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Multimedia and 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

Lecturer in (Computer Science)

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Contents of Assignments

I. Images Work out your graphical

approach by planning yourapproach, organizing yourtools, and configuring yourcomputer workspace

Differentiate among bitmap,vector, and 3-D images anddescribe the capabilitiesand limitations of all three

Describe the use of colorsand palettes in multimedia

Cite the various image filetypes used in multimedia

II. Sounds Describe the components

and measurements ofsound

Use digital audio to record,process, and edit sound

Use MIDI and understand itsattributes, especially relativeto digitized audio

Compare and contrast theuse of MIDI and digitizedaudio in a multimediaproduction

List the important steps andconsiderations in recordingand editing digital audio

Determine which audio fileformats are best used in amultimedia project

Cite the considerationsinvolved in managing audiofiles and integrating theminto multimedia projects

Images

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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 expressedin 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).

Digital Image Format Captured Image Format

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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.

Graphics Software Programs

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The use of colors and palettes in multimedia

Cite the various image file types used in multimedia

Drawing programs Adobe IllustratorAdobe InDesignAdobe Effects

Paint programs – Paint Shop Pro

Image-editing programs – Photoshop (does the work of all 3)

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Sounds

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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

• Sound is energy, just like waves breaking on a sandy beach

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• 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 windows\Media 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.

Macintosh Windows

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

Basic Sound Recorder

Multimedia System Sounds

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WAV files – system sounds in Windows; they reside in the Windows\Media 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.

Setting proper recording levels to get a good, clean recording.

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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.

• 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

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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.

Sound synthesizer – typically built into the sound board on PCs, but an add-on board for Macintosh).

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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.

References

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https://www.google.com.pk/search? q=cello+and+piano&biw=1366&bih=571&source=lnms&tbm=isch&sa=X&ved=0ahUKEwilhrWQupXMAhUJUhQKHV_TDIsQ_AUIBygC#imgrc=mJxEFdk6Ki8unM%3A

http://www.academia.edu/6560317/ Multimedia_Making_It_Work_Eighth_Edition

http://highered.mheducation.com/sites/ 0071748466/student_view0/chapter4/index.html

Multimedia:Making It WorkEighth Edition