Bitmapped graphics flowgram

Bitmapped graphics flowgram

more about "untitled", posted with vodpod

Inspection

I don’t seem to be able to manage more than one post a month at the moment, last month I at lesat had the excuse of an inspection. HMIE are keen on blogs and online learning platforms it seems

So I have missed too many lessons to summarise them in the normal way here, but they are all on Studywiz, click the picture below to get there.

Also, I have been playing with Flowgram and came up with this so far (it is a work in progress) so now you can have me narrate the slides while you revise! I am sure this is what you have all been secretly waiting for…..

Audio data

more about "untitled", posted with vodpod

Capturing a digital image

Today we went through everything that happens when you take a digital picture (on a phone, camera, web cam etc).  We started by having a look two people  that came up with the all important device, a CCD (charge-coupled device, see wikipedia here for a good explanation).  You don’t need to remember who invented it, but you do need to know what a CCD does.  Hopefully the slide below goes some way to explaining that.

Authoring Software v.s. Presentation software

 

Today we tried to look at some examples of multimedia appplications created using authoring software.    Unfortunately they seemed to be a bit much for the network connection in school but you could have a look now if you are so inclined.  They were catapults, car maintenance, and furniture assembly.  The point about of all of them was that they are on the whole more complicated pieces of multimedia than you could create using presentation software (like Powerpoint).   

 

These are the notes from today.

Back to blogging…

This is my first post in ages, but I have to post as today I forced all of the higher class to set up their own blogs and write something about what we have been doing.  Which is …. multimedia

We had a quick look today at the difference between using a WYSIWYG editor and a text editor to make multimedia applications.   The reason the class created blogs was to try and demonstrate that WYSIWYG editors are easy to use and don’t require any prior knowledge of code, unlike typing in HTML into a text editor.  I am hoping the blogs will come in useful elsewhere too though….

Here are the notes the class received today.

Also, I had to clear up the fact that a common design process used for multimedia applications is known as a storyboard (a graphical representation of the layout of a multimedia application showing navigational links), as demonstrated here by this not particularly helpful, yogi bear episode storyboard.

SVG – Scalable Vector Graphics

Today we had a (limited) look at Scalable vector graphics. These share the same properties as all vector graphics; they are made up of descriptions of the shapes in them rather than pixels, they are resolution independent (they do not pixellise when zoomed in), they allow editing of individual objects etc etc. They are particularly used on the web for reasons best shown by the diagram below (from an excellent Wikipedia page about SVG)

The main idea is that you should have an understanding of how something like the text below, turns into the two shapes below it…..

  <rect x="80" y="60" width="250" height="250" rx="20"
fill="red" stroke="black" stroke-width="2px" />

<rect x="140" y="120" width="250" height="250" rx="40"
fill="blue" fill-opacity="0.7" stroke="black" stroke-width="2px" />


Here are my notes from today:

The Prelim.

Sorry there have not been many posts for a while, but then there have not been many Higher Computing lessons for a while. The prelim was yesterday morning and is now in the process of being marked.

If you took advantage of the chat room support the night before you would have realised that calculation questions would be important (along with a lot of other topics!).

If you want extra practice try this question:

A stereo audio file has been recorded at CD quality and is 3 minutes 12 seconds long. It is to be stored on a solid state flash drive. How much space will it take up in an uncompressed format?

Answers as comments please…..

RIFF files

Yet another acronym! Just one more to go along with PAM, PCM, ADPCM, MP3…..

This one (Resource Interchange File Format orRIFF) is a container file i.e. contains more than one type of data.

It is was created by Microsoft and IBM (according to Wikipedia anyway) as a multimedia content file. The header (first section) of the file determines what kind of data is in it. The picture below explains it better than I can.

Here is the slide from todays lesson:

Digitised Sound

This lesson I played some live radiohead (whose latest album was free to download) to try and get you thinking about capturing sound for digital use. For Higher Computing you need to be able to describe (in a 3 mark way) how sound is captured (microphone), changes into voltage, and is then digitised (by the ADC). You also need to have a good understanding of the terms sampling depth (how many bits are used to measure the analogue signal) and sampling frequency (how often the analogue signal is measured per second).

Interlacing, Dithering, Transparency and Anti Aliasing

You need to be able to describe all of these techniques in the exam however to understand them I think is best to see them actually in use. So, read the descriptions and then look at the powerpoint.

Interlacing

This refers to images which when downloading do not download line by line but appear initially blurry and then become clearer. JPEG supports interlacing. GIF does not.

Dithering

This is a technique designed to make an image with a low colour depth appear to have a higher colour depth. It mixes pixels from areas of flat colour, together, giving the impression of more colours than are available.

Transparency

This is the extent to which a part of an image can be made “see through”. Very useful when images are being used together or on top of each other.

Anti-Aliasing

This is another technique to make a graphic appear to be of higher quality than it actually is. The jagged edges that can appear on the edge of a graphic are made to appear smoother by adding extra colours and pixels.