Multimedia and-system-design-sound-images

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Multimediaand System Design
BSIT-Eve-6th
2016
Assignment Subject :
Multimedia
Institute Name:
University of Education Okara,
Campus (Renala Khurd)
Truth ,The Ultimate and Virtue
Submitted by:
Muhammad
Yameen Shakir
3001
Zubair Yaseen
3005
Submitted to:
Mam.Sobia
Lecturerin
(Computer
Science)
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Contentsof Assignments
I. Images
 Work out your graphical
approach by planning your
approach, organizing your
tools, and configuring your
computer workspace
 Differentiate among bitmap,
vector, and 3-D images and
describe the capabilities
and limitations of all three
 Describe the use of colors
and palettes in multimedia
 Cite the various image file
types used in multimedia
II. Sounds
 Describe the components
and measurements of
sound
 Use digital audio to record,
process, and edit sound
 Use MIDI and understand its
attributes, especially relative
to digitized audio
 Compare and contrast the
use of MIDI and digitized
audio in a multimedia
production
 List the important steps and
considerations in recording
and editing digital audio
 Determine which audio file
formats are best used in a
multimedia project
 Cite the considerations
involved in managing audio
files and integrating them
into multimedia projects

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Images
 Images are the main part of multimedia presentation
 Still images may be small or large, or even full screen. They may be colored,
placed at random on the screen, evenly geometric, or oddly shaped.
 Images are generated by the computer in two ways: as bitmaps (or
paint graphics) and as vector-drawn (or just plain “drawn”) graphics.
Bitmaps may also be called “raster” images.
 Likewise, bitmap editors are sometimes called “painting” programs.
 And vector editors are sometimes called “drawing” programs.
 Bitmaps are used for photo-realistic images and for complex drawings
requiring fine detail.
 Vector-drawn objects are used for lines, boxes, circles,
polygons, and other graphic shapes that can be mathematically expressed
in angles, coordinates, and distances.
 Both types of images are stored in various file formats and can be translated from
one application to another or from one computer platform to another.
 Typically, image files are compressed to save memory and disk space; many
bitmap image file formats already use compression within the file itself
for example, GIF, JPEG, and PNG.
Digital Image
 A digital image is represented by a matrix of numeric values each representing a
quantized intensity value.
 When I is a two-dimensional matrix, then I(r,c) is the intensity value at the position
corresponding to row r and column c of the matrix.
 The points at which an image is sampled are known as picture elements
 commonly abbreviated as pixels.
 The pixel values of intensity images are called Grey scale levels (we encode here
the “colour” of the image).
 The intensity at each pixel is represented by an integer and is determined from the
continuous image by averaging over a small neighbourhood around the pixel
location.
 If there are just two intensity values, for example, black, and white, they are
represented by the numbers 0 and 1; such images are called binary-valued images.
 If 8-bit integers are used to store each pixel value, the grey levels range from 0
(black) to 255 (white).

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Digital Image Format
 Captured Image Format
o The image format is specified by two main parameters: spatial resolution,
which is specified as pixels’ x pixels (e.g. 640x480) and colour encoding,
which is specified by bits per pixel.
o Both parameter values depend on hardware and software for input/output
of images.
 Stored Image Format
When we store an image, we are storing a two-dimensional array of
values, in which each value represents the data associated with a pixel in
the image. For a bitmap, this value is a binary digit.
Bitmap
 A bitmap is a simple information matrix describing the individual dots that are the
smallest elements of resolution on a computer screen or other display or printing
device.
 A one-dimensional matrix is required for monochrome (black and white);
 Greater depth (more bits of information) is required to describe more than 16 million
colours the picture elements may have.
 The state of all the pixels on a computer screen make up the image seen by the
viewer, whether in combinations of black and white or coloured pixels in a line of
text, a photograph-like picture, or a simple background pattern.

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Graphics Software Programs
The use of colors and palettes in multimedia
 Drawing programs
Adobe Illustrator
Adobe InDesign
Adobe Effects
 Paint programs
– Paint Shop Pro
 Image-editing programs
– Photoshop (does
the work of all 3)

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Cite the various image file types used in multimedia

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Sounds
 Sound is one of the most important element of multimedia.
 It is meaningful “speech” in any language, from a whisper to a scream.
 It can provide the listening pleasure of music, the startling accent of special
effects or the ambience of a mood setting background.
 Sound is the terminology used in the analogue form, and the digitized form of
sound is called as audio.
Power of Sound
• When something vibrates in the air is moving back and forth it creates wave of
pressure.
• These waves spread like ripples from pebble tossed into a still pool and when it
reaches the eardrums, the change of pressure or vibration is experienced as
sound.
• Acoustics – the branch of physics studies sound.
• Unit to measure Sound is decibels (dB).
• A decibel measurement is actually the ration between a chosen reference
point on a logarithmic scale and level that is experienced.
• Logarithmic scale is also used to measure earthquakes

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• Sound is energy, just like waves breaking on a sandy beach
• Too much volume can permanently damage the delicate receiving mechanism
behind your eardrums.
Sound is energy, caused by molecules vibrating
Cello and Piano
Multimedia Sound Systems
• Macintosh or windows operating system uses sound to make alert signal.
• System uses beep and warning sounds are available with the operating system.
• They provide several sounds for the system alert.
• In windows system sound are WAV files and they are found on windowsMedia
subdirectory.
• Windows makes use of WAV files as the default file format for audio and
Macintosh systems use SND as default file format for audio.

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 Sound Recorders for Windows
 Both Macintosh and Windows PC platform have the default sound.
Basic Sound Recorder
Macintosh Windows

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Multimedia System Sounds
 WAV files – system sounds in Windows; they reside in the WindowsMedia
subdirectory. Examples: start.wav, chimes.wav, ding.wav, logoff.wav,
notify.wav, recycle.wav, tada.wav and Microsoft sound.wav. You can assign
these sounds in system events such as Windows startup, warnings, clicks,
etc.
 AIF format – system sounds in OS X on Macintosh. You can only change the
system alert sound in this platform. Custom sound files may be put into
~/Library/Sounds.
 Digitally recorded audio or MIDI (Musical Instrument Digital Interface) – most
sound used in multimedia productions.
Digital Audio
• Created when sound wave is represented using numbers—digitizing.
• Digitized sound is sampled sound. Every nth fraction of a second, a sample of
sound is taken and stored as digital information in bits and bytes.
• Sampling rate or frequency – how often the samples are taken. Measured in
kilohertz, or thousands of samples per second.
• Bit depth, sample size, resolution, or dynamic range – how many numbers are
used to represent the value of each sample.
• Device independent – quality of audio is based on the quality of recording and
not the device on which it will be played.
• CD-quality: 44.1 kHz, 22.05 kHz, and 11.025 kHz –three sampling frequencies
most often used in multimedia.
• Quantization – rounding off to the nearest integer the value of each sample. If
the amplitude is greater than the intervals available, clipping of the top and
bottom of the wave occurs. Can produce an unwanted background hissing noise,
and clipping may severely distort the sound.
Preparing Digital Audio Files
• Fairly straightforward, analog source materials—music or sound effects
recorded on analog media such as cassette tapes—could be digitized by
recording onto computer-readable digital media by playing sound from one
device right into your PC using digitizing software.
• Focus on two crucial aspects:
 Balancing the need for sound quality against file size. Higher quality means
larger files, requiring longer download times on the Internet and more storage
space on a CD or DVD.

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 Setting proper recording levels to get a good, clean recording.
 Crucial aspects of preparing digital audio files are:
 Balancing the need for sound quality against available RAM and hard disk
resource.
 Setting appropriate recording levels to get a high-quality and clean recording.

File Size Versus Quality
• Sampling at higher rates (44.1 kHz or 22.05 kHz) more accurately captures the
high-frequency content of sound.
• Audio resolution (8- or 16-bit) determines the accuracy with which a sound can
be digitized. More bits yield a recording that sounds more like its original.
• Stereo recordings are more lifelike and realistic than mono recordings. Formulas
for determining size:
 Monophonic recording: sampling rate * duration of recording in seconds * (bit
resolution/8) * 1.
 Stereo recording: sampling rate * duration of recording in seconds * (bit
resolution/8) * 2.
(Sampling rate (in kHz) * 1000)
Setting Proper Recording Levels
• Digital audio recording and editing software will display digital meters to let you
know how loud your sound is.
• Unlike analog meter that usually have a 0 setting somewhere in the middle and
extend up into ranges like +5, +8, or even higher, digital meters peak out.
• To avoid distorting, do not cross over limits where the digital meter peaks out.
• Keep peak levels between -3 and -10.
Editing Digital Recordings
• Audacity is a free open source editing application for Windows, Macintosh, and
Linux operating systems (http://audacity.sourceforge.net).
• Multiple Tracks – being able to edit and combine multiple tracks (for sound
effects, voice-overs, music, etc.) and then merge the tracks and export them into
a “final mix” to a single audio file.

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• Trimming – removing “dead air” or blank space from the font of a recording and
any unnecessary extra time off the end. Accomplished by dragging the mouse
cursor over a graphic representation of your recording and choosing a menu
command such as Cut, Clear, Erase or Silence.
• Splicing and Assembly – removing the extraneous noises that inevitably creep
into a recording. Cutting and pasting together many shorter ones.
• Volume Adjustments – providing a consistent volume level for multiple
recordings. Use a sound editor to normalize the assembled audio file to a
particular level, 80 percent to 90 percent of maximum.
• Format Conversion – reading a format different from that read by presentation
or authoring program.
• Resampling or Down sampling – reducing the number of samples. Saves disk
space
• Fade-ins and Fade-outs – enveloping capacity for long sections. Helps to
smooth very beginning and very end of a sound file.
• Equalization – modifying a recording’s frequency content so that it sounds
brighter or darker also called digital equalization (EQ).
• Time Stretching – altering the length of a sound file without changing its pitch.
• Digital Signal Processing (DSP) – processing the signal with reverberation,
multistep delay, chorus, flange, and other special effects. Do not overdo the
sound effects.
• Reversing Sound – reversing all or a portion of a digital audio recording. Can
produce a surreal, otherworldly effect when played backward.
Making MIDI Audio
• Takes time and musical skill to work with MIDI (Musical Instrument Digital
Interface).
• You will need the following:
 Sequencer software – lets you record and edit MIDI data.

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 Sound synthesizer – typically built into the sound board on PCs, but an add-on
board for Macintosh).
 MIDI keyboard – useful for simplifying the creation of musical scores. Can easily
edit score.
• Device dependent – quality of the playback depends upon the end user’s MIDI
device.
• General MIDI numbering system – identifies instruments that can be
synthesized.
• A production tool rather than a delivery medium. The best way to create original
music.
Advantages of MIDI
• Much more compact and the size is completely independent of playback quality.
• Files embedded in web pages’ load and play quicker.
• If the MIDI sound source is of high quality, they may sound better than digital
audio files.
• 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.
• Completely editable—right down to the level of an individual note. The smallest
detail of a MIDI composition can be manipulated.
Disadvantages of MIDI
• Because MIDI data does not represent sound but musical instruments, playback
will be accurate only if the MIDI playback device is identical to the device used
for production.
• Cannot easily be used to play back spoken dialog, although expensive and
technically tricky digital samplers are available.
Music CDs
• ISO 10149 or Red Book (derived from the standard’s book jacket) – international
standard which is the method for digitally encoding the high-quality stereo of the
consumer CD music market.
• Developers of this standard claim that the digital audio sample size and sampling
rate of Red Book Audio (16 bits at 44.1 kHz) allow accurate reproduction of all
sounds that humans can hear.

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References
 https://www.google.com.pk/search?q=cello+and+
piano&biw=1366&bih=571&source=lnms&tbm=is
ch&sa=X&ved=0ahUKEwilhrWQupXMAhUJUhQK
HV_TDIsQ_AUIBygC#imgrc=mJxEFdk6Ki8unM%3
A
 http://www.academia.edu/6560317/Multimedia_Ma
king_It_Work_Eighth_Edition
 http://highered.mheducation.com/sites/007174846
6/student_view0/chapter4/index.html
 Multimedia:
Making It Work
Eighth Edition
