Missing signal in BASOP enc-dec path compared to float enc-dec path using selection test MASA at 24.4 kbps with DTX enabled

Basic info

• Float reference:
  • Encoder (float): ecb2d1dd
  • Decoder (float): ecb2d1dd
• Fixed point:
  • Encoder (fixed): fd8bc4cd
  • Decoder (fixed): fd8bc4cd

Bug description

See spectrogram below (left to right: float->float, BASOP->BASOP, diff between float and BASOP)

This can be also verified by listening that there is some speech missing in the BASOP path. Checking interop-combinations, it really seems to be BASOP encoder doing some kind of different decision or something here. As this is EXT output for MASA, the audio outputs are really just the transport channels decoded by core.

Ways to reproduce

Box folder: \Box_EXTERNAL_IVAS_BASOP_VERIFICATION\issues\issue-1307

Use the files provided in Box and these commands to reproduce

IVAS_cod -masa 2 BASOP_Selection_MUSHRA-7ab_s07.met -max_band fb -dtx 24400 48 BASOP_Selection_MUSHRA-7ab_s07.wav test_0309.bs
IVAS_dec EXT 48 test_0309.bs 0309_BASOP_Selection_MUSHRA-7ab_s07.wav_24k4_48-48___EXT.wav