Re: [hatari-devel] Re: Interesting sound problems with Hatari?

[David Savinkoff <dsavnkff@xxxxxxxxx>]

Hi,

Will Falcon sound be improved before this release?

----- David Savinkoff wrote:
> Hi,
> 
> This patch combines the two previous with a bit more.
> Don't apply this patch with my previous patches.
> Please test.
> 
> David Savinkoff
> 
> ----- David Savinkoff wrote:
> > ----- Laurent Sallafranque wrote:
> > > Hi,
> > > 
> > > First, sorry for not replying sooner, I was not at home this week end.
> > > I've just discovered you patches.
> > > 
> > > I did write the whole crossbar sound code 3 years ago, and if I remember 
> > > correctly, David added some more precise values and filters (while he 
> > > was increasing the STE DMA sound part).
> > > 
> > > I added the 0 after reading a sound because of the DSP part in the 
> > > crossbar (on the real Falcon) (I was really concerned by the DSP part at 
> > > this time).
> > > 
> > > When the DSP sends a data to the SSI, this value is played by the 
> > > crossbar directly into the DAC part.
> > > If then you tristate the DSP (or stop it, reboot it or whatever stops 
> > > the sounds), there's no more sound coming out of the DAC.
> > > But if I didn't put zeros after reading the value (into hatari), the 
> > > sound (coming from the DSP) was looping forever into the circular DAC 
> > > buffer.
> > > 
> > > maybe this should be done differently, but I still think that a played 
> > > sound into the DAC buffer should be erazed.
> > 
> > Another way is to repeat the last good sample (instead of inserting zeros).
> > This is what a DAC will do when the data stops.
> > 
> > Note that inserting samples (filtered or otherwise) will not be used to hide
> > correctable problems.
> > 
> > > That's the same if the crossbar does a DMA --> DAC connection (the sound 
> > > read from the DMA (Falcon MEMORY) should be set to 0 after being read 
> > > (to remove the circular buffer sound playing forever).
> > > 
> > > Only the source of the sound should remain unchanged (mainly the DMA 
> > > memory), whereas the DSP sounds are volatile (computed once, sent once 
> > > to the SSI, played once by the DAC, and forgotten after this).
> > > 
> > > I like the idea of the patch by David (a FIFO, which allows to read a 
> > > sound only once).
> > > 
> > > 
> > > Doug, the *if (n) *patch is a great idea.
> > > I was just thinking that is n is > 1 (let's say n = 5), maybe we should 
> > > reset to 0 the whole values between n=1 and n=5 ?
> > > 
> > > I'll have a closer look too at this problem.
> > > 
> > > Regards
> > > 
> > > Laurent
> > > 
> > 
> > 
>