tor-browser

commit f39ec41ab8aaca989ab7462dfa48771933b1367d
parent 5c85e9ee89e50d6fd5fd8ee689046aabb1db0ab1
Author: Andrew Osmond <aosmond@gmail.com>
Date:   Thu,  4 Dec 2025 19:41:54 +0000

Bug 2004118 - MediaCodec NDK requires at least one subsample for whole sample encrypted blocks. r=media-playback-reviewers,jolin

This is the same issue that bug 1759936 fixes, but on the NDK pathway.
This was missed because it is done in the Java code instead of where we
initially create the crypto info sample in GetCryptoInfoFromSample for
RemoteDataDecoder.

Differential Revision: https://phabricator.services.mozilla.com/D275103

Diffstat:
M
dom/media/eme/mediadrm/MediaDrmRemoteCDMParent.cpp
 | 
62
++++++++++++++++++++++++++++++++++++--------------------------

1 file changed, 36 insertions(+), 26 deletions(-)
diff --git a/dom/media/eme/mediadrm/MediaDrmRemoteCDMParent.cpp b/dom/media/eme/mediadrm/MediaDrmRemoteCDMParent.cpp
@@ -777,35 +777,45 @@ already_AddRefed<MediaDrmCryptoInfo> MediaDrmRemoteCDMParent::CreateCryptoInfo(
   // Deep copy the plain and encrypted sizes so we can modify them.
   nsTArray<size_t> plainSizes(cryptoObj.mPlainSizes.Length());
   nsTArray<size_t> encryptedSizes(cryptoObj.mEncryptedSizes.Length());
-  uint32_t totalSubSamplesSize = 0;
-  for (const auto& size : cryptoObj.mPlainSizes) {
-    plainSizes.AppendElement(size);
-    totalSubSamplesSize += size;
-  }
-  for (const auto& size : cryptoObj.mEncryptedSizes) {
-    encryptedSizes.AppendElement(size);
-    totalSubSamplesSize += size;
-  }
-
-  auto codecSpecificDataSize =
-      CheckedInt<size_t>(aSample->Size()) - totalSubSamplesSize;
-  if (!codecSpecificDataSize.isValid()) {
-    MOZ_ASSERT_UNREACHABLE("totalSubSamplesSize greater than sample size");
-    return nullptr;
-  }
+  if (numSubSamples > 0) {
+    uint32_t totalSubSamplesSize = 0;
+    for (const auto& size : cryptoObj.mPlainSizes) {
+      plainSizes.AppendElement(size);
+      totalSubSamplesSize += size;
+    }
+    for (const auto& size : cryptoObj.mEncryptedSizes) {
+      encryptedSizes.AppendElement(size);
+      totalSubSamplesSize += size;
+    }
 
-  // Size of codec specific data("CSD") for Android java::sdk::MediaCodec usage
-  // should be included in the 1st plain size if it exists.
-  if (codecSpecificDataSize.value() && !plainSizes.IsEmpty()) {
-    // This shouldn't overflow as the the plain size should be UINT16_MAX at
-    // most, and the CSD should never be that large. Checked int acts like a
-    // diagnostic assert here to help catch if we ever have insane inputs.
-    auto newLeadingPlainSize = codecSpecificDataSize + plainSizes[0];
-    if (!newLeadingPlainSize.isValid()) {
-      MOZ_ASSERT_UNREACHABLE("newLeadingPlainSize overflowed");
+    auto codecSpecificDataSize =
+        CheckedInt<size_t>(aSample->Size()) - totalSubSamplesSize;
+    if (!codecSpecificDataSize.isValid()) {
+      MOZ_ASSERT_UNREACHABLE("totalSubSamplesSize greater than sample size");
       return nullptr;
     }
-    plainSizes[0] = newLeadingPlainSize.value();
+
+    // Size of codec specific data("CSD") for Android java::sdk::MediaCodec
+    // usage should be included in the 1st plain size if it exists.
+    if (codecSpecificDataSize.value() && !plainSizes.IsEmpty()) {
+      // This shouldn't overflow as the the plain size should be UINT16_MAX at
+      // most, and the CSD should never be that large. Checked int acts like a
+      // diagnostic assert here to help catch if we ever have insane inputs.
+      auto newLeadingPlainSize = codecSpecificDataSize + plainSizes[0];
+      if (!newLeadingPlainSize.isValid()) {
+        MOZ_ASSERT_UNREACHABLE("newLeadingPlainSize overflowed");
+        return nullptr;
+      }
+      plainSizes[0] = newLeadingPlainSize.value();
+    }
+  } else {
+    // MediaCodec expects us to provide at least one subsample. Whole-block full
+    // sample encryption does not carry subsample information, so we need to
+    // synthesize it by creating a subsample as big as the sample itself. See
+    // bug 1759936.
+    numSubSamples = 1;
+    plainSizes.AppendElement(0);
+    encryptedSizes.AppendElement(aSample->Size());
   }
 
   const CopyableTArray<uint8_t>* srcIV;