Compression methods

What is the purpose of Run-length Encoding (RLE)?

To compress sequences of repeated data.

How does RLE compress data?

It replaces consecutive identical elements with a single value and a count.

What is the best use case for RLE?

Effective for data with long runs of repeated values, such as simple graphics or monochrome images.

What is a primary disadvantage of Run-length Encoding?

Ineffective for data without many repeated sequences.

What is the purpose of Huffman Encoding?

To provide efficient, variable-length coding based on frequency of data elements.

How does Huffman Encoding create its coding system?

By creating a binary tree where more frequent elements have shorter codes.

What is the best use case for Huffman Encoding?

General-purpose text and data compression.

What are the advantages of Huffman Encoding?

Optimal for prefix codes; no wasted bits.

What are the disadvantages of Huffman Encoding?

Requires two passes over data (one to build the tree, one to encode).

What is the purpose of Delta Encoding?

To store differences between sequential data points rather than absolute values.

How does Delta Encoding work?

It records the difference between each element and its predecessor.

What is the best use case for Delta Encoding?

Time series data or any data with small changes between consecutive elements.

What is an advantage of Delta Encoding?

Effective when changes between data points are small.

What is a disadvantage of Delta Encoding?

Less effective if data changes drastically.

What does LZW Compression use to encode data?

A dictionary-based approach to encode sequences of data.

How does LZW Compression work?

It builds a dictionary of data sequences and replaces repeated sequences with references to the dictionary.

What is the best use case for LZW Compression?

Text files and images, such as GIF format.

What is an advantage of LZW Compression?

No need to transmit the dictionary; efficient for repetitive data.

What is a disadvantage of LZW Compression?

Can be less effective on small datasets or highly varied data.

What type of compression does JPEG use?

Lossy compression.

What is unique about JPEG's compression methods compared to RLE, Huffman, Delta, and LZW?

JPEG can discard some image data permanently, while the others are lossless.

What transformation does JPEG use in its compression process?

Discrete Cosine Transform (DCT).

What is the purpose of quantization in JPEG compression?

To reduce the precision of less visually significant frequencies.

How does JPEG improve compression efficiency?

By converting images from RGB to YCbCr color space, separating luminance from chrominance.

What coding method does JPEG often utilize as part of its compression process?

Huffman encoding.

How does JPEG process images to compress them?

In 8x8 pixel blocks.

What is a potential drawback of JPEG's block-based processing?

Can lead to blockiness or artifacts at high compression levels.

MPEG Standard

A set of video compression standards that includes I-Frames (intraframe), P-Frames (predicted frames), and B-Frames (bidirectional frames), which are combined into a Group of Pictures (GOP) for video compression.

I-Frame

Intra Frames (I-Frames) are coded using information only from the picture itself, providing potential random access points into the compressed video.

P-Frame

Predicted Frames (P-Frames) are coded with respect to the nearest previous I- or P-frames, using motion compensation for improved compression.

B-Frame

Bidirectional Frames (B-Frames) use both past and future pictures as reference, offering the most compression but requiring the most computation.

Group of Pictures (GOP)

A GOP is formed by combining I-Frames, P-Frames, and B-Frames to efficiently encode video sequences.

Motion Compensation

Motion compensation predicts a frame's data based on a reference image, using methods like macro-block matching to encode differences.

Perceptual Audio Coding

Techniques like MPEG Layer-3 exploit human hearing properties to reduce audio file size with minimal perceptible quality loss.

Streaming Multimedia

Streaming breaks data into packets so users can begin playing media without downloading the entire file, leveraging existing