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WorksheetsCrash Course Computer Science #21 - Compression
Total questions: 17
Worksheet time: 12mins
How do files get squeezed into a smaller size?
reduction
compression
shrinking
constrict
What number represents full intensity for colors in a pixel?
(a)
One way to compress data is to reduce repeated or redundant information. The most straightforward way is called...
run-length encoding
repeated-line encoding
reverse-logic encoding
retroactive-line encoding
After compression, how many bytes is our PacMan image?
(a)
A compression (a) that has this characteristic is called (b) compression, because we don't lose anything. The (c) data is identical to the original before compression, bit for bit.
What's the most common color block in our example?
white-yellow
black-yellow
yellow-yellow
white-white
How does the Huffman tree organize data?
lower frequencies at the bottom
lower frequencies at the top
What is the Huffman code for white-white?
(a)
Using the Huffman tree to compress Pac Man, we used only __ - significantly less than the original 48 bytes!
14 bits
14 bytes
24 bits
24 bytes
Both (a) encoding and (b) coders are (c) compression techniques. No information is lost; when you (d) , you get the original file.
Compression that removes unnecessary or less important information is called __ compression techniques.
lossy
lousy
lofty
lengthy
Lossy compression is willing to lose quality with...
vocal ranges
bass range
ultrasonic range
all of these
How much smaller are .MP3 files versus .WAV or .FLAC files?
2x
5x
10x
50x
Which image file type uses lossy compression to simplify 8x8 pixel blocks for compression?
.RAW
.JPEG
.GIF
.PNG
In video, a lot of pixels remain the same, such as in a background. This is called
temporal redundancy
background compression
peripheral blur
same-edge pixel repeation
The fanciest video compression formats find similar patches between frames. They can copy them forward and apply simple effects, such as
shift
rotation
lighten
darken
MPEG-4 videos are often __ smaller than the original, uncompressed file.
10-50x
20-200x
50-300x
45-125x
