Harmonisation of bitstream handling for EVS and IVAS encoder

Basic info

• Float reference:
  • Encoder (float):
  • Decoder (float):
• Fixed point:
  • Encoder (fixed): c17cc4c5
  • Decoder (fixed):

Bug description

In the current basop development, the bitstream is handled differently between EVS and IVAS, which makes it none straightforward to reuse EVS function inside IVAS code.

in the branch voiceage/bitstream (!1339 (merged) ), I added 2 activated switches :

• HARM_PUSH_BIT : harmonise bitstream manipulation
• HARM_ENC_INIT : Harmonise part of the initialisation, more work could be required

and 1 non active switch :

• HARM_SCE_INIT : aims was to harmonise SCE initialisation between IVAS and EVS, but it is not completed

@malenovsky, @venkateshsa , everything is bit exact so far. More work could be done to remove one of the bitstream(_fx).c file, because so far, functions are sometimes in one file, sometimes in the other. But that can be done in a second step.

@venkateshsa, if you can merge it into the main when you feel the time is right, it would make the testing and consolidation of the encoder much more easy