The AOLTV set top box contains a 56K modem and an RF input and runs middleware based on the Liberate platform. It is a "thick client" (meaning all rendering is done on the box itself does not require extensive server infrastructure) and is capable of receiving ATVEF transport A triggers. 1 MB of ram is available for content. Accordingly, all that is needed for a development environment is the AOLTV set top box, an RF video source, a phone line and a server connected to the internet. Finally, the AOLTV set top box can be purchased at local retailers making it one of the easiest places to develop ITV.

Through a partnership with AOL, additional features such as contextual chats, E-commerce and online polling can be implemented without taxing your infrastructure. However it should be noted that AOL has fairly rigid guidelines for what is allowable stylistically and linguistically in their environment and this must be allowed for in your development cycle.

Finally, AOL is one of the few vendors who make their development materials publicly available. The complete AOLTV development guide is available:

• http://developers.aoltv.com

First and foremost it should be noted that the AOLTV box has a 56k modem which attaches via the traditional telephone lines. This means that content must be kept as small as possible, AOL recommends a maximum size of 30k per page. Additionally there have been some modifications to both HTML and JavaScript that must also be addressed (see "code issues" below).

Like most ITV systems, AOLTV will automatically adjust the overall size of a page to keep it within the window and enlarge text to make sure it is readable in a television environment. The dimensions of the entire screen are 602x458. However the only time you can use the full screen is when you want to create a single background image. AOLTV considers the "content safe area" of the television to be 585x380, not including a 36 pixel high branding and navigation area on the top of the page. This is the area considered to be viewable on all consumer television sets. Generally speaking, pages wider than this will be resized while pages taller than this will scroll. In order to avoid unpredictable behavior it is recommended that pages be kept smaller than 585x380.

AOLTV does not automatically adjust color for the television environment, however all colors used should be NTSC compliant.

The AOLTV browser default font face is Swiss 721 BT, bold. Default text size (HTML Size 3) is 18 point. Headlines are 20 pt. (size 4). It should be noted that users can choose a scale of small, medium or large for all fonts which defines how settings in the range 1 through 7 are interpreted in the <font>, <basefont> and heading (<h1> through <h6>) are interpreted. This function may be disabled via JavaScript, and code for this is included in the AOLTV developers manual.

Generally speaking, AOLTV supports HTML 3.2 and JavaScript 1.1. However there are some significant limitations and enhancements that must be accounted for. JavaScript implementation has been modified extensively for life in a low CPU power / memory environment and has extended functionality for interfacing with the set top box. Table functions within AOLTV also differ significantly HTML 3.2. AOL has modified table implementation for life in a television environment and for parsing of non conforming HTML. For more on these subjects see the AOLTV developers guide.

AOLTV supports following file formats: .GIF, JPG, PNG, WNG, WAV, MID. Additionally there is limited support for Flash 3.0, but it is suggested these be kept small and uncomplicated.

AOLTV

Revised Monday, 10-Mar-2003 14:33:12 CST - h - © 2000 - 2003 Local Enhancement Collaborative & - Please Comment