Observation on encoder signal precision for pre-processing

Basic info

• Fixed point:
  • Encoder (fixed): 54ea1f0f

Description

The signal below have been extracted for the EVS at 13.2 kbps and ISM-1 at 13.2 kbps for 16kHz input signal.

The first 2 figures are showing the signals entering the preproc module and the 3 other figures are showing the signal after resampling to 12.8kHz

Basically IVAS noise floor at the pre-processing stage is higher than EVS which can certainly affect some decision computed in preproc (thinking about #1276 (closed) and #1272 (closed)).

For all figures, from top to bottom:

• input (missing on the last figure)
• float signal
• EVS fix-point
• IVAS fix-point