Add metadata_obu_metadata to UserMetadata.

This allows specifying Metadata OBUs in a textproto.

PiperOrigin-RevId: 859715078

Author: Googler

iamf/cli/proto/BUILD

@@ -126,6 +126,7 @@ proto_library(
         ":codec_config_proto",
         ":encoder_control_metadata_proto",
         ":ia_sequence_header_proto",
+        ":metadata_obu_proto",
         ":mix_presentation_proto",
         ":parameter_block_proto",
         ":temporal_delimiter_proto",

iamf/cli/proto/user_metadata.proto

@@ -18,6 +18,7 @@ import "iamf/cli/proto/audio_frame.proto";
 import "iamf/cli/proto/codec_config.proto";
 import "iamf/cli/proto/encoder_control_metadata.proto";
 import "iamf/cli/proto/ia_sequence_header.proto";
+import "iamf/cli/proto/metadata_obu.proto";
 import "iamf/cli/proto/mix_presentation.proto";
 import "iamf/cli/proto/parameter_block.proto";
 import "iamf/cli/proto/temporal_delimiter.proto";
@@ -47,5 +48,8 @@ message UserMetadata {
   // attempt to validate or process any side effects of adding the OBUs.
   repeated ArbitraryObuMetadata arbitrary_obu_metadata = 11;
 
-  // Next ID: 13
+  // Metadata OBUs.
+  repeated MetadataObuMetadata metadata_obu_metadata = 13;
+
+  // Next ID: 14
 }