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

[Nicolas Pomarède]

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 ?

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.


> 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.

Nicolas