What’s the significance of 0? Is it just playing a sound on the key press?
Is it something more nuanced like playing the sound on the press without waiting for the next frame to tick?
Is it something more nuanced like playing the sound on the press without waiting for the next frame to tick?
Harmonix keysounding works a bit differently. If you press the strum bar with the wrong frets pressed, it plays a generic error noise and cuts out the guitar/bass/drum portion of the song until you play another note correctly. It's arguably easier to chart since you just need separate audio tracks for each instrument, but the main reason this was done was to avoid a second Konami lawsuit.
[0]: https://www.gamedeveloper.com/pc/exclusive-exploring-i-guita...
A few years prior they did NOT have that kind of money. The history of Guitar Hero is that RedOctane was involved in manufacturing third-party softpads for people importing DDR home games from Japan. They saw GuitarFreaks in a Japanese arcade and contracted Harmonix to build a game around a guitar controller. The game they made, Guitar Hero, was startlingly low budget, with loads of covers[1]. Nobody had any money to license patents.
In terms of the cost of actually keysounding a track, relative to Harmonix's patent workaround... I'm not entirely sure. It could go either way. I could imagine some automated/cheap way to do 'good enough' keysounding could have been made, especially since they're already charting out note data.
[0] For example, I said Harmonix was involved in the ITG lawsuit but it was actually RedOctane who published ITG. I'd edit my comment but I can't find the edit link.
[1] Which arguably worked in the game's favor - I do remember people noting that the all-masters-all-the-time approach of Guitar Hero World Tour made playing vocals feel strange.
You know those YouTube videos of people playing whole songs on a DAW control surface? beatmania is literally just that with a scrolling note chart and a judgment of your performance, except it came out in like 1997.