⏱️ Do It Now
Create a OneNote Page and copy this into the title:
Y10 AU – P10 – Compression
Copy this into a OneNote Page and complete it
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📝 Do It Now |
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Answer each of the following: (1) State what we call the number of individual sound recordings taken per second (2) Explain the impacts of increasing the bit depth of a sound file (3) Describe how we can calculate the size of a sound file in KibiBytes |
🛝 Lesson Slideshow
🎓 Lesson Activities
- Activity 1
- Activity 2
- Activity 3
- Lossy Image Sim
- Lossless Image Sim
- Dictionary Sim
📝 Activity 1 – Comparing Lossy and Lossless Image Compression
In OneNote
Take screenshots of yourself using the Lossy Image Sim and Lossless Image Sim.
(1) Explain how both types of compression work
(2) Discuss the differences between each
📝 Activity 2 – Your own Dictionary Compression
(1) Enter a phrase / song lyric / quote into the Dictionary Sim.
(2) Use it to explain how dictionary compression is carried out on text.
(3) Compare it to lossless image compression.
📝 Activity 3 – Advantages of Compression
In OneNote, complete One of these two tasks:
Task A
(1) Why does compression make files quicker to download?
(2) How can compression help someone with a limited mobile data allowance?
(3) Why is compression important for music and video streaming services such as Spotify or YouTube?
(4) What is one disadvantage of using lossy compression?
Task B
“Without compression, many of the online services we use every day would not work as effectively.”
Explain why this statement is true, referring to:
- file size,
- download times,
- streaming,
- storage space.
Lossy Image Compression Simulator
Select a colour and click the pixels to create an image. Increase the compression tolerance to make the computer treat similar colours as identical.
Original Image
Original File Size: 384 bits
Compressed File Size: 0 bits
Saving: 0%
Compressed Data File
Image After Decompression
Lossless Image Compression Simulator
Create an image using the pixels below. The simulator will build an index table, replace each 24-bit colour with a short code and then compress repeated pixels.
Original Image
Unique Colours: 0
Original Size: 384 bits
Compressed Size: 0 bits
Saving: 0%
Index Table
| Pixel Colour | Original 24-bit Binary | Short Code |
|---|
Compressed File Data
Image After Decompression
Dictionary Compression Demonstrator
Enter a sentence and see how dictionary compression replaces repeated words with short binary codes.
