Question: In EVS (Enhanced Voice Services) codec, as per 3GPP standards, how are the five speech signal classes efficiently encoded for transmission?
Option 1: Using a single bit to select between two primary categories (Voiced/Unvoiced) with additional context.
Option 2: Employing three bits to directly represent each of the five distinct classes.
Option 3: Encoding with only two bits, leveraging contextual information from preceding frames for TRANSITION class differentiation.
Option 4: Not encoding them at all; relying on receiver-side inference based on signal patterns.
Explanation: The correct approach minimizes the number of bits used for encoding while maintaining informational integrity. Option 3 utilizes just two bits for encoding the five classes, exploiting contextual dependency of TRANSITION classes on the preceding frame's classification, thus optimizing bandwidth usage without compromising essential differentiation between signal types.