Assert in stereo_dft_generate_comfort_noise_fx of BASOP decoder for float encoder MASA bitstream using DTX and rate switching

Basic info

• Float reference:
  • Encoder (float): de0a9fca
• Fixed point:
  • Decoder (fixed): d68c8f84

Bug description

There is an assert in frame 2417 of BASOP decoder when fed with bitstream from selection material based bitstream of MASA generated with float encoder using DTX and rate switching.

The stack trace:

This issue might be related to #1218 (closed) but happens in different place in the function.

Ways to reproduce

Box folder: ...\Box_EXTERNAL_IVAS_BASOP_VERIFICATION\issues\issue-1220

Use this command line with the bitstream provided in Box

IVAS_dec EXT 48 test_2006.bs 2006_BASOP_Selection_P800-8b_cat2.wav_generic_start_384k_20frames_48-48___EXT.wav

For reference, also inputs are provided in Box and you can use this command line to generate the bitstream with float encoder

IVAS_cod -masa 2 BASOP_Selection_P800-8b_cat2.met -max_band wb -dtx generic_start_384k_20frames.bin 48 BASOP_Selection_P800-8b_cat2.wav test_2006.bs