Category Archives: 6. External Sites

3. Multimedia, Computing Higher

Work for Tuesday 11th March

Today you are going to investigate the different types of bitmap graphics file we will use during the course.  You must create a presentation which covers Bitmap,GIF,JPEG & PNG file formats. You can use your notes, the scholar website and other websites including this one to do your research. A clear example of each file type must be included in the presentation, this should show some advantage or disadvantage of the image format. Please use the point below to help you in your investigation.

Description of the storage of graphic data in compressed and uncompressed file formats, including simple description of the techniques used within each file for compression and data storage, including:

  • bitmap (indexed colour or CLUT), 24-bit bitmap and compressed bitmap (RLE),
  • GIF (animation, (non)-interlaced, LZW),
  • JPEG (description of factors involved),
  • PNG (CLUT or RGB, transparency, compressed)
1. Computer Systems, Computing Higher, Revision

Answers to today’s Starter Questions

These were taken from the 2008 Section 1.

1a(i)Describe how bit-mapped images are stored. 1 KU
  • An array/grid of pixels
  • Each dot/pixel has a binary value
  • Each pixel stored as a bit/byte/binary value/black=1 & white=0
  • Accept black=1 and white=0 type answer but not the colour of each pixel
  • Any one from above 1 mark (Not “the colour of pixels are stored” or “individual pixels” or “pixel by pixel”)

1a(ii) Describe how vector images are stored. 1 KU

  • As a number/list of objects (each of which has attributes defining the objects)
  • Objects are defined by attributes/mathematical description
  • Accept an example object used to describe eg rectangle and attributes
  • Any other valid
  • 1 mark for any of the above

1b Is the above image bit-mapped or vector? Justify your answer.2 PS

  • Bit-mapped (1 mark)
  • Composed of grid of (individual) pixels
  • Does not contain/is not comprised of (collection of discrete) objects
  • It is pixelated
  • It is a photograph/taken with a digital camera
  • 1 mark for any valid bullet point (Not painting or resized)

2a Explain how the heuristic detection technique is used to detect a virus.1 KU

  • It looks for a suspicious pattern of behaviour (which was previously associated with a virus)
  • Accept use of a valid example to illustrate concept
  • Any other valid
  • 1 mark

2b Explain why a trojan horse is not classified as a computer virus. 1 PS

  • A trojan horse is not self replicating
  • Does not infect other files
  • 1 mark for any one of the above (do not accept a description of what a trojan horse does)
3. Multimedia, Computing Higher

Introduction to Multimedia

So we got started on booklet 1. In this unit we will focus more on the technical aspects of multimedia.

Today we looked at the development process of multimedia and the key thing you should have taken away was this idea of target audiences. Any multimedia application must be focused on it’s target audience. A multimedia application for a primary school child will look far different than one created for a University student.

We then went on to HTML and how a WYSIWYG editor differs from a text editor.

Tomorrow you will be working with these notes.