[Enhancement] Expanded "Extra Soundtrack" Feature

[Chalking]

I think it's great that Woof allows for the use of the extras.wad file from the recent Doom I+II rerelease for on the fly switching between MIDI, Remixed, and recordings of the sc55 music of Doom.

It would be really nice if this feature could be expanded in 2 ways.

One would be the addition of a "Custom" setting, which could automatically load music from a file maybe with the name "custom", like custom.wad or custom.zip.
I personally like to use fan made FLAC recordings of the Doom soundtracks on a Roland SC55, which offers higher quality than that found in extras.wad, but I'd like to be able to switch back and forth between it and the MIDI and remix soundtracks. Loading it from -file just overwrites all of the Extra Soundtrack options.
It would also be nice for the purpose of using other soundtracks as well, such as the Doom 3DO soundtrack, or the custom fan made Plutonia soundtrack, or any other custom soundtracks the user may want to use, without having to sacrifice the ability to switch between the other soundtrack options in the menu.
To that end it might be nice to just have Woof recognize a folder named "custom soundtrack" or something like that, and then recognize any wad or zip files within that folder, and populate them as Extra Soundtrack options. I'm not sure how viable it would be to implement it that way though.

The other way it would be nice to have this feature expanded would be to recognize the digital soundtracks from Sigil and have them load when selecting the Remix option.
I'm not sure if maybe that's already a feature and I'm just doing something wrong, but having SIGIL_SHREDS.wad in my Woof folder doesn't have the soundtrack load unless I load it through -file. I feel like it would make sense to have it load through this Extra Soundtrack option.

Thank you so much for your consideration and continued work on such a great port! :)

[fabiangreffrath]

This feature works by providing a TRAKINFO lump (which extras.wad already contains) that provides pointers to additional music tracks by lump name based on the SHA-1 checksum of the original MIDI track lump which they are supposed to replace.

See for example:
https://www.doomworld.com/forum/topic/152784-kex-doom-ignoring-custom-trakinfo-definitions/

[Chalking]

Thank you for the explanation, I checked out the link you provided and I think I mostly understand how this works.

So based on your explanation, whatever wad the user loads would have to include a TRAKINFO lump in order to be included in the Extra Soundtrack option.
I'd still like to ask if there is any way for the feature to be expanded to support wads that don't have one included to be loaded using the Extra Soundtrack option? For example to somehow autogenerate the TRAKINFO if the user designates that it's a soundtrack mod somehow, like placing the wad in a Extra Soundtrack folder?

I'm looking at extras.wad in Slade3, as well as sigil.wad and sigil_shreds.wad, and I understand how it would be necessary for a TRAKINFO lump to designate the variations of H_E1M1 and 0_E1M1 in extras.wad for example.
But in the case of sigil_shreds, there are no variations, only one version of each song which correlates to the original Midi versions, i.e. D_E5M1 in sigil.wad = D_E5M1 in sigil_shreds.wad. Which is how I assume it's able to load it when loaded through -file.

In this case though, would it be possible to only load the replacements when placed in an Extra Soundtrack folder, and then selected in the Extra Soundtrack option in the menu (an item in the Extra Soundtrack options could just be populated with the name of the wad filename)?

I personally think it would be a simpler solution for most users than having to create a custom pwad that includes TRAKINFO for every single music replacement wad one might want to use.
A user might be savvy enough to be able to load all the Doom wads they want but might not be able to create a TRAKINFO lump, much less WANT to for every single music mod they want to use.
With the information you've provided, I probably could at this point for sigil_shreds and any others, but other users may not be able to, and even if someone like me were to create a pwad with a TRAKINFO lump and distribute it on a modding forum, I doubt most users would even know that it's necessary or know what they're looking for, like how I didn't before your explanation.

I just think it would be nice to somehow make on-the-fly soundtrack swapping simpler and more intuitive for end users.

Hopefully some of my above suggestions are worth anything, but thank you very much for reading regardless. :)