Computer Science

• How are Character stored

  • Each character is given a unique binary code.
• Unicode


  Unicode uses more (usually 16 or 32) bits per character.
• How are Images stored

  Images are split into pixels . Each pixel can only have one

  colour
• How many bits are used per pixel ?

  Each colour has to be given a unique binary colour code
• ASCII

  Each colour has to be given a unique binary colour code
• Resolution

  The height and width of the image in pixels
• Colour depth


  how many colours are available
• Effects of Changing resolution

  • higher resolution = more pixels, better quality image but larger file size. 
• Effects of changing Colour depth

  • Bigger colour depth = more colours, better quality image but larger file size. 
• How is a sound wave stored

  The amplitude of the sound wave is sampled at regular intervals.
• Sample Rate

  How often the samples are taken
• Bit depth

  • how many bits are used for each sample. Usually 16.
• Lossy compression

  reduces the file size by removing data that is not needed
• LOSSLESS compression

  • rewrites the data in a more efficient way.
• Benefits of Compression


  Files take up less space on disk

  Files are quicker to send