Re: [hatari-devel] Cracks in the sound (YM+DMA)

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

On 17/03/2013 22:28, David Savinkoff wrote:
> Hi
>
> This patch works well, but is incompatible with older snapshots.
>
> Hatari plays DMA sound at the same level as before (unless you
> use an old snapshot). New snapshots made with the newly patched
> version will work properly with the newly patched version.
>
> The problem is with using an old memory snapshot as the old gain
> is used (in your case: 1.0/(65536.0*65536.0) ) which makes the
> gain half as much as required.
>
> If you did the snapshot with the patched version (the other way
> around), you would get double the volume: 2.0/(65536.0*65536.0)
>
> As can be seen in the preliminary observations, the patch was
> double checked.
>
> Note that DmaSnd_Init_Bass_and_Treble_Tables() can be executed
> after all MemorySnapShot are restored, thus, overwriting the
> erroneous gain from old snapshots. If this were done then
> MemorySnapShot_Store(&lmc1992, sizeof(lmc1992));
> would not be necessary. (see dmaSnd.c)

Hello,

you're right, I tried the same snapshot with the 2 different Hatari 
version, but I didn't notice lmc1992 was part of the snapshot, which as 
you say explain the x2 factor in my tests.

I tested again with 2 different snapshots corresponding to the 2 Hatari 
version, and volume is indeed the same.

I don't think it's necessary to reinit lmc1992 after restoring a 
snapshot, as long as such changes happen during the dev version, it's OK 
if snapshot are not compatible with each others.

So, case closed, sorry for the noise and the wasted time :)

Nicolas