Tools for creating multimedia applications. What are multimedia applications and tools for their development?
Review
What is multimedia
Multimedia in Delphi
TMediaPlayer component
Two types of programs that use multimedia
Example program with multimedia
- Review
- Delphi makes it easy and simple to include multimedia objects such as sounds, videos and music into the program. IN this lesson discusses how to do this using Delphi's built-in TMediaPlayer component. The management of this component in the program and obtaining information about the current state are discussed in detail.
- What is multimedia
- There is no exact definition of what it is. But at this moment and in this place, it is probably better to give as much as possible general definition and to say that “multimedia” is a term that refers to almost all forms of animation, sound, video that are used on a computer.
To give such a general definition, it must be said that in this lesson we are dealing with a subset of multimedia, which includes:
1. Display video in Microsoft's Video for Windows (AVI) format.
2. Play sounds and music from MIDI and WAVE files.
This task can be accomplished using dynamic Microsoft libraries Multimedia Extensions for Windows (MMSYSTEM.DLL), the methods of which are encapsulated in the TMediaPlay component, located on the System page of the Delphi Component Palette.
Playing media files may require some hardware and software. So to play sounds you need a sound card. Microsoft Vid software is required to play AVI on Windows 3.1 (or WFW)
- eo.
- Multimedia in Delphi
Delphi has a TMediaPlayer component that gives you access to all the basic media programming features. This component is very easy to use. In fact, it's so simple that many novice programmers will find it easier to create their first program that plays video or music rather than displaying the classic "Hello World" message.
· Ease of use can be perceived in two ways:
· On the other hand, you may find that not all features are implemented in the component. If you want to use low-level functions, you will have to dig quite deep using the Delphi language.
This lesson does not cover the details of internal calls. multimedia functions when the component is running. All you need to know is that the component is called TMediaPlayer, and that it gives access to a set of routines created by Microsoft called the Media Control Interface (MCI). These routines give the programmer easy access to a wide range of multimedia devices..
- Actually working with TMediaPlayer is intuitive and obvious
TMediaPlayer component
First, let's create a new project, then place the TMediaPlayer component (System Palette page) on the form, as shown in Figure 1.
Fig.2: TMediaPlayer properties in the Object Inspector
on this property and select a file name with the extension AVI, WAV or
M.I.D. In Fig. 2, the AVI file DELPHI.AVI is selected. Next you need to set the AutoOpen property to True. After completing these steps, the program is ready to run. After launching the program, click green button
- “play” (far left) and you will see a video (if you selected AVI) or hear sound (if you selected WAV or MID). If this does not happen or an error message appears, then two options are possible:
- You entered an incorrect file name. You have not configured multimedia correctly in Windows. This means that either you do not have the appropriate hardware, or the necessary drivers are not installed. Drivers are installed and configured in Control Panel
, hardware requirements are given in any book on multimedia (you need a sound card, for example, compatible with Sound Blaster). So, you have the opportunity to play AVI, MIDI and WAVE files
just specifying the file name.
Another important property of the TMediaPlayer component is Display. Initially, it is not filled and the video is played in a separate window. However, you can use, for example, a panel as a screen to display the video. You need to place the TPanel component on the form and remove the text from the Caption property. Next, for TMediaPlayer, in the Display property, select Panel1 from the list. After this, you need to launch the program and click the “play” button (see Fig. 3)
- Fig.3: Playing AVI on the panel.
- ·
Sometimes you need to provide users with an easy way to play as wide a range of files as possible. This means that you will need to give the user access to the hard drive or CD-ROM, and then allow him to select and play the appropriate file. In this case, the form usually contains TMediaPlayer, which provides playback control.
· Sometimes a programmer may want to hide the existence of a TMediaPlayer component from the user. That is, play sound or video without the user caring about its source. In particular, sound can be part of a presentation. For example, displaying a graph on the screen may be accompanied by an explanation recorded in a WAV file. During the presentation, the user does not even know about the existence of TMediaPlayer. He works in background. To do this, the component is made invisible (Visible = False) and controlled programmatically.
- Example program with multimedia
In this chapter we will look at an example of building an application with multimedia of the first type. Create a new project (File | New Project). Place TMediaPlayer on the form; place the components TFileListBox, TDirectoryListBox, TDriveComboBox, TFilterComboBox to select the file. In the FileList property for DirectoryListBox1 and FilterComboBox1, set FileListBox1. In the DirList property for DriveComboBox1, put DirectoryListBox1. In the Filter property for FilterComboBox1, specify the required file extensions:
AVI File(*.avi)|*.avi
WAVE File(*.wav)|*.wav
MIDI file(*.MID)|*.mid
Let it be double click with the mouse in FileListBox1 the selected file will be played. In the OnDblClick event handler for FileListBox1, specify
Procedure TForm1.FileListBox1DblClick(Sender:TObject);
begin
with MediaPlayer1 do
begin
Close;
FileName:=FileListBox1.FileName;
Open;
Play;
end;
end;
The appearance of the form is shown in Fig. 4
Fig.4: Initial view project
Save the project, run it, select required file and double click on it with the mouse. MediaPlayer should play this file in a separate window.
As mentioned above, the video can be played inside a form, for example, in a panel. Let's slightly modify the project and add a TPanel there (see Fig. 5). In the Display property for MediaPlayer1, specify Panel1. You need to remove the inscription from the panel (Captio n)
and property BevelOuter = bvNone. To switch from a window to a panel during playback, place a TCheckBox on the form and write in the OnClick event handler for it:
procedure TForm1.CheckBox1Click(Sender: TObject);
Start_From: Longint;
begin
with MediaPlayer1 do begin
if FileName="" then Exit;
Start_From:=Position;
Close;
Panel1.Refresh;
if CheckBox1.Checked then
Display:=Panel1
else
Display:=NIL;
Open;
Position:=Start_From;
Play;
end;
end;
Launch the project and play the video. Click on the CheckBox.
During program execution, you may need to display the current state of the MediaPlayer object and the video itself (time elapsed since the start of playback, length of the video). For this, the TMediaPlayer object has the corresponding properties and events: Length, Position, OnNotify, etc. Let's add a progress indicator (TGauge) to the project, which will display in percentage how much time has passed (see Fig. 6). You can use a timer to update the indicator readings. Place a TTimer object on the form, set its Interval = 100 (100 milliseconds). In the OnTi event handler m er you need to write:
procedure TForm1.Timer1Timer(Sender: TObject);
begin
with MediaPlayer1 do
if FileName<>"" then
Gauge1.Progress:=Round(100*Position/Length);
end;
Launch the project, select the file (AVI) and double-click on it. When playing a video, the progress indicator should display the percentage corresponding to the elapsed time (see Fig. 6).
16.12.1997
Review of software for developing multimedia software products.
Multimedia - fast and easy Author's development tools and their classification Scripting language Visual data flow control Frame Scripting language card Timeline
Review of software for developing multimedia software products.
Currently, a significant part of educational, entertainment and informational programs on the consumer market falls into the category of multimedia. Using multimedia technologies, small-circulation advertising and informational products are also created - catalogues, directories, various presentations. Increased productivity and capabilities modern computers , as well as the rapid increase in the number of multimedia programs, will likely forever change the way people receive information. The computer's ability to immediately find a tiny element from a huge mass of data has always been one of its most important features. Since video and audio can be saved along with the text on a CD-ROM, it has become real and to study the subject. Using hyperlinks (a software method by which various terms, articles, images, sounds and video fragments are internally linked together according to certain logical criteria), the material is not difficult to present so that users can view it in the most convenient way - by association. Encyclopedias, almanacs, collections of reference books, interactive games, educational programs and even movies with accompanying scripts, actor biographies, director's notes and analytical reviews make multimedia perhaps the most exciting and creative area of the computer world.
What can help us, ordinary users, enter this fascinating and exciting world? Of course, those tools that allow you to combine the created individual parts into a single, complete whole - into a multimedia application. Such funds can be divided into three groups:
It is practically very difficult to draw a clear boundary between these groups. For example, one of the best presentation programs, Astound, has some features of a proprietary development tool; many proprietary tools allow you to distribute applications created with their help via the Internet, etc.
By by and large There are two main ways to create a multimedia application: use specialized development tools or do programming directly. When it comes to presentations, the second method is meaningless; in other cases, options are possible. The first method saves money and time, but we lose in the efficiency of the program. This is a price to pay for development speed. Direct programming is a more expensive pleasure, but some proprietary programs are not cheap. In addition, you are faced with the need to master special techniques to work with them and a number of restrictions, although even here you can find a way out. The optimal path would be in the middle - the use of ready-made packages with the expansion of their functions using programming languages, but, unfortunately, this is not always feasible.
Obviously, the task of choosing the necessary tool for creating a multimedia application is not as simple as it seems at first glance, and there is no universal solution suitable for all occasions. Therefore, it is the selection stage itself that is very important in the development process, because if you make a mistake, then time and money can be lost in vain, and sometimes these are irreparable losses. We will try to help you take the first step down the right path in a meaningful way. Any recommendations are a subjective thing: they should be taken into account, but you do not need to follow them literally, because there are many nuances that are quite difficult to take into account. So final choice- is up to you, but, naturally, it must be reasonable.
So, the easiest way to develop multimedia applications is to use modern programs for creating presentations. Let's start with them.
Multimedia - fast and easy
Modern presentation creation programs are increasingly focused on multimedia. Most interesting example PowerPoint 97 can serve Microsoft. By the number of visual and animation effects it becomes on par with many authored multimedia tools. The presence of a script without the ability to choose used to distinguish programs for developing presentations from authoring systems. But now that too is over. In PowerPoint 97, a presentation doesn't have to follow a rigid script from start to finish—it can branch freely depending on the user's response.
PowerPoint 97 allows you to create complex program add-ins using Visual Basic. Built-in Internet support and various other improvements have made this program a leader in the world of multimedia presentations, and the presence of a Russian-language version has solved all the problems associated with the use of an English-language interface.
Other presentation programs include Macromedia Action!, Gold Disk Astound and Asymetrix Compel. They were described in sufficient detail on the pages of PC World. We will turn our attention to the author's development tools.
Author's development tools and their classification
An authoring tool (authoring system) is a program that has pre-prepared elements for developing interactive software. Such systems differ in their specialization, capabilities and ease of development. There is currently no automated authoring system that allows you to build an application entirely in a point-and-click manner, although modern tools come pretty close.
Using an authoring system is actually an accelerated form of programming: you don't have to delve into the intricacies of the language or, worse than that, in details of the functioning of the Windows API (Application Programming Interface - interface application programs), but must understand how programs work. At the same time, there is no need to be afraid of the word “programming”. Many systems have a fairly friendly user interface, and for simple projects you can do without this process altogether.
In general, developing an interactive multimedia project in an authoring system requires significantly less time than using pure programming tools. This means a reduction in the cost of work several times. However, the creation of multimedia components (graphics, text, video, sound, animation, etc.) is not affected at all by the choice of authoring system; the time gain in preparing the final product in this case is obtained due to the accelerated construction of the prototype, and not due to the choice of the author's system instead of some programming language.
As for the classification of authoring systems, quite a lot of attempts have already been made in this direction. They are based on the so-called author metaphor - a methodology in accordance with which the author system performs its tasks. I would like to emphasize that:
The classification proposed by Jamie Siglar seems to be the most complete today. We will take it as a basis in our further journey into the world of authoring systems.
According to this classification, eight types of authoring systems can be distinguished, using the following metaphors:
Note that classification in itself is not an end in itself. This is just a means to make an informed choice of the necessary tool in accordance with the specifics of your multimedia project and its budget. Let's look at the types of authoring systems in more detail.
Scripting language
The author's method "Scripting Language" is closest in form to traditional programming. This powerful, object-oriented programming language defines (using special operators) the interaction of media elements, the location of active zones, button assignments, synchronization, etc. It is usually the central part of such a system; editing of multimedia elements within the program (graphics, video, sound, etc.) is presented either in a minimal form or is absent altogether. Scripting languages change. When choosing a system, pay attention to the extent to which the language is object-based or object-oriented. Using this method slightly increases the development period (additional time is required to individually study the capabilities of the system), but as a result, more powerful interaction of elements can be obtained. Since many scripting languages are interpretive, such systems have rather low performance compared to other authoring tools.
Scripting language based systems include:
An example of a multimedia application made using the Grasp system is the CD-ROM Space Shuttle. It was developed by Amazing Media and Follett Software in 1993 and was sold under The Software Toolworks brand (including in our stores). This CD is an encyclopedia on American space exploration. Space program Shuttle with brief description the history of the project, the astronaut training process and 53 specific flights. Audio commentary on still images and digitized video are widely used here, although not always sufficient good quality. The application runs in DOS directly from the CD-ROM.
Fine flow control
This proprietary method ensures minimal development time; It is best suited for quickly prototyping a project or completing tasks that need to be completed within as soon as possible. Its basis is the Icon Palette, which contains all sorts of functions for the interaction of program elements, and the Flow Line, which shows the actual connections between the icons. Authoring systems built on the basis of this method have the slowest executable modules, because every interaction entails all sorts of permutations. However, the most mature packages, such as Authorware or IconAuthor, are extremely powerful and have a lot of potential.
The main advantage of this method is that it allows you to speed up work on application design. You move icons from the palette onto the page layout, and the resulting document becomes your application's blueprint. Next, you need to double-click on the icons, and the appeared dialog boxes will expect commands from you to link the components into a single whole and form a dialogue with the user.
The use of authoring systems of this type is the most suitable way for building multimedia applications with complex interaction functions, similar programs machine learning and multimedia kiosks. Such authoring systems can be very expensive - up to several thousand dollars. What is the reason for such high price? The fact is that developers sell you not only software, but also the right to distribute applications created with its help in large quantities.
In terms of ease of learning, these programs occupy an intermediate position between authoring systems based on the “card with a script language” metaphor and systems based on a timeline.
Of course, there are a significant number of functions and variables that require learning. However, if you have already created your application using the icon palette, then there is nothing easier than creating new applications based on your templates.
Systems based on graphical data flow control include:
An example of a multimedia application made using the Authorware system is the ABBA Nostalgia CD-ROM. The disc was developed by the Russian company VEKS in 1996. This is an interactive encyclopedia of the work of the famous Swedish group ABBA in Russian. It contains almost 100 pages of text, more than 400 photographs, recordings (6.5 hours of music, including all hits!), including rare and previously unpublished in Russia, biographies and descriptions of the creative path of the ensemble's soloists in the period from 1969 to 1995 The use of a powerful authoring tool made it possible to complete the project with a small team of developers. The application starts in Windows system directly from CD-ROM.
Frame
The Frame method is similar to the Flow Control method. It also usually includes an icon palette (Icon Palette); however, the connections drawn between icons can represent complex branching algorithms. Authoring systems built using this method are very fast, but require the use of a good automatic debugger, since errors are visually subtle. The best programs of this kind, such as Quest, allow you to associate a compiled language with a scripting language (when creating an application, C or Apple Media Kit is used as the scripting language).
Frame-based systems include:
Script Language Card
This is a very powerful method in its capabilities (through the included scripting language), however, it requires precise and rigid structuring of the plot. It is excellent for hypertext applications and especially for navigation-intensive applications (the most notable example being famous game Myst, developed in the author's HyperCard system).
The capabilities of programs of this type are easily extensible using XCMD and DLL modules. Such systems are often used for developing general-purpose application programs, and their best representatives allow all objects (including individual graphic elements) to be prepared within the authoring system. Many entertaining and game programs are going through the prototyping stage this method before coding in a compiling programming language.
One of the advantages is the easiest learning process. The systems come with a variety of templates, examples and ready-made user interface graphics, as well as interactive tutorials. Thanks to this, development occurs quite quickly.
The Astound and Compel programs, which occupy an intermediate position between presentation creation programs and authoring systems, are also sometimes classified as this type of authoring system. Very easy to learn, they allow you to develop quite interesting applications.
The main disadvantage of authoring systems based on a card with a scripting language is the inability to provide precise control of synchronization and execution of parallel processes. For example, a sound file must start and end before the next scripted event can begin.
Card-based scripting language systems include:
An example of a multimedia application created using the author's Toolbook system is the CD-ROM "English for Every Day", developed by the Russian company New Media Generation in 1996. Specifics of the intensive course of study in English according to the method of T.A. Graphova went well with this metaphor. The development was completed sufficiently high level and awarded for excellent design. The application operates in a Windows environment and requires the installation of separate files on your hard drive to speed up operation.
Timeline
In terms of the structure of the user interface, the authoring system based on the "Timeline" method resembles a sound editor for multi-channel recording. Synchronized items are shown in different horizontal "tracks" with work connections reflected through vertical columns. The main elements of this method are the “troupe” (cast) - a database of objects and the score (score) - a frame-by-frame schedule of events occurring with these objects. The main advantage of the method is that it allows you to write a behavior script for any object. Each appearance of an object from the troupe in one of the channels of the score is called a sprite and is also considered an independent object. To control sprites depending on user actions, an object-event scripting language is built into the package. Similar systems are used to create many commercial application programs.
Timeline-based authoring systems are best suited for animation-intensive applications or those that require synchronization of different multimedia components. These systems are easily extended to handle other functions (such as hypertext) through modules such as XOBJ, XCMD and DLL. Their main drawback is the difficulty of mastering them due to the need to learn a fairly powerful scripting language.
Timeline based systems include:
Most known system, built using this method, is also the most popular authoring multimedia system in general. This is Macromedia Director. With its help, quite complex commercial applications and even computer games are developed. An example is "Frankenstein. Through the eyes of the monster" - a rather complex adventure game, similar in structure to Myst. The player takes on the role of a monster created by Dr. Victor Frankenstein. The goal of the game is to travel through the doctor's castle and its surroundings to reveal terrible secrets and solve numerous riddles.
Hierarchical objects
Here, as in object-oriented programming, the object metaphor is used. Although learning to work with these development tools is not easy, thanks to the visual representation of objects and information components of a multimedia project, you can create quite complex designs with a developed plot. A typical representative of this kind of tools is mTropolis - one of the most promising authoring systems. Such systems are usually quite expensive and are used mainly by professional multimedia application developers.
Systems based on hierarchical objects include:
Hypermedia links
The hypermedia link metaphor is similar to the frame metaphor in which conceptual connections between elements; however she lacks visual representation connections. Authoring systems built using this method are very easy to learn, although training is required to work effectively with them.
By using authoring systems with hypermedia links, you can create a variety of hypertext applications with multimedia elements. They have the same areas of application as systems built using the Card with Scripting Language method, but are more flexible (due to the elimination of cards).
The author's HyperMethod system is already familiar to readers (see "PC World", #11/97). It is used to develop a wide variety of multimedia applications. In particular, with its help, an encyclopedia on CD-ROM “Russian Museum. Painting” was prepared.
Markers (tags)
Token-based systems use special tag commands in text files (eg, SGML/HTML and WinHelp) to link pages to enable interaction and combine media elements. They generally have limited tracking capabilities and are best suited for preparing dialogues. reference materials, like dictionaries and manuals. With the development of the Internet, such systems have found wide application in creating pages for nodes of this global computer network.
Token-based systems include:
The number of editors dedicated to creating HTML pages is growing rapidly every day. They are distributed commercially or as shareware, and there are quite a few free programs. Moreover, the quality of a program is not necessarily determined by the cost category it belongs to.
Of course, the world of authoring systems is not limited to the programs listed above. Quite complete lists presented on the Internet number about 70 such systems, and their number (which does not include presentation creation programs and various HTML editors) is constantly increasing. But for a person making his choice, he needs to start by getting to know the best of them.
Using programming languages
As we have already emphasized, in comparison with proprietary development tools, universal programming languages turn out to be more flexible and provide the opportunity to obtain a faster application. But the best representatives of the world of authoring systems are quite successfully trying to overcome all obstacles. IN modern conditions flexibility and speed of work sometimes fade into the background, giving way to high speed of development. This explains the increased interest in such systems from developers. In Russia, the spread of proprietary systems is hampered by their exorbitant prices, and in general it is quite difficult to purchase them. In addition, for many users, especially non-professionals in computer technology, the English-language interface of the system can negate all its advantages. But let's get back to programming.
If you ask professional Russian developers of multimedia applications what tools they use, the answer will be clear - programming languages, most often C++, Delphi, less often Visual Basic. The few authoring systems are used only in isolated cases. But the situation is gradually changing. More and more proprietary instruments are appearing on legal terms, and they can already be purchased. But is it worth it? The question is, of course, interesting, and it makes sense to talk about it in more detail.
Choosing the right tool
Creating a multimedia application does not begin with choosing the necessary development tool. First of all, you need to determine what information and how you are going to use it. And only after that you can move on to choosing a tool that will allow you to most fully express your ideas.
Let's assume that the question of what kind of application you want to create has already been decided and the time has come to select the necessary tools for implementing the project. Based on the recommendations above, try to find the type of authoring system that is most suitable for your task. Select programs that are of the type you need.
Try to find out more about your pre-selected programs. Foreign experts in the field of multimedia advise asking the developers for demo versions for this. For example, demo discs with Director, Authorware and Icon Author systems are sent free of charge or for a minimal fee. By working with these versions, you will better understand the capabilities and limitations of the systems. Additional information Many of them can be obtained via the Internet by contacting the sites of the development companies. The table given here should help you in this search.
In Russia, personal computers with operating systems DOS and Windows. It is for this platform that recommendations are given below for choosing an authoring system, taking into account the possibility of purchasing certain software products in our country.
Web applications
If you don't want to become a professional Webmaster and create HTML pages occasionally, then text will be your best choice. Word editor 97 (and no language problems!).
More quality work provide free or shareware HTML editors that can be found on the Internet. In particular, try Arachnophilia, freely distributed by the developer Paul Latus himself. It’s worth saying a few words about this program.
Firstly, it has no difficulties when creating Russian HTML pages, which is very rare even for commercial editors. Secondly, it is convenient for any user: from beginner to professional. For example, at famous program FrontPage has a bad habit of correcting the source text you type, even if it fully complies with the HTML specification, which limits your creativity. The author of Arachnophilia offers a simple way to combat this evil, and therefore the joint use of these two editors will remove such restrictions. Please also take into account the fact that a lightweight version of Front Page with a set of templates called FrontPad is included with the package Internet Explorer 4.0, distributed free of charge.
Presentations
For those who do not create presentations often, we can recommend the Russian version PowerPoint programs 97. It is part of Office 97. It is worth paying attention to the promising new product of the Club voice technologies" - presentation program "Talking Mouse for the Home" with a built-in speech synthesizer. All texts will be read with the correct pronunciation, and you are given the opportunity to customize it according to your needs. The only drawback of these two programs is their orientation to Windows 95. For Windows users 3.1, a Macromedia Action system would be a good choice! If you find it necessary to purchase the Macromedia Director package, then the elements developed in it can be used in Action! without any transformation.
Application prototypes
Authoring systems based on visual data flow control or using a card with a scripting language are best suited for developing prototypes. Perhaps the demo versions of Authorware or Icon Author will be enough to quickly create a prototype of your application. Full versions are still very expensive, especially for non-professionals. Multimedia Toolbook is also a good choice. You will like this system so much that you may want to complete the final version with its help.
Interactive programs
In this case, it makes sense to use Macromedia Director. But remember that to master this program you will have to put in some effort. If you don't want to spend money on purchasing an authoring system, opt for MediaView, HM-Card or Formula Graphics.
MediaView - Name new version Multimedia Viewer Publishing Toolkit. Previously it cost $695.00. Now it is distributed free of charge. Compared to the previous version, this program has become more difficult to learn and master (you must be able to program at least a little in Visual Basic), but also more powerful.
HM-Card - a shareware program that is similar in capabilities to HyperMethod. According to the developers, you do not need to know a programming language to create an application with its help.
Formula Graphics - A free program that provides a quick and easy way to implement multimedia projects in the Windows environment. It has its pros and cons, but the fact that it is distributed free of charge decides a lot. Register your version with the developers and you will have access to additional features of the package.
Training programs
To create training programs, some companies release separate versions of their main products. For example, there is a version of Multimedia Toolbook CBT with special templates for developing such programs. If you are going to use animation in the learning process, then you can stop at Macromedia Director.
Hypertext applications
Here, preference should be given to systems based on hypermedia links (HM-Card or any program of this type) and cards with a script language (Multimedia Toolbook). Pay attention to the HyperMethod program. Low price, ease of learning basic capabilities (so you can create your first application without programming), speed of arranging hyperlinks taking into account cases, support for multimedia functions and compatibility with HTML - this is not a complete list of its distinctive features. Following the example of their foreign colleagues, Russian developers have released a demo version and educational materials. And maybe this program will be yours best assistant when building multimedia applications.
In reality, the domestic software market, unfortunately, still provides a limited selection of MediaView, PowerPoint, HyperMethod and FrontPage (taking into account the user-friendly product support in Russia). And in the end, you will have to choose between PowerPoint and HyperMethod if price matters to you and documentation with a help system in Russian is important.
Pushkov Alexander Igorevich - information support engineer at the Education and Training Center in St. Petersburg. The author can be contacted by E-Mail: [email protected].
Encyclopedia "Russian Museum. Painting"
This encyclopedia was created for the centenary of the State Russian Museum, which is located in the Mikhailovsky Palace. She talks in detail about the museum's exhibition and quite fully introduces us to the paintings of Russian artists of the 8th - early 20th centuries. The CD-ROM includes about 200 reproductions of paintings and their fragments. Each painting is accompanied by an article-annotation, which outlines the history of its creation, describes the plot, gives a biography of the artist, and even provides poems dedicated to the painting itself or the author. In addition, the program includes a dictionary that contains articles about fine arts and artistic styles, as well as the most common terms. Those interested in the history of Russian painting will find here systematized, although brief information about all famous artists represented in the Russian Museum.
Multimedia Albums
A good example of multimedia encyclopedias created on the basis of our own, specially developed for this GUI, are the discs "Cold Weapons" and "World of Cats", developed by SBG Publishing and published by 1C.
The album "Edged Weapons" presents the most diverse types of weapons of all times and peoples - from Paleolithic stone axes to ultra-modern shooting knives of paratroopers. Shown here are the first universal tools that served their owners for both economic activity and defense; all types of bladed weapons (throwing, slashing, bladed, piercing) and military equipment (armor); The history of the origin and use of swords, spears, halberds, swords, dirks, etc. is very interestingly presented.
You will get acquainted with legends and myths, learn about how damask blades were tempered, what a Russian warrior wore before battle, what weapons were used in battle in different historical periods, receive complete and reliable information about exotic types and forms of bladed weapons, about their collectible samples .
The album “The World of Cats” tells a fascinating and detailed story about these lovely creatures, which from ancient times have seemed unusually mysterious to man. You will learn about when the first representatives of the cat family appeared, how and why they were domesticated, how many breeds of wild and domestic cats are currently known, as well as whether cats always fall on four paws and how to decipher the “conversation” between a cat and a cat that takes place March evening. The richly illustrated album tells about the behavior of your pets at home and the hunting habits of their fellow predators in their respective habitat.
The authors tried to talk about the most interesting breeds of domestic cats, how to care for them and how to raise them, about the ailments that these long-time human companions suffer from, and how to treat them.
Tools for creating multimedia applications
|
Product |
Development company |
Development OS |
Playback OS |
Type |
Price, dollars |
Internet address |
| PowerPoint 97 | Microsoft | Windows 95 | Windows 95 | Presentations | 339 | http://www.microsoft.com/ products/prodref/127_ov.htm |
| Action! | Macromedia | Windows | Windows | Presentations | 229 | http://www.MacOSromedia.com |
| Astound | Gold Disk | Windows | Windows | Presentations | 200 | http://www.golddisk.com/astound.com |
| Compel | Asymetrix | Windows | Windows | Presentations | - |
Two types of multimedia programs
Sometimes you have to provide a simple path for users to play as wide a range of files as possible and then let them select and play the appropriate file. In this case, the form usually contains TMediaPlayer, which provides playback control.
Sometimes a programmer may want to hide the existence of a TMediaPlayer component from the user. That is, play sound or video without the user caring about its source. In particular, sound can be part of a presentation. For example, displaying a graph on the screen may be accompanied by an explanation recorded in a WAV file. During the presentation, the user does not even know about the existence of TMediaPlayer. It works in the background. To do this, the component is made invisible (Visible:= False;) and controlled programmatically.
In this chapter we will look at an example of building an application with multimedia of the first type. Create a new project (File | New Project). Place TMediaPlayer on the form; place (WIN 3.1 page) components TFileListBox, TDirectoryListBox, TDriveComboBox, TFilterComboBox for file selection. In the FileList property for DirectoryListBox1 and FilterComboBox1, set FileListBox1. Set the DirList property for DriveComboBox1 to DirectoryListBox1. In the Filter property for FilterComboBox1, specify the required file extensions:
AVI File (*.avi) | *.avi
WAVE File (*.wav) | *.wav
MIDI file (*.MID) | *.mid
Let's say we want to double-click on the FileListBox1 component to play the selected file. Then in the OnDblClick event handler for FileListBox1 you should write:
Procedure TForm1.FileListBox1DblClick(Sender:TObject);
with MediaPlayer1 do
The appearance of the form is shown in Fig. 4.
Fig.4. Initial view of the project
Save the project, run it, select the desired file and double-click on it. MediaPlayer should play this file in a separate window.
As mentioned above, the video can be played inside a form, for example, in a panel. Let's slightly modify the project and add a TPanel there (see Fig. 5). Set the Display property for MediaPlayer1 to Panel1. You need to remove the caption from the panel (Caption) and assign the property BevelOuter:= bvNone;
To switch from a window to a panel during playback, place a TCheckBox on the form and write in the OnClick event handler for it:
Start_From: Longint;
with MediaPlayer1 do
if FileName ="" then Exit;
Start_From:= Position;
if CheckBox1.Checked then Display:= Panel1
else Display:= NIL;
Position:= Start_From;
Launch the project and play the video. Click on the CheckBox component.
Fig.5. Added video playback panel
and window/panel switch
During program execution, you may need to display the current state of the MediaPlayer object and the video itself (time elapsed since the start of playback, length of the video). For this, the TMediaPlayer object has the corresponding properties and events: Length, Position, OnNotify, etc.
Let's add a progress indicator (TGauge) to the project, which will display in percentage how much time has passed (see Fig. 6). You can use a timer to update the indicator readings. Place a TTimer object on the form and set it to
Interval:= 100; (100 milliseconds).
In the OnTimer event handler you need to write:
with MediaPlayer1 do
if FileName<>"" then
Launch the project, select the file (AVI) and double-click on it. When playing a video, the progress indicator should display the percentage corresponding to the elapsed time (see Fig. 6).
The DEMOVideo listing is below.
SysUtils, WinTypes, WinProcs, Messages, Classes, Graphics, Controls,
Forms, Dialogs, ExtCtrls, Gauges, FileCtrl, StdCtrls, MPlayer;
TForm1 = class(TForm)
MediaPlayer1: TMediaPlayer;
CheckBox1: TCheckBox;
FileListBox1: TFileListBox;
DirectoryListBox1: TDirectoryListBox;
DriveComboBox1: TDriveComboBox;
FilterComboBox1: TFilterComboBox;
Button1: TButton;
procedure FileListBox1DblClick(Sender: TObject);
procedure Timer1Timer(Sender: TObject);
procedure CheckBox1Click(Sender: TObject);
procedure Button1Click(Sender: TObject);
(Private declarations)
(Public declarations)
procedure TForm1.FileListBox1DblClick(Sender: TObject);
with MediaPlayer1 do
FileName:= FileListBox1.FileName;
procedure TForm1.Timer1Timer(Sender: TObject);
with MediaPlayer1 do
if FileName<>"" then
Gauge1.Progress:= Round(100*Position/Length);
procedure TForm1.CheckBox1Click(Sender: TObject);
Start_From: Longint;
with MediaPlayer1 do
if FileName ="" then Exit;
Start_From:= Position;
if CheckBox1.Checked then
Display:= Panel1
Position:= Start_From;
procedure TForm1.Button1Click(Sender: TObject);
if FileListBox1.FileName ="" then Exit;
with MediaPlayer1 do
FileName:= FileListBox1.FileName;
Fig.6. Complete AVI, WAV playback application
What is multimedia
Multimedia in Delphi
TMediaPlayer component
Two types of programs that use multimedia
Example program with multimedia
Review
- Delphi makes it easy and simple to include multimedia objects such as sounds, videos and music into the program. This tutorial discusses how to do this using Delphi's built-in TMediaPlayer component. The management of this component in the program and obtaining information about the current state are discussed in detail.
- What is multimedia
- There is no exact definition of what it is. But at this moment and in this place, it is probably better to give the most general definition possible and say that “multimedia” is a term that applies to almost all forms of animation, sound, video that are used on the computer.
To give such a general definition, it must be said that in this lesson we are dealing with a subset of multimedia, which includes:
1. Display video in Microsoft's Video for Windows (AVI) format.
2. Play sounds and music from MIDI and WAVE files.
This task can be accomplished using the Microsoft Multimedia Extensions dynamic library for Windows (MMSYSTEM.DLL), the methods of which are encapsulated in the TMediaPlay component located on the System page of the Delphi Component Palette.
Playing media files may require some hardware and software. So to play sounds you need a sound card. To play AVI on Windows 3.1 (or WFW), you must install Microsoft Video software.
- Multimedia in Delphi
- Delphi has a TMediaPlayer component that gives you access to all the basic multimedia programming features. This component very easy to use. In fact, it's so simple that many novice programmers will find it easier to create their first program that plays video or music rather than displaying the classic "Hello World" message.
Ease of use can be perceived in two ways:
On the one hand, this makes it possible for anyone to create multimedia applications.
On the other hand, you may find that not all features are implemented in the component. If you want to use low-level functions, you will have to dig quite deep using the Delphi language.
This lesson does not describe the details of internal calls to multimedia functions when the component is running. All you need to know is that the component is called TMediaPlayer, and that it gives access to a set of routines created by Microsoft called the Media Control Interface (MCI). These routines give the programmer easy access to a wide range of multimedia devices. Actually working with TMediaPlayer is intuitive and obvious.
- TMediaPlayer component
First, let's create a new project, then place the TMediaPlayer component (System Palette page) on the form, as shown in Figure 1.
Fig.1: TMediaPlayer component on the form.
The TMediaPlayer component is designed like a device control panel with buttons. Just like on a tape recorder, there are buttons for “play”, “rewind”, “record”, etc.
Having placed the component on the form, you will see that the Object Inspector contains the "FileName" property (see Fig. 2). Click twice
Fig.2: TMediaPlayer properties in the Object Inspector
on this property and select a file name with the extension AVI, WAV or
M.I.D. In Fig. 2, the AVI file DELPHI.AVI is selected. Next you need to set the AutoOpen property to True.
After completing these steps, the program is ready to run. After launching the program, click the green “play” button (far left) and you will see a video (if you selected AVI) or hear the sound (if you selected WAV or MID). If this does not happen or an error message appears, then two options are possible:
- You entered an incorrect file name.
- You have not configured your multimedia correctly in Windows. This means that either you do not have the appropriate hardware, or you have not installed necessary drivers. Installation and configuration of drivers is done in the Control Panel; hardware requirements are given in any book on multimedia (you need a sound card, for example, compatible with Sound Blaster).
So, you have the opportunity to play AVI, MIDI and WAVE files simply by specifying the file name.
Another important property of the TMediaPlayer component is Display. Initially, it is not filled and the video is played in a separate window. However, you can use, for example, a panel as a screen to display the video. You need to place the TPanel component on the form and remove the text from the Caption property. Next, for TMediaPlayer, in the Display property, select Panel1 from the list. After this, you need to launch the program and click the “play” button (see Fig. 3)
Fig.3: Playing AVI on the panel.
- Two types of multimedia programs
- Sometimes you need to provide users with an easy way to play as wide a range of files as possible. This means that you will need to give the user access to the hard drive or CD-ROM, and then allow him to select and play the appropriate file. In this case, the form usually contains TMediaPlayer, which provides playback control.
Sometimes a programmer may want to hide the existence of a TMediaPlayer component from the user. That is, play sound or video without the user caring about its source. In particular, sound can be part of a presentation. For example, displaying a graph on the screen may be accompanied by an explanation recorded in a WAV file. During the presentation, the user does not even know about the existence of TMediaPlayer. It works in the background. To do this, the component is made invisible (Visible = False) and controlled programmatically.
- Example program with multimedia
In this chapter we will look at an example of building an application with multimedia of the first type. Create a new project (File | New Project). Place TMediaPlayer on the form; place the components TFileListBox, TDirectoryListBox, TDriveComboBox, TFilterComboBox to select the file. In the FileList property for DirectoryListBox1 and FilterComboBox1, set FileListBox1. In the DirList property for DriveComboBox1, put DirectoryListBox1. In the Filter property for FilterComboBox1, specify the required file extensions:
AVI File(*.avi)|*.avi
WAVE File(*.wav)|*.wav
MIDI file(*.MID)|*.mid
Let the selected file be played by double-clicking the mouse in FileListBox1. In the OnDblClick event handler for FileListBox1, specify
Procedure TForm1.FileListBox1DblClick(Sender:TObject);
with MediaPlayer1 do
FileName:=FileListBox1.FileName;
The appearance of the form is shown in Fig. 4
Fig. 4: Initial view of the project
Save the project, run it, select the desired file and double-click on it. MediaPlayer should play this file in a separate window.
As mentioned above, the video can be played inside a form, for example, in a panel. Let's slightly modify the project and add a TPanel there (see Fig. 5). In the Display property for MediaPlayer1, specify Panel1. It is necessary to remove the inscription from the panel (Caption)
and property BevelOuter = bvNone. To switch from a window to a panel during playback, place a TCheckBox on the form and write in the OnClick event handler for it:
procedure TForm1.CheckBox1Click(Sender: TObject);
Start_From: Longint;
with MediaPlayer1 do begin
if FileName="" then Exit;
Start_From:=Position;
if CheckBox1.Checked then
Position:=Start_From;
Launch the project and play the video. Click on the CheckBox.
Fig.5: Added a panel for video playback and a window/panel switch.
During program execution, you may need to display the current state of the MediaPlayer object and the video itself (time elapsed since the start of playback, length of the video). For this, the TMediaPlayer object has the corresponding properties and events: Length, Position, OnNotify, etc. Let's add a progress indicator (TGauge) to the project, which will display in percentage how much time has passed (see Fig. 6). You can use a timer to update the indicator readings. Place a TTimer object on the form, set its Interval = 100 (100 milliseconds). In the OnTimer event handler you need to write:
procedure TForm1.Timer1Timer(Sender: TObject);
with MediaPlayer1 do
if FileName<>"" then
Gauge1.Progress:=Round(100*Position/Length);
Launch the project, select the file (AVI) and double-click on it. When playing a video, the progress indicator should display the percentage corresponding to the elapsed time (see Fig. 6).
Fig.6: Complete application for playing AVI, WAV and MDI files.
- The concept of "multimedia"
- Technology for creating multimedia applications
- Types of multimedia applications
- Tools for creating multimedia applications
Currently, many companies and firms use various types of computer technology for holding seminars, business meetings, trainings and other events. To make information more rich, memorable and visual, multimedia technologies are most often used. These are both hardware multimedia tools and application software packages that allow you to process various types of information, such as text, graphics and sound. There are different concepts of multimedia:
- Multimedia– technology that describes the procedure for the development, operation and use of information processing tools of various types ;
- Multimedia– computer hardware (the presence in the computer of a CD-Rom Drive - a device for reading CDs, a sound and video card, with the help of which it is possible to reproduce sound and video information, a joystick and other special devices) ;
- Multimedia is the combination of several means of presenting information in one system. Typically, multimedia refers to the combination in a computer system of such means of presenting information as text, sound, graphics, animation, video images and spatial modeling. This combination of means provides a qualitatively new level of information perception: a person does not just passively contemplate, but actively participates in what is happening. Programs using multimedia are multimodal, that is, they simultaneously affect several senses and therefore arouse increased interest and attention among the audience .
A colorfully designed multimedia application in which the presence of illustrations, tables and diagrams is accompanied by elements of animation and soundtrack, facilitates the perception of the material being studied, promotes its understanding and memorization, gives a more vivid and succinct idea of objects, phenomena, situations, stimulating the cognitive activity of students.
There is a fairly wide variety of different technological techniques aimed at developing high-quality multimedia applications. There are a few basic technology guidelines to follow when creating and then using these applications.
The basis for creating a multimedia application can be a material content model, which is a way of structuring the material based on breaking it into elements and visual representation in the form of a hierarchy.
At the initial stage of designing a multimedia application, the material content model allows you to:
- clearly define the content of the material;
- present the content in a clear and understandable form;
- determine the component composition of a multimedia application.
Taking into account the achievements of psychology allows us to formulate a number of general recommendations that should be taken into account when developing a method for visualizing information on a computer screen:
- information on the screen must be structured;
- visual information should periodically change to audio information;
- The color brightness and/or sound volume should be varied periodically;
- The content of the visualized material should not be too simple or too complex.
When developing the frame format on the screen and its construction, it is recommended to take into account that there is a meaning and relationship between objects that determine the organization of the visual field. It is recommended to arrange objects:
- close to each other, since the closer objects are to each other in the visual field (other things being equal), the more likely they are organized into single, holistic images;
- By the similarity of processes, since the greater the similarity and integrity of the images, the more likely they are to be organized;
- taking into account the properties of continuation, since, than more items in the visual field they find themselves in places corresponding to the continuation of a regular sequence (they function as parts of familiar contours), the more likely they are to be organized into integral unified images;
- taking into account the peculiarities of highlighting the subject and background when choosing the shape of objects, the size of letters and numbers, color saturation, text location, etc.;
- without overloading visual information details, bright and contrasting colors;
- Highlighting the material intended to be remembered by color, underlining, font size and style.
When developing a multimedia application, it is necessary to take into account that objects depicted in different colors and against different backgrounds are perceived differently by humans.
An important role in the organization of visual information is played by the contrast of objects in relation to the background. There are two types of contrast: direct and reverse. With direct contrast, objects and their images are darker, and with reverse contrast, they are lighter than the background. In multimedia applications, both types are usually used, both separately in different frames, and together, within the same picture. In most cases, the reverse contrast dominates.
It is preferable to run multimedia applications in direct contrast. Under these conditions, an increase in brightness leads to an improvement in visibility, and in the opposite direction - to a deterioration, but numbers, letters and signs presented in reverse contrast are recognized more accurately and faster than in direct contrast, even at smaller sizes. The larger the relative sizes of the parts of the image and the higher its brightness, the lower the contrast should be, the better the visibility. Comfortable perception of information from the monitor screen is achieved with a uniform distribution of brightness in the field of view.
To optimize the study of information on a computer screen, developers of multimedia applications are recommended to use logical accents. Logical accents are usually called psychological and hardware techniques aimed at attracting the user’s attention to specific object. The psychological effect of logical stress is associated with a decrease in the time of visual search and fixation of the visual axis in the center of the main object.
The most commonly used techniques for creating logical emphasis are: depicting the main object in a brighter color, changing the size, brightness, location, or highlighting with a flashing glow. A quantitative assessment of logical stress is its intensity. Intensity depends on the ratio of the color and brightness of the object in relation to the background, on the change relative sizes object in relation to the size of objects in the background of the image. The best is to highlight either with a brighter or more contrasting color; worse is to highlight with a flashing glow, changing the size or brightness.
After reviewing and analyzing existing domestic and foreign systems Based on the technology for creating multimedia applications, we can propose the following classification of the most common multimedia applications and their concepts.
Multimedia applications are divided into the following types:
- presentations;
- animation videos;
- games;
- video applications;
- multimedia galleries;
- audio applications (sound file players);
- applications for the web.
In table 1 presents the basic concepts of multimedia applications and their types.
Table 1. Basic concepts of multimedia applications
Multimedia application view |
Concept |
|
Presentation |
Presentation (from English) presentation) – a way of visual representation information using audiovisual media. The presentation is a combination of computer animation, graphics, video, music and sound, which are organized into a single environment. Typically, a presentation has a plot, script, and structure organized to convenient perception information |
|
Animation videos |
Animation – multimedia technology; reproduction of a sequence of pictures giving the impression of a moving image. The moving image effect occurs when the video frame rate is more than 16 frames per second |
|
Games |
A game is a multimedia application aimed at satisfying the needs for entertainment, pleasure, stress relief, as well as the development of certain skills and abilities. |
|
Video and video players |
Video films are a technology for developing and demonstrating moving images. Video players – video management programs |
|
Multimedia galleries |
Galleries – collection of images |
|
Audio players (digital audio) Web applications |
Audio file players are programs that work with digital audio. Digital audio is a way of representing an electrical signal through discrete numerical values of its amplitude Web applications are individual web pages, their components (menus, navigation, etc.), data transfer applications, multi-channel applications, chats, etc. |
When studying the technology of creating multimedia applications, a scenario is built that describes how they will be created. In this regard, it is logical to assume that each multimedia application consists of various components (various topics). By identifying the composition of multimedia applications, you can break them down into the following components: choosing the theme of the multimedia application being created, markup work area(scales and backgrounds), frames, using layers, creating symbols of different types, including variables and writing scripts in a programming language, working with sound files, adding text, creating effects, using and importing images, using ready-made component libraries, creating navigation, using text markup languages and scripting languages.
In turn, multimedia applications can be divided into the following subtypes. The basic concepts of subtypes of multimedia applications are presented in Table. 2.
Table 2. Basic concepts of subtypes of multimedia applications
There are many technical tools for creating a multimedia product. The creator-developer must select the editor program that will be used to create hypertext pages. There are a number of powerful multimedia development environments that allow you to create rich multimedia applications. Packages such as Macromedia Director, Macromedia Flash or Authoware Professional are highly professional and expensive development tools, while FrontPage, mPower 4.0, HyperStudio 4.0 and Web Workshop Pro are their simpler and cheaper counterparts. Tools such as Power Point and text editors(eg Word) can also be used to create linear and non-linear multimedia resources. The development environment for multimedia applications is also Borland Delphi.
The development tools listed are provided with detailed documentation that is easy to read and understand. Of course, there are many other development tools that can be used with equal success instead of those mentioned.
Currently, there are very few automated training systems for the technology of creating multimedia applications; they are almost impossible to find. Similar to such systems are Internet pages that contain a selection of lessons, books and articles on this topic. Most of these sites are aimed at the topics “Flash lessons for creating multimedia elements” or “Creating multimedia in Macromedia Director”.
Let's look at some of them.
International club of flash masters( http://www.flasher.ru )
The site presents a large number of articles and lessons on Macromedia Flash, and they are divided into the following categories: programming, effects, animation, navigation, sound, useful tips, 3D, beginners, etc.
The lessons in the “International Flash Masters Club” are a description of the sequence of steps that are proposed for users to complete. After completing such steps completely, the learner can make the same multimedia component that is described in this lesson. Technologies for creating a full-fledged multimedia application are not presented on the site, but you can view ready-made works of professionals or advanced users.
An overview of books that help in mastering flash technology is also presented. Registration for computer graphics school is underway. on a paid basis. Competitions for the best works are constantly held.
«
Lessonsflash"(
http://flash.demiart.ru/ )
The site “Flash Lessons” is one of the projects of the Demiart.ru studio, it is dedicated to self-study of Macromedia Flash based on lessons collected from the best experts in the world working with flash. The lessons describe the creation of various components and effects for various multimedia applications. In addition to lessons, flash tutorials are collected here. You can also download a demo version of the Macromedia Flash development environment. Discuss emerging issues on the forum.
Based on the results of the analysis, we can conclude that the most complete information is presented on the portal A Flash Developer Resource Site, but the domestic training system, presented in the form of the website of the “International Club of Flash Masters,” attracts with its design and convenient location of links. But to view them you need a flash player, not earlier than version 7.
