Compression: Crash Course Computer Science

The video tutorial covers the basics of file compression, starting with the need for smaller file sizes for efficient storage and transmission. It explains lossless compression techniques like run-length encoding and dictionary-based methods, including Huffman coding. The tutorial also delves into lossy compression, focusing on perceptual coding for audio and images, and concludes with video compression techniques that utilize temporal redundancy.

Why is compression important for file storage and transmission?

• It reduces file size for easier storage and faster transmission.

• It makes files more complex.

• It changes the file format.

• It increases the file size.

What is the primary goal of run-length encoding?

• To add more metadata to files.

• To change the color of pixels.

• To reduce redundant data by encoding runs of identical values.

• To increase the number of bytes.

How does Huffman coding achieve compression?

• By replacing frequent data blocks with longer codes.

• By using a fixed-length code for all data blocks.

• By adding extra bytes to the data.

• By using a frequency-sorted tree to generate efficient codes.

What is a key characteristic of lossless compression?

• It is not suitable for text files.

• It only works with audio files.

• It allows for perfect reconstruction of the original data.

• It permanently removes some data.

What is perceptual coding in audio compression?

• Encoding all frequencies at the same precision.

• Increasing the file size for better quality.

• Discarding or reducing precision based on human perception.

• Removing all low-frequency sounds.

Why are MP3 files significantly smaller than uncompressed audio files?

• They are stored in a different file format.

• They discard data that is less important to human perception.

• They use lossless compression techniques.

• They add more data to improve quality.

How does JPEG compression reduce file size?

• By converting images to grayscale.

• By enhancing color variations.

• By discarding high-frequency spatial data that humans don't perceive well.

• By increasing the number of pixels.

What is temporal redundancy in video compression?

• The similarity of pixels between video frames.

• The repetition of audio tracks.

• The addition of extra frames.

• The use of high-resolution images.

How do video compression formats handle similar patches between frames?

• By copying patches forward and applying simple effects.

• By converting frames to black and white.

• By discarding all similar patches.

• By retransmitting all pixels in each frame.

What can happen if video compression is too heavy?

• The video becomes longer.

• Hilarious entropy effects occur due to incorrect patch data.

• The video player stops working.

• The video quality improves.