Author
| Crystal clean PCM 8bit samples on the poor PSG
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EVPON
msx lover
Posts: 94 |  Posted: February 18 2007, 14:49 |
Then nobody know a program that uses little samples
(low quality) under Basic? Maybe the old PSG-SAMPLER?
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NYYRIKKI
online
msx master
Posts: 1506 | Posted: February 19 2007, 11:24 |
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viejo_archivero
online
msx addict
Posts: 438 | Posted: February 19 2007, 11:30 |
I assume that playing those quality samples will cost LOTS of CPU time... but it will be possible to make "little" things while the player is running? (quick reads to joystick/cursor, tiny gfx transfers to vram...). And another question, this program just launches a sample or you can set a list of consicutive samples to be played? (that would be interesting, as you can build little sampled "songs" or loops...). Thnx!
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EVPON
msx lover
Posts: 94 | Posted: February 19 2007, 11:48 |
Thanks NYYRIKKI  |
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pitpan
msx master
Posts: 1368 | Posted: February 19 2007, 12:20 |
Viejo: I'm afraid that PSG samples requiere loads of CPU time. You can sync some code, but it is a painfull task. Ask Dioniso to know more, because his BEEPERTRON uses synched code for differents tasks while playing PSG samples.
Regarding SCC samples, I do think that something could be done, because the SCC replay feature works as a simple DMA. But again, all code should be accurately synched to replay functions.
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ARTRAG
online
msx master
Posts: 1593 | Posted: February 19 2007, 12:40 |
Vejo:
it is hard, but all you ask for can be done.
Having more samples in ram/rom and playing them as in a sequencer is very easy.
More difficult is to modify th ereplayer to add interaction.
The pcm replayer has some spare time had can be used for other purposed (VRAM transfer, I/O etc)
but the code must keep its cycle accurate syncronization.
Look at the asm files and put your code where now there are dummy instructions.
keep the timing corrcet and everithing will work.
Lower is the frequency, higher the spare time you can use for your code.
Good luck
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NYYRIKKI
online
msx master
Posts: 1506 | Posted: February 19 2007, 13:07 |
If you don't care about some little noice, you can play samples with interrupts enabled and put your other tasks in interrupt routine. I used this method on Alternative party demo's end animation (look picture) and it worked out quite well.
( Download: http://msx.fi/nyyrikki )
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ARTRAG
online
msx master
Posts: 1593 | Posted: February 19 2007, 16:37 |
Nice idea!
In this case it is mandatory to avoid the bios overhead in the INT routine.
All those push/pop usually are not required and waste a lot of time.
Try using IM2 or putting RAM in page 0 (if you have 64Kram)
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