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Old 15 January 2017, 11:41   #93
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Join Date: Mar 2012
Location: Norfolk, UK
Posts: 577
Originally Posted by Anakirob View Post
Is playing samples at rates higher than the Paula can actually output a feature of the Paula, or is there some kind of coding trick used in module replayers to allow these notes?
It's just a side-effect of how Paula works. The sample rate is set by telling Paula how many clocks to wait between emitting samples, and there's nothing stopping you from setting that sample rate very high. However, if Paula is ready to play a new sample before it's arrived, the previous word of data is repeated, which causes the glitches you talked about.

The limit is in how quickly the DMA system can feed fresh data to Paula. The DMA system is in sync with the video display, and only one word of data per channel can be fetched per scanline. That's why the maximum sample rate varies slightly between PAL and NTSC systems. It's also why with 31KHz video modes those glitches disappear - because the audio DMA slots are now roughly twice as frequent.
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