BASOP encoder OSBA: audible differences and spectral holes in the background noise

Basic info

• Float reference:
  • Encoder (float): f7a0e207 (ivas-float-update)
  • Decoder (float): f7a0e207 (ivas-float-update)
• Fixed point:
  • Encoder (fixed): 0ca1f14f (main)

Bug description

In the SBA part of the external output, the timbre of at least the W,Y, and X channels sounds different. A HF noise component that is present with the floating point encoder is missing with the fx encoder.

In the spectrogram, holes are visible upon very close inspection. Left is the float, right the fixed-point encoder.

Ways to reproduce

Box folder: ...\Box_EXTERNAL_IVAS_BASOP_VERIFICATION\issues\issue-1238

./IVAS_cod_fx -ism_sba 3 3 obj1.csv obj21.csv obj3.csv -max_band SWB 256000 48 input.wav bit_fx
./IVAS_cod -ism_sba 3 3 obj1.csv obj21.csv obj3.csv -max_band SWB 256000 48 input.wav bit
./IVAS_dec EXT 48 bit[_fx] dec[_fx].wav