Understanding SCTE-35 and Its Applications
SCTE, short for The Society of Cable and Telecommunications Engineers, is a non-profit organization that sets technical standards for the cable telecommunications and video industry. SCTE-35, first published in 2001, serves as the signaling standard for advertising and program control for content providers and distributors. It identifies ad breaks, program content, blackouts, and extensions during live programs. SCTE-35 messages have evolved from cue tones in cable TV to embedded metadata for modern streaming applications.
Use Cases and Benefits of SCTE-35
SCTE-35 markers play a crucial role in ad insertion, allowing for targeted dynamic ad replacement and increased monetization opportunities for broadcasters. They also signal program boundaries, including chapters, ad breaks, and extensions, enhancing the user experience with automated editing processes. Additionally, SCTE-35 helps in signaling blackouts, ensuring compliance and seamless content replacement when necessary.
Types of SCTE-35 Markers
There are five command types defined in the SCTE-35 specification, with splice_insert and time_signal being the most important for modern workflows. Splice_insert commands mark splice events for inserting new content like ads seamlessly, while time_signal commands, combined with segmentation descriptors, can handle various use cases, such as program boundary markers, ensuring precise content segmentation.
Implementing SCTE-35 in Streaming Workflows
In MPEG-2 transport streams, SCTE markers are carried on their own PID within the stream mux. These streams are typically used for contribution feeds and are transmitted over satellite, fiber paths, or through streaming protocols like SRT. For HLS, the Bitmovin Live Encoder supports a range of HLS tags that are generated when SCTE-35 triggers are detected from the MPEG-TS input stream, enabling seamless integration of SCTE-35 markers in HLS workflows.