Data Representation

Data Representation

1. Digital Images

   • Made of tiny blocks called pixels
   • The more pixels, the higher resolution the image
   • The higher the resolution, the more memory needed
   • Can be either bitmaps or vectors
   • Bitmaps
     • Used for smartphones, digital cameras and online
     • Each colour is stored as a binary number
     • Common image files are JPEG, GIF and PING

2. Compression

   • Compression is used to reduce file sizes and change various attributes of an image file
   • Attributes include file type, resolution, dimensions and bit depth
   • Can have lossless compression - does not lose picture quality as compressed e.g. PNG
   • Can have lossy compression - permanently removes data, loses picture quality e.g. JPG

3. Audio

   • Affected by:
     • Sample Rate - the number of audio samples captured every second
     • Bit Depth - the number of bits available for each clip
     • Bit Rate - the number of bits used per second of audio
   • Measured in Hertz, or Cycles per Second. This is the frequency or speed
   • How loud the sound is is called Amplitude