Decoder crash for low bitrate OSBA in ivas_spar_dec_upmixer_sf_fx()

Basic info

• Float reference:
  • Encoder (float): b63c033f
  • Decoder (float):
• Fixed point:
  • Encoder (fixed):
  • Decoder (fixed): a584f6ee

Bug description

The fixed point decoder crashes with an assert:

Assertion failed: (0), function L_add, file basop32.c, line 1661.

Ways to reproduce

Box folder: ...\Box_EXTERNAL_IVAS_BASOP_VERIFICATION\issues\issue-1465

./IVAS_cod_flt_ref -ism_sba 4 1 ISM4SBA1_4-av-compressed-idential_rot.{0,1,2,3}.csv -max_band FB 32000 48 ISM4SBA1_4-av-compressed-idential_rot_48.10dB.wav bit
./IVAS_dec_fx ext 48 bit out.wav

This crash also occurs for the following configurations:

• for the +10dB version of the input vector at 13.2, 16.4, 24.4 and 32 kbps, decoding to ext/binaural/binaural_room_ir/binaural_room_reverb at 32 or 48 kHz
• for the 0dB version of the input vector at 16.4 kbps decoding to binaural/binaural_room_ir/binaural_room_reverb with either FER@48 kHz or JBM at 32 or 48 kHz