Symbol Codes and Decoding Concepts

The video tutorial discusses symbol codes, focusing on uniquely decodable codes and their importance in lossless compression. It explains the mathematical definition of uniquely decodable codes and explores desirable properties such as compression efficiency, speed, and simplicity. The tutorial provides examples of encoding and decoding processes, highlighting the differences between codes A and B. It concludes with an introduction to prefix codes, emphasizing their instantaneous decoding capability.

What is a key characteristic of symbol codes?

• They can have variable-length code words.

• They are always uniquely decodable.

• They are only used for error correction.

• They have fixed-length code words.

What does it mean for a code to be uniquely decodable?

• Each sequence of code words corresponds to a unique sequence of source symbols.

• Different sequences of source symbols generate the same code sequence.

• Each code word can represent multiple source symbols.

• The code words are all the same length.

Why is unique decodability important in lossless compression?

• It ensures that the original data can be perfectly reconstructed.

• It allows for faster encoding.

• It reduces the size of the code words.

• It simplifies the encoding process.

Which of the following is NOT a desirable property of a code?

• Good compression efficiency

• High computational complexity

• Fast encoding and decoding

• Simplicity in implementation

What is a common method for encoding a sequence of symbols?

• Encoding all symbols as zeros

• Randomly assigning code words to symbols

• Using a fixed-length code for each symbol

• Using a lookup table to find the corresponding code word

In the decoding example, what was the first step in determining the source symbol?

• Checking the length of the code word

• Guessing based on previous symbols

• Identifying the first symbol in the code sequence

• Comparing the code word to a predefined list

Why was code A easier to decode than code B in the example?

• Code A required less lookahead to determine the source symbol.

• Code B had more symbols.

• Code A had shorter code words.

• Code B was not uniquely decodable.

What is a prefix code?

• A code where no code word is a prefix of another

• A code with fixed-length code words

• A code used only for error correction

• A code that is not uniquely decodable