Figure 2. Analogous insertion of advertisements in digital content
The insertion of digital programs
Digital Program Insertion (DPI) is a fully digital version of local content insertion. The IPR requires that original content include marks for the insertion of advertisements within the transport stream (TS) of the MPEG-2 format, as an integral part of the Information Service (SI) tables, in accordance with the SCTE 351 standard. Special encoders allow the creation of program insertion markers in the transport flow (TS) during the contribution process. These digital markers are assimilated to the "input tones" used in the analog insertion of advertisements. In the headend, insertion markers are detected in the transport flow by the splice unit. Embed bookmarks cause the video server to initiate insertion of relevant advertisements automatically. Communication between the splice unit and the video server is based on the SCTE 302 protocol.
Benefits of IPR
Digital satellite and cable systems deliver an increasing number of channels to their viewers. Increasingly, these contents reach in compressed formats to the digital connection boxes (STB-Set Top Boxes) in the homes of customers. These systems require broadcasters to use Digital Turn Around (DTA) solutions, which remove a digital program from national sources and incorporate it into the multiplexed flows of multiple digital channels - digital input and digital output. Systems based on DTA technology benefit from the use of IPRs.
Since the programming remains in MPEG-2 format throughout the process, the multiple stages of encoding and decoding are not present, and therefore the quality of the image is preserved. The quality of the contents is based exclusively on the original encoding parameters, controlled by the broadcasters.
The costs of the equipment are significantly reduced compared to the costs of analogous insertion as there are no requirements for decoders to convert original content and local advertisements into analogous formats. Similarly, there is no need for encoders to recompress modified content to digital formats. The savings in equipment costs are multiplied in proportion to all the digital channels that the local service provider offers on their system.
Another aspect that must be taken into consideration for DPI systems relates to the different bit rates of original and local content. Due to the limitations on the bandwidth of the systems and the fact that advertisements are stored in CBR format, the DPI system must have the ability to adjust to the bit rate of local content, in order to fit with the original programs. This process, known as Transrating or speed change, is executed in the digital domain. Transrating may also be required for modified content in order to be properly combined in multiplexing of multiple channels that have limitation on the accumulated bit rate. A single device can now execute the speed change function and at the same time develop the splice functions.
Scopus DPI System
Scopus Network Technologies, a provider of digital TV delivery solutions, has created the technology that provides broadcasters with complete solutions for their DPI needs. Scopus provides complete solutions for end-to-end ad insertion, based on its iconic IVG-7000 smart video access gates and Scopus Codico encoders and receivers, which offer advanced DPI capabilities. Figure 3 illustrates Scopus' DPI solution for its distributors, direct satellite broadcast (DBS)and cable TV operators.
The IVG-7000 is designed to allow service providers to offer targeted services to their subscribers. This is a scalable head end system in a single unit, contained in a 1-RU chassis and encompassing advanced technologies in order to provide "completely customized solutions".
In the distribution or contribution location, Scopus encoders allow the injection of SCTE 35 markers for the insertion of advertisements. The IVG-7000 achieves powerful digital processing, statistical multiplexing, bit rate reduction, flexible enhancement and extensive flow monitoring. Conditional access control (CA) can be achieved from the IVG.
The DPI system in the local head end becomes a rather simplified solution with the use of the Scopus IVG-7000. The original contents are received and decrypted using Scopus Integrated Decoder Receivers (IRDs). The IVG then allows service providers to combine splicing, programming, speed switching and multiplexing functions into a single device. This coordinates the video server using a defined SCTE 30 interface. Additionally, the IVG can take care of the insertion of advertisements for multiple programs simultaneously, thus reducing the need to perform individual splicing operations for each program.
Along with this flexible insertion of advertisements, the Scopus system offers notable features such as PSI/SI and PSIP processing, electronic programming guide (EPG) insertion, CA integration, complete network management and customized services such as pay per view (PPV).
IVG drastically reduces the amount of hardware required to achieve local content insertion, while increasing system flexibility to service providers.
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