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Re: Paulo Simoes Lance replayer
Posted by: joska Jun,28.2015-16:07 

> I doubt that there is a way to have a fully OS compatible player as timer C is
> the system timer but timer D is also used for RS232 comunications.
> Of course you can say who cares about RS232 and you would be right at this
> stage.

Yes. Using Timer C means that you can't use GEM or access disks, atleast not with TOS 2 and higher. Timer D only affects the MFP serial port. So neither is ideal, but Timer D has less impact.

> A timer will always be required for BPM as you can see in the Amiga reference
> Protracker 2.x source (look for CIA programming).

I know too little about mods and modplayers. If I understand this correctly - BPM means a variable "tick" interval, right? Google say from 10ms to 78ms, whereas the old, VBL-based tick-length is fixed at 20ms.

I understand that this requires a timer on the Amiga, since playing mods on the Amiga is very different from on an STE (or a PC for that matter). On the Amiga you need to instruct Paula to change sample, frequency and volume in real time, whereas on the STE/TT/Falcon the CPU copies and mixes the samples to a buffer and applies effects/pitch while doing so. Then the DMA hardware outputs this buffer at a fixed sample rate. So there would be no need for a timer to use BPM in this case - except for volume as your player use the LMC for this and thus needs to do this in real-time.

I wonder how much sound quality will suffer if volume is adjusted per VBL instead? It would make the player a LOT more useful in demos/games since you don't have to worry about timer C when doing rasters/screensplits/border busting. The Timer C handler in your code is pretty short though. A bit busy this weekend but will try to experiment a bit with this. Very interesting stuff, I've had Ataris since 1988 but have never really looked into audio until now.

> You can scrap that and move it always to the VBL but you may loose some
> quality.

I did scrap that and I can't hear any difference on my STE.




[All messages in this thread]

Topic Posted by  Date 
Paulo Simoe's Lance replayer joska Jun,18.2015-13:54
  Re: Paulo Simoe's Lance replayer evil Jun,18.2015-15:38
    Re: Paulo Simoe's Lance replayer joska Jun,18.2015-20:22
      Re: Paulo Simoe's Lance replayer joska Jun,19.2015-11:10
        Re: Paulo Simoe's Lance replayer Grazey/PHF Jun,19.2015-18:52
        Re: Paulo Simoe's Lance replayer joska Jun,20.2015-11:53
  Re: Paulo Simoe's Lance replayer joska Jun,21.2015-22:46
    Re: Paulo Simoe's Lance replayer joska Jun,22.2015-01:11
      Re: Paulo Simoe's Lance replayer mikro Jun,22.2015-08:15
        Re: Paulo Simoe's Lance replayer joska Jun,22.2015-09:00
          Re: Paulo Simoe's Lance replayer ljbk Jun,24.2015-14:16
            Re: Paulo Simoe's Lance replayer joska Jun,24.2015-15:28
              Re: Paulo Simoes Lance replayer ljbk Jun,24.2015-21:04
                Re: Paulo Simoes Lance replayer joska Jun,25.2015-00:20
  Re: Paulo Simoe's Lance replayer joska Jun,26.2015-10:30
    Re: Paulo Simoe's Lance replayer evil Jun,26.2015-12:01
      Re: Paulo Simoe's Lance replayer joska Jun,26.2015-13:25
        Re: Paulo Simoes Lance replayer ljbk Jun,26.2015-19:34
          Re: Paulo Simoes Lance replayer ljbk Jun,26.2015-19:36
      Re: Paulo Simoes Lance replayer ljbk Jun,26.2015-20:00
        Re: Paulo Simoes Lance replayer joska Jun,26.2015-20:53
          Re: Paulo Simoes Lance replayer ljbk Jun,26.2015-23:09
            Re: Paulo Simoes Lance replayer joska Jun,28.2015-18:38
              Re: Paulo Simoes Lance replayer joska Jun,29.2015-14:38
          Re: Paulo Simoes Lance replayer evil Jun,27.2015-18:10
            Re: Paulo Simoes Lance replayer ljbk Jun,27.2015-22:32
              Re: Paulo Simoes Lance replayer joska Jun,28.2015-16:07
            Re: Paulo Simoes Lance replayer joska Jun,28.2015-16:09


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