Unit 2: 5 Lossy vs Lossless

Lossy Comprension

• All the data is lost, but the image is very clear.

• Eliminates the data which is not noticeable.

• Eliminates the data which IS noticeable.

• Does not eliminate the data which is NOT noticeable.

Lossless Compression

• All the data is lost, but the image is very clear.

• Eliminates the data which is not noticeable.

• Eliminates the data which IS noticeable.

• Does not eliminate the data which is NOT noticeable.

An image has 10,000 colors, but then reduces the colors to only 1,000. What type of compression is this?

• Lossy Compression

• Einstein Compression

• Lossless Compression

• No Compression

What type of compression is normally used with text data?

• Lossy Compression

• No Compression

• Transform Coding Compression

• Lossless Compression

What types of data use lossy compression effectively?

• Video

• Graphic Pictures

• Audio

• Text

Which is true of either lossy or lossless compression techniques?

• Lossless compression throws away unimportant details that a human being will likely be unable to detect.

• Lossy compression techniques are no longer commonly used.

• Lossless compression is fully reversible, meaning the original file can be recreated bit for bit.

• Lossy compression is only possible on files that are at least one gigabyte in size before compression.

Which is true of either lossy or lossless compression techniques?

• Lossy compression is best suited for situations where some loss of detail is tolerable, especially if it will not be detectable by a human

• Both lossy and lossless compression techniques will result in some information being lost from the original file.

• Neither lossy nor lossless compression can actually reduce the number of bits needed to represent a file.

• Lossless compression is only used in situations where lossy compression techniques can't be used.

Consider these two files:

A 1-minute video of a cat pouncing ferociously on a twisty tie. A download of "The Lion King", a 1.5-hour animated film

Is it possible for "The Lion King" to have a smaller file size than the shorter cat video?

• Yes, as long as "The Lion King" video is compressed with an open non-patented standard.

• Yes, If "The Lion King" video is compressed with a lossy compression algorithm.

• No, "The Lion King" video will always take up more space than the 1-minute cat video.

Tom is recording an album of songs using a digital audio recording application, and he wants the recordings to be high quality.

Which advice will best help him to achieve his goal?

• He should save the audio using a lossless compression algorithm.

• He should save the audio using a lossy compression algorithm at high quality setting.

• He should save the file on a USB drive, not his internal hard drive.

• He should add metadata to the file with the title, artist, and genre.

A still screenshot of the Apple homepage A 5-second video of the same Apple homepage

Is it possible for the video to take up less space than the image?

• Yes, but only if there is no movement in the video recording of the Apple home page.

• Yes, but only if the video is saved in the Quicktime .mov file format.

• No, the video will always take up more space than the image.

• Yes, if the video is compressed with a lossy compression algorithm.