diff --git a/packager/media/formats/wvm/wvm_media_parser.cc b/packager/media/formats/wvm/wvm_media_parser.cc
index 8fa47e6e37..30ced3dd1d 100644
--- a/packager/media/formats/wvm/wvm_media_parser.cc
+++ b/packager/media/formats/wvm/wvm_media_parser.cc
@@ -1113,9 +1113,10 @@ bool WvmMediaParser::ProcessEcm() {
   std::vector<uint8_t> asset_key(
       encryption_key.key.begin(),
       encryption_key.key.begin() + kAssetKeySizeBytes);
-  std::vector<uint8_t> iv(kInitializationVectorSizeBytes);
+  // WVM format always uses all zero IV.
+  std::vector<uint8_t> zero_iv(kInitializationVectorSizeBytes, 0);
   AesCbcDecryptor asset_decryptor(kCtsPadding, AesCryptor::kUseConstantIv);
-  if (!asset_decryptor.InitializeWithIv(asset_key, iv)) {
+  if (!asset_decryptor.InitializeWithIv(asset_key, zero_iv)) {
     LOG(ERROR) << "Failed to initialize asset_decryptor.";
     return false;
   }
@@ -1132,7 +1133,8 @@ bool WvmMediaParser::ProcessEcm() {
       content_key_buffer.begin() + 20);
   scoped_ptr<AesCbcDecryptor> content_decryptor(
       new AesCbcDecryptor(kCtsPadding, AesCryptor::kUseConstantIv));
-  if (!content_decryptor->InitializeWithIv(decrypted_content_key_vec, iv)) {
+  if (!content_decryptor->InitializeWithIv(decrypted_content_key_vec,
+                                           zero_iv)) {
     LOG(ERROR) << "Failed to initialize content decryptor.";
     return false;
   }