Computer Science unit 2.1

    Cards (17)

    • Bitmaps are constructed by pixels
    • Each pixel of a bitmap is stored in binary
    • The number of bits required for each pixel depends on the amount of colours
    • The number of bits for each pixel is known as what?
      Colour depth
    • Metadata is what?
      additional data stored within the image
    • The greater the colour depth and resolution, the larger the file size of the image
    • Photographs are stored in 24-bit colour depth
    • Sound file size - total number of bits in a sound
    • sound file size can be calculated by number of samples per second x number of bits per sample x length of sample
    • bit depth - the number of bits stored per sample
    • the higher number of bits or sampler per second, the greater the quality and bigger the file size
    • sample rate - number of samples per second
    • compression reduces the number of bits in a file making the capacity higher and data transfer quicker
    • lossy compression - greatly reduces the file size and some data is lost reduces the quality
    • lossy compression is suitable for images sound and video cannot be used on text and executable files
    • lossless compression - data is not lost it is encoded differently and can be turned back into original format
    • lossless compression can be used on all types of data it does not reduce file size and is most suitable for documents and executable files