What does the number for scroll speed mean?

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Topic Starter
Erkfir
Does anyone have any answers as to what the scroll speed number actually refers to (e.g. I use a fixed scroll speed of 30.... but 30... what?).

I can't seem to find any answers anywhere about this.

Based on what I've observed, (I'm pretty sure) the rate of how fast the notes fall depends on your hit position placement as well as whatever scroll speed you've set.

So I was just wondering if anyone happened to know the magic formula to calculate how fast the notes actually move at a certain scroll speed and hitpos (in pixels per millisecond or a similar unit).
Full Tablet
The hitposition only changes the position notes have to be when pressed (assuming top-to-bottom scroll direction, a hitposition of 240 means notes have to be pressed when the bottom pixel row of the notes touch the middle of the screen, with a value of 480 notes have to be pressed when they touch the bottom of the game window).

The speed notes fall only depends on the scroll speed, the time between the bottom of the notes appearing at the top of the window and the bottom of the notes touching the bottom of the window is about 13720/scroll_speed milliseconds, in the fixed scroll speed scale.

Numbers are from memory (I measured them years ago), so they might be slightly off.
Topic Starter
Erkfir
Ahh yeah my mistake on the hit position thing. I mixed it up since for the project I'm working on, I needed to know the hit position so I knew the total distance a note would have to travel before it reaches the hit position (but I forgot hit position isn't a factor for the actual note speed in mania).

Actually, I did read your post on the same topic before when I was looking around but my (very rough) observed values didn't match up at all to yours. I just did a big dumb and divided two values the wrong way around before and my values actually do match up with your formula ( I was doing speed = time / distance instead of speed = distance / time )

I still do wonder how osu gets it's scroll value without the use of the magic number of 13720 haha.
abraker

Full Tablet wrote:

The speed notes fall only depends on the scroll speed, the time between the bottom of the notes appearing at the top of the window and the bottom of the notes touching the bottom of the window is about 13720/scroll_speed milliseconds, in the fixed scroll speed scale.
Actually, width of stage seems to affect scroll speed too. I don't really know what's the formula for that tho. Some players using default skin are impressed when I tell them I use 33 fixed speed while they use 21 or 22 because my column sizes are 85 but default skin is 30.
Topic Starter
Erkfir
Actually I wouldn't think that column width would affect how fast the notes fall since you could have different columns of varying column width but all the notes would still fall at the same rate. It probably just seems faster when the columns are narrower even though its the same speed.
Full Tablet

abraker wrote:

Full Tablet wrote:

The speed notes fall only depends on the scroll speed, the time between the bottom of the notes appearing at the top of the window and the bottom of the notes touching the bottom of the window is about 13720/scroll_speed milliseconds, in the fixed scroll speed scale.
Actually, width of stage seems to affect scroll speed too. I don't really know what's the formula for that tho. Some players using default skin are impressed when I tell them I use 33 fixed speed while they use 21 or 22 because my column sizes are 85 but default skin is 30.
When I measured it, I tried varying the width of the columns, but I didn't measure any difference in the time it took each row of pixels of the notes to cross the screen.

Using very tall notes increases the time you have to perceive the notes slightly, since you could see the bottom of the notes appear on the screen but then pay attention to the center of the notes while they are going down. I think this applies to players that use circle or arrow notes that align with the receptors in the middle rather than the bottom.

I think it is mostly a matter of perception. Based on my perception (things that are small seem to move slower), my hypothesis before measuring was that higher column size made the scroll speed higher (which is the opposite of what those players that use the default skin seem to perceive).
Stickman92
it's just perception, try comparing 2 extreme cases. Column width of 10 & 100. The scroll speed doesn't change. Only the note size.

E.G. Its an analogy to ColumnWidth
a cockroach sprinting at 1m/s is ridiculously fast for its size. (ColumnWidth 10)
a human walking at 1m/s is slow for its size. (ColumnWidth 10 000)
regardless, they both still moving at 1m/s (scroll speed)
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