MAVA Multimedia Suite - Documentation

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Last change: 12.03.2004 (jh)

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Chapter 3 - First Steps

On this page you can find information about working with MMEd and MMP. For this purpose, it is necessary that both applications have been installed successfully. The chapter begins with a simple example and contains first details about the usage of MMP and MMEd. Further examples demonstrate further concepts and an advanced usgae of MMEd, round up this chapter.

Before you can start, you have to download a zip file which contains a basic directory structure used in the following examples. After downloading the file, unpack it on your hard disk. In both, MMP and in MMEd, you can define this directory later as your working directory.

As an alternative, you can create the directory structure by hand. But then, the examples will be missing. If you prefer this procedure, proceed as follows: Create a directory "testdocuments" in a directory of your choice (e.g. "e:\mava\testdocuments") and the subdirectories "sound", "image" and "media" in the directory "testdocuments". The example documents of this chapter will refer to this directory structure.

Now, start MMEd and add the MMEd extensions if you haven't done this so far. Download the die MMEd extensions and unzip this file (note the folder, in which you have unpacked it). In order to add an extension you have to select the tab "Extensions" in the preferences menu (File -> Preferences). Using the "Add Extensions" button you can add an extension (it has the ending ".jar") by choosing it in the file selection dialog. It is possible to select several files at once. In the foldernoted above, you can find the extensions. After installing the extensions, MMEd will provide a set of media items and operators. Check the success of the installation by selecting the sub menus "media selection" or "operator selection" from the "selections" menu. Both windows will show several icons.

3.1 An Introductive Example

In this first example a simple multimedia presentation is created and played out. This example shows the main charateristic of a multimedia presentation: Its dependence on time. This means that not every thing can be seen immediately. The author defines not only what can bee seen where, he or she also defines when it can be seen. This is different to a document created with a word processing program.

Let's start with a description of our first multimedia presentation. At first an audio file starts to play. Some seconds later an image appears in the presentation area. It will vanish shortly before the audio file stops to play. In this example, you combine different media (that's why it is called multimedia) in a certain temporal order. If the temporal order can be influenced by the user of the presentation it is called an interactive multimedia presentation.

First of all, you need two files containing the multimedia data. Copy a picture (gif or jpg format) in the subdirectory "image" and an audio file (mp3 format) in the subdirectory "sound". Now you can create the document. Later you will refer to this directory - so you should remember, where you have stored it.

Start the authoring tool MMEd. First, create a new document by choosing "New document..." in the File menu or by clicking on the corresponding symbol on the menu bar. Specify a name for your document in the dialog window "Document name". In this example enter "My first document" as name of the document and select the "BaseContainer" symbol. Now, the Ok button should be enabled.

Next, select "icon view" from the views menu. A blank page will appear. Additionally you have to open the operator selection window and the media selection window in the selections menu.

Now, you will create the content of the document. Bring the "media selection" window to the foreground. It displays all media items MMEd currently provides.

Drag and drop an audio and an image symbol into the "My first document" window. Now, put the operator selection window into the foreground. Make sure that the checkbox "Active" is disabled. Search for the "while" operator, which determines that two media items will be presented simultaneously. If you have found the operator, put it into "My first document" using drag & drop. On the left side of the operator a red dot appears, on the right side a blue one. These dots are used to connect the operator to media items. Media items, which are connected to an operator by a red dot, are source media items and media items connected by a blue dot are called destination media items. Press the left mouse button on the red dot and drag it to the audio symbol. Now, the "while" operator is connected to the audio element. As next step, connect the blue dot of the "while" operator to the target, the image symbol. The temporal behavior of the presentation is determined by the while operator.

In order to determine the spatial arrangement of the media contained in the document, you need another operator. Search in the "Operator selection" window for the "center" operator and add it to the document. This operator has only a dot on its right side. Connect the center operator to the image symbol. The center operator has to center a media item on the presentation surface of a document. Now, the structure of the document is defined, only the details are missing.

Details of the presentation are specified by parameters of the operators and media items in the dialog "Element properties...". You can open it by clicking on the media item with the right mouse button. Now open the properties of the "while" operator. As you can see, the operator has two properties (Delay1 and Delay2). Enter as Delay1 and also as Delay2 "10000". Numerical data have to be specified in milliseconds, thus the delays will both last for 10 seconds.

Now, set the parameters for the audio element. Open its element properties dialog. This media item has two parameters (URL and Duration). Click on the "Open file..." button to select the file, which you want to play. In this example it is the file, which you have copied to the directory "testdocuments/sound". After selecting the file the "Run inspector" button will be active. If you push the button, the inspector will insert the play length into the textfield for the property "duration" automatically. You can specify the length manually, too. Enter 30000 as duration, and close the dialog by clicking the "Ok" button.

Specify the image item in the same way. The picture should be stored in the directory "testdocuments/image". In this case, running the inspector determines the size of the picture (i.e. its width and height). Now, the creation of the document is finished.

In order to store the document, select "Save as..." from the file menu. Select the directory "testdocuments" and enter "Testdocument.mavaed" as file name. Now your document is saved. There are two different document formats, one, ending in "mavaed" is capable for editing, the other, ending in "mava" is the non-editable presentation format. Now you have to create the presentation format. Select "Export" in the file menu - this will create a file named "Testdodument.mava" in the same directory. Exit MMEd by selecting "Close MMEd" in the file menu.

Next, you have to start MMP. After MMP started, push the "Open" button on the tool bar and select your directory and the file "Testdocument.mava" in the file dialog. After loading the document, push the "Start" button on the tool bar. Now, you can look at your first multimedia document, created with the MAVA Multimedia Suite.

3.2 An Exercise

Change the parameters of the audio file and the while-operator and look at the result during the presentation of the changed document. In order to reduce the effort of editing and testing documents, there is a shortcut, for starting the presentation system. You can call the so called MAVA Viewer by selecting "Start MMP" from the menu "Tools" or by clicking on the icon of the menu. Before the MAVA Viewer starts, the system saves the opened document automatically in the presentation format. Remember that in this case your document has not been saved in the format which is capable for editing ("mavaed").

3.3 Another document

This example shows the usage of effect operators. Effect operators are used in conjunction with temporal operators (e.g. start, stop, while). For example, an effect operator can be used to move a media item on the screen during the presentation. This is shown in this example.

Take the first example ("Testdocument.mavaed"). Open the file in MMEd. To keep the first document, select in the "File" menu the item "Save as..." and save the document with a new file name (e.g. "Testdocument-2.mavaed").

Now, you can begin to specify the effect described above. Open the operator selection, select the operator filter "animation" from the list and activate the filter by setting a checkmark into the "active" field. Now there are only three operators displayed. Drag the "moveTo"-operator into your document and place it below the image symbol. The effect operator represents a third type of connection, identifiable by the green dot above the operator symbol. Media items, which are connected to an effect operator are called "effect media". Now connect the effect operator to the image symbol by pressing the left mouse button on the green dot and move the cursor over the image symbol. There you can release the mouse button. A green connecting line will inform you that the effect operator was successfully connected to the image symbol.

In the following the temporal aspects and the parameters of the effect operator are specified.

The temporal aspect is specified by temporal operators. The simplest method is to use the start and the stop operator. Set the filter on "Temporal" in the operator selection. Then drag a start and a stop operator close to the effect operator. Connect both temporal operators to the effect operator, i.e. the effect operator is the goal medium for both temporal operators. Insert 5000 as time (instant) into the properties menu of the start operator and 14.000 into properties menu of the stop operator. Define the parameters Delay1 and Delay2 of the while operator by entering 2000 in each case.

At last, specify the parameters of the effect operator. Enter the following values: XOffset 290, YOffset 500, Frames 10. XOffset and YOffset describe, to which position the media moves and "Frames" determines how many pictures per second (Frames Per Second) will be displayed. The field "Duration" can remain empty.

If you're playing the presentation now, you can observe, that the image moves out of the presentation area. If you downloaded the ZIP file for the document structure, you can find this example (ASimpleEffectExample.mavaed) in the appropriate directory.

3.4 The usage of containers - An interactive travel guide

Containers offer the possibility to structure MAVA documents. They can contain media items and operators. Additionally, they are application-specific (for example a question in the application area computer-based training). Because they are application-specific, they are connected with particular operators from their area of application. This will be demonstrated by the following example of an interactive travel guide.

If you've downloaded and added all MMED extensions, then you also installed the extension "Location-based Multimedia Presentation". You can check if it is installed by checking the tab "MMEd extensions" in the Preferences dialog.

This extension provides two containers and five operators. Open, as you have learned in the first example, the media and the operator selection window. Both windows offer a filter. This can be used in order to limit the quantity of the displayed symbols. For both filters you can select "location" and checkmark the "active" checkbox. Then you can only see these elements, which belong to the interactive travel guide.

The two containers serve to structure an interactive travel guide. The container "LocationArea" represents the area, which has to be covered by the travel guide. The container "Location" serves to contain the presentation of an object of interest.

The "default" operator specifies, which part of the presentation has to be displayed, if the user does not touch any object of interest. The "setLocation"-operator has to define the position of the object of interest within the location area. The "circle"- and "rectangle"-operator define a rectangular or circular area surrounding the object of interest. If the user enters the area, a presentation pertaining to the object of interest will start. Now, we will create a simple example using these elements.

For that purpose, create a new document at first. Select the appropriate menu option, name the document and select the container "LocationArea" as root. Click "Ok" to generate the document. Open the icon view in the menu or in the tool bar. An empty window opens, just like in the first example.

Put two location containers into the window by the drag and drop method. Now drag a "default" operator into the window and place it near to the "Location" container. Then put a "setLocation" container near to the other container and another "circle" operator, too. Connect the "default" operator to the first "Location" container. Then connect the "set location" and the "circle" operator to the second "Location" container.

Now the parameters of the operators and media items must be specified. At first we specify the parameters of the "LocationArea" container. Additionally you have to open the "tree view" (menu View >Tree view). The tree view shows the structure of the document as a tree. The containers introduce a contains-relationship between the container and the media items and operators, which can be represented as a tree. The properties of the language elements can be specified in the context menu, which will be displayed by pressing the right mouse button, in the icon view as well as in the tree view. Invoke the properties menu for the "LocationArea" container, which you'll find on the very top of the tree. As value for AreaE and AreaN enter in each case 0. For AreaWidth and AreaHeight enter respectively 100. Call the context menu of the setLocation operator and enter for LocationE and LocationN in each case 50. As parameter "radius" for the "circle" operator enter 10. Now, you've got an interactive travel guide.

Now the appearance on the screen has to be specified. Additionally, use the "center" operator, just like in the first example. Connect both "Location"-containers respectively with a "center"-operator. Afterwards call the properties menus of the "Location" containers, enter 120 as width and as height, too, and select a background color of the container. This will allow you differentiating the presented containers afterwards.

If you have had problems to create the document, you can download it from here.

Now you can save and play the document. In the tool bar you'll find a button, which looks like the "Play"-button on a video recorder, so you can test the document you're editing by means of a player, which is integrated into the editor. This will open three windows, the document, a "Navigation Control" window and a "Location Map" window. If no MapImageUrl is specified, you've to resize it first. Test your MMEd knowledge by trying to find the dialog in which you can specify this property. If you've increased the window, you can see the sensitive circle around the object of interest ("Location" container). Click into this circle and watch the presentation's reaction.

Test the example to learn more about the use of the operators by it.

On the basis of this example we will discuss another MMEd feature, the so called operator filter, which is available in the icon view of a container. Put the icon view window of the LocationArea container into the foreground. If necessary, open the window by clicking on the container in the tree view. On the upper left side of the window you can find the operator filter. There you can select a filter in the combobox and you switch it on or off in the checkbox "activate". Select "location" and activate the filter, thus the two center operators will disappear. Then select "spatial" as operator filter. Now all operators except for the two "center" operators will vanish. This functionality can be used to filter for application specific aspects of the document, while editing (either the spatial ones or those of application area "interactive travel guide").

In order to find containers in the tree view and the icon view easily, you can name them. If you look at the two "Location" containers you certainly notice that the symbols are named "unknown <Location>". Invoke for both containers the properties menu and change their names (parameter: name). You can name any media element (pictures, audio, video,...) in this way.

Here, we demonstrated by means of a rather abstract example, how an application-specific concept can be integrated into the MAVA approach. The demo applet shows, how an interactive travel guide, based on this concept, could look like. There is a map deposited. The "Location" containers contain presentations of real sights in Lanzarote. Of course, this example is also not complete.

3.5 An exercise

One of the most important properties of a container is, that it can contain a complete presentation itself. Open the icon view of a "Location"-container (in the tree view) and create a small presentation in it, similarly to the first example. Re-run the presentation in verify that the presentation matches your intention.

3.6 Summary

In this chapter you became acquainted with the basics of the creation of multimedia documents with the MAVA Multimedia Suite. In the next chapters you will find an enumeration of the MMP and MMEd features. You can read them sequentially and use the features gradually to create documents. In appendix A, you can find a short description of available media items and operators.

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