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AUDIO NAVIGATION TECHNICAL INFORMATION THE NEED FOR AUDIO NAVIGATION Audio Description is the process of aurally describing visual elements of a motion picture or television program to enable visually impaired persons to better understand what cannot be discerned from the sound track. However, to enable audio description on a television set, the user needs to access the SAP audio channel through a visual menu. On a DVD, audio description would be accessed through the Set-Up menu, or by changing the audio stream directly with the remote control. However, both of these methods provide no audible feedback making it difficult for a blind or low-vision user to enable Audio Description without assistance. In fact, on a DVD, a blind or low-vision user has no option other than playing the main movie by pressing "enter" after the disc has been inserted (and that assumes that "play movie" is the default option after inserting a disc). A visually impaired person desires independence like everyone else, and a DVD with Audio Navigation allows the blind and low-vision to access a DVD as easily as a sighted person by speaking the name of each menu as the user enters that menu, and speaking the name of each option as it is highlighted. A DVD with Audio Navigation gives a visually impaired user full and independent access to all features contained on a disc including chapter selection menus, additional audio streams (such as Audio Description or director's commentary), and special features (such as deleted scenes or "making of" documentaries) that are commonly included on motion picture DVD releases. AUDIO NAVIGATION BASICS DVD menus come in two varieties; still and slide show. A still menu contains the graphic elements for the menu but do not have a length of time associated with them. A slide show menu is also a still menu, but has a time duration associated with it. At the end of that duration, a command is executed that returns the menu to the beginning (common), or directs the DVD to another location. A slide show can also have an audio stream playing in the background. Usually, that audio is music. Audio Navigation is generated by creating individual menu graphics for each option available on the menu, and associating an audio file that speaks the name of that menu with that graphic. For example, if the Main Menu has options for "play movie", "chapter selections", "special features", and "set-up", a total of five individual graphics with the corresponding audio file need to be created. The first graphic speaks the name of the menu the user has just entered, and can also speak the list of options on that menu. The second graphic highlights the first option, "play movie" and speaks the same. The same is repeated for the other three options. When a user presses the arrow keys on the remote control to scroll through the menu options, the DVD actually moves between the individual graphics (slide show menus) representing the options for that menu. Scrolling from "play movie" to "chapter selections" moves the DVD to the "chapter selections" slide show menu and plays the audio file that speaks the name. The user either presses ENTER, or scrolls to the next option (and the next slide show menu graphic). IMPORTANT: IT IS THIS MOVING FROM GRAPHIC TO GRAPHIC THAT INTRODUCES AN APPROXIMATE DELAY OF ONE SECOND FROM THE TIME YOU PRESS THE ARROW KEY UNTIL THE NEXT OPTION BECOMES AVAILABLE. Audio Navigation was first created by the National Center for Accessible Media and used on the DVD release of their series "Abraham and Mary Lincoln: A House Divided". ISSUES CONCERNING AUDIO NAVIGATION Adding Audio Navigation to a DVD increases the authoring requirements by about three to four times the normal load. A single menu created for standard DVD navigation needs to be multiplied by the number of options on each menu plus one (for the name of the menu) for Audio Navigation. Plus, the narration needs to be scripted and recorded for the Audio Navigation. Finally, there are the complexities involved with authoring a DVD with 5 to 8 times the number of PGC's (PGC is the standard name for an individual piece of media used in a DVD; each menu option, and each video is a separate PGC) the author would normally have to deal with. Bottom line, it takes about three to four times longer to author a DVD with Audio Navigation increasing the cost of authoring by about three to four times. Additionally, Audio Navigation takes up digital real estate on the disc as does an audio description audio stream. Many Hollywood feature films have audio description created for use in theaters, but rarely is audio description added as an "bonus" feature when that movie is released on DVD. The reason is money. The market segment for Audio Description and Audio Navigation is not large enough to entice producers to include these features at the expense of an additional "directors commentary" track or "behind the scenes" featurette that can used as a selling point to the general public. BOTTOM LINE: Audio Navigation and Audio Description are vitally important features to visually impaired users who have as much desire for entertainment as sighted users, but their numbers aren't large enough to convince movie studios to include these features. ALTERNATIVE APPLICATIONS OF AUDIO NAVIGATION While it is hoped and encouraged that Hollywood feature films will begin to incorporate more accessibility features in the near future, there are many other entertainment, informational, and educational programs that are being produced by organizations and educational institutions. Many, if not most, of these programs are not intended to generate a profit and are funded by grants or sponsorship money, and would be of great value to visually impaired users if accessibility features were added to them. Producing a DVD with Audio Navigation requires significant resources, high-level DVD authoring software, and a skilled DVD author. However, many non-feature film program producers do not have the resources, software or talent available to them to consider adding Audio Navigation as demonstrated by the National Center for Accessible Media. It is for this reason that DeKalb Video Productions has created several alternative methods of Audio Navigation. These alternative methods require fewer resources and are more economical to implement than Audio Navigation as described by the National Center for Accessible Media. These alternative methods are detailed later in this article. DISCLAIMER: Audio Navigation as described by the National Center for Accessible Media is the most usable implementation of this technology and is the preferred method of Audio Navigation. However, it is the opinion of DeKalb Video Productions that easier to implement methods must be made available to organizations and institutions who create and disseminate media but are not able to implement the National Center for Accessible Media method. DVD AUTHORING SOFTWARE REQUIREMENTS FOR AUDIO NAVIGATION To create the highest level of Audio Navigation, the following features must be available from the DVD authoring software: Ability to create "hidden" buttons Ability to create slide show (duration) menus Complete control over button routing Auto-action buttons Ability to set highlighted buttons Access to SPRM's and GPRM's Multiple PRE and POST commands per PGC Ability to use DUMMY PGC's Support for multiple audio streams Ability to set TITLE and ROOT menu PGC's Ability to re-use assets within a VTS without doubling the bit budget Because of the large number of PGC's used, DVD authoring systems with a graphical view of the authoring environment are significantly easier to use than packages that "list" the available PGC's since you can group PGC's that make up a menu together and separate them from other groups of PGC's. Most authoring software packages are list view. In addition, authoring software that does not add an abstraction layer over the DVD specification (abstraction layers simplify authoring, but reduce the overall power of the software) are better suited for creating Audio Navigation. The following are DVD authoring packages that are highly recommended for creating Audio Navigation: SONIC SCENARIST. Professional level authoring package that gives the author access to 100% of the DVD specification. Expensive! $8,000 for Studio (limited to 1 VTS per disc), $15,000 for Advanced, and over $20,000 for Professional. PC only. SONIC CREATOR/FUSION. Features similar to Scenarist, but only $4,000 and up depending on configuration. Mac only. DVD MAESTRO. No longer developed, but system is still widely used at the highest level. DVD STUDIO PRO 2. Very full feature set, but an abstraction layer application. Around $1,000. Mac only. SONIC REEL DVD. Abstraction layer application that lacks the feature set necessary for full implementation of Audio Navigation, but highly recommended for simpler methods because of it's graphical authoring interface. About $700 METHODS OF AUDIO NAVIGATION (Fully functional examples of these methods and information on how to create them will be in the "Audio Navigation Instructional DVD" to be produced by DeKalb Video Productions) AUDIO NAVIGATION as described by the National Center for Accessible Media. Consists of two separate menus systems that the user toggles between. Both systems look and act the same, except the Audio Navigation menu speaks the name of each menu, and then the name of each option as the user scrolls through the list (and adds the 1 second delay). Prescribed method for toggling between menus is to press "1" and then the ENTER key on the remote control. A set-up menu should also allow for Audio Navigation to be turned on and off. Audio Navigation is implemented by using individual PGC's for each menu name, and each menu option. How It Works First play informs user that Audio Navigation is available and how to access it. DVD goes to standard navigation main menu. User presses "1" and ENTER and is sent to an identical menu with Audio Navigation. DVD goes to main menu and announces the name. User is informed to use the arrow keys to make their selections, and press ENTER to go to that selection. User presses DOWN arrow. This command links to a hidden button that is set to "auto-action" and immediately (and without additional input from the user) branches the DVD to the PGC for the first option on the menu. After about 1 second, the first selection is highlighted on the screen, and less than a second later, the narrater speaks the name of that option. User presses DOWN arrow again, and hidden "auto-action" button branches to next option PGC with audio file that speaks the name of that option. User presses ENTER and is sent either to a MPEG movie/video files, or another menu with Audio Navigation. TECHNICAL DETAILS: Individual graphics for menu selections can be created one by one with highlight element drawn on the graphic, or created as a standard navigation menu with a highlight layer and buttons, and then duplicated with adjustments then made to individual tracks. Forced selection highlight buttons need to be turned off and a GPRM used to hold the value of SPRM8 (the highlight button value) and the highlight button set to the value of that GPRM. Will need to use a GPRM to hold the current ON/OFF state of Audio Navigation (necessary in order to branch back to the correct menu when exiting out of the movie). ADVANTAGES: Ease of use for the audience, very accurate. DISADVANTAGES: Difficult and time-consuming to create. Requires high-level software and skilled author. AUDIO-ASSISTED NAVIGATION as developed by DeKalb Video Productions. This system combines standard DVD navigation and Audio Navigation into a single menu. Pressing UP and DOWN navigates normally. Pressing the LEFT arrow announces the name of the current menu and the list of options available on it, and pressing the RIGHT arrow announces the name of the currently highlighted selection. The menu and Audio Navigation PGC's are visually identical and pressing the ENTER key at any time sends the user to their selection. How It Works First play informs user that Audio Navigation is available and how to access it. DVD goes to the main menu. User presses UP and/or DOWN keys; DVD navigates normally. User presses LEFT arrow key goes to a hidden "auto-action" button that sends the DVD to an identical PGC that announces the name of the menu and the list of options on that menu. Returns to main menu still PGC. User presses RIGHT arrow key and hidden "auto-action" button branches to appropriate PGC that announces the name of the currently highlighted option. Returns to main menu still PGC. User presses ENTER at any time and goes to the MPEG movie/video file, or another menu. ADVANTAGES: Only one menu system needs to be authored, therefore less expensive. Accurate and easy to use. DISADVANTAGES: Annoying to users who are used to using the LEFT and RIGHT arrow keys for navigating around a DVD. Menus should only be vertical. Deviates from the way a DVD normally behaves. Requires high-level software and skilled author. TECHNICAL DETAILS: Menu PGC is a standard still menu, and the menu list and option PGC's are identical but slide show PGC's (with durations and audio files). All buttons on every menu must be in the same order. Three buttons are created for each option. The first button is hidden and auto-action and branches to the Menu Name and List of Options PGC. The second button is the option, and the third is hidden and auto-action and branches to the PGC that announces the name of that option. The first highlight is button 2. Pressing LEFT sets the highlight to 1, so a PRE command in the menu name and list PGC stores the value of SPRM8 to a GPRM, then adds 1 (a value of 1024 in Scenarist, or just 1 button value in many abstraction-layer packages) to the value of the GPRM, and sets the highlight to that GPRM. A POST command branches back to the still main menu with the current highlight still in that GPRM (and is set to it). NOTE: A DUMMY PGC sets the value of that GPRM to button 2 when entering that menu for the first time. Pressing the RIGHT arrow engages button 3 which branches to the PGC with the audio file that announces that option name. A PRE command stores SPRM8 to the highlight value GPRM, then subtracts 1 button value and sets the highlight button. A POST command returns to the main menu still PGC. SIMPLE AUDIO NAVIGATION 1 as created by DeKalb Video Productions. Each screen shows only one option, plus "previous" and "next" options. User either presses enter for that option, or UP/DOWN and ENTER for the next option. While using "auto-action" would preclude the use of ENTER, it is expected that only lower level authoring systems that don't support this feature would be used to create this method. An entry screen should give the user the option of standard DVD navigation, or Audio Navigation. ADVANTAGES: Relatively easy to create using most authoring systems. Accurate. DISADVANTAGES: Very slow to use. Still a lot of graphics to be created, and audio files to be recorded. AUDIO MENUS (SIMPLE AUDIO NAVIGATION 2) as created by DeKalb Video Productions. Created exactly like a standard DVD, except that all menus are slide show menus (with duration) that contain an audio file that lists each option and the number button on the remote control to push to access that option. This method is dependent upon the DVD highlighting the menu button number directly from a command from the remote control. An entry screen should give the user the option of standard DVD navigation, or Audio Navigation. ADVANTAGES: Very easy to create and author. DISADVANTAGES: The least accurate method of Audio Navigation; very easy for the user to hit the wrong button. DVD Production | Accessible DVDs | Video Production Introduction | Talking Menus | Tech Info | "How To" DVD FREE WEB COUNTER