diff --git a/protobuf_definitions/message_formats.proto b/protobuf_definitions/message_formats.proto
index 45168018..2296ccf5 100644
--- a/protobuf_definitions/message_formats.proto
+++ b/protobuf_definitions/message_formats.proto
@@ -5,6 +5,7 @@ syntax = "proto3";
 
 package blueye.protocol;
 import "google/protobuf/any.proto";
+import "google/protobuf/duration.proto";
 import "google/protobuf/timestamp.proto";
 option csharp_namespace = "Blueye.Protocol.Protobuf";
 
@@ -972,6 +973,7 @@ message MultibeamPing {
 
   bytes ping_data = 10; // Ping data (row major, 2D, grayscale image)
   GuestPortDeviceID device_id = 11; // Device ID of the sonar
+  optional google.protobuf.Timestamp frame_generation_timestamp = 12; // Timestamp when the frame was generated
 }
 
 
@@ -1020,6 +1022,17 @@ message MultibeamDiscovery {
   GuestPortDeviceID device_id = 7; // Device ID of the sonar
 }
 
+// Frame offset for multibeam recordings index cache
+message MultibeamFrameOffset {
+  google.protobuf.Duration duration = 1; // Duration from the start of the recording
+  int64 offset = 2; // Offset in bytes from the start of the file
+}
+
+// Multibeam recording index cache
+message MutltibeamRecordingIndex {
+  repeated MultibeamFrameOffset frame_offsets = 1; // List of frame offsets
+}
+
 // PersistentStorageSettings defines settings for writing various types of data in the persistent storage on the drone
 //
 // Some of the data is written during factory calibration (acc calibration), while other data is written during user