MP4 support for Common Encryption 'cbcs' scheme.

media/formats/mp4/mp4_stream_parser.cc

Index: media/formats/mp4/mp4_stream_parser.cc
diff --git a/media/formats/mp4/mp4_stream_parser.cc b/media/formats/mp4/mp4_stream_parser.cc
index dbd736df941a6542415faa81490e0bb290ec448f..dc785d2ee87c5beb322abd7e863ea36240dc302e 100644
--- a/media/formats/mp4/mp4_stream_parser.cc
+++ b/media/formats/mp4/mp4_stream_parser.cc
@@ -17,6 +17,7 @@
 #include "base/time/time.h"
 #include "build/build_config.h"
 #include "media/base/audio_decoder_config.h"
+#include "media/base/encryption_scheme.h"
 #include "media/base/media_tracks.h"
 #include "media/base/media_util.h"
 #include "media/base/stream_parser_buffer.h"
@@ -33,6 +34,41 @@
 namespace media {
 namespace mp4 {
 
+namespace {
+
+EncryptionScheme GetEncryptionScheme(const ProtectionSchemeInfo& sinf) {
+  if (!sinf.HasSupportedScheme())
+    return Unencrypted();
+  FourCC fourCC = sinf.type.type;
+  EncryptionScheme::CipherMode mode = EncryptionScheme::CIPHER_MODE_UNENCRYPTED;
+  EncryptionScheme::Pattern pattern;
+  bool pattern_encryption = false;
+  switch (fourCC) {
+    case FOURCC_CENC:
+      mode = EncryptionScheme::CIPHER_MODE_AES_CTR;
+      break;
+#if BUILDFLAG(ENABLE_CBCS_ENCRYPTION_SCHEME)
+    case FOURCC_CBCS:
+      mode = EncryptionScheme::CIPHER_MODE_AES_CBC;
+      pattern_encryption = true;
+      break;
+#endif
+    default:
+      DLOG(WARNING) << "Unsupported encryption scheme: " << fourCC;
+      break;
+  }
+#if BUILDFLAG(ENABLE_CBCS_ENCRYPTION_SCHEME)
+  if (pattern_encryption) {
+    uint8_t crypt = sinf.info.track_encryption.default_crypt_byte_block;
+    uint8_t skip = sinf.info.track_encryption.default_skip_byte_block;
+    pattern = EncryptionScheme::Pattern(crypt, skip);
+  }
+#endif
+  return EncryptionScheme(mode, pattern);
+}
+
+}  // namespace
+
 MP4StreamParser::MP4StreamParser(const std::set<int>& audio_object_types,
                                  bool has_sbr)
     : state_(kWaitingForInit),
@@ -316,7 +352,8 @@ bool MP4StreamParser::ParseMoov(BoxReader* reader) {
       DVLOG(1) << "is_audio_track_encrypted_: " << is_audio_track_encrypted_;
       audio_config.Initialize(
           codec, sample_format, channel_layout, sample_per_second, extra_data,
-          is_audio_track_encrypted_ ? AesCtrEncryptionScheme() : Unencrypted(),
+          is_audio_track_encrypted_ ? GetEncryptionScheme(entry.sinf)
+                                    : Unencrypted(),
           base::TimeDelta(), 0);
       has_audio_ = true;
       audio_track_id_ = track->header.track_id;
@@ -368,7 +405,8 @@ bool MP4StreamParser::ParseMoov(BoxReader* reader) {
           // No decoder-specific buffer needed for AVC;
           // SPS/PPS are embedded in the video stream
           EmptyExtraData(),
-          is_video_track_encrypted_ ? AesCtrEncryptionScheme() : Unencrypted());
+          is_video_track_encrypted_ ? GetEncryptionScheme(entry.sinf)
+                                    : Unencrypted());
       has_video_ = true;
       video_track_id_ = track->header.track_id;
       media_tracks->AddVideoTrack(
@@ -574,11 +612,9 @@ bool MP4StreamParser::EnqueueSample(BufferQueue* audio_buffers,
 
   if (decrypt_config) {
     if (!subsamples.empty()) {
-    // Create a new config with the updated subsamples.
-    decrypt_config.reset(new DecryptConfig(
-        decrypt_config->key_id(),
-        decrypt_config->iv(),
-        subsamples));
+      // Create a new config with the updated subsamples.
+      decrypt_config.reset(new DecryptConfig(decrypt_config->key_id(),
+                                             decrypt_config->iv(), subsamples));
     }
     // else, use the existing config.
   } else if ((audio && is_audio_track_encrypted_) ||