Overflow in W_extract_l

Basic info

• Fixed point: 7847d456

Bug description

An overflow has been detected when extracting the lower part of a 64bits word. This is certainly not a desirable. This happen when using the stereo 2, command line (thus the TD part of the stereo) and the down-mixing of that sub-mode is still problematic. So I suggest, to review this issues once #1136 (closed) is solved to check if it is still a problem or not

Ways to reproduce

IVAS_cod -STEREO 2 16400 48.\ivas-codec\scripts\testv\stvST48c.wav bit16400