BASOP encoder: large difference signal in SBA with LTV at 48 kbps

Basic info

• Float reference:
  • Encoder (float):f7a0e207ee3622eb02c14e84586485b5795d912f
  • Decoder (float):f7a0e207ee3622eb02c14e84586485b5795d912f
• Fixed point:
  • Encoder (fixed):339e804c

Bug description

There is a large difference signal between BASOP and float in the W and other channels in the decoded HOA3 output. This becomes audible as missing HF content and less crisp atacks in BASOP, particularly around 1:38, where shakers appear. Other channels are potentially affected too. The difference seems to occur exactly at the onset of the shakers.

This is the spectrogram of the difference signal between the W channels obtained with the two encoders.

Ways to reproduce

The HOA3 LTV used as input.

BASOP

./IVAS_cod -sba 3 48000 48 ../ivas-pc-testfiles/ltv48_HOA3.wav bit_fx 
../ivas-codec/ivas-float-update/IVAS_dec HOA3 bit_fx dec_fx.wav

float

../ivas-codec/ivas-float-update/IVAS_cod -sba 3 48000 48 ../ivas-pc-testfiles/ltv48_HOA3.wav bit
../ivas-codec/ivas-float-update/IVAS_dec HOA3 bit dec.wav

The issue can also be seem with 96 kbps and possibly other bitrates.