FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
 Japanese English 

"FM" speed tech question...
Goto page Previous  1, 2
Post new topic   Reply to topic    MagicEngine Forum Index -> Bug/Problem Reports
View previous topic :: View next topic  
Author Message

Joined: 04 Apr 2002
Posts: 1166
Location: France

PostPosted: Sat May 11, 2002 11:11 pm    Post subject: Re: Oh... Reply with quote

Jabberwok wrote:
I see your point... a new ME core definitely sounds sweet Very Happy and kinda makes this whole tread useless then... Have any info on the ETA of this new core? or maybe this is a secret?

Yes, this is *top* secret. Wink
No infos yet, but don't expect it in the near future, I will have the time to release a few more betas before v1.0 is ready.

im guessing that the 'infamous' screen stretch WILL be part of this new core hehehe....

We will have screen strectch before version 1.0. Smile
David Michel
Back to top
View user's profile Send private message
David Shadoff

Joined: 10 May 2002
Posts: 83
Location: Toronto, Ontario, Canada

PostPosted: Sun May 12, 2002 8:01 pm    Post subject: Re: "FM" speed tech question... Reply with quote

ethylene wrote:

Yeah, about the CD desynching. I had this, too, at one point, but don't anymore. I know that you are way more knowledgeable than most of us here, David, but still I'd like to suggest you try these settings:

    60 Hz refresh rate
Does that help?

Actually it makes the problem much worse. In this mode, my Athlon 1.33GHz causes too many VSYNC interrupts, so the PSG music sequencer advances at about double speed.

Also, I like to have my monitor refresh around 72Hz, and i like to use the windowed mode. David's suggestion of adjusting the internal timer is perfect, but I don't know how/what to adjust internally...

My suggestion was based on the following information:
(a) exactly 60Hz is actually wrong. NTSC is 59.97 Hz
(b) internal timers in the PC are not reliable to this level of accuracy
(c) at a high level, the programmer is able to monitor how quickly the sound is drained from the DirectSound buffer, and is also able to count how many FPS are actually displayed (sometimes a frame is delayed slightly, or the timer is inaccurate). Fine-tuning adjustments can be made 2-3 times per second, to ensure that sound and motion are synchronized.

That's really all I meant to say.

- Dave

Actually, with the new code for Win2000/XP, this should become simpler, as I expect that the CDROM sound is ripped from the disc, and played as 44,100 Hz sound samples through DirectSound - and since we all know that there are 75 frames of CDDA audio per second, and 59.97 VBLANK periods, that we can count "virtual seconds" within each subsystem over certain timing periods, and ensure that they are kept in balance.

On the other hand, maybe the video subsystem of the PCE makes some kind of adjustment to the "59.97" VBlanks per second, based on the "vsync width", "# lines before frame", "# lines in frame", etc. measurements as defined to the VDC chip.

So, maybe it isn't too easy - but if anybody knows these technical details, David Michel does.
Back to top
View user's profile Send private message

Joined: 24 Apr 2002
Posts: 532
Location: Quebec, Canada

PostPosted: Mon May 13, 2002 2:39 am    Post subject: Omg... Reply with quote

We will have screen strectch before version 1.0.

**Place drool here....** Very Happy

The new 1.0 core and screen stretch will place ME far from reach from the other PCE emulators... oh ya. This may be premature, but I smell perfection down the road Smile .
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    MagicEngine Forum Index -> Bug/Problem Reports All times are GMT + 1 Hour
Goto page Previous  1, 2
Page 2 of 2

Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

Powered by phpBB © 2001, 2005 phpBB Group