Interactive Video Composition and Presentation Systems

The appendix provides the source code for one implementation of the invention. The appendix is in two parts, the first being the source code for the composition or composer and the second being the source code for the presentation or conductor.

The source code for the composer is dated Mar. 14, 1986, and comprises the following modules: BLDWIN (pages 1 to 3); CMPEV (pages 1 to 11); CMPTV (pages 1 and 2); CONTROL (pages 1 to 23); DISKIO (pages 1 to 3); GRAFCNTL (pages 1 to 18); GRAPHICS (pages 1 to 6); KBD (pages 1 to 11); LIT (pages 1 to 12); MATCH (pages 1 to 7); PRIM (pages 1 to 18); PUTEVT (pages 1 to 3); READEVT (pages 1 to 14); RTF (pages 1 to 3); RWACK (pages 1 to 3); RWCALC (pages 1 and 2); RWGRAPH (pages 1 to 4); RWKBD (pages 1 to 5); RWLINE25 (pages 1 to 4); RWMISC (pages 1 to 3); RWNEXT (one page); RWSETV (pages 1 to 4); RWSWITCH (pages 1 to 3); RWVIDEO (pages 1 to 6); R.sub.-- LIT (pages 1 and 2); R.sub.-- MISC (one page); R.sub.-- SPEECH (pages 1 to 3); R.sub.-- STILL (pages 1 and 2); R.sub.-- TOUCH (pages 1 to 3); R.sub.-- WAIT (pages 1 and 2); SPRIM (pages 1 to 16); STD2 (pages 1 to 9); STDWIN (pages 1 to 15); STILL (pages 1 to 5); TCH (pages 1 to 20); WFORMAT (pages 1 and 2); WIND (pages 1 to 15); WORDS (pages 1 to 7); WRITEEVT (pages 1 to 9); WTF (pages 1 to 3); W.sub.-- LIT (pages 1 to 3); W.sub.-- MISC (pages 1 and 2); W.sub.-- SPEECH (pages 1 to 3); W.sub.-- STILL (pages 1 and 2); W.sub.-- TOUCH (pages 1 to 3); and W.sub.-- WAIT (pages 1 and 2).

The source code for the conductor is dated Mar. 13, 1986, and comprises the following modules: ALL.sub.-- CALC (pages 1 to 3); ASSIGNIT (pages 1 and 2); BLDINDEX (pages 1 and 2); BRANCHES (pages 1 to 13); BREAKOUT (pages 1 to 5); BUG.sub.-- PROC (pages 1 to 7); CHG.sub.-- ATT (pages 1 to 4); CHG.sub.-- DIR (pages 1 and 2); CHKEVT (one page); CHKNUM (one page); CHKSTR (one page); CHKTIME (one page); CMALLOC (one page); CMDLIST (pages 1 to 5); CMD.sub.-- PROC (pages 1 to 3); CNDPMAIN (pages 1 to 7); COLLIDE (pages 1 and 2); COPYRHT (pages 1 and 2); CURSOR (pages 1 and 2); DEVICERD (pages 1 to 3); DEVICEWT (pages 1 to 3); DO.sub.-- BATCH (one page); DO.sub.-- CMD (one page); EXTRACT (pages 1 to 6); FD.sub.-- FILES (pages 1 to 3); FINDCMD (pages 1 and 2); FUNCT11 (pages 1 to 24); FUNCT2 (pages 1 to 8); FUNCT3 (pages 1 and 2); FUNCT41 (pages 1 to 17); F.sub.-- DUMMY (one page); GETCCF (pages 1 to 3); GETEVENT (pages 1 and 2); GETM.sub.-- OP (pages 1 and 2); GETPLAYR (one page); GET.sub.-- KEY (pages 1 and 2); GET.sub.-- OP (pages 1 and 2); GET.sub.-- TCH (pages 1 and 2); GRAPHICS (pages 1 to 6); IBTRACE (pages 1 and 2); INTLACE (one page); LINE.sub.-- 25 (pages 1 to 4); LOADPLYR (one page); ICON.sub.-- PRO (pages 1 to 4); INITVID (pages 1 and 2); LOADPLYR (pages 2 and 3); LOGERROR (pages 1 to 6); NEXT.sub.-- OP (one page); NSTRING (pages 1 to 3); PLAYFROM (pages 1 and 2); PRESDATA (pages 1 to 5); PRO.sub.-- LOOP (pages 1 to 3); PRTTOKEN (pages 1 to 3); PRT.sub.-- CMD (pages 1 to 5); PUTBTABL (one page); PUTGTABL (one page); PUTNTABL (one page); PUTSTABL (pages 1 and 2); PUTTOKEN (pages 1 and 2); RESUME (pages 1 and 2); SBOX (pages 1 and 2); SCANBRCH (pages 1 and 2); SCANBYTE (pages 1 and 2); SCANEVT (pages 1 and 2); SCANLINE (pages 1 and 2); SCANNUM (pages 1 and 2); SCANSTR (pages 1 and 2); SETCMD (pages 1 to 7); SETFNPTR (pages 1 and 2); SETTCH (pages 1 and 2); SOLIDSYS (pages 1 and 2); SPEAK.sub.-- FI (pages 1 to 3); SPK.sub.-- PROC (one page); SPK.sub.-- TST (pages 1 to 3); STOPVID (pages 1 and 2); SYNC (pages 1 and 2); TCH.sub.-- PROC (pages 1 to 5); TICTIME (one page); TRIM.sub.-- END (one page); T.sub.-- ACTION (pages 1 to 3); UNSTACK (pages 1 and 2); USERPROC (pages 1 to 3); USER.sub.-- IN (pages 1 to 4); USR.sub.-- FILE (pages 1 to 7); VDISI (pages 1 and 2); VDIS2 (pages 1 and 2); VID.sub.-- PROC (one page); VIS.sub.-- POLL (pages 1 and 2); VIS.sub.-- PROC (pages 1 and 2); WAITPOLL (pages 1 and 2); WRTSTR10 (pages 1 to 4); and WRT.sub.-- TCH (one page).

1. Field of the Invention

The present invention generally relates to an information providing system and, more particularly, to an interactive multi-media presentation system and a method for developing the presentation. The invention has broad application in the area of user interactive information systems such as, but not limited to, computer aided education. The invention facilitates the presentation of all manner of information which may be useful in various business contexts including sales, training and the like.

2. Description of the Prior Art

Interactive video training has become important as an effective technique in the field of computer aided education. A number of input technologies including keyboard, touch screen and light pen may be used to accept inputs and responses from a student user. Video disks are used to provide visual data in the form of graphics and animation to a display screen and audio signals to a speaker or speakers. A voice synthesizer may also be used to provide instructions and provide feedback to the student user on each answer. The programmed course of instruction may be designed to stop at any point to provide additional levels of instruction or even to repeat previous instruction as reinforcement depending on the student user's responses.

Interactive video training is but one aspect of a broader field of information presentation. Much the same techniques may be advantageously applied in other areas. For example, a sales presentation might be composed so that a prospective customer could use the presentation to determine what his needs were and how best to satisfy those needs. There are other areas where, for example, the need exists to provide the general public with information about a particular place or time in history or about an exhibit such as at a National Park or museum. Rather than the typical prerecorded tape which may be activated by an interested party, it would be desirable to provide an information system which the user could tailor to his or her individual interests.

Creating the programs for interactive video training courses and, more generally, information presentation systems has been a difficult and time consuming task. In the past, interactive video presentations have been designed manually and then subsequently coded into a computer program by program developers. This process has made such presentations expensive and limited their number to those applications for which the cost could be justified.

It is therefore an object of the subject invention to provide a method for developing a computer aided video presentation which may be practiced by persons who are relatively inexperienced in the use of computers.

It is a further object of the invention to provide a composition system which facilitates the development of an interactive multi-media presentation.

The objects of the invention are attained by a program for specifying the execution of independent, multi-media tasks along a synchronizing time line, preferably in the form of a spreadsheet matrix with event elements making up the rows and the time periods, the columns. The media which may be used in the practice of the invention include various pieces of hardware such as touch screens, graphics displays, voice synthesizers, video disk players, keyboards, and light pens as described above. These devices correspond to the rows of the matrix. The activities of multiple independent devices are synchronized by having the columns of the matrix represent moments in time. Thus, all activities specified in one column appear to happen simultaneously, while activities specified in multiple columns appear to happen successively, moving from left to right in the matrix.

The matrix used in the practice of the invention is similar to the GNATT chart concept used in the field of project management to schedule the activities of men and machines across time.

In designing a presentation, the information provider types into a series of matrices indications of which devices will be operating in a desired sequence and for a specified period of time. In the context of the invention, each event is a filled-in spreadsheet matrix. Each spreadsheet matrix includes information indicating the next event. The next event may be the next event in sequence or it may be conditional on which input is made by a user. The input may be selected by the user in response to a prompt to choose from among several possible inputs which are presented. It is also possible, because of the time line in the spreadsheet matrix, to provide a default next event should the user fail to make a choice within a predetermined period of time. The default next event does not need to be one of the events that would have occurred had the user made a selection within the predetermined period of time. The control in each spreadsheet event is also specifiable in all other events in the presentation, thereby allowing complex multi-media presentations to be designed by a user who is relatively unsophisticated in using computers. Thus, a single presentation may comprise hundreds or even thousands of filled-in spreadsheet events.

The program that permits the information provider to compose the presentation is referred to herein as the "composer". Once a presentation has been composed, the user for whom the information is intended may use the presentation by means of a second program referred to herein as the "conductor". The conductor is the run time program for the composer. The end user need only have a copy of the composed presentation and the conductor program in order to use the system. Only the information provider needs to have both the composer and the conductor programs. Thus, in the context of a host computer with a plurality of terminals, the terminals assigned to the end users would not be able to access the composer program but a terminal assigned to the information provider would. In the case of a plurality of stand alone computers, the composer program does not need to be distributed to the end users. The end users need only receive the composed presentation and the conductor program.

The reason why the author of a presentation requires both the composer and the conductor programs is to allow the author to test his presentation during the process of writing it. For example, after having written a sequence of events, the author would run the sequence using the conductor to see whether the information is presented in a manner which is satisfactory to him. If it is not, the author can return to the composer and edit the presentation. The composer supports several editing features including adding and deleting events, modifying events by the insertion or removal of columns to place forgotten event elements in the appropriate time sequence or remove superfluous event elements, and to change the sequence in which events are presented.

The foregoing and other objects, aspects and advantages of the invention will be better understood from the following detailed description of a preferred embodiment of the invention with reference to the drawings, in which:

FIG. 1 is a representation of a computer display screen showing the initial time-line used to author an event in a presentation according to the subject invention;

FIG. 2 is a representation similar to FIG. 1 showing a pop-up menu for the video segment of the time-line;

FIG. 3 is a representation similar to FIG. 1 showing the specification of a video still in the time-line;

FIG. 4 is a representation similar to FIG. 1 showing the pop-up graphics menu;

FIG. 5 is a representation similar to FIG. 4 but showing the fade and wipe pop-up menu selected from the graphics menu;

FIG. 6 is a representation similar to FIG. 4 but showing the move option pop-up menu partially overlaying the graphics menu;

FIG. 7 is a representation similar to FIG. 1 showing the pop-up menu for literals;

FIG. 8 is a representation similar to FIG. 1 showing the touch screen design option pop-up menu;

FIG. 9 is a representation similar to FIG. 1 showing the line 25 pop-up menu;

FIG. 10 is a representation similar to FIG. 9 but showing the line 25 pop-up option menu which lists additional video control options;

FIG. 11 is a representation similar to FIG. 1 showing the pop-up menu for sound;

FIG. 12 is a representation similar to FIG. 11 but showing the pop-up word list;

FIG. 13 is a representation similar to FIG. 1 showing the pop-up menu for answer analysis;

FIG. 14 is a representation similar to FIG. 1 showing the pop-up menu for the indicators;

FIG. 15 is a representation similar to FIG. 1 showing the pop-up menu for video disk loading and unloading; and

FIG. 16 is a block diagram showing the overall structure of the conductor program according to the invention.

As mentioned, two separate computer programs are used to allow the information provider the ability to author information which can be displayed on the screen of a host connected computer terminal or a stand alone computer system. The first of these is the composer program which gives the information provider the ability to author or compose a presentation. A presentation is the information the end user sees and/or hears at the host connected computer terminal or stand alone computer system. The authoring process consists of the instructor using a time-line to control the media of the presentation. The media can consist of graphic frames, video disk frames and sound.

The second computer program is the run time program which will be referred to as the conductor. The conductor is the application that takes the information authored by the information provider using the composer and performs the functions indicated in the time-line of each event in the course of the presentation. In general, the conductor is the program that resides in the end user's computer terminal or stand alone computer system to present the information to the end user.

The author of a presentation has the capability to present to the end user moving video pictures, still video pictures, graphic frames, text, and sound from either a video disk or a speech synthesizer. With the flexibility of the hardware devices, it is possible for the author to use media mixing to produce a variety of visual and audio effects. The author can define more than one type of user input. The input can be, for example, touch points on a touch screen display and/or the keyboard. The author can direct a presentation based on the points touched by the user or make decisions based on variable data input from the keyboard.

Preparing a presentation begins by the author deciding what information is to be presented during the presentation. Once the information has been decided upon, the author then determines what type of media will be used to present the information. All video and sound required may be created and placed on a video disk. A map of what is on the video disk, both video and sound, is made to allow the author to easily locate any video or sound data that may be required at any point in the presentation. Any graphics that may be needed are made with an all points addressable (APA) or bit mapped frame creator and editor. Once all the information is available, the author can create an outline of how the presentation is run. This outline can be made using any text editor, and the outline should include information such as what graphics are to be displayed with what video and sound. Any input allowed and what decisions are to be made based on the input from the end user should also be included. Once this outline is made, it is used during the composer process as a guide for the author. From the outline, the author should be able to fill in the time-line provided during the composer process to perform the indicated steps of the presentation.

The hardware required to run the composer and conductor are a microcomputer such as the IBM Personal Computer (PC), PC/XT or PC/AT, a vision head, and a video disk player. It is not necessary that the composer and conductor use the same type of PC; however, whichever type of PC is used, it is required to have 512K bytes of memory, an Enhanced Graphics Adaptor (EGA), and a General Purpose Interface Bus (GPIB). The vision head is a hardware device that contains a medium resolution graphics display, a touch screen, two speakers, and a voice synthesizer chip, all of which technology is known in the art. The IBM PCs use a keyboard that has ten function keys labeled F1 to F10 and a combination numeric and cursor keypad. The arrow keys on this keypad can be used to position the cursor on the display screen; however, other cursor positioning devices such as a mouse, track ball, joy stick or the like can be used to position the cursor on the screen.

As mentioned, the composer refers to the authoring process which allows the author to create a presentation. There are several steps involved in creating a presentation, and each of these steps corresponds to an option on the composer menu, an example of which is shown below.

As can be seen from the menu, two profiles must be created, the author profile and the presentation profile. These profiles are used by the composer and the conductor to identify information about the author, the equipment being used and the functions available.

A time-line is used in the authoring process. The time-line is a type of spreadsheet which controls and synchronizes graphic frames, video disks, a touch screen, a voice synthesizer and other hardware connected to the system. One such spreadsheet is required for each event in the presentation. The spreadsheet is arranged in a matrix with event elements making up the rows and the time periods, the columns.

When first beginning the time-line process, the time-line will be empty as shown, for example, in FIG. 1 of the drawings. As seen in the menu shown above, the author also has the ability to erase an event and test an event while in the composer program. It is useful to erase an event if the event has been authored incorrectly or design changes have been made. When an event is erased, its time-line is cleared of all entries. The author can use the conductor program to test an event without leaving the composer program. This helps the author to locate any problems while still in the authoring process.

Beginning first with the author profile, this option allows the author to identify information about the author and the equipment being used. This information is supplied by the author in a fill-in-the-blanks menu provided for that purpose. Using a similar fill-in-the-blanks menu, the author can next create or change the presentation profile. The presentation profile is used to identify information about the presentation such as the maximum pause time, system color, pause key label, replay key label, continue key label, help key label, and the like.

After creating the author profile, the presentation profile and the outline, the actual presentation can be authored. This corresponds to option 4 on the composer menu shown above. The presentation to be authored is indicated in the composer menu beside the "Presentation=" field. The name shown in the example above is "Vision". The presentation name can be changed by selecting option 1 of the composer menu and changing the "Presentation Name" field in the author profile.

Initially, the outline is displayed with the cursor positioned at the first event. Another event may be selected by moving the cursor using the up and down arrow keys on the computer keyboard. While in the authoring process, pressing function key F7 will list the event names and pressing another function key F8 will display any available help. Pressing function key F10 will end the option and return to the composer menu.

Once the cursor is correctly positioned beside the desired event, pressing function key F2 will begin the authoring process. A screen is displayed showing the outline of the selected event and an empty time-line as shown in FIG. 1. In FIG. 1, the outline is shown at the top of the display, and the time-line is shown at the bottom. In the time-line, the rows are event elements and the columns are times. The cursor is positioned on the video segment row at time 0. The cursor can be moved around the time-line using the four arrow or cursor control keys on the computer keyboard.

With specific reference to FIG. 1, the time row indicates the length of time, in tenths of seconds, an event element will take to complete. The total amount of time for an event is displayed in the last non-empty column. The time-line will automatically reflect the time it takes for a video segment to play. The user may alter the time manually using designated keys, except when playing a video segment, but initially the time row is displayed with tenth second increments.

A video segment is a set of consecutive video picture. To specify a video segment, the starting frame number is entered. A pop-up window is displayed at the bottom right corner of the screen as shown in FIG. 2. As indicated by the brackets in FIG. 2, the cursor is positioned at the first field in the pop-up window labeled "player". An entry is made in each field and the enter key is pressed. After the enter key is pressed, the cursor moves to the next field, and after entering a value for the last field, the pop-up window disappears and the cursor is positioned in the next time column of the video segment row. The ending frame number of the video segment must be entered in this column. Once entered, the composer program calculates the time it will take the video segment to play at a predetermined rate. The times in the time row are automatically altered, beginning with the column containing the ending frame number, to reflect the time it will take to play the video segment.

The next row in the time-line is labeled "video stills". A video still is a single frame on a video disk. All that is required to specify a video still is to enter the frame number of a frame from the video disk. This has been done in FIG. 3. No pop-up window will appear because a video still displays only video; there is no audio.

Upon pressing the enter key, the cursor is repositioned at the row labeled "graphics". Graphics frames can be either APA (all points addressable or bit mapped) frames or NAPLPS (North American Presentation Level Protocol Syntax) frames. The frame name of a graphic frame must be entered. Once entered, a pop-up menu is displayed at the bottom right corner of the screen as shown in FIG. 4. Option 1 of the pop-up menu, fade routine, allows the author to select from several different fade and wipe techniques. Fades and wipes are transition routines that dictate how a graphic will replace a previous graphic on the screen. They allow for a smooth presentation by eliminating abrupt changes on the screen. When this option is selected, a menu listing the available fade techniques is displayed at the lower right corner of the screen as shown in FIG. 5. Once the fade technique has been chosen, a time value between 0 and 99 must be entered. This value specifies how fast the fade or wipe will occur. The time value is in tenths of a second, from 0 to 99 tenths. After selecting a fade or wipe routine and a time value, the graphics menu of FIG. 4 is redisplayed to allow another selection.

Option 2 of the graphics pop-up menu of FIG. 4, transparent colors, allows the author to specify which color or colors are to be transparent. A video segment or video still can be displayed behind a graphic frame on the display screen. The video shows through the graphic in the areas in which color has been made transparent.

Option 3 of the graphics pop-up menu of FIG. 4, move window, allows the author to move the window to a precise position. A pop-up menu is displayed which prompts the author for an upper left row and column and a lower right row and column as shown in FIG. 6. Upon entering the values for the rows and columns, the pop-up menu for the move window is removed uncovering the graphics pop-up menu which it overlayed.

Option 4 of the graphics pop-up menu of FIG. 4, examine screen, allows the author to see what the graphic specified in the time-line currently looks like. The graphic is displayed with grid numbers superimposed across the top and down the left side. These numbers are helpful in deciding where to position literals and touch areas on the screen. After examining the graphic, the function key F10 may be pressed to keep the graphic and return to the pop-up graphics menu. If the graphic is not correct, the function key F3 may be pressed to cancel the current processing and return to the time-line. Option 5, return to time-line, causes the pop-up graphics menu to disappear and the cursor to be positioned on the next row labeled "literals".

Literals allow the author to display messages on the screen. A literal label is required and may either be created by the author or by pressing function key F4. The labels created by pressing F4 are in the sequence LT1, LT2, etc. After entering a label, a pop-up menu is displayed at the lower right corner of the screen as shown in FIG. 7. The author is prompted for the screen width and the row and column where the literal should be positioned. A graphics screen is then displayed and the author is prompted to enter the literal. Once the literal is entered, it can be moved around the screen using the arrow or cursor control keys on the keyboard. The color of the literal can be changed using the function keys F1 and F2. When a literal color has been selected, it is accepted by pressing function key F9. The background color can be changed by pressing function key F4. When a background color has been selected, it is accepted by pressing function key F10. The literal processing may be canceled by pressing function key F3. In either case, the time-line is then redisplayed.

The next row on the time-line is labeled "touch". A touch area is an area on the screen that has been activated to respond to touch. The author has complete flexibility in the size, location and number of touch areas. However, the touch area must always be a rectangle. In the implemented system, sixty touch areas are supported, ten of which are reserved for system use. A touch label is required and can either be created by the author or by pressing function key F4. F4 generates labels in the sequence TC1, TC2, etc. After entering a label, the author is prompted for the number of touch areas as shown in FIG. 8. A graphics screen is then displayed with a blinking cursor. The cursor must be positioned at a point corresponding to the upper left corner of the touch area. This is done using the arrow or cursor control keys on the keyboard. When the cursor is in the correct position, the enter key is pressed. The author can then enlarge and shrink the area with the cursor control keys. The down and right arrows enlarge the area and the up and left keys shrink the area. When the touch area is positioned appropriately, the enter key is pressed and a touch area is automatically assigned to the area. The remaining touch areas, if any, are created in the same way. When the specified number of touch areas have been created, function key F10 is pressed to indicate approval of all the defined touch areas. The author is prompted for various kinds of visual or auditory feedback associated with each active area. The author is then prompted for a branch event for each touch area. When all branch events have been entered, the author has the option of saving this touch area format to be used with other graphics, and then the time-line is redisplayed.

The next row on the time-line in FIG. 1 is labeled "line 25". Line 25 allows the author to specify what user control options are to be displayed at the bottom of the screen; e.g., pause and replay. These options are touch areas that give the end user control over the presentation of information. A line 25 label is required and may either be created by the author or by pressing function key F4. F4 generates labels in the sequence BR1, BR2, etc. Once a label is entered, a selection menu is displayed at the lower right corner of the screen as shown in FIG. 9. The brackets in the pop-up menu indicate the location of the cursor. It will be noted that a "Y" has been entered in the pause field. This gives the user the ability to pause the video. When this option is chosen by the author, a second pop-up menu is displayed as shown in FIG. 10. This pop-up menu lists additional user control options. For example, the resume option gives the user the ability to resume the video after a pause.

After the detail screen name is entered in the pop-up menu shown in FIG. 10, the menu disappears and the cursor is repositioned on the row of the time-line labeled sound. Sound allows the author to specify words and phrases for the voice synthesizer. A sound label is required and may be created by the author or by pressing function key F4. The labels generated by the F4 key are in the sequence SP1, SP2, etc. A pop-up menu is displayed which prompts the author for the word or words to be spoken. This pop-up menu is shown in FIG. 11. The author is given the option of reviewing the word list before entering a word or words in this menu. If the author chooses to review the word list, the author is first prompted to enter a starting letter. The word list, beginning with this letter, is displayed to the right side of the pop-up menu as shown in FIG. 12 which shows words from the list beginning with the letter "d". The list can be scrolled using the arrow or cursor control keys on the keyboard. A word is selected by positioning the cursor on the word and pressing the enter key. The word then appears in the "Enter Words to Speak" field of the pop-up menu. If the author decides not to review the word list, the cursor is positioned in the "Enter Words to Speak" field, and the words can be entered through the keyboard. If a word is entered which is not in the word list, the message "word not found" is displayed. If the word or phrase is valid, the menu disappears, and the cursor is repositioned on the row labeled keyboard input in the time-line.

Keyboard input allows the author to specify variables and valid user input for these variables. The author is prompted for a variable to be used to match words. It must begin with a "$" if its value is to be alphanumeric or a "%" if its value is to be numeric. A label is required to identify the match word or phrase. The label can be created by the author or by pressing function key F4. The labels generated by the F4 key are in the sequence AN1, AN2, etc. The author is then prompted for the match words or phrases and the appropriate branch event in the case of a match. The pop-up menu for this is shown in FIG. 13. Up to five match words or phrases and branch events are allowed. Pressing the enter key moves the cursor through the fields. The author may also specify an event to branch to if a match was not found. After entering the branch event for the else condition, the pop-up menu disappears, and the cursor is repositioned on the row labeled indicators in the time-line.

An indicator is a switch that can be set on or off by the author. The indicator can be tested for an on or off position and branching can occur based on the switch settings. There are sixteen switches available to the author. A label is required which can be created by the user or by pressing function key F4. The labels generated by the F4 key are in the sequence SW1, SW2, etc. After entering a label, a pop-up menu is displayed at the lower right corner of the screen as shown in FIG. 14. The set line in the menu allows the author to set a switch on or off. To set the switch on, the author replaces the corresponding "X" with a "Y". To set the switch off, the author replaces the corresponding "X" with a "N". The test line in the menu allows the author to test one or more switches. Each switch can be tested for either an on or off position. For each switch to be tested, the corresponding "X" is replaced with a "Y" or "N". The operator line of the menu specifies what operation is to be performed on the switch settings. The value line is to indicate how many of the switches are tested correctly. Branching to another event is based on the result of the operator and value. The author specifies the event to be performed based on a positive result or a negative result.

The miscellaneous row of the time-line provides other authoring functions which are not defined within any of the other rows. The functions available on this line are logging and video disk loading and unloading. The author can specify that each item of an event be recorded into a log file. The author specifies when logging of the event is to start and stop using the log and nolog control words in the miscellaneous line. When log appears in the miscellaneous line, all information about the event is logged until either the end of the event is reached, a branch to another event occurs, or a nolog appears in the miscellaneous line.

The miscellaneous line also allows for the loading and unloading of the video disk player. To unload the video disk, the author types the word "unload" in the miscellaneous line. A pop-up menu then appears prompting for the player number and user load prompt as shown in FIG. 15. The author specifies which player is to be loaded; i.e., player 1 or player 2. The user prompt field indicates whether the user will be prompted with a standard load screen. If a "Y" is entered, a screen will be displayed showing the user how to load the video disk player. The user must touch the screen before the video disk is actually loaded. If an "N" is entered, the video disk will be loaded without prompting the user. After entering a response to the user prompt field, the pop-up menu disappears and the cursor returns to the time-line.

The process just described is repeated for each event in the presentation; however, it will be understood of course that not every event element will be filled in and, in some cases, only a single event element will be filled in for a given event in the presentation. The author typically proceeds through the outline filling in each event time-line until the presentation has been completely composed.

As mentioned, the conductor is the runtime facility for the composer application. What this means is that once a presentation has been authored, only the conductor is required to run the presentation. In other words, only the author requires both the composer and the conductor applications. The end users need to have only the conductor application in their computer terminal or stand alone computer. The conductor takes the information authored with the time-lines during the authoring process and performs the media mixing indicated by each time-line. The conductor uses the vision head as the interface device for input/output to the end user.

Referring now to FIG. 16, there is shown the overall block diagram of the structure of the conductor program. The heart of the program is the time-line controller which interfaces with the device environment sampler and a logic analyzer. The logic analyzer interfaces with a read event file module, an event file parser, a command stager, and a staged command dispatcher. Processing is carried out in these modules while waiting for an external event, such as a user response, to occur. The following program written in Program Design Language (PDL) describes this processing:

The PDL code for reading an event file is as follows:

The PDL code for parsing an event file is as follows:

The PDL code for staging commands is as follows:

The PDL code for the logic analyzer/event logger is as follows:

The PDL code for the time-line controller is as follows:

Source code for an implementation of the conductor is included in the appendix. This source code was written using the PDL listings above.

While the invention has been described in terms of a specific preferred embodiment, those skilled in the art will understand that the invention can be practiced with modifications and variations in both software and hardware within the scope of the appended claims. For example, the preferred embodiment of the invention has been described in terms of current technology which includes video disk players. However, it will be understood that the invention is not limited to this particular technology and can support any type of video, graphic and audio storage medium whether in digital or analog format. Further, the source code appendicies for the composer and conductor are included by way of specific illustrative example only, and those skilled in the art will recognize that other and different code could be written to implement the claimed invention. ##SPC1## ##SPC2## ##SPC3## ##SPC4## ##SPC5## ##SPC6##