3D graphics
Aug 1, 2010 12:00 PM, By Boromy Ung
3D TV channel branding goes modular.
Figure 1. A single-card, channel branding processor can insert multiple layers of 3Gb/s/HD/SD graphics.
Select figure to enlarge.
It's no longer necessary to have a dedicated channel branding box to play out sophisticated graphics, such as stereoscopic 3D and full-frame, animated HD graphics. The reality is that modular products, commonly used for signal processing, are now plenty powerful enough to take on serious graphics work, which previously required a much bigger form factor.
Before looking more closely at how 3D TV channel branding graphics can be played out and controlled using modules, it's worth reviewing the core functionality of the latest generation of high-performance graphics modules. A single-card channel branding processor can now insert multiple layers of 3Gb/s/HD/SD graphics, including animations, stills and automated character generation. (See Figure 1.) It can also offer temperature insertion, video/audio mixing and multichannel audio playout for automated voice-overs and stings.
Naturally, this move to a card-based format can reduce space and power requirements considerably, sometimes by as much as 70 percent, and it also contributes to significant cost efficiencies. Importantly, these benefits are achieved without affecting essential manual control and system integration capabilities, which must be just as effective as those of stand-alone graphics devices.
Figure 2. A dual-card channel branding system offers interstitial playout for episodic promos and other types of full-frame branding graphics.
Select figure to enlarge.
For even more advanced graphics effects, the capabilities of a processor card can be extended to include instantaneous interstitial playout for episodic promos and full-frame graphics, as well as other types of rich branding such as lower thirds. This can be achieved by using a second card module with solid-state clip playout to feed the main graphics processor. (See Figure 2) This combination enables the latest modular graphics solutions to tackle the full breadth of channel branding requirements, and this can all be achieved using a familiar Adobe After Effects prerendered graphics workflow.
This type of workflow can offer full creative flexibility, along with a high level of efficiency in terms of the speed of production, the low level of manning and the accuracy of the graphics created. The process involves using a graphics automation plug-in for Adobe After Effects, which enables graphics template fields to be populated from a spreadsheet with all the key promo details from traffic, including the channel name, what's coming up next, when it's happening, etc. The fully populated graphics templates can then be quality checked, saved as flattened files and subsequently transferred to the correct playout device by the media asset management system. (See Figure 3)
Stereoscopic 3D graphics, with attention-grabbing or subtle perspective effects, can be inserted with a single processor card, using a combination of internally stored graphics and external graphics sources. In Figure 3, a single 1.5Gb/s signal for side-by-side stereoscopic 3D is branded using two internal fill/key stores for the left and right graphics. This same process can also be used with the top-bottom stereoscopic 3D format. (See Figure 4)
Figure 3. This illustrates a prerendered graphics workflow using automation plug-in for Adobe After Effects 3D TV graphics.
Select figure to enlarge.
With this type of configuration, stereoscopic 3D graphics can be created using standard graphics tools like Adobe's Premiere and After Effects, and managed with existing media management tools. While these 3D graphics are fairly straightforward to create, the positioning and control of the graphics is a much more complex issue, in view of the changing perspective of 3D TV programming. (See Figure 5)
For instance, when a program has a near (negative) depth, with the 3D effect appearing to come out of the screen to the viewer, there is a requirement to have the logo positioned in front of the action to maintain a natural perspective. During a sequence with a flat perspective, or a far depth (with the perspective effect going into the distance), the branding graphics need to be just in front of the action. If the perspective, or Z-depth, positioning of the graphic is incorrect at any point, the channel branding may lose its 3D effect or, worse, the presence of the logo or graphic may interfere with the 3D effect of the program itself.
The Z-depth of a channel branding graphic can be changed to best suit a program sequence by adjusting the horizontal separation of the left and right branding graphics. This method of controlling the Z-depth of elements is often called horizontal image translation. By separating the right and left images of the graphics in one direction, the graphics will appear to come out of the screen. Conversely, when the left and right branding graphics are moved horizontally relative to each other in the other direction, they will appear to move into the screen.
Controlling the Z-position of 3D graphics is relatively simple; what is more difficult is deciding when to move them! There are multiple options for automated and manual control of the Z-depth of channel branding graphics. One of the factors that influences the best approach to adopt is the type of content to be played out, in terms of whether it is live or prerecorded.
Branding live 3D content
Many of the initial applications for 3D TV are live events, such as sports and other big entertainment action. With this type of programming, playout automation can be used for driving graphics, like bugs, on and off for different segments. However, it can't easily be used for Z-depth control due to the unpredictable nature of live programming. In this case, it's often best to supplement the automated control of branding with manual Z-depth control, using a branding control panel with depth presets. By using presets, the operator can quickly and easily rectify incorrect graphics Z-depth issues, using smooth depth adjustment transitions.
Figure 4. Shown here is a stereoscopic 3D channel branding module with Z-depth control.
Select figure to enlarge.
In the future, it's anticipated that advances in 3D metadata playout will enable more sophisticated automated control. The channel branding processors will be able to read Z-depth metadata, probably in a similar manner to reading AFD metadata, and automatically adjust the position of the channel branding to optimize the presentation.
Another related automated control option is dynamic measurement of the Z-depth by the channel branding processor, or an associated signal processor, and performing on-the-fly adjustment of the branding graphics according to the depth data. This may represent a good backup solution in the absence of Z-depth metadata. However, both of these advanced automated control techniques are still in the formative stages and are not fully proven to date.
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