[hatari-devel] STE sound breakage with lower sound frequencies

[Eero Tamminen]

Hi,

On tiistai 08 helmikuu 2011, Nicolas Pomarède wrote:
> Le 07/02/2011 23:15, Eero Tamminen a écrit :
> > I tried Utopos demo.
> > 
> > If I use "--sound 11025" or "--sound 16000", there's just a short
> > "dup"[1] sound and then no sound at all.  With e.g. 22kHz or 48kHz,
> > sound works fine for STE emulation too.
> > 
> > The issue happens also for Hatari from end of december and for Hatari
> > v1.4. Keyclick on STE TOS works for Hatari v1.4 even at 11025Hz
> > though.
> 
> Yes, I can reproduce similar issues ; not related to my latest changes,
> certainly there since a long time and specific to dma sound.
> 
> It seems that if Hatari starts with a too low freq then there's no sound
> (changing sound freq with F12 don't correct it). But if I start Hatari
> in default mode (44.1 kHz) in my case and change freq with F12 to 11025,
> I still get sound.
> Do you have the same behaviour ?

Yes.  If I change the freq from options, there's no problem.


> So, it's not the freq change, but probably some inits based on the
> starting sound freq that are not correct.
> 
> I'll try to give it a look later.

Hm. Does anybody know a good Falcon program to test for the same issue?


> > Well, the possible issue is quite theoretical, but can happen also not
> > just by explicit user time change, but e.g. by automatic switch
> > to/from daylight savings or due to NTP update.  NTP time corrections
> > are typically so small (say few secs) that Hatari wouldn't freeze for
> > very long time though. :-)
> 
> ntp corrections should even be smaller than that. Except for a "brutal"
> ntpdate that can be started when computer boots, changes made by ntp are
> made with much smaller resolution than milli sec to avoid disturbing all
> processes ; as for daylight saving, it should affect representation of
> time relative to your timezone, but not the global time counted in
> seconds since 1/1/1970.

OK, so only user's own time modifications would be an issue and in this
very unlike case user can probably "connect the dots" and understand
why it happened.  :-)


	- Eero