Boulder Dash, More time needed?

[BryanFRitt]

MAIN MENU > LEVELSET > BOULDER DASH > VARIOUS > BOULDER DASH 3 ATARI > 10: INTERMISSION 2 /1
~/.rocksndiamonds/tapes/bd_boulder_dash_3_atari/010.tape

This level seems like it needs another second(or so?) to be able to complete in time.
(same goes for level 030: INTERMISSION 2 / 2 , ...?)

[Holger]

This is most likely due to the problem that caves designed for NTSC C64 computers do not play at the same speed than on a PAL C64. Some more details:

According to reports intermission 3 cannot be solved on the PAL-C64 version, as the arrival of Rockford was delayed for too long due to the frequency (original in NTSC 5/6 faster). As a result the fireflies explode too fast. (not verified yet)...

(See https://www.c64-wiki.com/wiki/Boulder_Dash)

The game time is counted in a raster line interrupt, which causes a PAL machine to have only 50 Boulder Dash seconds in a real minute. In case, you can't play a NTSC game on your PAL machine, you can try to patch it. Though virtually all fanmade Boulder Dash caves are designed for PAL machines for some reason:

(See https://www.gratissaugen.de/erbsen/BD-Inside-FAQ.html)

That means that the time is running out on PAL machines after fewer game frames than on a NTSC machine, effectively rendering some levels unsolvable.

As far as I know, only very few intermission levels are affected by this problem, which do not have to be solved in the original game to continue (and which also do not have to be solved in R'n'D if playing with multiple lives like on the C64 or in GDash).

[BryanFRitt]

roughly PAL is 50 half frames per second, NTSC is 60 half frames per second.

More exact ≈ to lesser exact ≈ to even lesser exact
24×1000÷1001 ≈ 119.88/5=23.976 ≈ 24
...? ≈ 50/2=25 (?is this 119.88×5/24=24.975?)
30000÷1001 ≈ 119.88/4=29.97 ≈ 60/2=30
https://en.wikipedia.org/wiki/List_of_b ... eo_formats

(original in NTSC 5/6 faster)

Saying something is (y (times) faster/slower) is like multiplying the compared to speed by (1+y,1-y)
Saying something is (z (times) the speed) is like multiplying the the compared to speed by (z).

I think they meant the speed of NTSC is 6/5 the speed of PAL, or NTSC is 1/5 faster than PAL, or PAL is 5/6 the speed of NTSC, or PAL is 1/6 slower than NTSC.
(I see this could throw off non math people, or people trying to do this quickly. Hopefully I said things correctly. )

60 NTSC frames is done in the same time as 50 PAL frames. (25 PAL Frames)/Sec * ((60 half NTSC Frames)/sec)/((50 half PAL Frames)/sec) = (30 NTSC Frames)/sec. 60/50=30/25=6/5

That means that the time is running out on PAL machines after fewer game frames than on a NTSC machine, effectively rendering some levels unsolvable.

Random Thoughts... Could this be NTSC/PAL toggled somehow without confusing tape issues? add a warning that the level would have to be restarted if it would be?, An appropriate pre-decision of NTSC/PAL made?, or would it be better just to leave it alone? Could/Would this ruin something else? Would this cause a possibly confusing duplication of solution tapes, a version for PAL, a version for NTSC?, ... Also don't want to make things worse by compensating the wrong way.