Severe distortion in signal decoded from 13.2kbps bitstream encoded by fixed point encoder with ambisonics signals at 16kHz and -26LKFS

Basic info

• Float reference:
  • Encoder (float):00ba8bcd
  • Decoder (float):00ba8bcd
• Fixed point:
  • Encoder (fixed):24f29d12

Bug description

Bitrate: 13.2kbps

Signal level: -26LKFS

Input format: HOA1/2/3

Sample rate: 16kHz

Observations:

• When rendered to binaural, severe distortion was heard in the signal decoded from bitstream produced by the fixed point encoder.

• Obvious waveform and spectral differences were observed between signals decoded from fixed-point and floating-point encoded bitstreams, as illustrated by the following figure

  

Ways to reproduce

Box folder: ...\Box_EXTERNAL_IVAS_BASOP_VERIFICATION\issues\issue-1197

Command lines: see cmds.txt in the above Box folder