRecvStream) {
 TEST_F(WebRtcVoiceEngineTestFake, OpusSupportsTransportCc) {
   const std::vector<cricket::AudioCodec>& codecs = engine_->send_codecs();
   bool opus_found = false;
-  for (cricket::AudioCodec codec : codecs) {
+  for (const cricket::AudioCodec& codec : codecs) {
     if (codec.name == "opus") {
       EXPECT_TRUE(HasTransportCc(codec));
       opus_found = true;
diff --git a/modules/audio_coding/audio_network_adaptor/fec_controller_plr_based_unittest.cc b/modules/audio_coding/audio_network_adaptor/fec_controller_plr_based_unittest.cc
index de66717fba..d3f54ee1e9 100644
--- a/modules/audio_coding/audio_network_adaptor/fec_controller_plr_based_unittest.cc
+++ b/modules/audio_coding/audio_network_adaptor/fec_controller_plr_based_unittest.cc
@@ -422,7 +422,7 @@ TEST(FecControllerPlrBasedTest, SingleThresholdCurveForEnablingAndDisabling) {
 
   // Test that FEC is turned on whenever we're on the curve or above it,
   // independent of the starting FEC state.
-  for (std::vector<NetworkState> states_list : {on, above}) {
+  for (const std::vector<NetworkState>& states_list : {on, above}) {
     for (NetworkState net_state : states_list) {
       for (bool initial_fec_enabled : {false, true}) {
         auto states =
diff --git a/modules/audio_coding/audio_network_adaptor/fec_controller_rplr_based_unittest.cc b/modules/audio_coding/audio_network_adaptor/fec_controller_rplr_based_unittest.cc
index 8e8704ee73..4438a236c9 100644
--- a/modules/audio_coding/audio_network_adaptor/fec_controller_rplr_based_unittest.cc
+++ b/modules/audio_coding/audio_network_adaptor/fec_controller_rplr_based_unittest.cc
@@ -462,7 +462,7 @@ TEST(FecControllerRplrBasedTest, SingleThresholdCurveForEnablingAndDisabling) {
 
   // Test that FEC is turned on whenever we're on the curve or above it,
   // independent of the starting FEC state.
-  for (std::vector<NetworkState> states_list : {on, above}) {
+  for (const std::vector<NetworkState>& states_list : {on, above}) {
     for (NetworkState net_state : states_list) {
       for (bool initial_fec_enabled : {false, true}) {
         FecControllerRplrBased controller(
diff --git a/modules/audio_mixer/audio_mixer_test.cc b/modules/audio_mixer/audio_mixer_test.cc
index b60787755d..f9c5c39c81 100644
--- a/modules/audio_mixer/audio_mixer_test.cc
+++ b/modules/audio_mixer/audio_mixer_test.cc
@@ -122,7 +122,7 @@ int main(int argc, char* argv[]) {
   const std::vector<std::string> input_files = parse_input_files();
   std::vector<webrtc::test::FilePlayingSource> sources;
   const int num_channels = FLAG_stereo ? 2 : 1;
-  for (auto input_file : input_files) {
+  for (const auto& input_file : input_files) {
     sources.emplace_back(input_file);
   }
 
diff --git a/modules/bitrate_controller/loss_based_bandwidth_estimation.cc b/modules/bitrate_controller/loss_based_bandwidth_estimation.cc
index e5c032b5cb..3015d3dd0f 100644
--- a/modules/bitrate_controller/loss_based_bandwidth_estimation.cc
+++ b/modules/bitrate_controller/loss_based_bandwidth_estimation.cc
@@ -124,7 +124,7 @@ void LossBasedBandwidthEstimation::UpdateLossStatistics(
     return;
   }
   int loss_count = 0;
-  for (auto pkt : packet_results) {
+  for (const auto& pkt : packet_results) {
     loss_count += pkt.receive_time.IsInfinite() ? 1 : 0;
   }
   last_loss_ratio_ = static_cast<double>(loss_count) / packet_results.size();
diff --git a/modules/rtp_rtcp/source/rtcp_receiver.cc b/modules/rtp_rtcp/source/rtcp_receiver.cc
index e047e0a48e..4499b11aba 100644
--- a/modules/rtp_rtcp/source/rtcp_receiver.cc
+++ b/modules/rtp_rtcp/source/rtcp_receiver.cc
@@ -440,7 +440,7 @@ void RTCPReceiver::HandleSenderReport(const CommonHeader& rtcp_block,
     packet_information->packet_type_flags |= kRtcpRr;
   }
 
-  for (const rtcp::ReportBlock report_block : sender_report.report_blocks())
+  for (const rtcp::ReportBlock& report_block : sender_report.report_blocks())
     HandleReportBlock(report_block, packet_information, remote_ssrc);
 }
 
diff --git a/p2p/base/mdns_message.cc b/p2p/base/mdns_message.cc
index 52ba70c8ab..e4fe7cc894 100644
--- a/p2p/base/mdns_message.cc
+++ b/p2p/base/mdns_message.cc
@@ -353,7 +353,7 @@ bool MdnsMessage::Write(rtc::ByteBufferWriter* buf) const {
   header_.Write(buf);
 
   auto write_rr = [&buf](const std::vector<MdnsResourceRecord>& section) {
-    for (auto rr : section) {
+    for (const auto& rr : section) {
       if (!rr.Write(buf)) {
         return false;
       }
@@ -361,7 +361,7 @@ bool MdnsMessage::Write(rtc::ByteBufferWriter* buf) const {
     return true;
   };
 
-  for (auto question : question_section_) {
+  for (const auto& question : question_section_) {
     if (!question.Write(buf)) {
       return false;
     }
diff --git a/p2p/base/port.cc b/p2p/base/port.cc
index dd8c0ecb37..f7ba6c97a4 100644
--- a/p2p/base/port.cc
+++ b/p2p/base/port.cc
@@ -957,7 +957,7 @@ void Port::UpdateNetworkCost() {
   // Network cost change will affect the connection selection criteria.
   // Signal the connection state change on each connection to force a
   // re-sort in P2PTransportChannel.
-  for (auto kv : connections_) {
+  for (const auto& kv : connections_) {
     Connection* conn = kv.second;
     conn->SignalStateChange(conn);
   }
diff --git a/p2p/base/stun_request.cc b/p2p/base/stun_request.cc
index f97ca869bf..088cbc8a5c 100644
--- a/p2p/base/stun_request.cc
+++ b/p2p/base/stun_request.cc
@@ -69,7 +69,7 @@ void StunRequestManager::SendDelayed(StunRequest* request, int delay) {
 }
 
 void StunRequestManager::Flush(int msg_type) {
-  for (const auto kv : requests_) {
+  for (const auto& kv : requests_) {
     StunRequest* request = kv.second;
     if (msg_type == kAllRequests || msg_type == request->type()) {
       thread_->Clear(request, MSG_STUN_SEND);
@@ -79,7 +79,7 @@ void StunRequestManager::Flush(int msg_type) {
 }
 
 bool StunRequestManager::HasRequest(int msg_type) {
-  for (const auto kv : requests_) {
+  for (const auto& kv : requests_) {
     StunRequest* request = kv.second;
     if (msg_type == kAllRequests || msg_type == request->type()) {
       return true;
diff --git a/p2p/base/turn_port_unittest.cc b/p2p/base/turn_port_unittest.cc
index 931f908a70..80af11d97f 100644
--- a/p2p/base/turn_port_unittest.cc
+++ b/p2p/base/turn_port_unittest.cc
@@ -401,7 +401,7 @@ class TurnPortTest : public testing::Test,
     if (connections.empty()) {
       return false;
     }
-    for (auto kv : connections) {
+    for (const auto& kv : connections) {
       if (!CheckConnectionFailedAndPruned(kv.second)) {
         return false;
       }
diff --git a/p2p/client/basic_port_allocator_unittest.cc b/p2p/client/basic_port_allocator_unittest.cc
index 061eb339dc..5ecb81bb4d 100644
--- a/p2p/client/basic_port_allocator_unittest.cc
+++ b/p2p/client/basic_port_allocator_unittest.cc
@@ -764,7 +764,7 @@ TEST_F(BasicPortAllocatorTest, TestIgnoreOnlyLoopbackNetworkByDefault) {
   EXPECT_TRUE_SIMULATED_WAIT(candidate_allocation_done_,
                              kDefaultAllocationTimeout, fake_clock);
   EXPECT_EQ(4U, candidates_.size());
-  for (Candidate candidate : candidates_) {
+  for (const Candidate& candidate : candidates_) {
     EXPECT_LT(candidate.address().ip(), 0x12345604U);
   }
 }
diff --git a/pc/jsep_transport_controller.cc b/pc/jsep_transport_controller.cc
index 9cecc105f0..fa0aa7d7f1 100644
--- a/pc/jsep_transport_controller.cc
+++ b/pc/jsep_transport_controller.cc
@@ -672,7 +672,7 @@ RTCError JsepTransportController::ValidateAndMaybeUpdateBundleGroup(
 
   // The BUNDLE group containing a MID that no m= section has is invalid.
   if (new_bundle_group) {
-    for (auto content_name : new_bundle_group->content_names()) {
+    for (const auto& content_name : new_bundle_group->content_names()) {
       if (!description->GetContentByName(content_name)) {
         return RTCError(RTCErrorType::INVALID_PARAMETER,
                         "The BUNDLE group contains MID:" + content_name +
@@ -688,7 +688,7 @@ RTCError JsepTransportController::ValidateAndMaybeUpdateBundleGroup(
 
     if (new_bundle_group) {
       // The BUNDLE group in answer should be a subset of offered group.
-      for (auto content_name : new_bundle_group->content_names()) {
+      for (const auto& content_name : new_bundle_group->content_names()) {
         if (!offered_bundle_group ||
             !offered_bundle_group->HasContentName(content_name)) {
           return RTCError(RTCErrorType::INVALID_PARAMETER,
@@ -699,7 +699,7 @@ RTCError JsepTransportController::ValidateAndMaybeUpdateBundleGroup(
     }
 
     if (bundle_group_) {
-      for (auto content_name : bundle_group_->content_names()) {
+      for (const auto& content_name : bundle_group_->content_names()) {
         // An answer that removes m= sections from pre-negotiated BUNDLE group
         // without rejecting it, is invalid.
         if (!new_bundle_group ||
@@ -740,7 +740,7 @@ RTCError JsepTransportController::ValidateAndMaybeUpdateBundleGroup(
   // If the |bundled_content| is rejected, other contents in the bundle group
   // should be rejected.
   if (bundled_content->rejected) {
-    for (auto content_name : bundle_group_->content_names()) {
+    for (const auto& content_name : bundle_group_->content_names()) {
       auto other_content = description->GetContentByName(content_name);
       if (!other_content->rejected) {
         return RTCError(
@@ -775,7 +775,7 @@ void JsepTransportController::HandleRejectedContent(
   // then destroy the cricket::JsepTransport.
   RemoveTransportForMid(content_info.name);
   if (content_info.name == bundled_mid()) {
-    for (auto content_name : bundle_group_->content_names()) {
+    for (const auto& content_name : bundle_group_->content_names()) {
       RemoveTransportForMid(content_name);
     }
     bundle_group_.reset();
@@ -881,7 +881,7 @@ std::vector<int> JsepTransportController::GetEncryptedHeaderExtensionIds(
   }
 
   std::vector<int> encrypted_header_extension_ids;
-  for (auto extension : content_desc->rtp_header_extensions()) {
+  for (const auto& extension : content_desc->rtp_header_extensions()) {
     if (!extension.encrypt) {
       continue;
     }
diff --git a/pc/peer_connection.cc b/pc/peer_connection.cc
index 2b4a48db7a..3be5ca3fa3 100644
--- a/pc/peer_connection.cc
+++ b/pc/peer_connection.cc
@@ -838,7 +838,7 @@ PeerConnection::~PeerConnection() {
   // Need to stop transceivers before destroying the stats collector because
   // AudioRtpSender has a reference to the StatsCollector it will update when
   // stopping.
-  for (auto transceiver : transceivers_) {
+  for (const auto& transceiver : transceivers_) {
     transceiver->Stop();
   }
 
@@ -874,12 +874,12 @@ PeerConnection::~PeerConnection() {
 void PeerConnection::DestroyAllChannels() {
   // Destroy video channels first since they may have a pointer to a voice
   // channel.
-  for (auto transceiver : transceivers_) {
+  for (const auto& transceiver : transceivers_) {
     if (transceiver->media_type() == cricket::MEDIA_TYPE_VIDEO) {
       DestroyTransceiverChannel(transceiver);
     }
   }
-  for (auto transceiver : transceivers_) {
+  for (const auto& transceiver : transceivers_) {
     if (transceiver->media_type() == cricket::MEDIA_TYPE_AUDIO) {
       DestroyTransceiverChannel(transceiver);
     }
@@ -1624,7 +1624,7 @@ rtc::scoped_refptr<RtpSenderInterface> PeerConnection::CreateSender(
 std::vector<rtc::scoped_refptr<RtpSenderInterface>> PeerConnection::GetSenders()
     const {
   std::vector<rtc::scoped_refptr<RtpSenderInterface>> ret;
-  for (auto sender : GetSendersInternal()) {
+  for (const auto& sender : GetSendersInternal()) {
     ret.push_back(sender);
   }
   return ret;
@@ -1634,7 +1634,7 @@ std::vector<rtc::scoped_refptr<RtpSenderProxyWithInternal<RtpSenderInternal>>>
 PeerConnection::GetSendersInternal() const {
   std::vector<rtc::scoped_refptr<RtpSenderProxyWithInternal<RtpSenderInternal>>>
       all_senders;
-  for (auto transceiver : transceivers_) {
+  for (const auto& transceiver : transceivers_) {
     auto senders = transceiver->internal()->senders();
     all_senders.insert(all_senders.end(), senders.begin(), senders.end());
   }
@@ -1656,7 +1656,7 @@ PeerConnection::GetReceiversInternal() const {
   std::vector<
       rtc::scoped_refptr<RtpReceiverProxyWithInternal<RtpReceiverInternal>>>
       all_receivers;
-  for (auto transceiver : transceivers_) {
+  for (const auto& transceiver : transceivers_) {
     auto receivers = transceiver->internal()->receivers();
     all_receivers.insert(all_receivers.end(), receivers.begin(),
                          receivers.end());
@@ -1669,7 +1669,7 @@ PeerConnection::GetTransceivers() const {
   RTC_CHECK(IsUnifiedPlan())
       << "GetTransceivers is only supported with Unified Plan SdpSemantics.";
   std::vector<rtc::scoped_refptr<RtpTransceiverInterface>> all_transceivers;
-  for (auto transceiver : transceivers_) {
+  for (const auto& transceiver : transceivers_) {
     all_transceivers.push_back(transceiver);
   }
   return all_transceivers;
@@ -1880,7 +1880,7 @@ RTCError PeerConnection::HandleLegacyOfferOptions(
 
 void PeerConnection::RemoveRecvDirectionFromReceivingTransceiversOfType(
     cricket::MediaType media_type) {
-  for (auto transceiver : GetReceivingTransceiversOfType(media_type)) {
+  for (const auto& transceiver : GetReceivingTransceiversOfType(media_type)) {
     RtpTransceiverDirection new_direction =
         RtpTransceiverDirectionWithRecvSet(transceiver->direction(), false);
     if (new_direction != transceiver->direction()) {
@@ -1914,7 +1914,7 @@ PeerConnection::GetReceivingTransceiversOfType(cricket::MediaType media_type) {
   std::vector<
       rtc::scoped_refptr<RtpTransceiverProxyWithInternal<RtpTransceiver>>>
       receiving_transceivers;
-  for (auto transceiver : transceivers_) {
+  for (const auto& transceiver : transceivers_) {
     if (!transceiver->stopped() && transceiver->media_type() == media_type &&
         RtpTransceiverDirectionHasRecv(transceiver->direction())) {
       receiving_transceivers.push_back(transceiver);
@@ -2107,7 +2107,7 @@ RTCError PeerConnection::ApplyLocalDescription(
     }
     std::vector<rtc::scoped_refptr<RtpTransceiverInterface>> remove_list;
     std::vector<rtc::scoped_refptr<MediaStreamInterface>> removed_streams;
-    for (auto transceiver : transceivers_) {
+    for (const auto& transceiver : transceivers_) {
       // 2.2.7.1.1.(6-9): Set sender and receiver's transport slots.
       // Note that code paths that don't set MID won't be able to use
       // information about DTLS transports.
@@ -2147,10 +2147,10 @@ RTCError PeerConnection::ApplyLocalDescription(
       }
     }
     auto observer = Observer();
-    for (auto transceiver : remove_list) {
+    for (const auto& transceiver : remove_list) {
       observer->OnRemoveTrack(transceiver->receiver());
     }
-    for (auto stream : removed_streams) {
+    for (const auto& stream : removed_streams) {
       observer->OnRemoveStream(stream);
     }
   } else {
@@ -2192,7 +2192,7 @@ RTCError PeerConnection::ApplyLocalDescription(
   }
 
   if (IsUnifiedPlan()) {
-    for (auto transceiver : transceivers_) {
+    for (const auto& transceiver : transceivers_) {
       const ContentInfo* content =
           FindMediaSectionForTransceiver(transceiver, local_description());
       if (!content) {
@@ -2526,7 +2526,7 @@ RTCError PeerConnection::ApplyRemoteDescription(
     std::vector<rtc::scoped_refptr<RtpTransceiverInterface>> remove_list;
     std::vector<rtc::scoped_refptr<MediaStreamInterface>> added_streams;
     std::vector<rtc::scoped_refptr<MediaStreamInterface>> removed_streams;
-    for (auto transceiver : transceivers_) {
+    for (const auto& transceiver : transceivers_) {
       const ContentInfo* content =
           FindMediaSectionForTransceiver(transceiver, remote_description());
       if (!content) {
@@ -2610,19 +2610,19 @@ RTCError PeerConnection::ApplyRemoteDescription(
     }
     // Once all processing has finished, fire off callbacks.
     auto observer = Observer();
-    for (auto transceiver : now_receiving_transceivers) {
+    for (const auto& transceiver : now_receiving_transceivers) {
       stats_->AddTrack(transceiver->receiver()->track());
       observer->OnTrack(transceiver);
       observer->OnAddTrack(transceiver->receiver(),
                            transceiver->receiver()->streams());
     }
-    for (auto stream : added_streams) {
+    for (const auto& stream : added_streams) {
       observer->OnAddStream(stream);
     }
-    for (auto transceiver : remove_list) {
+    for (const auto& transceiver : remove_list) {
       observer->OnRemoveTrack(transceiver->receiver());
     }
-    for (auto stream : removed_streams) {
+    for (const auto& stream : removed_streams) {
       observer->OnRemoveStream(stream);
     }
   }
@@ -2774,7 +2774,7 @@ void PeerConnection::RemoveRemoteStreamsIfEmpty(
   // TODO(https://crbug.com/webrtc/9480): When we use stream IDs instead of
   // streams, see if the stream was removed by checking if this was the last
   // receiver with that stream ID.
-  for (auto remote_stream : remote_streams) {
+  for (const auto& remote_stream : remote_streams) {
     if (remote_stream->GetAudioTracks().empty() &&
         remote_stream->GetVideoTracks().empty()) {
       remote_streams_->RemoveStream(remote_stream);
@@ -3510,7 +3510,7 @@ void PeerConnection::Close() {
   ChangeSignalingState(PeerConnectionInterface::kClosed);
   NoteUsageEvent(UsageEvent::CLOSE_CALLED);
 
-  for (auto transceiver : transceivers_) {
+  for (const auto& transceiver : transceivers_) {
     transceiver->Stop();
   }
 
@@ -4151,7 +4151,7 @@ void PeerConnection::GetOptionsForUnifiedPlanOffer(
   // and not associated). Reuse media sections marked as recyclable first,
   // otherwise append to the end of the offer. New media sections should be
   // added in the order they were added to the PeerConnection.
-  for (auto transceiver : transceivers_) {
+  for (const auto& transceiver : transceivers_) {
     if (transceiver->mid() || transceiver->stopped()) {
       continue;
     }
@@ -4921,7 +4921,7 @@ bool PeerConnection::HasRtpSender(cricket::MediaType type) const {
 
 rtc::scoped_refptr<RtpSenderProxyWithInternal<RtpSenderInternal>>
 PeerConnection::FindSenderForTrack(MediaStreamTrackInterface* track) const {
-  for (auto transceiver : transceivers_) {
+  for (const auto& transceiver : transceivers_) {
     for (auto sender : transceiver->internal()->senders()) {
       if (sender->track() == track) {
         return sender;
@@ -4933,7 +4933,7 @@ PeerConnection::FindSenderForTrack(MediaStreamTrackInterface* track) const {
 
 rtc::scoped_refptr<RtpSenderProxyWithInternal<RtpSenderInternal>>
 PeerConnection::FindSenderById(const std::string& sender_id) const {
-  for (auto transceiver : transceivers_) {
+  for (const auto& transceiver : transceivers_) {
     for (auto sender : transceiver->internal()->senders()) {
       if (sender->id() == sender_id) {
         return sender;
@@ -4945,7 +4945,7 @@ PeerConnection::FindSenderById(const std::string& sender_id) const {
 
 rtc::scoped_refptr<RtpReceiverProxyWithInternal<RtpReceiverInternal>>
 PeerConnection::FindReceiverById(const std::string& receiver_id) const {
-  for (auto transceiver : transceivers_) {
+  for (const auto& transceiver : transceivers_) {
     for (auto receiver : transceiver->internal()->receivers()) {
       if (receiver->id() == receiver_id) {
         return receiver;
@@ -5105,7 +5105,7 @@ void PeerConnection::StopRtcEventLog_w() {
 
 cricket::ChannelInterface* PeerConnection::GetChannel(
     const std::string& content_name) {
-  for (auto transceiver : transceivers_) {
+  for (const auto& transceiver : transceivers_) {
     cricket::ChannelInterface* channel = transceiver->internal()->channel();
     if (channel && channel->content_name() == content_name) {
       return channel;
@@ -5220,7 +5220,7 @@ RTCError PeerConnection::PushdownMediaDescription(
   RTC_DCHECK(sdesc);
 
   // Push down the new SDP media section for each audio/video transceiver.
-  for (auto transceiver : transceivers_) {
+  for (const auto& transceiver : transceivers_) {
     const ContentInfo* content_info =
         FindMediaSectionForTransceiver(transceiver, sdesc);
     cricket::ChannelInterface* channel = transceiver->internal()->channel();
@@ -5571,7 +5571,7 @@ cricket::CandidateStatsList PeerConnection::GetPooledCandidateStats() const {
 std::map<std::string, std::string> PeerConnection::GetTransportNamesByMid()
     const {
   std::map<std::string, std::string> transport_names_by_mid;
-  for (auto transceiver : transceivers_) {
+  for (const auto& transceiver : transceivers_) {
     cricket::ChannelInterface* channel = transceiver->internal()->channel();
     if (channel) {
       transport_names_by_mid[channel->content_name()] =
@@ -5748,7 +5748,7 @@ void PeerConnection::OnTransportControllerDtlsHandshakeError(
 }
 
 void PeerConnection::EnableSending() {
-  for (auto transceiver : transceivers_) {
+  for (const auto& transceiver : transceivers_) {
     cricket::ChannelInterface* channel = transceiver->internal()->channel();
     if (channel && !channel->enabled()) {
       channel->Enable(true);
@@ -6508,7 +6508,7 @@ void PeerConnection::OnTransportControllerGatheringState(
 void PeerConnection::ReportTransportStats() {
   std::map<std::string, std::set<cricket::MediaType>>
       media_types_by_transport_name;
-  for (auto transceiver : transceivers_) {
+  for (const auto& transceiver : transceivers_) {
     if (transceiver->internal()->channel()) {
       const std::string& transport_name =
           transceiver->internal()->channel()->transport_name();
diff --git a/pc/peer_connection_bundle_unittest.cc b/pc/peer_connection_bundle_unittest.cc
index 8f44c395d9..5b1a23a2e9 100644
--- a/pc/peer_connection_bundle_unittest.cc
+++ b/pc/peer_connection_bundle_unittest.cc
@@ -95,7 +95,7 @@ class PeerConnectionWrapperForBundleTest : public PeerConnectionWrapper {
 
   cricket::VoiceChannel* voice_channel() {
     auto transceivers = GetInternalPeerConnection()->GetTransceiversInternal();
-    for (auto transceiver : transceivers) {
+    for (const auto& transceiver : transceivers) {
       if (transceiver->media_type() == cricket::MEDIA_TYPE_AUDIO) {
         return static_cast<cricket::VoiceChannel*>(
             transceiver->internal()->channel());
@@ -116,7 +116,7 @@ class PeerConnectionWrapperForBundleTest : public PeerConnectionWrapper {
 
   cricket::VideoChannel* video_channel() {
     auto transceivers = GetInternalPeerConnection()->GetTransceiversInternal();
-    for (auto transceiver : transceivers) {
+    for (const auto& transceiver : transceivers) {
       if (transceiver->media_type() == cricket::MEDIA_TYPE_VIDEO) {
         return static_cast<cricket::VideoChannel*>(
             transceiver->internal()->channel());
diff --git a/pc/peer_connection_ice_unittest.cc b/pc/peer_connection_ice_unittest.cc
index 4ef5458002..aa7cc7f686 100644
--- a/pc/peer_connection_ice_unittest.cc
+++ b/pc/peer_connection_ice_unittest.cc
@@ -211,7 +211,7 @@ class PeerConnectionIceBaseTest : public ::testing::Test {
         static_cast<PeerConnectionProxyWithInternal<PeerConnectionInterface>*>(
             pc_wrapper_ptr->pc());
     PeerConnection* pc = static_cast<PeerConnection*>(pc_proxy->internal());
-    for (auto transceiver : pc->GetTransceiversInternal()) {
+    for (const auto& transceiver : pc->GetTransceiversInternal()) {
       if (transceiver->media_type() == cricket::MEDIA_TYPE_AUDIO) {
         // TODO(amithi): This test seems to be using a method that should not
         // be public |rtp_packet_transport|. Because the test is not mocking
diff --git a/pc/peer_connection_integrationtest.cc b/pc/peer_connection_integrationtest.cc
index 4091006656..c28f0de187 100644
--- a/pc/peer_connection_integrationtest.cc
+++ b/pc/peer_connection_integrationtest.cc
@@ -347,7 +347,7 @@ class PeerConnectionWrapper : public webrtc::PeerConnectionObserver,
   std::vector<rtc::scoped_refptr<RtpReceiverInterface>> GetReceiversOfType(
       cricket::MediaType media_type) {
     std::vector<rtc::scoped_refptr<RtpReceiverInterface>> receivers;
-    for (auto receiver : pc()->GetReceivers()) {
+    for (const auto& receiver : pc()->GetReceivers()) {
       if (receiver->media_type() == media_type) {
         receivers.push_back(receiver);
       }
@@ -2237,7 +2237,7 @@ TEST_P(PeerConnectionIntegrationTest, AnswererRejectsAudioAndVideoSections) {
   } else {
     callee()->SetRemoteOfferHandler([this] {
       // Stopping all transceivers will cause all media sections to be rejected.
-      for (auto transceiver : callee()->pc()->GetTransceivers()) {
+      for (const auto& transceiver : callee()->pc()->GetTransceivers()) {
         transceiver->Stop();
       }
     });
@@ -2551,7 +2551,7 @@ TEST_P(PeerConnectionIntegrationTest, GetBytesReceivedStatsWithOldStatsApi) {
 
   // Get a handle to the remote tracks created, so they can be used as GetStats
   // filters.
-  for (auto receiver : callee()->pc()->GetReceivers()) {
+  for (const auto& receiver : callee()->pc()->GetReceivers()) {
     // We received frames, so we definitely should have nonzero "received bytes"
     // stats at this point.
     EXPECT_GT(callee()->OldGetStatsForTrack(receiver->track())->BytesReceived(),
diff --git a/pc/peer_connection_interface_unittest.cc b/pc/peer_connection_interface_unittest.cc
index 9180f1d245..038e42c9b3 100644
--- a/pc/peer_connection_interface_unittest.cc
+++ b/pc/peer_connection_interface_unittest.cc
@@ -2664,7 +2664,7 @@ TEST_P(PeerConnectionInterfaceTest, CloseAndTestStreamsAndStates) {
   } else {
     // Verify that the RtpTransceivers are still present but all stopped.
     EXPECT_EQ(2u, pc_->GetTransceivers().size());
-    for (auto transceiver : pc_->GetTransceivers()) {
+    for (const auto& transceiver : pc_->GetTransceivers()) {
       EXPECT_TRUE(transceiver->stopped());
     }
   }
diff --git a/pc/rtc_stats_collector.cc b/pc/rtc_stats_collector.cc
index 245293aa33..e66a504b45 100644
--- a/pc/rtc_stats_collector.cc
+++ b/pc/rtc_stats_collector.cc
@@ -536,7 +536,7 @@ void ProduceSenderMediaTrackStats(
   // TODO(hbos): Return stats of detached tracks. We have to perform stats
   // gathering at the time of detachment to get accurate stats and timestamps.
   // https://crbug.com/659137
-  for (auto sender : senders) {
+  for (const auto& sender : senders) {
     if (sender->media_type() == cricket::MEDIA_TYPE_AUDIO) {
       AudioTrackInterface* track =
           static_cast<AudioTrackInterface*>(sender->track().get());
@@ -604,7 +604,7 @@ void ProduceReceiverMediaTrackStats(
     std::vector<rtc::scoped_refptr<RtpReceiverInternal>> receivers,
     RTCStatsReport* report) {
   // This function iterates over the receivers to find the remote tracks.
-  for (auto receiver : receivers) {
+  for (const auto& receiver : receivers) {
     if (receiver->media_type() == cricket::MEDIA_TYPE_AUDIO) {
       AudioTrackInterface* track =
           static_cast<AudioTrackInterface*>(receiver->track().get());
@@ -1118,7 +1118,7 @@ void RTCStatsCollector::ProduceMediaStreamStats_s(
   std::map<std::string, std::vector<std::string>> track_ids;
 
   for (const auto& stats : transceiver_stats_infos_) {
-    for (auto sender : stats.transceiver->senders()) {
+    for (const auto& sender : stats.transceiver->senders()) {
       std::string track_id =
           RTCMediaStreamTrackStatsIDFromDirectionAndAttachment(
               kSender, sender->internal()->AttachmentId());
@@ -1126,7 +1126,7 @@ void RTCStatsCollector::ProduceMediaStreamStats_s(
         track_ids[stream_id].push_back(track_id);
       }
     }
-    for (auto receiver : stats.transceiver->receivers()) {
+    for (const auto& receiver : stats.transceiver->receivers()) {
       std::string track_id =
           RTCMediaStreamTrackStatsIDFromDirectionAndAttachment(
               kReceiver, receiver->internal()->AttachmentId());
@@ -1152,14 +1152,14 @@ void RTCStatsCollector::ProduceMediaStreamTrackStats_s(
   RTC_DCHECK(signaling_thread_->IsCurrent());
   for (const RtpTransceiverStatsInfo& stats : transceiver_stats_infos_) {
     std::vector<rtc::scoped_refptr<RtpSenderInternal>> senders;
-    for (auto sender : stats.transceiver->senders()) {
+    for (const auto& sender : stats.transceiver->senders()) {
       senders.push_back(sender->internal());
     }
     ProduceSenderMediaTrackStats(timestamp_us, *stats.track_media_info_map,
                                  senders, report);
 
     std::vector<rtc::scoped_refptr<RtpReceiverInternal>> receivers;
-    for (auto receiver : stats.transceiver->receivers()) {
+    for (const auto& receiver : stats.transceiver->receivers()) {
       receivers.push_back(receiver->internal());
     }
     ProduceReceiverMediaTrackStats(timestamp_us, *stats.track_media_info_map,
@@ -1422,7 +1422,7 @@ RTCStatsCollector::PrepareTransceiverStatsInfos_s() const {
            std::unique_ptr<cricket::VideoMediaInfo>>
       video_stats;
 
-  for (auto transceiver : pc_->GetTransceiversInternal()) {
+  for (const auto& transceiver : pc_->GetTransceiversInternal()) {
     cricket::MediaType media_type = transceiver->media_type();
 
     // Prepare stats entry. The TrackMediaInfoMap will be filled in after the
@@ -1495,11 +1495,11 @@ RTCStatsCollector::PrepareTransceiverStatsInfos_s() const {
       }
     }
     std::vector<rtc::scoped_refptr<RtpSenderInternal>> senders;
-    for (auto sender : transceiver->senders()) {
+    for (const auto& sender : transceiver->senders()) {
       senders.push_back(sender->internal());
     }
     std::vector<rtc::scoped_refptr<RtpReceiverInternal>> receivers;
-    for (auto receiver : transceiver->receivers()) {
+    for (const auto& receiver : transceiver->receivers()) {
       receivers.push_back(receiver->internal());
     }
     stats.track_media_info_map = absl::make_unique<TrackMediaInfoMap>(
diff --git a/pc/rtp_receiver.cc b/pc/rtp_receiver.cc
index 837175a634..60f5ea8659 100644
--- a/pc/rtp_receiver.cc
+++ b/pc/rtp_receiver.cc
@@ -211,9 +211,9 @@ void AudioRtpReceiver::set_stream_ids(std::vector<std::string> stream_ids) {
 void AudioRtpReceiver::SetStreams(
     const std::vector<rtc::scoped_refptr<MediaStreamInterface>>& streams) {
   // Remove remote track from any streams that are going away.
-  for (auto existing_stream : streams_) {
+  for (const auto& existing_stream : streams_) {
     bool removed = true;
-    for (auto stream : streams) {
+    for (const auto& stream : streams) {
       if (existing_stream->id() == stream->id()) {
         RTC_DCHECK_EQ(existing_stream.get(), stream.get());
         removed = false;
@@ -225,9 +225,9 @@ void AudioRtpReceiver::SetStreams(
     }
   }
   // Add remote track to any streams that are new.
-  for (auto stream : streams) {
+  for (const auto& stream : streams) {
     bool added = true;
-    for (auto existing_stream : streams_) {
+    for (const auto& existing_stream : streams_) {
       if (stream->id() == existing_stream->id()) {
         RTC_DCHECK_EQ(stream.get(), existing_stream.get());
         added = false;
@@ -410,9 +410,9 @@ void VideoRtpReceiver::set_stream_ids(std::vector<std::string> stream_ids) {
 void VideoRtpReceiver::SetStreams(
     const std::vector<rtc::scoped_refptr<MediaStreamInterface>>& streams) {
   // Remove remote track from any streams that are going away.
-  for (auto existing_stream : streams_) {
+  for (const auto& existing_stream : streams_) {
     bool removed = true;
-    for (auto stream : streams) {
+    for (const auto& stream : streams) {
       if (existing_stream->id() == stream->id()) {
         RTC_DCHECK_EQ(existing_stream.get(), stream.get());
         removed = false;
@@ -424,9 +424,9 @@ void VideoRtpReceiver::SetStreams(
     }
   }
   // Add remote track to any streams that are new.
-  for (auto stream : streams) {
+  for (const auto& stream : streams) {
     bool added = true;
-    for (auto existing_stream : streams_) {
+    for (const auto& existing_stream : streams_) {
       if (stream->id() == existing_stream->id()) {
         RTC_DCHECK_EQ(stream.get(), existing_stream.get());
         added = false;
diff --git a/pc/rtp_transceiver.cc b/pc/rtp_transceiver.cc
index b04c20c4b6..8c7b575a4b 100644
--- a/pc/rtp_transceiver.cc
+++ b/pc/rtp_transceiver.cc
@@ -62,12 +62,12 @@ void RtpTransceiver::SetChannel(cricket::ChannelInterface* channel) {
         this, &RtpTransceiver::OnFirstPacketReceived);
   }
 
-  for (auto sender : senders_) {
+  for (const auto& sender : senders_) {
     sender->internal()->SetMediaChannel(channel_ ? channel_->media_channel()
                                                  : nullptr);
   }
 
-  for (auto receiver : receivers_) {
+  for (const auto& receiver : receivers_) {
     if (!channel_) {
       receiver->internal()->Stop();
     }
@@ -150,7 +150,7 @@ absl::optional<std::string> RtpTransceiver::mid() const {
 }
 
 void RtpTransceiver::OnFirstPacketReceived(cricket::ChannelInterface*) {
-  for (auto receiver : receivers_) {
+  for (const auto& receiver : receivers_) {
     receiver->internal()->NotifyFirstPacketReceived();
   }
 }
@@ -215,10 +215,10 @@ absl::optional<RtpTransceiverDirection> RtpTransceiver::fired_direction()
 }
 
 void RtpTransceiver::Stop() {
-  for (auto sender : senders_) {
+  for (const auto& sender : senders_) {
     sender->internal()->Stop();
   }
-  for (auto receiver : receivers_) {
+  for (const auto& receiver : receivers_) {
     receiver->internal()->Stop();
   }
   stopped_ = true;
diff --git a/pc/sdp_serializer.cc b/pc/sdp_serializer.cc
index cdaddd7199..8b0d69685b 100644
--- a/pc/sdp_serializer.cc
+++ b/pc/sdp_serializer.cc
@@ -81,7 +81,7 @@ rtc::StringBuilder& operator<<(
 rtc::StringBuilder& operator<<(rtc::StringBuilder& builder,
                                const SimulcastLayerList& simulcast_layers) {
   bool first = true;
-  for (auto alternatives : simulcast_layers) {
+  for (const auto& alternatives : simulcast_layers) {
     if (!first) {
       builder << kDelimiterSemicolon;
     }
diff --git a/pc/stats_collector.cc b/pc/stats_collector.cc
index 178f05e6b9..03eb59cf64 100644
--- a/pc/stats_collector.cc
+++ b/pc/stats_collector.cc
@@ -875,7 +875,7 @@ void StatsCollector::ExtractBweInfo() {
 
   // Fill in target encoder bitrate, actual encoder bitrate, rtx bitrate, etc.
   // TODO(holmer): Also fill this in for audio.
-  for (auto transceiver : pc_->GetTransceiversInternal()) {
+  for (const auto& transceiver : pc_->GetTransceiversInternal()) {
     if (transceiver->media_type() != cricket::MEDIA_TYPE_VIDEO) {
       continue;
     }
@@ -916,7 +916,7 @@ void StatsCollector::ExtractMediaInfo() {
 
   {
     rtc::Thread::ScopedDisallowBlockingCalls no_blocking_calls;
-    for (auto transceiver : pc_->GetTransceiversInternal()) {
+    for (const auto& transceiver : pc_->GetTransceiversInternal()) {
       if (!transceiver->internal()->channel()) {
         continue;
       }
diff --git a/pc/test/peer_connection_test_wrapper.cc b/pc/test/peer_connection_test_wrapper.cc
index 089a78000e..e2015f84e8 100644
--- a/pc/test/peer_connection_test_wrapper.cc
+++ b/pc/test/peer_connection_test_wrapper.cc
@@ -281,10 +281,10 @@ void PeerConnectionTestWrapper::GetAndAddUserMedia(
     const webrtc::FakeConstraints& video_constraints) {
   rtc::scoped_refptr<webrtc::MediaStreamInterface> stream =
       GetUserMedia(audio, audio_options, video, video_constraints);
-  for (auto audio_track : stream->GetAudioTracks()) {
+  for (const auto& audio_track : stream->GetAudioTracks()) {
     EXPECT_TRUE(peer_connection_->AddTrack(audio_track, {stream->id()}).ok());
   }
-  for (auto video_track : stream->GetVideoTracks()) {
+  for (const auto& video_track : stream->GetVideoTracks()) {
     EXPECT_TRUE(peer_connection_->AddTrack(video_track, {stream->id()}).ok());
   }
 }
diff --git a/pc/track_media_info_map.cc b/pc/track_media_info_map.cc
index 459f3ea698..781737a085 100644
--- a/pc/track_media_info_map.cc
+++ b/pc/track_media_info_map.cc
@@ -47,7 +47,7 @@ void GetAudioAndVideoTrackBySsrc(
   // means one thread jump if on signaling thread and two thread jumps if on any
   // other threads). Is there a way to avoid thread jump(s) on a per
   // sender/receiver, per method basis?
-  for (auto rtp_sender : rtp_senders) {
+  for (const auto& rtp_sender : rtp_senders) {
     cricket::MediaType media_type = rtp_sender->media_type();
     MediaStreamTrackInterface* track = rtp_sender->track();
     if (!track) {
@@ -72,7 +72,7 @@ void GetAudioAndVideoTrackBySsrc(
       }
     }
   }
-  for (auto rtp_receiver : rtp_receivers) {
+  for (const auto& rtp_receiver : rtp_receivers) {
     cricket::MediaType media_type = rtp_receiver->media_type();
     MediaStreamTrackInterface* track = rtp_receiver->track();
     RTC_DCHECK(track);
@@ -126,10 +126,10 @@ TrackMediaInfoMap::TrackMediaInfoMap(
       &remote_video_track_by_ssrc, &unsignaled_audio_track,
       &unsignaled_video_track);
 
-  for (auto sender : rtp_senders) {
+  for (const auto& sender : rtp_senders) {
     attachment_id_by_track_[sender->track()] = sender->AttachmentId();
   }
-  for (auto receiver : rtp_receivers) {
+  for (const auto& receiver : rtp_receivers) {
     attachment_id_by_track_[receiver->track()] = receiver->AttachmentId();
   }
 
diff --git a/rtc_base/openssl_session_cache.cc b/rtc_base/openssl_session_cache.cc
index f74dfeade2..270abe8903 100644
--- a/rtc_base/openssl_session_cache.cc
+++ b/rtc_base/openssl_session_cache.cc
@@ -22,7 +22,7 @@ OpenSSLSessionCache::OpenSSLSessionCache(SSLMode ssl_mode, SSL_CTX* ssl_ctx)
 }
 
 OpenSSLSessionCache::~OpenSSLSessionCache() {
-  for (auto it : sessions_) {
+  for (const auto& it : sessions_) {
     SSL_SESSION_free(it.second);
   }
   SSL_CTX_free(ssl_ctx_);
diff --git a/rtc_base/unique_id_generator_unittest.cc b/rtc_base/unique_id_generator_unittest.cc
index 5b6ce4d42a..d0e8d9827c 100644
--- a/rtc_base/unique_id_generator_unittest.cc
+++ b/rtc_base/unique_id_generator_unittest.cc
@@ -90,7 +90,7 @@ TYPED_TEST(UniqueIdGeneratorTest, AddedElementsAreNotGenerated) {
   rtc::InitRandom(0);
   Generator generator2;
 
-  for (typename Generator::value_type value : known_values) {
+  for (const typename Generator::value_type& value : known_values) {
     generator2.AddKnownId(value);
   }
 
diff --git a/sdk/objc/api/peerconnection/RTCPeerConnection.mm b/sdk/objc/api/peerconnection/RTCPeerConnection.mm
index fde71a2d55..8d1ac46d06 100644
--- a/sdk/objc/api/peerconnection/RTCPeerConnection.mm
+++ b/sdk/objc/api/peerconnection/RTCPeerConnection.mm
@@ -579,7 +579,7 @@ void PeerConnectionDelegateAdapter::OnRemoveTrack(
   std::vector<rtc::scoped_refptr<webrtc::RtpTransceiverInterface>> nativeTransceivers(
       _peerConnection->GetTransceivers());
   NSMutableArray *transceivers = [[NSMutableArray alloc] init];
-  for (auto nativeTransceiver : nativeTransceivers) {
+  for (const auto &nativeTransceiver : nativeTransceivers) {
     RTCRtpTransceiver *transceiver = [[RTCRtpTransceiver alloc] initWithFactory:self.factory
                                                            nativeRtpTransceiver:nativeTransceiver];
     [transceivers addObject:transceiver];
diff --git a/test/call_config_utils.cc b/test/call_config_utils.cc
index 671220b800..af9ca11b99 100644
--- a/test/call_config_utils.cc
+++ b/test/call_config_utils.cc
@@ -22,7 +22,7 @@ VideoReceiveStream::Config ParseVideoReceiveStreamJsonConfig(
     webrtc::Transport* transport,
     const Json::Value& json) {
   auto receive_config = VideoReceiveStream::Config(transport);
-  for (const auto decoder_json : json["decoders"]) {
+  for (const auto& decoder_json : json["decoders"]) {
     VideoReceiveStream::Decoder decoder;
     decoder.video_format =
         SdpVideoFormat(decoder_json["payload_name"].asString());
diff --git a/test/scenario/simulated_time.cc b/test/scenario/simulated_time.cc
index af4acc36ed..5824c5fe21 100644
--- a/test/scenario/simulated_time.cc
+++ b/test/scenario/simulated_time.cc
@@ -326,7 +326,7 @@ void SimulatedTimeClient::CongestionProcess(Timestamp at_time) {
 
 void SimulatedTimeClient::PacerProcess(Timestamp at_time) {
   ProcessFrames(at_time);
-  for (auto to_send : sender_.PaceAndPullSendPackets(at_time)) {
+  for (const auto& to_send : sender_.PaceAndPullSendPackets(at_time)) {
     sender_.send_node_->OnPacketReceived(EmulatedIpPacket(
         rtc::SocketAddress() /*from*/, rtc::SocketAddress() /*to*/,
         sender_.send_receiver_id_, to_send.data, at_time));
diff --git a/test/scenario/video_stream.cc b/test/scenario/video_stream.cc
index 429c494f69..500a45d4e1 100644
--- a/test/scenario/video_stream.cc
+++ b/test/scenario/video_stream.cc
@@ -308,7 +308,7 @@ ColumnPrinter SendVideoStream::StatsPrinter() {
         VideoSendStream::Stats video_stats = send_stream_->GetStats();
         int width = 0;
         int height = 0;
-        for (auto stream_stat : video_stats.substreams) {
+        for (const auto& stream_stat : video_stats.substreams) {
           width = std::max(width, stream_stat.second.width);
           height = std::max(height, stream_stat.second.height);
         }
diff --git a/video/receive_statistics_proxy.cc b/video/receive_statistics_proxy.cc
index 8ad6ef5c62..28e2becba2 100644
--- a/video/receive_statistics_proxy.cc
+++ b/video/receive_statistics_proxy.cc
@@ -275,7 +275,7 @@ void ReceiveStatisticsProxy::UpdateHistograms() {
   // Aggregate content_specific_stats_ by removing experiment or simulcast
   // information;
   std::map<VideoContentType, ContentSpecificStats> aggregated_stats;
-  for (auto it : content_specific_stats_) {
+  for (const auto& it : content_specific_stats_) {
     // Calculate simulcast specific metrics (".S0" ... ".S2" suffixes).
     VideoContentType content_type = it.first;
     if (videocontenttypehelpers::GetSimulcastId(content_type) > 0) {
@@ -297,7 +297,7 @@ void ReceiveStatisticsProxy::UpdateHistograms() {
     aggregated_stats[content_type].Add(it.second);
   }
 
-  for (auto it : aggregated_stats) {
+  for (const auto& it : aggregated_stats) {
     // For the metric Foo we report the following slices:
     // WebRTC.Video.Foo,
     // WebRTC.Video.Screenshare.Foo,
diff --git a/video/video_analyzer.cc b/video/video_analyzer.cc
index e29d53eb48..c81c9b7c43 100644
--- a/video/video_analyzer.cc
+++ b/video/video_analyzer.cc
@@ -458,7 +458,7 @@ void VideoAnalyzer::PollStats() {
     if (send_stats.media_bitrate_bps > 0)
       media_bitrate_bps_.AddSample(send_stats.media_bitrate_bps);
     size_t fec_bytes = 0;
-    for (auto kv : send_stats.substreams) {
+    for (const auto& kv : send_stats.substreams) {
       fec_bytes += kv.second.rtp_stats.fec.payload_bytes +
                    kv.second.rtp_stats.fec.padding_bytes;
     }
diff --git a/video/video_quality_test.cc b/video/video_quality_test.cc
index c8b2041f68..08fea89f99 100644
--- a/video/video_quality_test.cc
+++ b/video/video_quality_test.cc
@@ -477,7 +477,7 @@ void VideoQualityTest::FillScalabilitySettings(
     // lists. To use a default value for an element, use -1 or leave empty.
     // Validity checks performed in CheckParamsAndInjectionComponents.
     RTC_CHECK(params->ss[video_idx].streams.empty());
-    for (auto descriptor : stream_descriptors) {
+    for (const auto& descriptor : stream_descriptors) {
       if (descriptor.empty())
         continue;
       VideoStream stream =
@@ -513,7 +513,7 @@ void VideoQualityTest::FillScalabilitySettings(
   params->ss[video_idx].selected_sl = selected_sl;
   params->ss[video_idx].inter_layer_pred = inter_layer_pred;
   RTC_CHECK(params->ss[video_idx].spatial_layers.empty());
-  for (auto descriptor : sl_descriptors) {
+  for (const auto& descriptor : sl_descriptors) {
     if (descriptor.empty())
       continue;
     std::vector<int> v = VideoQualityTest::ParseCSV(descriptor);