diff --git a/libwvdrmengine/cdm/core/src/cdm_session.cpp b/libwvdrmengine/cdm/core/src/cdm_session.cpp
index be59d203..af01ec3a 100644
--- a/libwvdrmengine/cdm/core/src/cdm_session.cpp
+++ b/libwvdrmengine/cdm/core/src/cdm_session.cpp
@@ -7,8 +7,7 @@
 #include <assert.h>
 #include <stdlib.h>
 
-#include <iostream>
-#include <sstream>
+#include <string>
 
 #include "cdm_engine.h"
 #include "clock.h"
@@ -607,9 +606,8 @@ CdmResponseType CdmSession::QueryOemCryptoSessionId(
     return NOT_INITIALIZED_ERROR;
   }
 
-  std::stringstream ss;
-  ss << crypto_session_->oec_session_id();
-  (*query_response)[QUERY_KEY_OEMCRYPTO_SESSION_ID] = ss.str();
+  (*query_response)[QUERY_KEY_OEMCRYPTO_SESSION_ID] =
+      std::to_string(crypto_session_->oec_session_id());
   return NO_ERROR;
 }
 
diff --git a/libwvdrmengine/cdm/core/src/client_identification.cpp b/libwvdrmengine/cdm/core/src/client_identification.cpp
index 1a1d864f..67dd9a2f 100644
--- a/libwvdrmengine/cdm/core/src/client_identification.cpp
+++ b/libwvdrmengine/cdm/core/src/client_identification.cpp
@@ -4,7 +4,7 @@
 
 #include "client_identification.h"
 
-#include <sstream>
+#include <string>
 
 #include "crypto_session.h"
 #include "license_protocol.pb.h"
@@ -146,9 +146,8 @@ CdmResponseType ClientIdentification::Prepare(
   }
   client_info = client_id->add_client_info();
   client_info->set_name(kKeyOemCryptoSecurityPatchLevel);
-  std::stringstream ss;
-  ss << (uint32_t)crypto_session_->GetSecurityPatchLevel();
-  client_info->set_value(ss.str());
+  client_info->set_value(
+      std::to_string((uint32_t)crypto_session_->GetSecurityPatchLevel()));
 
   if (!provider_client_token.empty()) {
     client_id->set_provider_client_token(provider_client_token);
diff --git a/libwvdrmengine/cdm/core/src/initialization_data.cpp b/libwvdrmengine/cdm/core/src/initialization_data.cpp
index 662c353c..fa5ae422 100644
--- a/libwvdrmengine/cdm/core/src/initialization_data.cpp
+++ b/libwvdrmengine/cdm/core/src/initialization_data.cpp
@@ -5,7 +5,7 @@
 #include "initialization_data.h"
 
 #include <string.h>
-#include <sstream>
+#include <string>
 
 #include "buffer_reader.h"
 #include "cdm_engine.h"
@@ -721,13 +721,7 @@ bool InitializationData::DetectEntitlementPreference(
   if (oec_version_string.empty()) {
     return false;
   }
-
-  uint32_t oec_version_int = 0;
-  std::istringstream parse_int;
-  parse_int.str(oec_version_string);
-  parse_int >> oec_version_int;
-
-  return oec_version_int >= 14;
+  return std::stoul(oec_version_string) >= 14;
 }
 
 }  // namespace wvcdm
diff --git a/libwvdrmengine/cdm/core/src/policy_engine.cpp b/libwvdrmengine/cdm/core/src/policy_engine.cpp
index c78cacb8..8e283c1b 100644
--- a/libwvdrmengine/cdm/core/src/policy_engine.cpp
+++ b/libwvdrmengine/cdm/core/src/policy_engine.cpp
@@ -5,7 +5,7 @@
 #include "policy_engine.h"
 
 #include <limits.h>
-#include <sstream>
+#include <string>
 
 #include "clock.h"
 #include "log.h"
@@ -271,7 +271,6 @@ void PolicyEngine::NotifySessionExpiration() {
 }
 
 CdmResponseType PolicyEngine::Query(CdmQueryMap* query_response) {
-  std::stringstream ss;
   int64_t current_time = GetCurrentTime();
 
   if (license_state_ == kLicenseStateInitial) {
@@ -288,11 +287,10 @@ CdmResponseType PolicyEngine::Query(CdmQueryMap* query_response) {
       policy_.can_persist() ? QUERY_VALUE_TRUE : QUERY_VALUE_FALSE;
   (*query_response)[QUERY_KEY_RENEW_ALLOWED] =
       policy_.can_renew() ? QUERY_VALUE_TRUE : QUERY_VALUE_FALSE;
-  ss << GetLicenseOrRentalDurationRemaining(current_time);
-  (*query_response)[QUERY_KEY_LICENSE_DURATION_REMAINING] = ss.str();
-  ss.str("");
-  ss << GetPlaybackDurationRemaining(current_time);
-  (*query_response)[QUERY_KEY_PLAYBACK_DURATION_REMAINING] = ss.str();
+  (*query_response)[QUERY_KEY_LICENSE_DURATION_REMAINING] =
+      std::to_string(GetLicenseOrRentalDurationRemaining(current_time));
+  (*query_response)[QUERY_KEY_PLAYBACK_DURATION_REMAINING] =
+      std::to_string(GetPlaybackDurationRemaining(current_time));
   (*query_response)[QUERY_KEY_RENEWAL_SERVER_URL] =
       policy_.renewal_server_url();
 
diff --git a/libwvdrmengine/cdm/core/test/policy_engine_unittest.cpp b/libwvdrmengine/cdm/core/test/policy_engine_unittest.cpp
index f346cd86..edf67c6e 100644
--- a/libwvdrmengine/cdm/core/test/policy_engine_unittest.cpp
+++ b/libwvdrmengine/cdm/core/test/policy_engine_unittest.cpp
@@ -6,7 +6,7 @@
 
 #include <algorithm>
 #include <memory>
-#include <sstream>
+#include <string>
 
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
@@ -51,13 +51,6 @@ int64_t GetLicenseRenewalDelay(int64_t license_duration) {
              : 0;
 }
 
-int64_t ParseInt(const std::string& str) {
-  std::stringstream ss(str);
-  int64_t ret;
-  ss >> ret;
-  return ret;
-}
-
 class HdcpOnlyMockCryptoSession : public TestCryptoSession {
  public:
   HdcpOnlyMockCryptoSession(metrics::CryptoMetrics* metrics) :
@@ -2017,9 +2010,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess) {
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
   EXPECT_EQ(kLowDuration - 100,
-            ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(kPlaybackDuration,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 }
 
@@ -2044,9 +2037,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_PlaybackNotBegun) {
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
   EXPECT_EQ(kLowDuration - 100,
-            ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(kPlaybackDuration,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 
   EXPECT_EQ(NO_ERROR, policy_engine_->Query(&query_info));
@@ -2056,9 +2049,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_PlaybackNotBegun) {
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
   EXPECT_EQ(kLowDuration - 200,
-            ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(kPlaybackDuration,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 }
 
@@ -2085,9 +2078,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_PlaybackBegun) {
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
   EXPECT_EQ(kLowDuration - 50,
-            ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(kPlaybackDuration,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 
   policy_engine_->BeginDecryption();
@@ -2102,9 +2095,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_PlaybackBegun) {
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
   EXPECT_EQ(kLowDuration - 200,
-            ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(kPlaybackDuration - 100,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 }
 
@@ -2144,9 +2137,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_Offline) {
   EXPECT_EQ(QUERY_VALUE_FALSE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
   EXPECT_EQ(kRentalDuration - 300,
-            ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(kPlaybackDuration - 100,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 }
 
@@ -2170,9 +2163,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_InitialRentalDurationExpired) {
   EXPECT_EQ(QUERY_VALUE_FALSE, query_info[QUERY_KEY_PERSIST_ALLOWED]);
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
-  EXPECT_EQ(0, ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+  EXPECT_EQ(0, std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(kPlaybackDuration,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 }
 
@@ -2192,9 +2185,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_InitialLicenseDurationExpired) {
   EXPECT_EQ(QUERY_VALUE_FALSE, query_info[QUERY_KEY_PERSIST_ALLOWED]);
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
-  EXPECT_EQ(0, ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+  EXPECT_EQ(0, std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(kPlaybackDuration,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 }
 
@@ -2232,9 +2225,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_CanPlayFalse) {
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
   EXPECT_EQ(kLowDuration - 100,
-            ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(kPlaybackDuration,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 }
 
@@ -2274,9 +2267,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_RentalDurationExpired) {
   EXPECT_EQ(QUERY_VALUE_FALSE, query_info[QUERY_KEY_PERSIST_ALLOWED]);
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
-  EXPECT_EQ(0, ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+  EXPECT_EQ(0, std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(kPlaybackDuration - kLowDuration,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 }
 
@@ -2317,8 +2310,8 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_PlaybackDurationExpired) {
   EXPECT_EQ(QUERY_VALUE_FALSE, query_info[QUERY_KEY_PERSIST_ALLOWED]);
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
-  EXPECT_EQ(0, ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
-  EXPECT_EQ(0, ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+  EXPECT_EQ(0, std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+  EXPECT_EQ(0, std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 }
 
@@ -2356,9 +2349,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_LicenseDurationExpired) {
   EXPECT_EQ(QUERY_VALUE_FALSE, query_info[QUERY_KEY_PERSIST_ALLOWED]);
   EXPECT_EQ(QUERY_VALUE_FALSE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
-  EXPECT_EQ(0, ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+  EXPECT_EQ(0, std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(kPlaybackDuration - kLowDuration,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 }
 
@@ -2399,9 +2392,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_RentalDuration0) {
   EXPECT_EQ(QUERY_VALUE_FALSE, query_info[QUERY_KEY_PERSIST_ALLOWED]);
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
-  EXPECT_EQ(0, ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+  EXPECT_EQ(0, std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(kPlaybackDuration - kLowDuration,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 }
 
@@ -2444,9 +2437,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_PlaybackDuration0) {
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
   EXPECT_EQ(0,
-            ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(LLONG_MAX,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 
   for (int i = 3; i <= 4; ++i) {
@@ -2462,9 +2455,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_PlaybackDuration0) {
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
   EXPECT_EQ(0,
-            ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(LLONG_MAX,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 }
 
@@ -2502,8 +2495,8 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_LicenseDuration0) {
   EXPECT_EQ(QUERY_VALUE_FALSE, query_info[QUERY_KEY_PERSIST_ALLOWED]);
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
-  EXPECT_EQ(0, ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
-  EXPECT_EQ(0, ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+  EXPECT_EQ(0, std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+  EXPECT_EQ(0, std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 }
 
@@ -2536,9 +2529,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_PlaybackAndRental0) {
   EXPECT_EQ(QUERY_VALUE_FALSE, query_info[QUERY_KEY_PERSIST_ALLOWED]);
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
-  EXPECT_EQ(10, ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+  EXPECT_EQ(10, std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(LLONG_MAX,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 
   policy_engine_->OnTimerEvent();
@@ -2549,9 +2542,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_PlaybackAndRental0) {
   EXPECT_EQ(QUERY_VALUE_FALSE, query_info[QUERY_KEY_PERSIST_ALLOWED]);
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
-  EXPECT_EQ(0, ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+  EXPECT_EQ(0, std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(LLONG_MAX,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 }
 
@@ -2588,9 +2581,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_PlaybackAndLicense0_WithoutPlayback)
   EXPECT_EQ(QUERY_VALUE_FALSE, query_info[QUERY_KEY_PERSIST_ALLOWED]);
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
-  EXPECT_EQ(10, ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+  EXPECT_EQ(10, std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(LLONG_MAX,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 
   policy_engine_->OnTimerEvent();
@@ -2604,9 +2597,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_PlaybackAndLicense0_WithoutPlayback)
   EXPECT_EQ(QUERY_VALUE_FALSE, query_info[QUERY_KEY_PERSIST_ALLOWED]);
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
-  EXPECT_EQ(0, ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+  EXPECT_EQ(0, std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(LLONG_MAX,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 }
 
@@ -2642,9 +2635,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_PlaybackAndLicense0_WithPlayback) {
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
   EXPECT_EQ(kRentalDuration - kPlaybackDuration + 10,
-            ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(LLONG_MAX,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 
   policy_engine_->OnTimerEvent();
@@ -2659,9 +2652,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_PlaybackAndLicense0_WithPlayback) {
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
   EXPECT_EQ(kRentalDuration - kPlaybackDuration - 10,
-            ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(LLONG_MAX,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 
   policy_engine_->OnTimerEvent();
@@ -2675,9 +2668,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_PlaybackAndLicense0_WithPlayback) {
   EXPECT_EQ(QUERY_VALUE_FALSE, query_info[QUERY_KEY_PERSIST_ALLOWED]);
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
-  EXPECT_EQ(0, ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+  EXPECT_EQ(0, std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(LLONG_MAX,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 }
 
@@ -2709,9 +2702,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_RentalAndLicense0_WithoutPlayback) {
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
   EXPECT_EQ(LLONG_MAX,
-            ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(kPlaybackDuration,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 
   policy_engine_->OnTimerEvent();
@@ -2726,9 +2719,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_RentalAndLicense0_WithoutPlayback) {
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
   EXPECT_EQ(LLONG_MAX,
-            ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(kPlaybackDuration,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 }
 
@@ -2764,9 +2757,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_RentalAndLicense0_WithPlayback) {
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
   EXPECT_EQ(LLONG_MAX,
-            ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(kPlaybackDuration - 10,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 
   policy_engine_->OnTimerEvent();
@@ -2781,9 +2774,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_RentalAndLicense0_WithPlayback) {
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
   EXPECT_EQ(LLONG_MAX,
-            ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(10,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 
   policy_engine_->OnTimerEvent();
@@ -2798,9 +2791,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_RentalAndLicense0_WithPlayback) {
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
   EXPECT_EQ(0,
-            ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(0,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 }
 
@@ -2841,9 +2834,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_Durations0) {
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
   EXPECT_EQ(LLONG_MAX,
-            ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(LLONG_MAX,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 }
 
@@ -2874,9 +2867,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_LicenseWithFutureStartTime) {
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
   EXPECT_EQ(kLowDuration,
-            ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(kPlaybackDuration,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 
   EXPECT_FALSE(policy_engine_->CanDecryptContent(kKeyId));
@@ -2892,9 +2885,9 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_LicenseWithFutureStartTime) {
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
   EXPECT_EQ(kLowDuration - 25,
-            ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(kPlaybackDuration - 15,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 }
 
@@ -2945,10 +2938,10 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_Renew) {
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
   EXPECT_EQ(kLowDuration - kLicenseRenewalRetryInterval,
-            ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(kPlaybackDuration + 5 - license_renewal_delay -
                 kLicenseRenewalRetryInterval - 15,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 }
 
@@ -3003,10 +2996,10 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_RenewWithFutureStartTime) {
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
   EXPECT_EQ(kLowDuration,
-            ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(kPlaybackDuration + 5 - license_renewal_delay -
                 kLicenseRenewalRetryInterval - 20,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 
   policy_engine_->OnTimerEvent();
@@ -3019,10 +3012,10 @@ TEST_F(PolicyEngineQueryTest, QuerySuccess_RenewWithFutureStartTime) {
   EXPECT_EQ(QUERY_VALUE_TRUE, query_info[QUERY_KEY_RENEW_ALLOWED]);
 
   EXPECT_EQ(kLowDuration - 20,
-            ParseInt(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_LICENSE_DURATION_REMAINING]));
   EXPECT_EQ(kPlaybackDuration + 5 - license_renewal_delay -
                 kLicenseRenewalRetryInterval - 40,
-            ParseInt(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
+            std::stoll(query_info[QUERY_KEY_PLAYBACK_DURATION_REMAINING]));
   EXPECT_EQ(kRenewalServerUrl, query_info[QUERY_KEY_RENEWAL_SERVER_URL]);
 }
 
diff --git a/libwvdrmengine/cdm/core/test/test_base.cpp b/libwvdrmengine/cdm/core/test/test_base.cpp
index a0951c92..dbfb6b13 100644
--- a/libwvdrmengine/cdm/core/test/test_base.cpp
+++ b/libwvdrmengine/cdm/core/test/test_base.cpp
@@ -11,7 +11,6 @@
 #include <openssl/cmac.h>
 #include <stdlib.h>
 
-#include <sstream>
 #include <string>
 #include <vector>
 
@@ -226,10 +225,10 @@ void WvCdmTestBase::SetUp() {
   // dynamically using an environment variable.  The model name will show up in
   // the license server logs as the part of the device idenfication as
   // "model_name".
-  std::stringstream ss;
-  ss << test_info->test_case_name() << "." << test_info->name();
+  std::string model_name =
+      std::string(test_info->test_case_name()) + "." + test_info->name();
   int overwrite = 1;  // Set value even if already set.
-  setenv("MODEL_NAME", ss.str().c_str(), overwrite);
+  setenv("MODEL_NAME", model_name.c_str(), overwrite);
   CryptoSession::SetCryptoSessionFactory(new TestCryptoSessionFactory());
   // TODO(fredgc): Add a test version of DeviceFiles.
 }
diff --git a/libwvdrmengine/mediadrm/src/WVDrmPlugin.cpp b/libwvdrmengine/mediadrm/src/WVDrmPlugin.cpp
index 9a7a091c..a4c74d17 100644
--- a/libwvdrmengine/mediadrm/src/WVDrmPlugin.cpp
+++ b/libwvdrmengine/mediadrm/src/WVDrmPlugin.cpp
@@ -12,7 +12,6 @@
 
 #include <endian.h>
 #include <string.h>
-#include <sstream>
 #include <stdlib.h>
 #include <string>
 #include <vector>
@@ -114,8 +113,8 @@ status_t WVDrmPlugin::openSession(Vector<uint8_t>& sessionId) {
 
   if (isCdmResponseTypeSuccess(res) &&
       info.count(QUERY_KEY_OEMCRYPTO_SESSION_ID)) {
-    OEMCrypto_SESSION oecSessionId;
-    istringstream(info[QUERY_KEY_OEMCRYPTO_SESSION_ID]) >> oecSessionId;
+    OEMCrypto_SESSION oecSessionId =
+        std::stoul(info[QUERY_KEY_OEMCRYPTO_SESSION_ID]);
     mCryptoSessions[cdmSessionId] = CryptoSession(oecSessionId);
     success = true;
   } else {
diff --git a/libwvdrmengine/mediadrm/src_hidl/WVDrmPlugin.cpp b/libwvdrmengine/mediadrm/src_hidl/WVDrmPlugin.cpp
index 360734ef..c26abf1b 100644
--- a/libwvdrmengine/mediadrm/src_hidl/WVDrmPlugin.cpp
+++ b/libwvdrmengine/mediadrm/src_hidl/WVDrmPlugin.cpp
@@ -10,6 +10,7 @@
 
 #include <list>
 #include <stdlib.h>
+#include <string>
 
 #include "WVDrmPlugin.h"
 
@@ -229,9 +230,8 @@ Status WVDrmPlugin::openSessionCommon(std::vector<uint8_t>& sessionId) {
 
   if (isCdmResponseTypeSuccess(res) &&
       info.count(wvcdm::QUERY_KEY_OEMCRYPTO_SESSION_ID)) {
-    OEMCrypto_SESSION oecSessionId;
-    std::istringstream(
-        info[wvcdm::QUERY_KEY_OEMCRYPTO_SESSION_ID]) >> oecSessionId;
+    OEMCrypto_SESSION oecSessionId =
+        std::stoul(info[wvcdm::QUERY_KEY_OEMCRYPTO_SESSION_ID]);
     mCryptoSessions[cdmSessionId] = CryptoSession(oecSessionId);
     success = true;
   } else {
diff --git a/libwvdrmengine/oemcrypto/test/oec_session_util.cpp b/libwvdrmengine/oemcrypto/test/oec_session_util.cpp
index 4ed98c50..63951d2f 100644
--- a/libwvdrmengine/oemcrypto/test/oec_session_util.cpp
+++ b/libwvdrmengine/oemcrypto/test/oec_session_util.cpp
@@ -22,7 +22,6 @@
 #include <iostream>
 #include <memory>
 #include <string>
-#include <sstream>
 #include <vector>
 
 #include "OEMCryptoCENC.h"
@@ -554,9 +553,9 @@ void Session::FillSimpleMessage(uint32_t duration, uint32_t control,
     if (global_features.api_version >= 12) {
       // For version 12 and above, we require OEMCrypto to handle kcNN for all
       // licenses.
-      std::stringstream stream;
-      stream << "kc" << global_features.api_version;
-      memcpy(license_.keys[i].control.verification, stream.str().c_str(), 4);
+      std::string kcVersion =
+          "kc" + std::to_string(global_features.api_version);
+      memcpy(license_.keys[i].control.verification, kcVersion.c_str(), 4);
     } else if (control & wvoec::kControlSecurityPatchLevelMask) {
       // For versions before 12, we require the special key control block only
       // when there are newer features present.
@@ -598,9 +597,9 @@ void Session::FillSimpleEntitlementMessage(
     if (global_features.api_version >= 12) {
       // For version 12 and above, we require OEMCrypto to handle kcNN for all
       // licenses.
-      std::stringstream stream;
-      stream << "kc" << global_features.api_version;
-      memcpy(license_.keys[i].control.verification, stream.str().c_str(), 4);
+      std::string kcVersion =
+          "kc" + std::to_string(global_features.api_version);
+      memcpy(license_.keys[i].control.verification, kcVersion.c_str(), 4);
     } else if (control & wvoec::kControlSecurityPatchLevelMask) {
       // For versions before 12, we require the special key control block only
       // when there are newer features present.
@@ -631,10 +630,10 @@ void Session::FillRefreshMessage(size_t key_count, uint32_t control_bits,
     if (global_features.api_version >= 12) {
       // For version 12 and above, we require OEMCrypto to handle kcNN for all
       // licenses.
-      std::stringstream stream;
-      stream << "kc" << global_features.api_version;
+      std::string kcVersion =
+          "kc" + std::to_string(global_features.api_version);
       memcpy(encrypted_license().keys[i].control.verification,
-             stream.str().c_str(), 4);
+             kcVersion.c_str(), 4);
     } else {
       // For versions before 12, we require the special key control block only
       // when there are newer features present.
diff --git a/libwvdrmengine/oemcrypto/test/oemcrypto_test.cpp b/libwvdrmengine/oemcrypto/test/oemcrypto_test.cpp
index 21da261c..1f9aa46d 100644
--- a/libwvdrmengine/oemcrypto/test/oemcrypto_test.cpp
+++ b/libwvdrmengine/oemcrypto/test/oemcrypto_test.cpp
@@ -22,7 +22,6 @@
 #include <iostream>
 #include <map>
 #include <string>
-#include <sstream>
 #include <utility>
 #include <vector>
 
@@ -5856,9 +5855,7 @@ TEST_F(UsageTableDefragTest, ReloadUsageEntryBadData) {
 }
 
 static std::string MakePST(size_t n) {
-  std::stringstream stream;
-  stream << "pst-" << n;
-  return stream.str();
+  return "pst-" + std::to_string(n);
 }
 
 // This verifies we can actually create two hundered usage table entries.