Chapter 6:Graphics & Multimedia

“ MULTIMEDIA is a seamless integration of data, text, image of all kinds and sound within a digital environment. ” FELDMAN, 1992

MULTIMEDIA IS THE USE OF A COMPUTER TO PRESENT AND COMBINE TEXT, GRAPHICS,AUDIO AND VIDEO WITH LINKS AND TOOLS THAT LET THE USER NAVIGATE, INTERACT, CREATE AND COMMUNICATE. Hofstetter, 2001

Images 2basic structures for graphics: bitmapped and vector-based. Bitmapped image files store image data as a map of individual pixels. GIF and JPEG are bitmapped formats. Vector-based image files store image data as a set of mathematical formulas that instruct the computer how to draw the image. Macromedia Flash is a vector-based format

Bitmap images formed from matrix of pixels problem : jagged or staircase effect image must be mapped to the matrix

solution to jagged : use antialiasing making something slightly fuzzy so that you can't see the jagged edges use different tones

Vector image bitmap image vector image Vector-based graphics use mathematical relationships between points and the paths connecting them to describe an image

Comparing bitmap and vector File size : vector is smaller Resize : Vector-based images can be easily resized, recolored, and reshaped without lowering their quality (color, detail, sharpness, etc.) Bitmaps are best used for photos and images with subtle shading. vector format are for page layout, hardcopy printing, line art or illustrations

Bitmap files format - BMP Bitmap - short for BitMaP created by microsoft file extension BMP weakness : uncompress  file size is big and is not supported by web used for Windows graphic

Bitmap files format - PCX PCX have.pcx entenxion the first graphics file format to become a standard for bitmap file storage on IBM PCs. used by ZSoft's PC Paintbrush program, which was licensed to Microsoft in the early 1980s, and later converted into Windows Paintbrush and distributed with Windows. this popular format is diminishing

Bitmap files format - TIFF TIFF = Tagged Image File Format Provides the highest quality but has large file sizes usually use for images from scanners

Bitmap files format - Gif Graphics Interchange Format pronounced "jiff" created by CompuServe use 8 bits  maximum color = 2 8 = 256 lossless method of compression - squashes the original image without losing any data good for images contain repetitive pattern / color

Bitmap files format - JPEG jpg or jpeg extension pronounced "jay-peg Lossy compression removes image details that are (in theory, at least) too small for the human eye to notice to make file size smaller suitable for photo but not for image composed largely of solid color blocks and lines

IMAGE (COLOR) DEPTH Image depth refers to the maximum number of colors used in bitmap Each pixel can have one or more bits of color information attached to it: # Bits# ColorsUses 12Text, line drawing 416Simple drawings and graphics 8256Natural images MPhotographic realism

IMAGE SIZE FILE Bitmap file size relates directly to the number of bits in the image: Size (in bytes) = (Height x Width x Color Depth)/8 Samples file sizes for different images sizes and color depths: Monocrome (640x480x1 bit)/8 = 38k bytes 256 color (640x480x8 bits)/8 = 307k bytes 16 M (640x480x24 bits)/8 = 922k bytes –High quality images are big! Image requirements will affect hardware and software selection, including graphics and authoring software, video graphics adapter, disk space and data transfer rates.

comparing file size jpg = 24KB pcx= 217KB bmp = 216 KB png = 127 KB tif = 157 KB gif = 56KB lowest quality because 256 colors only

Beckham.jpg 5KB Beckham.bmp 103KB

comparing - usage if u want to use for webpage : gif, jpeg and png only if u intend to print on paper … always save any picture u scan using tiff … otherwise jpg photo always use jpg plain text, 2d cartoons use gif

vector graphic used in:  Illustration/drawing programs such as Macromedia Freehand and Adobe Illustrator.  3D applications such as CAD/CAM, architectural rendering, and animation.  Charts and graphs in spreadsheet programs.

vector graphics wire frame view shaded view

Audio /sound The audio used in multimedia applications can be obtained in several ways: can be captured digitally using a microphone, CD-ROM, radio Synthesized: digitally recorded Sampling rate: number or sound snapshots the recording equipment takes each second

Software for recording sounds 1. Sound recorder ( program > accessories > entertainment ) Options for recording : Telephone : 8KHz Mono Radio : 22KHz Mono CD : 44KHz Stereo

Edit songsbackground music

Type of audio compressions : mp3, real player.

WinMX = to download software movie, mp3, picture.

Video  Comprises of photographic images that display at speeds of 15 to 30 frames per second and provide the appearance of motion in real-time.  Video compression works by taking advantage of the fact that only a small portion of the image changes from frame to frame. Thus, a video compression program might store the first reference frame and then, assuming that the following frames will be almost identical to it, store only the changes from one frame to the next.

Video compression - AVI Audio Video Interleaved (AVI) format, which is a standard on the Windows platform. AVI is viewable in a player application such as the MediaPlayer included with Windows, or directly on a Web page.

AVI Windows media player is used to open avi files

MPEG (Moving Pictures Experts Group) has developed standards for video compression and decompression. This method can reduce the size of video files up to 95 percent, while retaining near-television quality.

(MPEG) is a file format that compresses video files effectively, but is not as widely standardized as QuickTime or AVI. There are actually several variations of MPEG. The version generally used for Internet and CD-ROM is MPEG-1, which provides picture quality nearly comparable to VHS. MPEG-2 can provide SVHS picture quality.

Video compression - Quicktime QuickTime is Apple's award-winning, industry-standard, software architecture for creating and viewing digital media for Mac OS and Windows. The file extension is mov Supports Internet streamings