Run length encoding and dictionary coding for lossless compression

What is Run Length Encoding (RLE)?

A lossless compression technique that stores data as a value and a count of consecutive occurrences.

How does RLE reduce file size?

By replacing repeated values with a single value and a frequency count, reducing redundancy.

When is RLE most effective?

When data contains long runs of repeated values.

When is RLE inefficient?

When there is little or no repetition, as it may increase file size.

What is dictionary coding?

A lossless compression method where repeated patterns are stored in a dictionary and replaced with references (indexes).

How does dictionary coding reduce file size?

By replacing repeated patterns with shorter references, reducing the amount of data stored.

Why is dictionary coding effective for text?

Because text often contains repeated words or patterns, which can be stored once and reused

Explain how Run Length Encoding compresses data

Run Length Encoding compresses data by identifying sequences of repeated values. Instead of storing each value individually, it stores the value along with the number of times it occurs consecutively. This reduces the amount of data when there are long runs of repeated values.

Explain how dictionary coding compresses data.

Dictionary coding compresses data by storing repeated patterns in a dictionary. Each pattern is assigned a reference, such as an index number. Instead of repeating the full pattern, the compressed data stores the reference, reducing the total size of the data.