Energy overshoot in BWE ISM 1 in 13.2 kbps

Basic info

• Float reference:
  • Encoder (float): d4fe090c (20250826_branch_release_characterization_testing_ivas-float-update)
  • Decoder (float): d4fe090c
• Fixed point:
  • Decoder (fixed): 7d39c224 (20250826_branch_release_characterization_testing_main)

Bug description

Energy overshoot in BWE for ISM1 causing a glitch, 13.2 kbps, FL enc->FX dec. It does not occur FL enc->FL dec or FX enc->FX dec. It does occur at other bitrates for different items. It could be related to a similar issue reported on OMASA: #2000 And an older (now closed) issue on "High energy in high frequency of speech onset": #995 (closed)

FL enc->FL dec

FL enc->FX dec

Ways to reproduce

Box folder: ...\_EXTERNAL_IVAS_CHAR_MC\Issues\basop-issue-2001

IVAS_cod_flt_ref.exe -dtx -ism 1 cp11a2s07.wav.0.csv 13200 48 cp11a2s07.wav bit
eid-xor.exe -fer -vbr -bs g192 -ep g192 bit error_pattern.192 biterror
IVAS_dec_flt_ref.exe BINAURAL 48 biterror out_fl.wav

IVAS_dec_fx.exe BINAURAL 48 biterror out_fl_fx.wav