1. Data Representation
1. Information Theory: is the study of the most efficient ways to represent or encode information.
2. Data: is the raw information that is to be encoded in the computer.
3. File format: is the way information/data is encoded and stored in the computer.
4. Binary code: the form that almost all computers store information. Binary code stores data as numbers in the binary number system.
5. Binary Numbers are numbers made up of only the binary digits 0 or 1 and are numbers in Base 2 number system.
1. Bit: which is the smallest data element either 0 or 1.
2. Byte: which is 8 bits.
3. Kilobyte (Kb), which is 1024 bytes.
4. Megabyte (Mb), which is 1024 kilobytes.
5. Gigabyte (Gb), which is 1024 megabytes
6. Terrabyte (Tb), which is 1024 gigabytes.
1. Bitmap graphics – graphics that code the state of each dot or pixel (picture element) on the screen.
2. Vector graphics – graphics that consist of a set of instructions that recreates a picture made of objects.
3. Monochrome graphics – contains only two colors white and black.
4. Grayscale graphics – displays an image in shades of gray, typically using 256 shades of gray (8-bit depth).
5. 16-color graphic – displays an image of 16 colors (4-bit depth)
6. 256-color graphic – displays an image of 256 colors (8-bit depth).
7. 24-bit or true color graphic – displays an image up to 16.7 million colors (24-bit depth).
8. ASCII text – (American Standard Code for Information interchange) – encodes 128 symbols.
9. ANSI text – (American National Standards institute) – encodes 256 symbols.
10. Unicode text – 16-bit code can represent over 65,000 different symbols.
1. Data compression – recording of data so it requires few bytes of storage space.
2. File compression – compresses data in file. Commonly used file compression programs are WinZip and PkZip. Files are said to zipped and then unzipped.
3. Disk compression – compress data in special volume on hard drive. One commonly used disk compression program is DriveSpace.
4. Run Length encoding – is a compression technique that looks for patterns of bytes and replaces them with a message that describes the pattern.
5. Adaptive Pattern Substitution – compression technique designed specifically to compress text files. Looks for patterns of two or more bytes. When it finds such a pattern, it substitutes a byte pattern and is not used elsewhere in the file and makes a “dictionary entry”.
6. Lossy Compression – graphic file compression that loses some of the original data in graphic that in theory the human eye won’t miss.
7. JPEG (Joint Photographic Experts Group) – a commonly used lossy compression format.
8. TIFF – (Tag image File) – a commonly used non-lossy compression format.
9. BMP – (Bit Mapped Picture) – commonly used non-lossy and uncompressed format.
10. Dithering – uses patterns of two or more colors to produce illusion of additional colors and shading.
1. Sampling rate – refers to the number of times per second the sound is measured during the recording process. Sampling rate is measured in hertz (Hz).
2. Kilohertz (KHz) – One thousand hertz.
3. CD audio sampling rate – is 44.1 KHz.
4. Voice sampling rate – is often recorded at 11KHz because the lower sampling rate is still clearly understood.
5. Waveform audio – a digital representation of sound waveform stored as numeric data.
6. MIDI – (Musical Instrument Digital Interface) – sound files that contain instructions that MIDI instruments and MIDI sound cards use to recreate sound. The computer encodes the music as a sequence.
7. MIDI sequence – is a series of music tracks that includes the pitch of the note, when note begins, what instrument plays note, and volume and duration of note.
8. . WAV – is common file extension for a waveform sound file.
9. . MIDI – is common file extension for a MIDI sound file.
1. Digital video – is composed of a series of frames. Each time is essentially a still picture, which could be represented using the same techniques as a bitmapped picture.
2. Codec – compression/decompression format often used for digital video. Common video codec’s are
3. . AVI – file extension for Video for Windows codec files.
4. . MOV – QuickTime file extension for a commonly used video codec available for both Apple and IBM computers.
5. . MPG (Moving Pictures Expert Group) – file extension for commonly used video codec used on CD-ROMs and DVD discs.
