Question: In EVS (Enhanced Voice Services) codec, what is the primary purpose of cross-fading between the MDCT based TCX signal and the decoded CELP signal at the output sampling rate?
Option 1: To synchronize the sampling rates of MDCT and CELP signals
Option 2: To avoid discontinuities between the MDCT based TCX signal and the decoded CELP signal
Option 3: To enhance the bandwidth of the output voice signal
Option 4: To reduce the computational complexity of the decoder
Explanation: Cross-fading is utilized to smoothly transition between two different signal processing methods (MDCT based TCX and CELP decoding) at the output sampling rate, avoiding discontinuities by gradually blending the two signals during their overlap period.