Gaurav Bhatnagar

The WAV File Format

Waveform audio is one of the essential components of a multimedia system. Waveform audio can do anything within the practical limitations of memory, disk capacity, and sound card capabilities. The normal functions that one performs on tape recorder can also be done with waveform audio. One can read and write, store and retrieve, and manipulate the waveform audio. The voltage level determines the amplitude of the wave. The wave file not only contains the digital data required to produce sound, but also additional information such as the sampling rate, the type of audio data, and other critical data. Wave data comes in several formats, sampling rates, channels, and resolutions. The information appears in a format block called the Resource Interchange File Format or the RIFF chunk. The chapter also discusses the structure of the wave audio file and provides the steps for accessing the wave data and files.

Prelude to Audio

Voice is the predominant method by which human beings communicate. Human are so accustomed to speaking and listening that sound is taken for granted. But, sound exists in many different forms and each form has its own purpose and characteristics. This chapter provides a prelude to audio along with some practice exercises.

Authoring Multimedia in Visual Basic

Visual Basic does not provide any intrinsic controls or methods for integrating audio and video into the multimedia applications. The application depends on ActiveX controls for managing audio and video. The multimedia control allows managing media control interface (MCI) devices, which includes sound boards, audio players, or videodisc players. The multimedia control depends on the hardware and software configurations of a particular machine. Textual communication is the most common form of communication and is an intrinsic part of multimedia. In Visual Basic, there are means to use text creatively as part of multimedia. Visual Basic provides only one intrinsic control whose primary purpose is to display text, which is the label control. This chapter discusses the properties that make the label a useful control for multimedia applications. These are caption property, alignment property, autosize property, wordwrap property, and backstyle property. The use, advantages, and limitations of graphic methods are also discussed. Visual Basic is a powerful Windows development environment and is a rapid application development (RAD) tool. It is not able to provide all the functionality of the Microsoft Windows operating system that the operating system possesses.

An Interlude: Vision

This chapter reviews some of the properties of the eyes such as the fine resolution and the millions of hues that our eyes can distinguish between, and see where these may be applied in the design and construction of multimedia systems. The structure of the eye, vision, and the color resolution of the human eye are discussed. Human beings are quite good at perceiving colors in the middle of the visual field. That they can distinguish between so many different hues causes many problems for the graphic artist. An important consideration in working with digital data is the importance of knowing the limits of human perception. The human eye can make subtle distinctions in hue within the entire spectrum of colors. The resolution of the eye also has important connotations for graphics. There are many areas where the physical and biological circumstances play a role in what one see. The application of vision research to design is also discussed.

Prelude to Multimedia

This chapter provides a prelude to multimedia. There is a difference between news presented in a newspaper and shown on TV. This difference is very important to understand the multimedia. The chapter further provides an exercise to understand the main differences between newspaper and television.

File Formats and Web Graphics

This chapter discusses the size of graphics. The size can mean two things: one is the actual physical size of the graphic on the monitor or on the printout. The size of a digital graphic also refers to the size of the file on the computer. The file size of the bitmap is determined by the physical size and the amount of color information stored in each pixel. One can compress the image and store it in another file format. The quality and size of the picture is dependent on the amount of compression used. When graphics are used on the Web, one can try to use compression to reduce the file size without compromising too much on the quality of the graphics. Both JPEG and GIF support an interesting feature that is especially useful when they are used in Web pages. The strengths and weakness of JPEG compression and GIF compression are also provided.

An Interlude: The Properties of Light

This chapter discusses the properties of light and colors, and the properties of vision, which allows understanding various features of digital graphics. Sunlight contains ultraviolet rays that are not visible to us. Light bounces from certain surfaces and this property is called reflection. Refraction is the property of light to bend as it goes from one medium to another. The direction of the bend is determined by the speed of light in the two media. The most fundamental property of light is that it appears to travel in straight lines in a medium. Light of different colors corresponds to different wavelengths of the light wave. The analog of loudness of a sound wave in the case of light is called the intensity of light. Intensity is proportional to the square of the amplitude and gives a sensation of brightness. The intensity of light falls with the distance of the light source.

Chapter 8 – The Paint Shop Pro Interface

This chapter discusses the experiments that help one to get familiar with the interface of Paint Shop Pro and to be able to make simple graphics. Learning to use a software package is always an incremental process: the more one works on a system, the more one will understand its various features. Start Paint Shop Pro and spend a few seconds trying to find icons that one is already familiar with. It also provides instructions and guidelines to use various toolbars and tools available. An introduction to digital graphics is also given. Computer programs store their pictures as pixel maps. There are two types of graphics, so there are also two types of file formats for digital graphics: bit-mapped and vector formats. They may look the same on the screen or in print, but the Paint Shop Pro interface discovers and shows the difference between two. Some of the commonly used graphics editors used are Adobe Photo Shop, Fractal Design Painter, or Flash.

Music and Speech

This chapter discusses the digital audio—creating or synthesizing sounds using the computer. It gives an introduction to two aspects of audio synthesis, namely generation of music and of speech. Synthesized sounds are a set of instructions to the hardware audio device on how and when to produce sound. The Musical Instrument Digital Interface (MIDI) format is the most widely used digital format for generating synthesized sound. Sampled sounds are used where narration, testimonials, voice-overs, music, and sounds are required. Synthesized sound can be used to create a soothing atmosphere during a presentation or in a multimedia application. Human communication is dominated by speech and hearing. Speech is the most natural form of human communication. Speech is produced by inhaling, expanding the rib cage, and lowering the diaphragm, so that air is drawn into the lungs. The effects of speech are distortion, noise, and clipping. The synthesized speech consists of text-to-speech synthesis and speech-to-text synthesis. The speaker systems, vocabulary, and continuous speech and isolated-word system are also discussed. The chapter also provides a practice exercise.

Text in Multimedia and the Internet

This chapter discusses the different types of fonts and typefaces. Internet and multimedia conjure up images of videos, animation, pictures, and colors. Text plays an important part in multimedia and the Internet although it is a more limited. In multimedia, text is used for four major purposes: titles, menus, navigation, and content. Text in multimedia has to work together with other modes of communication, such as sound and graphics. This chapter also comes across various ways to make text work, as it is important because text remains the easiest option for technology. In multimedia and the Internet, information comes in from several modes—pictures, sound, and text. A typeface is a set of characters or letters that has a similar look. Typefaces are divided into two broad categories: serif and sans serif. The style, size, and screen display are the important factors. The selection of fonts should be made based on readability and focus. Writing hypertext documents is more difficult than writing text because the author must make sure the reader is able to absorb the information in the text and also the structure of the hyperdocument.