Category Archives: 3. Multimedia

1. Computer Systems, 3. Multimedia, Computing Higher

Number of colours

The Number of colours is calculated as using 2bit depth So we have the following. The phrase colour depth can be used in place of bit depth.

Colour Depth Number of Colours Description
1 2 Black and White
8 256 8bit
16 65,536 High Colour
24 16,777,216 True Colour

On a side note, I asked the maths department how to go from the number of colours to the colour depth.

Mr Barnstaple helpfully provided me with this

  • Colours = 2Bit Depth
  • Bit Depth=log(Colours)/log(2)

Which is I’m sure we will all agree very useful,  but it might be easier to memorise the table above 😉

PS if you want the proof  here it is Continue reading Number of colours →

1. Computer Systems, 3. Multimedia, Homework

Graphic file sizes calculations

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We covered this in class last week. Forrester have a good concise article on this subject

Please answer these questions

1. 600 x 300 pixels, 24 bit colour depth

2. 600 x 400, 16 bit colour depth

3. 600 x 600, 24 bit colour depth

4. An image is 6 inches by 8 inches, and has a resolution of 1200 dpi. It has a bit depth of 20.
(a) How many colours can the image store?
(b) What will be the file size of the image?

5. A photograph measures 10 inches by 7 inches, and has a resolution of 400 dpi. The number of colours each pixel can store is 65536.
(a) What is the bit depth of the image?
(b) What will be the file size of the image?

3. Multimedia, Computing Higher

Container files & CODECS

Codecs are instructions for “Compressing – Decompressing” or “Coding – Decoding” streams of data. These instructions can be either software or hardware based. Hardware based encoders/decoders are very fast and do not put strain on the CPU. This allows relatively low computing power devices like DVD players and the Raspberry Pi to display full screen videos.

You need to have the right codec installed to view the compressed files, although some programs have codecs built into them.

To find the codec of a file, it is necessary to look at the header information on the file, there are utilities to do this for you.

[kml_flashembed movie="http://www.youtube.com/v/_nPsBwMivCk" width="425" height="344" allowfullscreen="true" fvars="fs=1" /]

Container files contain several compressed files, the header is used to decompress the files. RIFF and MP4 are examples of container files.

3. Multimedia, Computing Higher

Authoring Package Vs Presentation Software

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FROM SCHOLAR

Follow 3 of the stages of the Software development process to complete this task, omitting ‘Analysis’, ‘Documentation’ and ‘Evaluation’.

You should create two versions of your completed design – one using Dreamweaver, the other using PowerPoint.

You do not have long to complete this task, so keep your designs SIMPLE.

The purpose of this task is not to produce fabulous, complete multimedia applications, but to use both a Presentation and Authoring package to complete the same task. This should allow you to compare both programs.

Your brief:

Create a multimedia application to introduce people to you and two of your interests.

You must complete this task using only 3 screens or pages.

Each screen must not contain any more than 2 images (although you can use a background) – Use the same images on both.

Your system should be easy to navigate, so design the navigation method carefully.

Step 1 Design

  • Design the navigation structure, showing how all 3 pages link together. Design the rough layout for each page, mentioning the content and navigation features.

Step 2 Implementation

  • Create your application using Powerpoint.

Step 3 Testing

  • Make sure that all the links and navigation features work. Make sure that each page is displayed/animated as you wish.

Step 4

  • Repeat Steps 2 & 3, this time using Dreamweaver.