Clarify overwriting of delayed DFT stereo signal

Basic info

• Float reference:
  • Encoder (float): ivas-codec main 08cd86420da38cb0eb176218999e5fca74ed4584
  • Decoder (float):
• Fixed point:
  • Encoder (fixed):
  • Decoder (fixed):

Bug description

A delayed signal part of DFT stereo is overwritten. Either it is not required or the overwriting action should be skipped for DFT stereo.

In the file lib_enc/swb_bwe_enc.c:

• At either line 551 or 577 an amount of Sample_Delay_HP samples are copied to new_input_hp, both cases for st->element_mode = IVAS_CPE_DFT
• At line 586 these samples are overwritten without any condition.

Related float issue: ivas-codec-pc/ivas-codec#1546

Ways to reproduce

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