Dry 2dir MASA encoded incorrectly

Basic info

• Commit SHA: main (e.g., SHA 7c54e695)
• Platform: all

Bug description

With a relatively specific MASA format input where the scene is acoustically dry and there is a single source analysed into the second direction of MASA format, the MASA metadata encoding path can result in wrong preprocessing of metadata. This results in wrong values being encoded and poor quality in the end.

Ways to reproduce

Encode metadata with aforementioned content.