Question: In a transition frame from CELP to HQ MDCT coding for Enhanced Voice Services (EVS), how is CELP coding utilized to minimize its impact on the HQ MDCT bit budget?
Option 1: CELP coding is applied to the entire frame, with all parameters fully updated.
Option 2: CELP coding is restricted to the first half of the frame, updating all CELP parameters.
Option 3: CELP coding covers the whole frame but only updates a subset of its parameters.
Option 4: CELP coding is constrained to the first subframe, coding a subset of parameters, and reusing LPC coefficients from the previous frame.
Explanation: This option correctly describes how CELP coding is modified during a transition to HQ MDCT to minimize its bit budget impact. By limiting CELP to the first subframe, only coding a subset of its parameters, and reusing LPC coefficients from the previous frame, the approach efficiently manages the bit allocation between the two coding modes in the transition frame, ensuring optimal performance for Enhanced Voice Services (EVS).