Question: What is the primary reason for adding a constant value (1) inside the log2 function when processing input energies in EVS (Enhanced Voice Services) codec?
Option 1: To ensure the converted energy values remain positive, aligning with the statistical model used by the noise estimator.
Option 2: To enhance the dynamic range of the input signals for better voice quality.
Option 3: To simplify the quantization process by reducing the number of bits required.
Option 4: To increase the processing speed on fixed-point processors by leveraging the 'norm' function.
Explanation: The addition of a constant (1) inside the log2 function is crucial to maintain positivity of the converted energy values. This is vital because the noise estimation relies on a statistical model that assumes positive energy values. Negative values would disrupt this model, potentially leading to unforeseen behavior in noise estimation and subsequently affecting voice service quality.