FFR Frame Question

[TheSaxRunner05]

So FFR runs in 30 FPS, so from what I understand, charts go through a conversion process which places every note on a frame. This means that most songs have notes that are fractions of a second late or early, correct? Also, this means songs with a constant BPM as a multiple of 30 can potentially be perfectly synced?

As a side note, didn't someone a few years ago make some data-mining lists in a thread with sortings of the song list by length, BPM, NPS, etc? If someone could find that I'd be appreciative.

[One Winged Angel]

Yes to the first part, no to the second.

Easiest way to understand bpm to frame conversion is to think of 16th streams. At 30 fps, there's 1800 frames in a second. Divide by 4 to get the bpm where all 16th notes are always exactly 1 frame apart from each other, 450 bpm. Halve that to get the bpm where 16ths are always 2 frames apart, 225 bpm. Any bpm between those two ranges will result in 16th streams containing some mess of 1 and 2 frame gaps.

If you want to find other bpms that convert perfectly, take 450 and divide it by the 16th frame gap you're looking for to determine the bpm needed.

450/3 = 150 bpm for all 3 frame gaps
450/4 = 112.5 bpm for all 4 frame gaps (makes sense, half of 225)
450/5 = 90 bpm for all 5 frame gaps

etc.

You can also calculate the bpms where streams are perfectly split between two types of frame gaps (as in they alternate between X and X+1 gaps indefinitely)

450/1.5 = 300 bpm for alternating 1 and 2 frame gaps
450/2.5 = 180 bpm for alternating 2 and 3 frame gaps

etc.

So any bpm from 301-449 will contain more 1 frame gaps than 2 frame gaps, and anything from 226-299 will contain more 2 than 1.

[noname219]

Originally Posted by TheSaxRunner05

As a side note, didn't someone a few years ago make some data-mining lists in a thread with sortings of the song list by length, BPM, NPS, etc? If someone could find that I'd be appreciative.

You're probably thinking about this thread by qqwref. No bpm there but you can find some (up to level id 1600ish) in the ingame song information.

[Frank Munoz]

If you wanna step a piece so that every frame is lined up to 192nd notes it'd have to be 37.5 bpm

[TheSaxRunner05]

Originally Posted by noname219

You're probably thinking about this thread by qqwref. No bpm there but you can find some (up to level id 1600ish) in the ingame song information.

Ah, I see. Do you know if there'd be a way for me to search more recent songs for 225, 150, or 90 BPM songs? There have been about 500-600 public songs released since that ingame song thread had been updated.

[noname219]

AFAIK there's no way, bpm aren't listed anywhere else. I asked qqwref how he found bpm for the old charts, it's all done manually :

"Heya. I think this is the program I was using: http://mzrg.com/FFR/draw-bpm2.html Basically you dump in the beatbox data, put in a BPM, and it will show you a 16th jack next to the chart. Then you can tweak the BPM until they match up well (keeping in mind that occasionally things will be a frame off due to rounding differences)."

[Samus Aran]

Originally Posted by One Winged Angel

At 30 fps, there's 1800 frames in a second.

what

[One Winged Angel]

yes we had no idea what I intended to type