Conditional full volume intro wehn using "Fade At Outro Start" mode

[daschuer]

Feature Description

"Fade At Outro Start" mode is described like:

Start crossfading at the outro start. If the outro is longer than the"
intro, cut off the end of the outro. Use the intro or outro length as"
the crossfade time, whichever is shorter. If no intro or outro are"
marked, use the selected crossfade time."

It defaults to "Skip Silence" mode in case tracks are not annotated.

We have the following use case for anotation:

• Skip long club outro
  • full outro is used if set (or intro if shorter)
• Prevent from transitions into lyrics
  • full intro is used if set (or outro if shorter)

Intro in is only considered as track load point as an alternative to silence end and main cue.

In #11648 we have the aditional requirement to limit the transition with only an outro set even more in case there is an annotaded club outro covering the native outro. Always use of the transition time spin box as a limit is not appropriate, because it is used as a optimal transition time not as a maximum. The workaround implemented in #11830 is to use the transition time in case an outro end is not set. This works as a dynamic length outro with some caveats.

Problem (this issue):
Tracks with a or non short intro, because a vocalist starts at the very beginning.
With a short into, we end up in a probably unwanted short transition:

--------|oo|oooooo---
     ---|ii|v-----	

With no intro-out set (default), we have:

----|oooooo|ooo---
 ---|v-----

Vocalse are not hearable, the issue we need to solve.

With no intro-in set #11830, we have:

----|oooooo|ooo---
     -----i|v-----
  --|tttttt|------		

This kind of works, but has caveeats.

• To track starts in the prerol or with unwanted ambient noise some tracks have
• outro is faded out and whe it is almost silence the new track (vocal) start

The behaviour of "Skip Silence Start Full Volume" would be:

----ooooooo|---
 ---|vvv------ < Full volume
  --|tttttt|------		

We may apply it here, if no intro end is set:

----|ooooo|---
 ---|vvv------ < Full volume

This will fully solve the issue for me, but becomes implicit the new default for all tracks.
What are diadvantages?