Higher noise floor observed in SBA fixed-point output

command line:

./IVAS_dec  HOA3 48 bit512 dec.wav
./IVAS_rend -i dec.wav -if HOA3 -o out.wav -of BINAURAL -fs 48

Observations High noise floor issue is observed across all bitrates and is not limited to very high frequency range. Issue is present at even 512 kbps as shown in the spectral analysis plot below. This plot was generated by decoding and rendering the bitstream (selecting 3.7s to EOF) present here: \Box_EXTERNAL_IVAS_BASOP_VERIFICATION\issues\issue-951\bit512

Decoder commit (main branch): 074e9116 Encoder commit: d9fdb374 renderer: d9fdb374

At low bitrates, this is probably fine but at very high bitrates like 512 kbps where we are close to transparency, such issues can be picked up in subjective tests (as seen in the tests conducted by Dolby).