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DVDs (Digital Versatile Discs) are organized into the following major types of components. These are: |
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| Tracks | A track is the movie! A track will contain at least one "piece" of actual video, called a "video stream". Up to nine (9) video streams can be associated with a track. The extra 8 can be used as alternate video or alternate camera angles. Many tracks can exist on a DVD. A track contains a minimum of a video clip or movie ("stream") of some length | |||
| Soundtracks | Soundtracks contain the sound (audio) and are associated with a particular track. Each track can contain up to eight (8) sound tracks. Usually they are synchronized to the video stream. Normally the extra 7 sound tracks, if included, are used for alternate languages. However there are actually no restrictions as to any content of any soundtrack. In other words, they can be anything. | |||
| Subtitles | Up to 32 subtitle channels or "buttons over video" (see "buttons over video" below) can be associated with each track. The typical use for subtitles is the same as for any film - to print the dialog of the movie in the native language or in other languages. Subtitles need not be limited to text messages. They can consist of any type of graphics. | |||
| Slide Shows | Slide Shows are sequences of still pictures displayed on the screen. A slide show can be configured to require the viewer to use the remote control to go to the next image or to automatically go to the next image after a specified number of seconds (the default is five (5) seconds). Images can be on the screen for different amounts of time or all of them can be visible the same amount of time. Each image can have a separate soundtrack or the entire slideshow can have a single soundtrack. Typically the soundtrack consists of music, but just as for a movie track, it can consist of anything. | |||
| Scripts | Scripts are sets of instructions that are executed by the DVD player. Scripts can be thought of as computer programs which the DVD player runs. Unlike with Tracks, Menus, and Slide Shows, scripts are not directly seen by the viewer. Scripts can be executed after the disc is inserted into the player, before a menu is displayed, of after a choice is made in a menu.
Possible uses of scripts include:
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| Menus | Menus allow the viewer to control what happens next. Each menu has an image in the background. The image can be a still image or moving (motion) video with or without sound. Motion menus typically play over and over again until the viewer makes a selection. Note that the starting point of the motion menu loop does not have to be the starting point of the motion video - it can loop back to the middle. This feature is usually used when the first part of the motion menu is to be played only once.
In front of the background is a set of "buttons" representing the possible menu options and the viewer may select the desired one with the remote control. The buttons may consist of any text or any graphics (it could be a picture), or both. The current option is usually highlighted in some fashion. The viewer can move to the next selection by using the arrow keys on the remote control. If the viewer decides to actually make the selection, he or she presses the remote control ENTER key. Another way to make a selection is to press the button's number on the numerical keypad on the remote control. Usually the buttons are not actually numbered on the menu, so the numbering may not be obvious at first. (Many people are not aware that the number keys on the remote directly select menu items - try it on a DVD!) The number of, shape of, and the locations of the buttons can be defined by the designer. Menu selections can link to other menus, tracks, slide shows, or scripts. Tracks, slide shows, and scripts can link to other menus, tracks, slide shows, or scripts. Typically, the viewer eventually sees some sort of a menu (a "main menu") after the disc is inserted in the player. |
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| Chapter Markers | Chapter markers indicate the starting points of scenes in a video. Chapter markers can be added when the movie is edited or just before the DVD data is laid out ("built") Up to 99 chapter markers can be used on a track. The word "chapter" has the same meaning as the word "scene". Most DVDs include at least one scene index menu which allows the viewer to start playing at the beginning of a specific scene. Often this is also called a "Chapter Index". Usually one can get to the scene menu from the "main menu". If there are many scenes in the index, it may require several chapter index menus to display all the scenes. The menus would normally be connected together with "next" or "back" buttons.
Fairly sophisticated scene index motion menus can be created that show rectangular areas where the clips from each scene appear to play as if each were on its own little "screen". Each little screen may be accompanied with a text description of that scene. (Surprisingly, the tools used by RTFFX allow this type of menu to be created easily and rapidly). |
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| Stories | A "story" is a selected sequence of video clips (portions of a movie). Chapter markers are used to specify the start of each clip. Additional special markers are added to specify the end of each video clip. The order in which the clips are played can be set up before the disc is created. Up to 98 stories can be included (if there are no other tracks or slideshows). One use for the "story" is to present "highlights" or a summary of a movie. A story can be started up from a menu selection. It could automatically be run from the main menu, for example, if the viewer user hasn't made a selection within a certain amount of time. A documentary about a movie which is on the same DVD containing the movie itself, can actually show scenes from the movie from within the documentary. In this instance, stories might each be made of a single scene. | |||
| Buttons Over Video | These are buttons which can appear over a video track at a certain time while it is playing. The viewer can press ENTER on the remote control when the button appears to cause some action to happen. Usually this feature is used to jump to "behind the scenes" footage showing how the current scene was made after which the DVD player continues from where it left off. | |||
| Multi-Angle Video | This is the ability to switch to other video tracks), which usually are shot from a different camera angle. The additional angles are the same length as the "main" video. The "Angle" button on the DVD remote control is used to select the desired angle. Additional camera angles tend to greatly reduce the amount of space available on the DVD since the video length is multiplied by the number of alternate tracks available. | |||
| Mixed Angle Video | This is the ability to switch to other tracks during certain sections of the "main" video. This is different from Multi-Angle Video in that the additional tracks are not as long as the "main" video and therefore much less space is taken up on the DVD. The effect is that alternate sets of scenes may be selected. Examples of this is include having several endings to a movie or having different levels of adult content. All of the additional sets of scenes must be the same length and all must occur at the same times). The "Angle" button on the DVD remote control is used to select the desired angle. | |||
| Aspect Ratio | Aspect ratio is the ratio of the width to the height of what you see on the screen. It applies to both the television screen size and the movie image size. So called "widescreen" uses a 16 by 9 (16:9) aspect ratio. So called "fullscreen" uses 4 by 3 (4:3). Television began its history using 4:3. DVD players have a setting allowing you to "tell" it which type of television you are using. The DVD player displays the video differently based on what the aspect ratio of the television as well as what the aspect ration of the movie is. For example, a 4:3 video may appear "vertically letterboxed" (vertical black bars on the sides) on a widescreen television, while a 16:9 movie may be "horizontally letterboxed" (horizontal black bars on the top and bottom) on a 4:3 screen. Another method besides letterboxing is "pan and scan" where the smaller TV shows only a part of the image and what part the viewer sees can be changed (that is, moved left or right) while the movie is playing, as if "panning" with the camera. The remarkable thing about this is that the DVD player can "see" the whole 16:9 image and it is moving the 4:3 "window" back and forth based on instructions actually written on the DVD. (Note: RTFFX does not support this type of "pan and scan" done by the DVD player [this method seems to rarely be used anyway]. However, if you need to pan and scan a 16:9 image, RTFFX can do it with a 2D special effects software package. The difference doing it this other way is that a 4:3 image is created that "pans and scans" and this 4:3 image is put on the DVD, not the 16:9 image. The DVD player doesn't know [or care] that this is not a 4:3 movie.) The other two TV/Movie combinations will result in the image filling the screen. Movies shot in higher aspect ratios (such as 2.3:1 [also referred to as "Super Panavision"]) could end up being letterboxed on top and bottom to a 16:9 wide screen or "pan and scanned" to a 4:3 television. So no matter what aspect ratio the video is, DVDs can do only 4:3 or 16:9.
Unless you have control over shooting of the video, you will not be able to change the aspect ratio of the video. Many consumer camcorders offer a "widescreen mode" which is really a letterboxed image and does not create a true widescreen image. A true widescreen image can be created by such a camera by adding an external adapter which squeezes the image horizontally onto a 4:3 frame. Such a squeezed image is called "anamorphic". DVD scripts can read the aspect ratio setting from the DVD player, if decisions need to be made on this setting. |
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| User actions | While a particular DVD element is being played or shown, user actions specify what the viewer is allowed to do at that point. For example, a copyright slide may be displayed and the viewer is not allowed to skip over it using the remote control. Unless requested otherwise, the default for every item on a DVD authored by RTFFX is to allow all user actions. | |||
| DVD-Rom Material | For use on a computer, optional DVD-ROM data can be added, if there is enough space left on the DVD. The data can consist of folders and files which are treated no differently than files and folders on a computer's hard drive. Usually this consists of bonus or alternate material. If you have RTFFX create a slideshow for you, normally copies of the images will be included (space permitting). There could even be a copy of a program to play the DVD.
When the DVD is played on a computer, selections made from menus can also cause your favorite web browser to start up and access a specific web page. The browser can also be started up at certain points when the DVD is playing a movie. If selected on a set-top DVD player, of course, this web access feature is ignored. |
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