Unit 1: Digital Content

analog-to-digital converter

(ADC)- Any device, such as a sound card, that converts analog data into digital data.

AAC

(Advanced Audio Coding) A file format that provides highly compressed audio files with very little loss of sound quality and is promoted by Apple on its iTunes Web site.

ASCII

(American Standard Code for Information Interchange) A code that represents characters as a series of 1s and 0s. Most computers use ASCII code to represent text, making it possible to transfer data between computers. Requires seven bits for each character. ASCII provides codes for 128 characters, including uppercase letters, lowercase letters, punctuation symbols, and numerals. For example, the ASCII code for an uppercase A is 1000001.

CDDA

(Compact Disc Digital Audio) An optical disc recording format for audio CDs.

SVG

(Scalable Vector Graphics) A graphics format designed specifically for Web display that automatically resizes when displayed on different screens.

OCR

(optical character recognition)- The ability of a device or software to digitize text from printed sources.

Ogg Vorbis

An open source audio file format.

WAV

An audio file format with the .wav extension that was Windows' original "native" sound format.

Digital Audio

Music or voice that has been digitized into files using sampling techniques; sometimes referred to as waveform audio.

ASF

(Advanced Systems Format) Microsoft's proprietary container format for streaming digital multimedia; typically holds WMV and WMA files.

AVI

(Audio Video Interleave) A video file format, developed by Microsoft, that was once the most common format for desktop video on the PC.

digital-to-analog converter

(DAC)- A device that converts digital data, such as 1s and 0s, in an audio file into continuous data, such as audio sounds.

GIF

(Graphics Interchange Format), pronounced "gif" or "jiff," was specifically designed to create images that can be displayed on multiple platforms, such as PCs and Macs. GIF graphics are limited to 256 colors, but the format supports simple animations. Once a popular format for Web pages, GIF is being replaced by JPEG and PNG. Use- web graphics and simple animations

MPEG

(Moving Picture Experts Group) A family of highly compressed container file formats and codecs for digital multimedia; MPEG-1, MPEG-2, and MPEG-4.

MIDI

(Musical Instrument Digital Interface) A standardized way in which sound and music are encoded and transmitted between digital devices that play music.

PNG

(Portable Network Graphics), pronounced "ping," is a graphics format designed to improve on the GIF format. A PNG graphic can display up to 48-bit True Color (trillions of colors). Unlike JPEG, PNG compresses bitmap files without losing any data, so compressed images retain the same high quality as the originals. PNG was developed as a public domain format without any restrictions on its use. Use- web graphics and other general uses

TIFF

(Tagged Image File Format), or TIF, is a flexible and platform-independent graphics file format supported by most photoediting software packages. Scanners and digital cameras commonly store bitmaps in TIFF format because it supports True Color and can be easily converted into other graphics file formats. Use- desktop publishing and any projects that require high resolution graphics; not supported by browsers

VOB

(Video Object) An industrystandard video format for standalone DVD players.

WMA

(Windows Media Audio) A file format with the .wma extension that is promoted by Microsoft and provides highly compressed audio files with very little loss of sound quality.

CCD

(charge-coupled device) One of the components in a digital camera that captures light from an image and converts it into color data.

JPEG

(pronounced "JAY-peg"), which stands for Joint Photographic Experts Group, is a graphics format with built-in compression that stores True Color bitmap data very efficiently in a small file. The JPEG format is popular for Web graphics and for photos attached to email messages. When creating a JPEG or converting an image to JPEG format, you can control the level of compression and the resulting file size. The compression process eliminates some image data, however, so highly compressed files suffer some quality deterioration. Use- general use, such as desktop publishing or Web pages, where flexibility in file size is important

Unicode

A 16-bit character-representation code that can represent more than 65,000 characters.

Digital Camera

A camera that takes and stores a digital image instead of recording onto film.

True Color

A color image with a color depth of 24 bits or 32 bits. Each pixel in a True Color image can be displayed using any of 16.7 million different colors.

Lossless Compression

A compression technique that is able to reconstitute all of the data in the original file; hence lossless means that this compression technique does not lose data.

MP3

A file format that provides highly compressed audio files with very little loss of sound quality.

WebM

A multimedia container format designed for HTML5 projects.

MOV

A multimedia file format, popular for digital videos, that works with QuickTime software.

File

A named collection of data (such as a computer program, document, or graphic) that exists on a storage medium, such as a hard disk or CD.

Ogg Theora

A non-proprietary container format (Ogg) and video codec (Theora).

Pixel Interpolation

A process that is used by graphics software to average the color of adjacent pixels in an image, usually when the image is enlarged.

Compression Ratio

A ratio such as 5:1 indicating the amount of compression that has been applied to a file. High compression ratios such as 35:1 indicate more compression so data can be contained in smaller files.

Wireframe

A representation of a 3-D object using separate lines, which resemble wire, to create a model.

Digital Video

A series of still frames stored sequentially in digital format by assigning values to each pixel in a frame.

Delimiter

A special character used to separate commands or formatting characters from the rest of the text in a file.

3-D Graphics

A type of digital graphics format that displays a three-dimensional image in a two-dimensional space.

Phoneme

A unit of sound that is a basic component of words and is produced by speech synthesizers.

UTF-8

A variable-length coding scheme that uses seven bits for common ASCII characters, but uses 16-bit Unicode as necessary.

Upconverting

Adding pixel data to video frames to increase the resolution.

Binary Number System

Also known as Base 2. A method for representing numbers using only two digits: 0 and 1. Contrast to the decimal number system, which uses ten digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.

Byte

An 8-bit unit of data that represents a single character. Usually abbreviated with a capital B.

Vector Graphic

An image generated from descriptions that specify the position, length, and direction in which lines and shapes are drawn.

Bitmap Graphic

An image, such as a digital photo, that is stored as a gridwork of colored dots.

Image Histogram

An interactive graph that can be used to adjust the colors in a digital photo.

Lossy Compression

Any data compression technique in which some of the data is sacrificed to obtain more compression.

Image Compression

Any technique that is used to reduce the size of a file that holds a graphic.

Digital Compositing

Assembling parts from multiple digital images into a single image.

Bit

BInary digiT- The smallest unit of information handled by a computer. A bit is one of two values, either a 0 or a 1. Eight bits constitute a byte, which can represent a letter or a number. Usually abbreviated with a lowercase b.

Digital Quantities

Bit- one binary digit Byte- 8 bits Kilobit- 1,024 or 2^10 bits Kilobyte- 1,024 or 2^10 bytes Megabit- 1,048,576 or 2^20 bits Megabyte- 1,048,576 or 2^20 bytes Gigabit- 2^30 bits Gigabyte- 2^30 bytes Terabyte- 2^40 bytes Petabyte- 2^50 bytes Exabyte- 2^60 bytes

Letterbox

Black bars added to a video file to fit it into a different aspect ratio.

Digitization

Converting non-digital information or media to a digital format through the use of a scanner, sampler, or other input device.

Analog Data

Data that is measured or represented on a continuously varying scale, such as a dimmer switch or a watch with a sweep second hand.

Binary Equivalent of Decimal Numbers

Decimal (Base 10) Binary (Base 2) 0 = 0 1 = 1 2 = 10 3 = 11 4 = 100 5 = 101 6 = 110 7 = 111 8 = 1000 9 = 1001 10 = 1010 11 = 1011 1000 = 1111101000

Pixelation

Describes the effect of increasing the size of an image until smooth edges become jagged.

Resolution Dependent

Graphics, such as bitmaps, in which the quality of the image is dependent on the number of pixels constituting the image.

Intraframe Compression

In a digital video, compression that takes place within a single frame, similar to the compression used for still images.

Photosites

In digital photography, each photosite is a single point on an image capture chip, equivalent to one pixel.

Rendering

In graphics software, the process of creating a 3-D solid image by covering a wireframe drawing and applying computer-generated highlights and shadows.

Data

In the context of computing and data management, data refers to the symbols that a computer uses to represent facts and ideas. Data can be a name, a number, the colors in a photograph, or the notes in a musical composition.

Cloning

In the context of digital graphics, the process of replicating a section of an image, often used to cover blemishes or fill in backgrounds.

Frame

In the context of digital video, one of the sequential images that are combined to produce video footage.

Bits or Bytes?

Kilobit (Kb or Kbit)(1024 bits) can be used for slow data rates, such as a 56 Kbps (kilobits per second) dial-up connection. Kilobyte (KB or Kbyte)(1024 bytes) is often used when referring to the size of small computer files. Megabit (Mb or Mbit)(1,048,576 bits) is used for faster data rates, such as a 25 Mbps (megabits per second) Internet connection. Megabyte (MB or MByte)(1,048,576 bytes) is typically used when referring to the size of files containing photos and videos. Gigabit (Gb or Gbit)(1024 megabits) is used for really fast network speeds. Gigabyte (GB or GByte)(1024 megabytes) is commonly used to refer to storage capacity.

Character Data

Letters, symbols, or numerals that will not be used in arithmetic operations (name, Social Security number, etc.).

Vector

Lines and curves that form simple shapes.

Numeric Data

Numbers that represent quantities and can be used in arithmetic operations.

ASCII Text

Plain unformatted text. Text files that contain no embedded formatting codes. .txt

BMP

Pronounced "bee-em-pee" or "bump," is the native bitmap graphics file format of the Microsoft Windows environment. Microsoft Paint, included as part of Microsoft Windows, creates BMP graphics files. The BMP format supports True Color and can be used for a wide variety of graphics applications, such as photographs, illustrations, and graphs. BMP files are often too large for email attachments. BMP graphics are not supported by most browsers, so they are not used on the Web. Use- graphical elements, such as buttons and other controls for graphical user interfaces

RAW

RAW image formats contain the unprocessed pixel data generated directly by a digital camera's sensor. Up to 12 bits of data can be stored for each of the red, blue, and green values for a pixel, so RAW files are very large. Cameras that offer a RAW format also supply proprietary software to convert RAW data to JPEG or TIFF. Use- photographic images before they are stored in other formats

Codec

Short for compressor/decompressor; a hardware or software routine that compresses and decompresses digital graphics, sound, and video files.

Pixel

Short for picture element; the smallest unit in a graphic image. Computer display devices use a matrix of pixels to display text and graphics.

Interframe Compression

Shrinking the size of a video by removing redundant data that is the same in two successive frames.

Extended ASCII

Similar to ASCII but with 8-bit character representation instead of 7-bit, allowing for an additional 128 characters. Using eight bits instead of seven bits allows Extended ASCII to provide codes for 256 characters. For example, Extended ASCII represents the uppercase letter A as 01000001.

Text-to-speech Software

Software that generates speech based on written text that is played back through a computer's sound card.

Audo Plugin

Software that works in conjunction with a browser to play audio that is accessed from Web sites.

Live Stream

Streaming data that carries an event happening in real time.

On-Demand Stream

Streaming media that starts and stops when requested, as opposed to a live stream.

Audio Compression

Techniques used to reduce the size of files that contain audio data.

Digital Data

Text, numbers, graphics, or sound represented by discrete digits, such as 1s and 0s.

File Name Extension

The characters in a file name after the period, such as .exe and .txt.

MIDI Messages

The commands that create MIDI music by specifying the note to play, its duration, and the instrument that plays it.

Container Formats

The formats for files that hold multiple types of media files, such as video and audio.

File Format

The method of organization used to encode and store data in a computer. Text formats include DOCX and TXT. Graphics formats include BMP, TIFF, GIF, and PNG. ; the typ

Bit Rate

The number of bits that are transmitted or processed per unit of time (usually per second); usually measured as bps (bits per second).

Color Depth

The number of bits that determines the range of possible colors that can be assigned to each pixel. For example, an 8-bit color depth can create 256 colors.

Frame Rate

The number of frames that are displayed in a video per second.

Image Resolution

The number of pixels in an image, usually expressed as horizontal pixels × vertical pixels.

Sampling Rate

The number of times per second a sound is measured during the recording process. It is expressed in hertz (Hz).

Clipping Path

The outline of an object in a digital image that can be used to cut out the object from its background.

Speech Synthesis

The process by which computers produce sound that resembles spoken words.

Speech Recognition

The process by which computers recognize voice patterns and words, and then convert them to digital data.

Alpha Blending

The process of combining a foreground color with background colors as when an image is pasted onto a background and the edges are blended to look more natural.

Video Capture

The process of converting analog video signals into digital data stored on a hard drive.

Transcoding

The process of converting audio and video files from one digital format to another, such as converting an MOV file into a Flash video file.

Digital Audio Extraction

The process of copying files from an audio CD and converting them into a format that can be stored and accessed from a computer storage device, such as a hard disk; sometimes referred to as ripping.

Inpainting

The process of reconstructing missing parts of digital images, usually by means of an algorithm built into graphics software.

Data Compression

The process of shrinking the size of a file by removing data or recoding it more efficiently. Commonly referred to as "zipping."

Rasterization

The process of superimposing a grid over a vector image and determining the color depth for each pixel.

Download

The process of transferring a copy of a file from a remote computer to a local computer's storage device.

Aspect Ratio

The ratio of the width and height of an image or display screen.

Binary

The representation of data using two states, such as off-on or 1-0.

Digital Cinematography

The use of digital cameras and storage to produce high-quality digital films.

Data Representation

The use of electronic signals, marks, or binary digits to represent character, numeric, visual, or audio data.

RGB Color Model

The use of red, green, and blue light that can be combined to create the full spectrum of colors.

Interlaced Scan

The way a display device builds an image by showing every other row of pixels, then going back and filling in the remaining rows.

Run-length Encoding

(RLE) A graphics file compression technique that looks for patterns of bytes and replaces them with messages that describe the patterns.

Audo Player

A device or software program that plays files containing audio data in one or more formats, such as MP3 or WAV.

Scanner

A device that converts a printed image into a bitmap graphic.

Digitizing Tablet

A device that provides a flat surface for a paper-based drawing and a "pen" used to create hand-drawn vector drawings.

Ray Tracing

A technique by which light and shadows are added to a 3-D image.

MIDI

Artificially created sound, usually found in MIDI music or synthesized speech.