External renderer BINAURAL_ROOM_REVERB format output level too high compared to internal rendering output

Bug description

This issue reflects the observations reported by Bytedance during SA4#127-e meeting in their contribution S4-240573, stating that:

When using an external renderer to render HOA, the loudness is + 3dB higher than when using decoder-inner_renderer, and the rendering effect is significantly different.

Ways to reproduce

Use the Python script IvasIntExtRendReverb.py provided. The steps include:

• IVAS encoding using a number of bitrates,
• IVAS decoding and (internal) binaural rendering with and without room acoustics,
• IVAS decoding pass-through, to be used as input for external renderer,
• IVAS rendering (external) with and without room acoustics.

Please note, that once using a reverb configuration with minimum T60 and zero DSR values rend_config_dry.cfg or deactivating the reverb function calls in the code, the difference between the internal and external rendering output remains.