Digital Data

• Data


  Facts and figures with no meaning
• Information


  Data with meaning
• Data


  • 121567
• Information


  • 080308 date of birth
• Bit


  1 bit (0 or 1)
• Computer memory capacity and external storage device capacity terms


  • Byte
  • Kilobyte KB
  • Megabyte MB
  • Gigabyte GB
  • Terabyte TB
  • Petabyte PB
• Character


  A letter or digit represented by 1 byte (8 bits)
• Data Types


  • Numeric (integer or real number)
  • Date/Time (Short, Medium, Long)
  • Character
  • Symbols (Single Letters, Numbers)
  • String (textual data)
• Computer systems are not intelligent
• Pixel


  The smallest unit of a digital image that can be displayed and edited, each with its own individual colour stored as binary digits
• Combining pixels


  Produces a full image
• Image resolution


  The quality of an image, the greater the resolution the greater the file size
• Bitmap graphics


  • Store details about every individual element (pixel) of the image
  • File size can be very large
  • Can be compressed to reduce file size
• Vector graphics


  • Store information about the components (lines, curves, shapes) that make up an image
  • Less information needs to be stored resulting in smaller file size
  • Quality doesn't depend on resolution
• Buffering and streaming a video


  1. Streaming allows viewing as video downloads in real time

  2. Buffer stores downloaded part of video before watching

  3. Buffering prevents disruptions from streaming delays
• Sample rate


  Number of audio sound samples captured per second to represent sounds digitally, measured in Hertz (Hz) or kiloHertz
• Bit rate


  Quantity of data measured in bits processed per unit of time, measured in kilobits per second (kbps)
• Bit depth


  Number of bits used to store each sound sample, higher quality sound requires higher bit depth (e.g. CD 16 bits, DVD 24 bits)
• Analogue-to-digital conversion


  1. Analogue-to-digital converter (ADC) converts analogue signal to digital

  2. Digital-to-analogue converter (DAC) converts digital signal to analogue
• Data portability


  Ability to transfer data between computers or software applications without re-entering the data
• Data compression types


  • Lossy compression (removes some data to reduce file size, quality can be reduced)
  • Lossless compression (doesn't lose any original data quality)
• Description


  • The number of bits and for each sound sample
  • The aty afdre reared in bis that is processed in a given amount of time
• Analogue signals


  • sound waves
  • temperature
• Analogue to digital converter (ADC)


  1. Samples a signal regularly

  2. Samples are then covered to digital format
• Sample rate


  The frequency at which samples are talen, measured in Hertz (Hz)
• Data portability


  The ability to transfer data from one computer to another or from one software application to another without having to re-enter the data
• File formats


  • JPEG
  • TIFF
  • PNG
  • PICT
  • GIF
  • BMP
  • CSV
  • RTF
  • MP3
  • MP4
  • MIDI
• JPEG


  • Joint Photographic Expert Group files support the compression of images
• TIFF


  • Tagged Image File Format files store bitmapped images
• PNG


  • Portable Network Graphics allow data compression of bitmapped graphics
• PICT


  • The standard file format for Apple graphics
• GIF


  • Graphics Interchange format supports bitmapped image
  • Animated GIFs combine a series of GIF images and display them one after the other
• CSV


  • A comma-separated value file is a text-format file used by database and spreadsheet applications
• RTF


  • Rich Text Format is used for text-based documents such as word processing
• MP3


  • A file format for compressing sound
• MP4


  • Similar to MP3 but a file format that compresses both sound and video
• MIDI


  • Musical Instrument Digital Interface allows sound samples to be interchanged between different digital musical instruments