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TheRyk
Registered: Mar 2009
Posts: 2060 |
SidTracker64 and CIA timer settings
Hey there!
I have no (E)IPhone or -pad or any other Apple hardware (apart from ancient 1990s iPod), so I must ask you.
In all the tunes by Jason Page but also other recent tunes done with SidTracker64 I see CIA flag as a rule but rather slightly messy timer settings, no matter if it's just 60Hz or multi speed tunes producing other values than put together here: http://csdb.dk/forums/?roomid=11&topicid=58416&showallposts=1
Might there be a bug in the timer calculation by the software?
Cheers
Ryk |
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JackAsser
Registered: Jun 2002
Posts: 1989 |
I've forward your question to my bro (Author if SidTracker64) on FaceBook and I'm sure he have a good answer. |
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JackAsser
Registered: Jun 2002
Posts: 1989 |
Just got the answer from my bro. The 64 50HZ VBL is not really 50Hz, but rather 50.125Hz. ST64 otoh uses exact BPM values since most musicians rather have a correct BPM than adjust to the VBL of a C64. So f.e. a 4x-tune running on VBL on the C64 is not really 200Hz but rather 200.5Hz. But when you set 200Hz in ST64 you get the correct 200Hz, and not 200.5Hz.
As a side note, a 50Hz tune in ST64 can of course be run using VBL on the C64 (50.125Hz) and would probably sound correct in almost every case anyway. |
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TheRyk
Registered: Mar 2009
Posts: 2060 |
Thx for the quick reply!
However, as you have close contact ;) to devoleper, ask him to consider if the "wrong" C64 ~50Hz as default for .SID-file output would make sense. Imho, it would, as it would be rather a pain in the ass(-es, e.g. of HVSC rippers) to adjust all the CIA timer settings manually for each released tune created with this tracker. The difference in terms of sound should be next to nothing, that's clear.
Cheers
Ryk |
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chatGPZ
Registered: Dec 2001
Posts: 11107 |
if the tunes use other CIA settings than standard 1/2/4 speed then the .sid file should contain the correct setup code for the timers. |
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TheRyk
Registered: Mar 2009
Posts: 2060 |
Would make things a great deal easier, indeed. |
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iAN CooG
Registered: May 2002
Posts: 3132 |
I don't actually give a damn =) if the settings are "wrong" they are because the author composed it like that, and are kept intact. |
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JackAsser
Registered: Jun 2002
Posts: 1989 |
Quote: if the tunes use other CIA settings than standard 1/2/4 speed then the .sid file should contain the correct setup code for the timers.
They do always contain CIA setup code since the BPM is set by the composer and the composer doesn't give a damn about VBL-integer speeds. |
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iAN CooG
Registered: May 2002
Posts: 3132 |
infact, the only drawback is that such tunes will be hardly used with the intended speed in a demo that requires play calls at specific raster positions.
There is some mixed case anyway, like for example Yokohama'87
It sets CIA speed to $502e, so it should run slightly slower than a normal 1x (should be $4cc7 for PAL) but in the end the prg uses normal VBL raster at position $88, so the CIA speed flag has been not set in the ripped sid by me, I keep the speed actually used by the release. |
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TheRyk
Registered: Mar 2009
Posts: 2060 |
Generally, I'm with you.
Quote:drawback is that such tunes will be hardly used with the intended speed in a demo that requires play calls at specific raster positions
Actually it is quite unlikely that CIA-timed tunes, esp. higher than 2x speed, will be used at all in demos with a great deal of rastertiming-based effects. If you use them anyway and have no stable CIA-timer values, you will of course just call them via $d012 splits so-and-so-often per frame, as dynamically rolling CIA-timer-values in each frame will fuck up even the cheapest sprite multiplexing or rasterbar effect.
Still, I ask myself, why not setting the "wrong" C64 values in SIDTracker64 - if the tune is supposed to be not only played but maybe even used in releases on a real C64, especially when the difference is so marginal.
It's just a suggestion, however. |
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algorithm
Registered: May 2002
Posts: 702 |
There are modifications that can update the data x4 in one hit and then gradually write these to the sid io in the designated raster areas possibly interleaved with rasters etc. |
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Digger
Registered: Mar 2005
Posts: 421 |
Haven't really found any other SIDTracker64 threads, so asking here:
Anyone have tried and written any intro/demo soundtrack using SIDTracker64? (apart from Mermaid for True Survivor)
Does it use custom (new) player or is it based on an existing one? |
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chatGPZ
Registered: Dec 2001
Posts: 11107 |
its a custom player |
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iAN CooG
Registered: May 2002
Posts: 3132 |
Player Identifier V1.00 and SIDId V1.09 help to find a player in HVSC =)
There are currently 88 SidTracker64 files.
For example the comeback demo from X-Ample has a tune by Goesta Feiweier made with it.
MUSICIANS/F/Feiweier_Goesta/Veterans_of_Style.sid
for a complete list just run, for example
pi.exe -s -pSidTracker64 c:\hvsc\*.sid |
