Format conversion of NSF (and presumably other console music archive formats)

[Smannesman]

Although it's possible to play .nsf files in WACUP using the NSF/NSFE Player (in_notyansf.dll ) plugin, it is either not possible, or I'm doing it wrong, to use the Format Converter to convert/export a track from a .nsf file.
It seems to be trying to use the 'access point' the plugin uses to select the track as the source file.

[dro]

Without checking the source code it could be a validity failure or the plug-in doesn't yet support the handling needed or it's one that due to concurrency issues prevents it whilst playback of the format handled by the plug-in (which affects a number of the vgm related input plug-ins due to how they reuse emulator cores unsafely).