8525 AQA GCSE 3.3.8 Huffman & RLE

Which type of compression ensures that all of the data is kept?

• Lossless

• Lossy

Lossy compression removes data that isn't needed...

• True

• False

The correct encoding of the letter C in this tree is...

• 11

• 10

• 01

• 00

Huffman trees use the _______________ of each character to work out their encoding.

• Frequency

• Order in ASCII

• Number value

How do you move through a Huffman tree?

• 0 = right 1= left

• 1 = left 2 = right

• 0 = left 1 = right

• 0 = middle 1 = back

How do you calculate the number of bits of a body of text in ASCII?

• Number of characters * 7

• Number of characters (including spaces) *7

• bits in Huffman * 7

• bits in Huffman / 7

Use this Huffman tree to encode "ban"

• 111001

• 100011

• 010

• 143

When is Run Length Encoding used?

• When we want to compress patterns of data
• When we want to decompress patterns of data
• When we want to encode running videos

Data compression is important for websites because:

• Your webpage will load faster
• Compressed images look better

The first line of this image in RLE would be...

• 8W, 1Bl, 20B, 1W

• 10B, 4Y, 17R, 2G

• 2G, 10P, 17Y, 2Bl