Legacy methods for transporting metadata often restrict the type, bandwidth, and utility of metadata payloads. Early metadata standards within the ST 2110 family, like ST 2110-40 Ancillary Data and ST 2110-31 AES3 Transparent Audio, were designed for backward compatibility and quick deployment, acting mainly as wire replacements. These standards impose unnecessary constraints, especially for user-defined and novel metadata applications, and complicate asynchronous or independent metadata flows by coupling them with other essence characteristics. ST 2110-41, the Fast Metadata Framework, represents a significant shift from these legacy methods. It enables user-defined metadata flows that operate independently and with the same ease as video and audio. SiriusXM is leveraging this framework to modernize content workflows from contribution to distribution, integrating existing standards with new, flexible approaches. This paper reviews the implementation of SCTE DPI triggers and proprietary data within ST 2110-41 flows, the overall architecture of professional media systems, and the limitations of the Fast Metadata Framework. It addresses issues such as heterogeneous essence synchronization and standards-setting constraints, while identifying areas for further research, including metadata storage and replay.
The ST 2110 family of standards offer several options for metadata transport, all with their advantages and disadvantages. ST 2110-41 offers the best trade off for new systems that want to use metadata flows innovatively while improving the operability and monitorability of the system. Existing metadata standards can be adapted with minimal changes and incompatibilities to support innovative applications. Synchronizing metadata and other essence flows is complex and needs appropriate consideration during system design. Research and development is needed to further remove constraints on metadata innovation.