Task: Learning Journal

Open your Learning Journal by clicking on the image below

Good notes will help you organise and process data and information

Run Length Encoding

data having the same value and are stored using requency/data pairs.

• This repeating string, called a run, is encoded into two bytes.
• The first byte represents the number of characters in the run and the second gives the character.
• For example, let's look at the following string:
  • aaabbbbbbccccccccc
  • This string length is 18 bytes.
  • Using run length encoding, this could be compressed to:
  • 3a6b9c
  • This string has been reduced to 6 bytes using RLE.

• RLE provides very good compression ratios where there are long runs of one particular value like the following 1-bit black and white image:

• When represented by a letter, the size of the file is 64 bytes: 8 bytes per line.
• Using Run Length Encoding will reduce the file size of this one character from 64 bytes to 48 bytes.

Task:

Open your student workbook at page 64 Read through the notes then complete the following tasks in your book.

1. Task 33
2. Task 34

When you are finished screenshot your answer into your Learning Journal

Below are some notes published by AQA you might wat to read for further infromation about Run Length Encoding