Re: [hatari-devel] DMA sound and Falcon

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Le 11/09/2016 à 19:17, Laurent Sallafranque a écrit :
> Hi,
>
> The sound become noisy after some seconds and then, return to clean
> after the same amount of time.
> It seems to be cyclic. clear sound -> degrades -> noisy sound -> becomes
> better -> clear sound -> ...
>
> Something I never added to the crossbar is that there are two 32 bytes
> buffers for the sound (in and out).
> I've got the schemas somewhere if someone need them.
>
> I know you added 1 little buffer to the Ste DMA that you feed after each
> hbl, but I don't understand exactly how you did it.
>
> I wish this make sense.

I don't think that's related. The STE DMA sound FIFO was only needed for 
a few programs requiring very strict timings, but it was not related to 
the frequency computation, it was required for program that monitor the 
current dma address.

> I think I was very careful with the frequencies conversions (int to frac
> or rounding), but I'm sure your advise and 4 eyes looking can only
> improve the code. ;)

I have no real explanation at the moment, I will first add some logs to 
better understand the difference between a good and a bad rendering.

Nicolas