Based on:
The calculation assumes a Normal Distribution of hit errors (centered at 0ms of error). Assuming a Normal Distribution doesn't seem to work well when using cheesing tactics (for example, hitting keys that have no notes to simplify movements needed to play); also, it tends to underestimate the amount of misses the player gets.
The values are compared this way:
- For a given Accuracy value, OD, and amount of notes in osu!mania, calculate the Standard Deviation (Unstable Rate) where the chances of getting at least the given Acc for the amount of notes is 50%.
- For that Standard Deviation, calculate the median DP% in stepmania (Judge 4, the most common Judge as far as I have seen) expected with the same amount of notes
The results in short:
Example: For a OD7 stepfile convert with no LNs, and about 1000 notes, getting a S grade is about as hard as getting 93.53% DP% in stepmania for the same stepfile on Judge 4.
- http://i.imgur.com/a5feuvR.png (Stepmania Timings Windows)
- http://aaronin.jp/ddrallcalc.html (DP system calculation for DDR, as far as I have seen, SM uses the MAX scale)
- osu!mania timing windows taken from the game client (it is the values shown in the known OD table, plus 0.5ms for each value; by using mods there are some small rounding errors)
The calculation assumes a Normal Distribution of hit errors (centered at 0ms of error). Assuming a Normal Distribution doesn't seem to work well when using cheesing tactics (for example, hitting keys that have no notes to simplify movements needed to play); also, it tends to underestimate the amount of misses the player gets.
The values are compared this way:
- For a given Accuracy value, OD, and amount of notes in osu!mania, calculate the Standard Deviation (Unstable Rate) where the chances of getting at least the given Acc for the amount of notes is 50%.
- For that Standard Deviation, calculate the median DP% in stepmania (Judge 4, the most common Judge as far as I have seen) expected with the same amount of notes
The results in short:
Example: For a OD7 stepfile convert with no LNs, and about 1000 notes, getting a S grade is about as hard as getting 93.53% DP% in stepmania for the same stepfile on Judge 4.