DigitizationMulti-media is a very large industry - the film/movie industry is an excellent example of how a single medium has grown in technology and employment. Actually, when it comes to movies, there is no singular medium to produce or to view movies anymore. Today there are many relatively new forms of media and technologies that demand new skills and result in new jobs. Just look at the credits that follow any movie. These are just a few categories;
- - Computer Generated Special Effects
- - Sound Effects
- - Video Footage
- - 3D AnimationObviously gaming, business and art for that matter employ many people. The web uses one technology and digitally it can display all different forms of media simultaneously
- - text
- - images
- - sound
- - videoUsers only need one tool - the web browser- not a cd player for music and a vcr to view a movieYour DVD player is more versatile than the old VCR. Now you can play your music and watch your movie in the
same player. You can play games on the same device and so on.
Digitization and Transmission The traditional media communication relied heavily on analog transmission . Analog signal, a variable signal that is
continuous in time and amplitude, as opposed to a digital or discrete signal. An analog signal uses some property of the
medium to convey the signal's information. Electrically, the property most commonly used is voltage followed
closely by frequency, current, and charge.Recent Enhancements have fundamentally changed the way in which media is transferred and displayed to users
with increased quality.All digital communications contain information within some sort of language of which both the sender and receiver must both
possess in advance in order for the communication to be successful.The word digital is used in the context of a logical 1(pulse
present and/or high) or a logical 0 (pulse absent and/or low). The program language determines the equipment's ability to utilize
these (binary codes)"Zeros" and "ones" to perform the desired task.
In 3 words, Digitalization in effect has changed the world of media; quality, combining & interactivity:
A) Improving media quality.
- - DVD vs. VHS
- - Digital Cable & Satellite TV vs Analog
- - DSL / Cable Modems vs traditional phone/fax modems
- - Web based & digital radio vs analog
B)(Analog) having, once segregated, traditional medium formats (text, image, sound & video) all
combined and sampled from the same melting pot. You can watch TV, listen to radio, read a
magazine all on the same machine at the same time.
C) Traditional analog TV offered little or no interactivity and therefore you were forced to see what the network
wanted you to see. However; with the latest advancements, you can become the director and choose what you
want to see and from what angle you want to see it. For example, the CBC now offers a service that lets the
customer have almost total control. Hockey Night in Canada Plus brings you the first interactive television
service in Canada to offer multiple camera angles, a player cam, replays, up -to-the-minute highlights and
on-demand team & game statistics so you never miss a moment of the action.
Computers work in Digital form.INPUT -> DIGITIZE -> OUTPUTExample:- Input of a photograph from a flat-bed scanner- Computer converts the image into digital format as a series of numbers that represent
each ‘pixel’ of the image- The computer then displays this image to the screen by reading the series of numbers
as it was storedPIXEL???? WHAT IS A PIXEL???
A computer records this image as a series of numbers that represent each pixel. To display the image the
computer converts the number to the colored pixels.
The number of pixels in an image is sometimes referred to as the resolution, although resolution has specific definition. Resolution indicates the size of the component that make an image. Resolution
units may be in lines/inch or lines/mm, as well pixels/inch. The result is that resolution affects the detail
or clearity of an image.
Pixel counts can be expressed as a single number, as in a "three-megapixel" digital camera, which has a nominal three million
pixels, or as a pair of numbers, as in a "640 by 480 display", which has 640 pixels from side to side and 480 from top to bottom
(as in a VGA display), and therefore has a total number of 640 × 480 = 307,200 pixels or 0.3 megapixels.
The pixels, or color samples, that form a digitized image (such as aJPEG file used on a
web page) may or may not be in one-to-one correspondence with screen pixels, depending
on how a computer displays an image.
Afile format is a particular way in which data is encoded for storage in a computer file. Since any computer storage, can only deal with bits, the computer must have some way of converting information to 0's and 1's and vice-versa. The 3 or 4 letters following the dot at the end of a file name indicate the format. When you save your final product in Photoshop you will likely choose from an assortment of formats that are meant for various purposes. One purpose would be compatibility. psd files are not compatible with many programs. One consideration might be quality. Another big consideration is file size. Converting your image usually results in compressing the file size at the same time.
Bitmap VS Vector Images
Bitmap Images- made up of pixels- when you zoom in - you can see the different pixels of color that make up the image- software : Adobe Photoshop, Paint Shop Pro
Vector Images- image is made up of mathematical equations- when you zoom in, the image remains just as it is- software : Adobe Illustrator, Macromedia Flash
An example of a vector image vs bitmap
In this course we will learn how to use Adobe Photoshop
Adobe Photoshop files have the extension *.psd - they save all the image information and are of high quality (and quite large in file size).
We will learn how to save images as other formats to reduce the file size as well be able to use that image in other software applications and over the web medium.One of these formats is JPEG (Joint Photographic Experts Group). When saving as a JPEG, Photoshop essentially compresses the file with the trade off of a lower quality image.
File Compression: Reducing the amount of information stored about a media piece and therefore reducing the file size by storing only selected ranges of the media elements. There is much to be said about data compression.. The size of the file and the format determines it's ability to be understood and the speed needed to process.
Data compression is particularly useful in communications because it enables devices to transmit or store the same amount of data in fewer bits. Compression means make smaller. There are a variety of data compression techniques, but only a few have been standardized. There are file compression formats such as ARC and ZIP, as well as image compression formats such as ***jpg, png, gif, and bmp ***. Ian's site explains how the image formats work.
Compressed Image formats fall into 2 categories:
a)Lossless data compression is a class of data compression algorithms that allows the exact original data to be reconstructed from the compressed data.
b)Lossy data compression which is the result of an averaging type of compression in which the media piece does not maintain all original information.Gif and png are image based compressions that are ‘lossless’ type of compressions. There is no quality loss just file size reduction.EXAMPLE : GIF images (Graphics Interchange Format)Same image pixel color 13 times in a row..423 423 423 423 423 423 423 423 423 423 423 423 423
Instead of storing 13 of 423’s , it would store one 423 to go for 13 times in a row.
The principle of Averaging (lossy)
Reducing the amount of information stored about a media piece and therefore reducing the file size by storing only the average bit information among similar elements of the media piece rather then the original bit information.EXAMPLE: JPEG (Joint Photographic Experts Group)445 448Instead of storing 445, 447, 449, 451, 449, 448 in 0 and 1’s - it would store the average of 448.
The principle of Range ReductionImage Compression - Reduction of the range of colors in the image, in other words you give limits to the possibilities of variation.
256 COLORS18 KB 128 COLORS13 KB 64 COLORS10 KB 32 COLORS7 KB 16 COLORS5 KB
An other Example : Sound - Can reduce the range of sound levels (‘loudness’). You still achieve different levels of loudness but you will notice a sharper, more contrasted difference
between soft/loud.The principle of Selectivity
When viewing a multimedia piece our eyes are drawn to some aspects of an image or frequencies of a sound than others. Selectivity codecs take advantage of this and save more information about the elements in our concentration and less of those objects we disregard.The principle of Frame Difference Compression
Reduces file sizes by only recording once the parts of the frame that do not change while only recording those that change constantly. This type of compression is mostly used with video.Book Sources
The Web Wizards Guide to Multimedia - James G. Lengel
Business Data Communications - 3rd Edition - William Stallings and Richard Van Slyke
Research the difference between analog transmission versus digital . Tell what you understand as being the pluses and minuses between them.
Questions: Digital Answers
1) Explain 3 major aspects of media improvement that resulted in the world going digital.
2) What are 2 means of generating digital images on a screen?
3) Explain the difference in the result of choosing between the 2 categories of file compression.
4) There are 4 approaches to reducing file size. List these different means of lightening the load of larger than necessary files.
5) Puzzle time
5. describes the detail an image
6. combined use of different mediums
7. compressed file format that loses image quality.
8. smallest single component of a digital image.
10. reducing the size of a file
11. sport results fall under this communication purpose
1. A billboard serves this communication purpose
2. online tutorials assist in fulfilling this communication purpose
3. message sent, received and understood
4. compression that does not compromise quality
9. image is made up of mathematical equations
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