ATVEF Transport B delivers the enhancement content along with the video and audio, within a digital broadcast signal. (ATVEF-A delivers content via the Internet.) The advantages of Transport B include: Scalability - No server loading issues with broadcast data. Wider reach - User does not need a full-time Internet connection. Faster transfer rates - Easily up to 1 Mbps. Content Pre-caching - Offers apparently instantaneous access. SERVES Future ATVEF Transport B DTV Tuners and Set Top Boxes Prototypes have been delivered for national trials. INGREDIENTS ATSC Encoding System Encodes the video program for DTV broadcast. ATSC / ATVEF-B Enhancement Data Server Assembles HTML and triggers for proper broadcast. Triveni Digital Skyscraper ATSC / ATVEF-B Multiplexing System Inserts triggers and HTML into DTV transport stream. Logic Innovations Transport Stream Multiplexer ATSC / ATVEF-B PSIP System Tells receivers where to find transport B triggers and HTML. Target Platform Platform Emulator Live ATVEF Generator - Optional This device creates HTML code and associated triggers on the fly, using traditional broadcast graphics methods. Chyron Lyric INSTRUCTIONS FOR THE PRODUCER Meet With Your Engineering Department Inserting ATVEF-B content into a broadcast stream is an equipment-intensive activity and will require the assistance of broadcast engineers. They must be involved in the decision to attempt this type of deployment. The configuration tasks in the "Instructions for the Engineer" below will be performed by them. Understand Transport A Transport B is a level of complexity beyond Transport A. Before continuing, read the recipe for ATVEF Transport A and use it as an ongoing reference. This recipe only outlines those areas that are unique to Transport B. Understand Transport B The key distinction of Transport B for the author is that content is sent BEFORE the trigger, so that it is available in the receiver cache when the user requests it. This requires knowledge of the transmission bandwidth, so you can estimate how long it will take the content to arrive. Typically, each enhancement is sent repeatedly until its trigger expires so that any user tuning in during the show can still utilize the enhancements. Plan For No Internet Your target ATVEF-B platform might not include an Internet connection. If so, eliminate all external links and transactions from your content plans. Plan For No Statistics Since your content will be broadcast, there is no way to track usage by server activity. You will need other means to determine the popularity of your content. Determine Cache Size The receiver cache size is the single-most important parameter for Transport B. It determines the nature of your content by limiting it's size in bytes. The ATVEF spec requires only 1 MB of cache. Your target platform may have more. Even so, you will likely need to plan the use of images carefully. Once the cache is full, the oldest content is replaced by new. If your content is still pointing to the discarded content, it will become a dead link. Plan for Synchronous or Static Enhancements Content in an ATVEF-B scenario can be synchronous where unique enhancements appear at specific times in the program. Or, it can be static, where a single large enhancement is available for the duration of the elected program. If you decide to provide synchronous enhancements, agree in the early stages of production on the specific points to be “enhanced”, as it can be difficult to find a good location for an enhancement in a fast paced television program. Additionally, ATVEF-B has certain constraints related to data transmission speed, discussed below, which can effect on placement of enhancements. Educate Video Producers Early in the production process, video producers need to be made aware of the unique constraints of ATVEF-B enhancements. Develop Content and Test Test your initial version for stability and graphic content on either the hardware or emulator provided by the vendor and adjust accordingly. Repeat until stable. Test Content on Target Platform After emulation testing, the only way to test your material in an actual broadcast environment is to actually broadcast it, using the insertion gear and receiver from your vendor. Because there are currently only prototype receivers capable of receiving ATVEF-B content (as of 6/01), you can probably test your content over whatever audio and video is being broadcast. Obviously this will be a problem once ATVEF DTV receivers begin to be more widely deployed. Hopefully, a solution is forthcoming. Broadcast the Program If you are inserting pre-scheduled enhancements, for the initial broadcast of the program and any repeats, lead the data server with the appropriate content and triggers. (See "Enter Data for Show" below.) If your are instead generating live enhancements, prepare the operator to perform this task. INSTRUCTIONS FOR THE ENGINEER Configure PSIP System The PSIP system must be configured to assign a unique PID of the proper type to the ATVEF enhancements for each video stream. Configure Video Multiplexer The video multiplexer must be configured to leave enough bandwidth available for the enhancements. Ideally, this parameter will be controlled dynamically by the needs of the current enhancements, so that the maximum number of bits are available at all times to improve the video quality. Configure Transport Stream Multiplexer The transport stream multiplexer (perhaps the same unit) must be configured to accept enhancement data from the data server, and insert it into the transport stream using the proper PID. Configure Data Server The data server must be configured for the desired bandwidth. This MUST not exceed the parameter set in the video multiplexer, if that parameter is fixed and not adaptive. Enter Data for Show If your system is not configured for live or automated operation, you will need to load HTML content, set pointers to the content, and set times and URLs for each trigger. Be aware that this manual approach requires the show to be broadcast at the presumed time for the entered trigger times to remain correct. It is likely that a large amount of this process will become automated. In this scenario, a central controller that is aware of scheduling, references what is coming in terms of data, does the necessary calculations and adjusts the various devices accordingly. This is currently being worked on by a number of vendors and we expect to see automation within a single vendors systems and then eventual standardization. DIAGRAMS Revised Monday, 10-Feb-2003 10:40:00 CST - h © 2000 - 2003 Local Enhancement Collaborative & .