Problem

Thanks for the report!
I've been recently contributing on that Plugin over the past weeks. So far I've only tested it with single-voice-per-staff scores that were created directly in MuseScore. I've not started from .kar files yet.

I'll download your files and see where the problem lies in the next week, whether it is the import into MuseScore that'll need fixing or that we're missing functionality in the Export Plugin.

I've briefly checked the Soldier.kar file, and I think your problem is the default import. If you simply open it up as it is now, you'll see that your melody is occasionally put into the 2nd voice. As the Exporter can only export from one voice those notes (and their lyrics) are skipped.

The creator of the .kar file has sometimes made two notes overlap, which is causing this issue. The real fix is looking up those notes that are in the 2nd voice and adjust them into the first voice, guessing what it should've been in the original .kar file.

A possible quickfix might be to fiddle a bit with the import settings. You can try setting the 'Max. voices' for the Electrical Piano ('Мелодия') to be 1 instead of the default 4. This should allow you to export to UltraStar with all lyrics, although I'm not entirely sure which of the overlapping notes we will put into the resulting file.

Please confirm if the export is 'better' for you after changing that setting.

As I understand it now, MuseScore only split into two voices because there are overlapping notes in the source-file. I'm curious to know how other software which uses .kar as input handles this (as a normal person can't sing two notes simultaneously).

Do you use a specific software package to play back the .kar files?

I've also just tested and confirmed that if the Exporter encounters a chord, it will use the lowest note within the chord as melody value.

Hi.
I wrote the UltraStar exporter, and I've just tested your file Soldier.kar.
If I set the Max Voices to 1 for each instrument when importing, then all of the notes and lyrics end up in one voice, and the UltraStar export works just fine.

This is NOT an error in the exporter. It is working as designed.
The problem lies in the way the creating program put the voices in the KAR files, and can either be fixed with the same program that created the KAR or you can force MuseScore to "flatten" all voices for one instrument into a single voice.

Support for voice selection when exporting to UltraStar is intentional and will be kept.
The correct way to deal with this problem is to either correct the KAR or to use the options available when importing into MuseScore.

If you would like to have an option implemented to flatten voices on export, please open a new issue as a feature request, and reference this issue as well as posting your sample KAR files again.

I don't know why you couldn't get Soldier.kar to work correctly, but MuseScore can import it correctly - see the attached Soldier.mscz and Soldier_Electric_Piano,_Мелодия.txt (the mp3 file is too large to attach, but you should be able to generate the mp3 and verify it works with the attached txt file.)

I opened Soldier.kar then set the max voices to 1 for each instrument, then set the character encoding to ANSI1251, the clicked apply. I then added a title and composer and exported.