Question: In the EVS Codec's DTX/CNG operation, what determines whether the CNG algorithm uses Linear Prediction-domain based coding mode (LP-CNG) or Frequency-domain based coding mode (FD-CNG)?
Option 1: The bit rate of the transmission (e.g., up to 24.4 kbps vs. higher rates)
Option 2: The type of input signal (e.g., SWB/FB vs. other types)
Option 3: The characteristics of the input signal
Option 4: The state of the Signal Activity Detector (SAD) flag
Explanation: According to the EVS Codec's operation, the choice between LP-CNG and FD-CNG modes is based on the input signal's characteristics. This selection ensures high-quality comfort noise reproduction by adapting to the specific traits of the input signal, whether it's more suited for linear prediction-domain or frequency-domain based coding.