ParamMC: ILD limiter in the encoder not save against coming from silence without a transient detected

Basic info

• Commit SHA: main
• Platform: all

Bug description

In the ParamMC a limiting is applied to the ILDs when the differences between frames would be too large. It is done only on non-transient frames. When having a small silent portion with a low energy portion following (as happens with the processing for selection testing where the items are concatenated to themselves before encoding), the transient detector does not detect a transient frame but the energy limitation is very large and leads to audible and visible artifacts.

Ways to reproduce

E.g. with FhG_5_1_Ambience_voice_01.wav from the 5.1 selection test material, coded with 64kbps, the repetition of the coded item shows missing energies for a number of frames in some bands at the beginning.