443 infs 3 multimedia applications question bank chapter 1: Introduction to Multimedia

1. Discuss the various factors that apply to the use of image in multimedia. x

2. Describe the capabilities and limitations of bitmap images.

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  Bitmaps are an image type most appropriate for photo-realistic images and complex drawings requiring fine detail.
  
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  Limitations of bitmapped images include large files sizes and the inability to scale or resize the image easily while maintaining quality.
  
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  A bitmap is a simple information matrix describing the individual dots of an image, called pixels.
  
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  The image’s bit-depth determines the number of colors that can be displayed by an individual pixel.
  
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  You can grab a bitmap image from a screen, scan it with a scanner, download it from a web site, or capture it from a video capture device.
  
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  You can then manipulate and adjust many of its properties, and cut and paste among many bitmaps using specialized image-editing or “darkroom” programs.
  
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  When you import a color or gray – scale bitmap from the Macintosh to windows , the colors will seem darker and richer.
  

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  Vector images are most appropriate for lines, boxes, circles, polygons, and other graphic shapes that can be mathematically expressed in angles, coordinates, and distances.
  
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  A vector object can be filled with color and patterns, and you can select it as a single object.
  
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  Vector-drawn objects use a fraction of the memory space required to describe and store the same object in bitmap form.
  
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  Most drawing programs can export a vector drawing as a bitmap.
  
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  Converting bitmaps to vector-drawn objects is difficult; however, autotracing programs can compute the boundaries of shapes and colors in bitmapped images and then derive the polygon object that describes those bounds.
  
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  Vector images require aplug-in (such as a flash player) for display on a web page.
  
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  Vector image cannot be used for photo-realistic images.
  

5. Discuss the difference between bitmap and vector graphics.

6. Define various aspects of 3 D modeling.

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  For 3-D, the depth (z dimension) of cubes and spheres must be calculated and displayed so that the perspective of the rendered object seems correct to the eye.
  
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  Objects and elements in 3-D space carry with them properties such as shape, color, texture, shading, and location.
  
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  To model an object that you want to place into your scene, you must start with a shape.
  
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  When you extrude a plane surface, it extends its shape some distance, either perpendicular to the shape’s outline or along a defined path.
  
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  When you lathe a shape, a profile of the shape is rotated around a defined axis (you can set the direction) to create the 3-D object.
  
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  Rendering is when the computer finally uses intricate algorithms to apply the effects you have specified on the objects you have created.
  

1. What do you mean by the Acoustics of sound? What it measures?

2. Define, sampling rate, bit depth and quantization.

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  The quality of this digital recording depends upon how often the samples are taken (sampling rate or frequency, measured in kilohertz, or thousands of samples per second)
  
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  How many numbers are used to represent the value of each sample (bit depth, sample size, resolution, or dynamic range).
  
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  The value of each sample is rounded off to the nearest integer (quantization).
  

The value of each sample is rounded off to the nearest integer (quantization), and if the amplitude is greater than the intervals available, clipping of the top and bottom of the wave occurs (see Figure 4-2).

4. Calculate the size of a mono recorded audio file of sampling rate at 22.05 kHz, 16 bit resolution for 10 seconds.

5. Calculate the size of a stereo-recorded audio file of sampling rate at 44.1 kHz, 16 bit resolution for 10 seconds.

1. Discuss the general principal of sound and how it can be used in a multimedia project. x

2. Define MIDI and explain its attributes.

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  MIDI data is not digitized sound; it is a shorthand representation of music stored in numeric form.
  
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  MIDI files tend to be significantly smaller than equivalent digitized waveform files.
  
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  MIDI data is device dependent; its playback depends on the capabilities of the end user’s system.
  
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  Because they are small, MIDI files embedded in web pages load and play more quickly than their digital equivalents.
  
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  You can change the length of a MIDI file (by varying its tempo) without changing the pitch of the music or degrading the audio quality. MIDI data is completely editable.
  
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  MIDI cannot easily be used to play back spoken dialog.
  
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  Working with MIDI requires familiarity with musical scores, keyboards, and notation as well as audio production.
  

4. List the important steps and considerations in recording and editing digital audio.

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  The file size (in bytes) of a digital recording is sampling rate * duration of recording in seconds * (bit resolution / 8) * number of tracks (1 for mono, 2 for stereo).
  
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  Consumer-grade audio compact discs are recorded in stereo at a sampling rate of 44.1 kHz and a 16-bit resolution. Other sampling rates include 22.05 and 11 kHz, at either 16 or 8 bits.
  
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  When recording (digitizing) audio, it’s important to keep the recording level near the maximum without going over it.
  

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  Important steps in digital sound editing include removing blank space from the start and end of a recording and normalizing the sound to bring all clips to approximately the same level.
  
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  The native sound file formats for most Macintosh sound editing software are the SND and AIF formats, and most authoring systems will read these formats. In Windows, the native sound file format for most editing software is a WAV file.
  
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  Many audio editors provide tools such as resampling, fade-ins and -outs, equalization, time stretching, various digital signal processing effects, and reversing sounds.
  

1. Discuss the principles of animation.

2. What is kyeframes and Tweening in animation?

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  The series of frames in between the keyframes are drawn in a process called tweening. Tweening is an action that requires calculating the number of frames between keyframes and the path the action takes, and then actually sketching with pencil the series of progressively different outlines.
  

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  Disney(which plays at 24 frames per second). A minute of animation may thus require as many as 1,440 separate frames.The term Cel derives from the clear celluloid sheets that were used for drawing each frame, which have been replaced today by acetate or plastic. Cels of famous animated cartoons have become sought-after, suitable-for-framing collector's items. Cel animation artwork begins with keyframes.
  

4. What is “kinematics” and “Inverse kinematics” in movement and motion of structure?

5. Define morphing.

1. Define animation and describe how it can be used in multimedia.

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  By definition, animation is the act of making something come alive.
  

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  Depending on the size of the project, you can animate the whole thing or you can just animate parts of it.
  

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  Visual effects such as wipes, fades, zooms, and dissolves, available in most authoring packages, are a simple form of animation.
  

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  Animation is an object actually moving across, into, or out of the screen.
  

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  Animation is possible because of a biological phenomenon known as persistence of vision and a psychological phenomenon called phi.
  

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  With animation, a series of images are changed very slightly and very rapidly, one after the other, seemingly blending together into a visual illusion of movement.
  
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  Television video builds 30 entire frames or pictures every second. Movies on film are typically shot at a shutter rate of 24 frames per second.
  

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  Cel animation, an animation technique made famous by Disney, uses a series of progressively different graphics on each frame of movie film.
  
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  Cel animation artwork begins with keyframes; these are the first and last frames of an action.
  
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  Tweening is an action that involves creating the frames to depict the action that happens between keyframes.
  
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  Computer animation programs typically employ the same logic and procedural concepts as cel animation.
  

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  You can usually set your own frame rates on the computer, but the rate at which changes are computed and screens are actually refreshed will depend on the speed and power of your display platform and hardware.
  
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  Kinematics is the study of the movement and motion of structures that have joints.
  
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  Inverse kinematics is the process in which you link objects such as hands to arms and define their relationships and limits, then drag these parts around and let the computer calculate the result.
  
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  Morphing is an effect in which one image transforms into another.
  

2. List the important consideration in converting from digital video to television.

3. Discuss video analog and digital technologies and displays.