Encoding ISM 4 with BR-Switching: Artifacts in BASOP > 5 kHz

Basic info

• Float reference:
  • Encoder (float): efe53129c9ed87a5067dd0a8fb9dca41db9c4add
  • Decoder (float): efe53129c9ed87a5067dd0a8fb9dca41db9c4add
• Fixed point:
  • Encoder (fixed): ac900052
  • Decoder (fixed): n/a

Bug description

When encoding 4 ISM with bitrate switching, there are a number of artifacts in the BASOP encoder > 5 kHz, especially for channel 1. The floatig-point decoder was used for both bitstreams.

BASOP (channel 1):

Float (channel 1):

Ways to reproduce

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

IVAS_cod -ism 4 ltvISM1.csv ltvISM2.csv ltvISM3.csv ltvISM4.csv ivas-codec/scripts/switchPaths/sw_24k4_256k.bin 48 ltv48_4ISM.wav bit.192

IVAS_dec EXT 48 bit.192 out.wav