Question 28 – Multimedia Systems (20 marks) Marks

Use a SEPARATE writing booklet.

(a) Define the following terms:

i) lossy, with regards to multimedia systems

Comments

Students struggled to define lossy correctly. Some knew that it

had something to do with compression, but most students failed

to display enough knowledge within their answer for two marks.

Simply stating it is a type of compression is not enough to get two

marks. Other people clearly had no idea what lossy was, or got it

confused with lossless (which loses-less data than lossy)

Sample Answer:

Lossy is a type of compression where data that is compressed is

removed from the file, and thrown away, unable to be recalled.

(eg, mp3)

2

ii) resolution, with regards to multimedia systems

Comments:

Students found this definition much easier to recall, but for a straight

recall of a definition, there was not enough detail in the question for

some students, or students that indicated that they (kind of) knew

what they were talking about without being explicit enough.

Sample Answer:

Resolution is the amount of pixels within a particular display or

image, normally measured by the pixels across x pixels down (eg,

800 x 600) and the amount of dots (or pixel) per inch

2

(b) Based on the storyboard below, explain how the website navigation

works.

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Comments:

This was a fairly generous question, which should have been really

easy to do….look at the storyboard and describe how the navigation

works. Most loss in marks here was due to too little detail.

Sample Answer

This hierarchical navigation storyboard has one main page that links

off to four other pages. (page 1, page2, page3, page 4). Page 4 then

further has links to external websites outside the scope of this

website. There is then information on each page (page 2, pictures;

page 2, sounds; page 3 videos and page 4, some text and web links).

All pages then link back to the home page (index.html), as is

indicated by the double headed arrow.

(c) Describe the role and skills of an individual who designs multimedia

systems

3

Comments:

Students mostly described roles without skills or vice versa. This is

essentially a recall questions, which would generally indicate lack of

study of the syllabus…you need to know every dot point!

Sample Answer:

Directly from the syllabus:the variety of fields of expertise required in the development of multimedia applications, including: – content providers – system designers and project managers – those skilled in the collection and editing of each of the media types – those skilled in design and layout – those with technical skills to support the use of the information technology being used

(d) Analyse the connection between multimedia systems and hardware.In your answer you should address TWO of the following:

primary and secondary storage processing

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displayingComments:

Most students had little idea about any of these, and in fact, often

confused primary and secondary storage and their purpose. Ie,

primary storage is RAM…link to processing power, secondary

storage as storage of files and programs when not in use. Marks

were generally awarded at a very low level by at least identifying a

type of display. Some students failed to do even this. You cannot

just identify types of hardware and hope for the best. Why are these

types of hardware specifically important within multimedia systems?

Sample Answer:

There is a connection between multimedia systems and hardware in

terms of primary and secondary storage and displaying. Primary and

Secondary storage are important aspects and strongly linked to

multimedia systems. Within MMS animations and videos require a

lot of storage space so that the MMS is a quality product. Due to the

advances in technology storage capacity has increased which leads

to better quality MMS solutions. Also, displaying is an important part

for MMS as it requires a good display device for higher resolutions

and better quality. With advancements within this area, so has MMS

continued to improve. Thus, both primary and secondary storage as

well as display hardware are closely linked.

Directly from the syllabus:

the demands placed on hardware by multimedia systems, including: – primary and secondary storage requirements as a result of: - bit depth and the representation of colour data - sampling rates for audio data – processing as a result of: - video data and frame rates - image processing, including morphing and distorting - animation processing, including tweening – display devices as a result of: - pixels and resolution

(e) A local musician is creating a DVD to store his recently authored music clips and music videos.

(i) Calculate the amount of memory (in bytes) needed to store one

song with the following details Sample rate 44 100 Sample size 1024 bits Stereo channels Duration of 30 seconds

Comments:Most students managed to correctly transcribe the formulas, and to put replacements into the formula. Many students left out the number of channels (x2) and thus got their final mark incorrect. Many students divided by 1024*8, which should have just been 8, since the question asked for the answer in bytes.

Sample Answer

= 44100 * 1024 * 2*308

= 2709504000/8=338688000

(ii) Calculate the amount of memory (in kilobytes) needed to store one music video with the following details

Screen size is 800 by 600 pixels Image requires 64 colours Plays at 24 frames per second Duration of 1 minute 10 seconds

Comments:Most students managed to correctly transcribe the formulas, and to put replacements into the formula. Some students forgot to convert the 1 minute 10 seconds to 70 seconds, and thus multiplied their formulas by 110.

Sample Answer=800*600*24*6*70/8*1024

= 48384000000/8 *1024

= 5906250

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The poor performance of all students in this question can be put down to the decision made to leave the exam early. The

IPT exam cannot be done in less than three hours…you should be writing for the entire time. Question 28 to answer

properly really requires two booklets. You should not be able to answer it in one. Ask for more booklets if you need

them.