diff --git a/cdm/include/cdm_host_file.h b/cdm/include/cdm_host_file.h
index c8dc9549..be0ee566 100644
--- a/cdm/include/cdm_host_file.h
+++ b/cdm/include/cdm_host_file.h
@@ -62,7 +62,7 @@ class File::Impl {
   explicit Impl(cdm::Host_4* const host_4) :
       file_api_(new File4Impl(host_4)) {}
 
-  ~Impl() {}
+  virtual ~Impl() {}
 
   static void RegisterFileFactory(IFileFactory* factory) { factory_ = factory; }
 
diff --git a/cdm/src/wv_content_decryption_module_1.cpp b/cdm/src/wv_content_decryption_module_1.cpp
index 94385c8f..8cfe4b11 100644
--- a/cdm/src/wv_content_decryption_module_1.cpp
+++ b/cdm/src/wv_content_decryption_module_1.cpp
@@ -299,7 +299,7 @@ cdm::Status WvContentDecryptionModule_1::DoSubsampleDecrypt(
     return cdm::kDecryptError;
 
   size_t output_size = 0;
-  for (int i = 0; i < encrypted_buffer.num_subsamples; ++i) {
+  for (uint32_t i = 0; i < encrypted_buffer.num_subsamples; ++i) {
     const cdm::SubsampleEntry& subsample = encrypted_buffer.subsamples[i];
     output_size += subsample.cipher_bytes + subsample.clear_bytes;
   }
@@ -313,7 +313,7 @@ cdm::Status WvContentDecryptionModule_1::DoSubsampleDecrypt(
   uint32_t block_ctr = 0;
   const cdm::SubsampleEntry* subsamples = encrypted_buffer.subsamples;
 
-  for (int i = 0; i < encrypted_buffer.num_subsamples; ++i) {
+  for (uint32_t i = 0; i < encrypted_buffer.num_subsamples; ++i) {
     const cdm::SubsampleEntry& subsample = subsamples[i];
 
     for (int is_encrypted = 0; is_encrypted < 2; ++is_encrypted) {
diff --git a/cdm/src/wv_content_decryption_module_4.cpp b/cdm/src/wv_content_decryption_module_4.cpp
index afcc3a72..969bb965 100644
--- a/cdm/src/wv_content_decryption_module_4.cpp
+++ b/cdm/src/wv_content_decryption_module_4.cpp
@@ -353,7 +353,7 @@ cdm::Status WvContentDecryptionModule_4::DoSubsampleDecrypt(
   if (!encrypted_buffer.subsamples) return cdm::kDecryptError;
 
   size_t output_size = 0;
-  for (int i = 0; i < encrypted_buffer.num_subsamples; ++i) {
+  for (uint32_t i = 0; i < encrypted_buffer.num_subsamples; ++i) {
     const cdm::SubsampleEntry& subsample = encrypted_buffer.subsamples[i];
     output_size += subsample.cipher_bytes + subsample.clear_bytes;
   }
@@ -367,7 +367,7 @@ cdm::Status WvContentDecryptionModule_4::DoSubsampleDecrypt(
   uint32_t block_ctr = 0;
   const cdm::SubsampleEntry* subsamples = encrypted_buffer.subsamples;
 
-  for (int i = 0; i < encrypted_buffer.num_subsamples; ++i) {
+  for (uint32_t i = 0; i < encrypted_buffer.num_subsamples; ++i) {
     const cdm::SubsampleEntry& subsample = subsamples[i];
 
     for (int is_encrypted = 0; is_encrypted < 2; ++is_encrypted) {