Convert atari st ym sound

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dub
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Convert atari st ym sound

Post by dub » Fri Jun 30, 2017 10:01 am

Hi,

I have an audio file ym for atari st that I would use. I use the sgdk in version 1.30 and I have added the program genres to convert and play music (great tool). The problem is that the file is in 50Hz which is good for the megadrive pal europe but I would also like to play it on a console at 60Hz.

Is it possible to play it at another frequency directly with genres or with the converted file asm code ?

I use this for parameters :

Code: Select all

PSG my_music "music1.ym"
{
	SOURCE SOURCE_ATARI
	DESTINATION DEST_PAL
	START_FRAME	0
	NO_LOOP
}
I also tried with DESTINATION DEST_NTSC

Moon-Watcher
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Re: Convert atari st ym sound

Post by Moon-Watcher » Fri Jun 30, 2017 12:35 pm

Doesn't Genres 2 do that work?

dub
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Re: Convert atari st ym sound

Post by dub » Sat Jul 01, 2017 7:05 am

It's also what I thought. Maybe I have to change something to tell genres that the console is in 60Hz.

dub
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Re: Convert atari st ym sound

Post by dub » Tue Jul 04, 2017 2:31 pm

I did another test with another ym file. I always have the same result, it is too fast on a 60Hz machine.

When I change DESTINATION DEST_PAL to DESTINATION DEST_NTSC, I have different values for tone but there is no value for timing. As the vblank is used to read the values and goes through a "SYS_setVIntCallback (& VBlank_sub);", the software reads the values too fast. Can pass out of vblank for sound ?

A test file with rom : https://www.dropbox.com/s/b9f51yj8kb6qxci/music_ym.zip

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KanedaFr
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Re: Convert atari st ym sound

Post by KanedaFr » Tue Jul 04, 2017 4:57 pm

yes, DEST only act on the tone value, nothing else.

dub
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Re: Convert atari st ym sound

Post by dub » Wed Jul 05, 2017 6:57 am

KanedaFr wrote:yes, DEST only act on the tone value, nothing else.
Thanks for the confirmation.
So I have to make a music at 60Hz. Or don't use the vblank but a counter to play the music every 1/50hz instead of 1/60hz. :mrgreen:

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KanedaFr
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Re: Convert atari st ym sound

Post by KanedaFr » Wed Jul 05, 2017 10:39 am

I think, now rereading my code and based on your comment, the *PAL and *NTSC thing is prone to confusion.

This define the clock rate (and not the rate) of the CPU used to render the sound
It's to convert a sound coming from any CPU to the z80 : 3.579545 MHz (NTSC), 3.546894 MHz (PAL)

So the 50/60hz has nothing to do there...

dub
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Re: Convert atari st ym sound

Post by dub » Wed Jul 05, 2017 1:12 pm

KanedaFr wrote: This define the clock rate (and not the rate) of the CPU used to render the sound
It's to convert a sound coming from any CPU to the z80 : 3.579545 MHz (NTSC), 3.546894 MHz (PAL)
Fine.
To be clear because I've a little brain, with the same ym file, playback will be faster with the NTSC z80.

Chilly Willy
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Re: Convert atari st ym sound

Post by Chilly Willy » Wed Jul 05, 2017 3:44 pm

I think the "standard" thing most folks do for PAL vs NTSC is in the vblank int handler to exit one time every six vblank ints without actually updating the sound/music. I've seen that in many ST programs, and Amiga programs where the vblank int is used to update the music score.

dub
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Re: Convert atari st ym sound

Post by dub » Wed Jul 05, 2017 3:50 pm

Chilly Willy wrote:I think the "standard" thing most folks do for PAL vs NTSC is in the vblank int handler to exit one time every six vblank ints without actually updating the sound/music. I've seen that in many ST programs, and Amiga programs where the vblank int is used to update the music score.
Thanks I'll try this.

I add this code and it works well.

Code: Select all

void VBlank_sub( )
{
	// Play music 60 Hz
	curTime++;
	if (curTime < 5)
	{
		gameTitle_Update();
	} else {
		curTime = 0;
	}
}

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