Repurposing TV for Streaming
Now that content has been properly formatted for presentation on the target reception devices, the compression encoders produce bit streams that are compatible with each delivery channel.
Automated Graphics Assembly
As mentioned, use of template-based graphics is an efficient way to assemble graphics just in time to take to air. For sophisticated data-dependent graphics, the elimination of manual intervention and integration of database access is a powerful process and minimizes the time-to-air. This is particularly useful in a live production or news show, where the PCR is organized chaos! For breaking news, production assistants can manually enter data into pre-produced templates; they can be previewed and taken to air in seconds.
Figure 6 illustrates the basic graphics template assembly technique used for simultaneous three-screen distribution. Program video and audio is formatted for each channel as previously described. Graphics for the TV broadcast are switched and composited in the PCR. An insert is assembled from a template populated with a head shot and competitor information. A commercial billboard indicates sponsorship of the insert graphic.
Figure 6. Multiple platform graphics play-to-air
For Internet distribution, video is scaled and displayed in a media player window; audio is downmixed. Each graphic element has been reformatted and repositioned for the PC presentation. The TV billboard is displayed as a banner ad along the top of the screen and the headshot and player info is present on the right of the page. Naturally, the page is supplemented by hypertext links and additional data.
Cell phone repurposing is a little trickier. Video is downscaled and audio is downmixed to mono. The billboard is reformatted and located in the upper right portion of the display as a branded "info button" that alerts the user that additional information is available on a sub screen. This screen is the template assembled graphic with head shot and player info. Interactive capabilities, similar to the web implementation, can be added.
A Holistic Approach
Even though this article takes a TV-centric view of the multiple-platform, the ultimate goal for a broadcaster is the development of a holistic approach to implementation of an integrated infrastructure that supports the three-screen universe. Just to be clear: by integrated, I mean an infrastructure that is designed from the outset to facilitate the most efficient and flexible workflow possible for producing and assembling content for any distribution channel.
Broadcast systems that address integrated production, multiple distribution channels, and multiple reception devices process program content in terms of audio and video. As such, graphics are treated as part of the video frame and down converted as ordinary video.
This can lead to sizing, aliasing, and legibility problems due to "pixel per graphic element" problems. For example, vertically down scaling a graphic designed for 1080 lines will result in fractional pixels when down converted for 240 and 144 line displays. To avoid these issues, graphics departments create a version of each graphic for each of the three-screens.
No doubt, in time the increased power and adaptability of broadcast equipment and the development of integrated production applications and content creation tools will evolve to support fully automated repurposing of TV content for web and handheld devices; as they say, necessity is the mother of invention.
Philip J. Cianci (philipjcianci [at] verizon.net) has been working with HDTV for more than 20 years and is the author of the upcoming Focal Press book Technology and Workflows for Multiple Channel Distribution.