Upload
ralph-morrison
View
217
Download
0
Embed Size (px)
Citation preview
© Boardworks Ltd 20141 of 7
2.5 Representing images and sounds
Teacher’s notes in the Notes Page
Flash activity (these are not editable)Icons:
Unit 2 Digital Media
Worksheet or support sheet available
© Boardworks Ltd 20142 of 7
Curriculum linksCurriculum links
This presentation supports the following areas of knowledge in the Naace Curriculum Framework for KS3 ICT:
This presentation supports the following sectionsof the Programme of Study for KS3 Computing:
understand how instructions are stored and executed within a computer system; understand how data of various types (including text, sounds and pictures) can be represented and manipulated digitally, in the form of binary digits
Technical Understanding – Programming and control
© Boardworks Ltd 20143 of 7
Learning objectives
how images are represented in binary
how metadata is used in image files
how colour depth and resolution affect file size
how sound is stored in digital form
what affects the size and quality of an audio file
what can be done with image and sound data after it has been digitized.
By the end of this presentation we will have learned:
© Boardworks Ltd 20144 of 7
Representation of sound
Like colour, sound is not digital but analogue. However, to be stored by a computer it must be in a digital format.
While analogue signals can have any value, digital signals must store data using only the values 0 and 1.
How could you store analogue sound waves like the ones above using binary?
© Boardworks Ltd 20145 of 7
Sampling
© Boardworks Ltd 20146 of 7
File size
What factors do you think affect the size and quality of a sound file?
The higher the sample rate, the higher the sound quality will be. The file size will also be larger because more samples require more storage space.
Even at a relatively low sample size, uncompressed digital music files stored in RAW format are often very large. Compression reduces the size of the files by applying algorithms and codecs to store repeated patterns in the data.
© Boardworks Ltd 20147 of 7
After digitizing
After the data has been digitized, the computer is able to:
work with the data to display a picture, play a sound or calculate new values and new data
store the data on other devices, hard drives and memory sticks and display stored data on the screen
use specialist software to edit the sound or image
share the data with others through email, WiFi or Bluetooth
copy or back up the data.
© Boardworks Ltd 20148 of 7
Want to see more?
To see more of what Boardworks can offer, why not
order a full presentation, completely free? Head to:
http://www.boardworks.co.uk/ictpresentation
This is only a sample of one of thousands of
Boardworks ICT and Computing PowerPoints.