Re: [hatari-devel] sound bug

[Laurent Sallafranque <laurent.sallafranque@xxxxxxx>]

Hi,

I think there are 2 problems here :

- one with the general sound quality of Hatari (which is, from my point of vue, dependant of the CPU accuracy (because the crossbar code is related to the cpu time)

- one which is the every 4-5 times crappy sound problem which is not related to the crossbar code (else, we would not have good quality sound sometimes).
I think it's more a problem of synchro with SDL or something like that, but I'pm pretty sure that the problem is not in the crossbar algos (switching to 11 khz and back to 50 khz sometimes fix the crappy sound problem, but if you do this and activate  "trace crossbar" in the debugger, you'll notice that there's no crossbar event involved, so no change in the crossbar structure, but only in the "SDL" part of hatari.

I don't think the solution is in an improvement of the crossbar algos (I may be wrong of course).

Laurent
 



Le 26/06/2014 00:26, Douglas Little a écrit :

Hi David,

I use the following to reduce sound latency:
--sound-buffer-size 10
--sound-sync 1

Thanks, I will try this with my cygwin build to see if it has any impact. It might help with debugging the audio.

 

Which programs are good for trying Falcon sound settings?

TBH the problem I reported seems quite regular with my own program and Laurent has reported the same with his program - so my guess is it happens to all Codec-based audio replay. It's just a matter of luck whether you get correct sound or not. Around 80% of the time you'll get a result which seems ok, but only 50% or less it's actually 'correct' and glitch-free.

I say 'glitch-free' but I think there are some other problem which cause occasional gaps/clicks - I expect that is a separate thing. (I get the same clicks and gaps if I top another window in the host OS).

Some of the time the bug presents itself as some low level noise or chopping which could be dismissed as lowish quality samples - but it is not. Fiddling with the audio quality buttons causes the noise to either get worse or disappear. Sometimes you can't tell if the problem is present until you 'clear' it by doing this, because it can be subtle.

I think it affects everyone but is going unnoticed a lot of the time. It is more noticed if you are actively monitoring the audio quality of your own program, since the attention is more focused.

Occasionally the problem is so obvious though, it's not possible to hear the audio at all - just noise/garbage.

Interested to know if anyone can reproduce. I'll try to upload a sample program which shows this issue as soon as I am able.

Doug.