HOME WORK
ACTIVITY 1
1.
a)
b)
What is meant by lossless and lossy file compression?
✓ Lossless file compression is a type of file compression in which the original file can be restored
after decompression.
✓ Lossy file compression is a type of file compression where some of the original detail is lost
because certain parts of the original file cannot be retrieved after decompression.
Give an example of a lossless file format and an example of a lossy file format.
✓ Lossless file compression examples : ZIP, Brotli, WebP, and PNG
✓ Lossy file compression examples : MPEG, MP3 and JPEG
2.
a)
b)
Describe how music picked up by a microphone is turned into a digitized music file in a computer.
✓ The microphone picks up music (the analog sound). The analogue to digital converter (ADC) will
transform the analog data into digital data. This indicates it will convert it to binary code. It will
then be saved in the computer.
Explain why it is often necessary to compress stored music files. Describe how the music quality is
essentially retained.
✓ It is sometimes important to compress stored audio files since they would be significantly larger if
they were not compressed and you would not be able to fit as many songs on a Mp3 CD. The music
quality will never be as good as the original, but it will enough for most purposes.
3.
a)
b)
What is meant by run length encoding?
✓ RLE is a lossless compression method that shrinks a file based on identical data. It is only useful
when there is a long sequence of repeating units/bits.
Describe how RLE compresses a file. Give an example in your description.
✓ Run length encoding turns a series of identical values into a code that includes the character and
the number indicating the length of the run. For example, using run length encoding, the letters
"aaabbbcccddd" become a(3)b(3)c(3)d(3).
4.
a)
b)
Describe the differences between bit-map images and vector graphics.
✓ The distinction between bit-map pictures and vector graphics is that bitmaps are composed of
pixels, whereas vector graphs are composed of geometric objects drawn. Bitmaps cannot be resized
without lowering the image quality; however vector pictures may be resized without lowering the
image quality.
A software designer needs to incorporate images into her software to add realism.
Explain what she needs to consider when deciding between using bit-map images and vector graphics in her
software.
✓ When deciding whether to use bit-map images or vector graphics in her software, she should take
into account the fact that vector images are less frequently used when the image needs to be
drawn to scale or is not realistic like a bit map would be. Additionally, bit mat images will perform
better than vector graphics when used to edit photos in photo editing software like Photoshop.
Name: Fikir Zelalem