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Author Topic: PC Engine behaves differently  (Read 622 times)

Offline tildearrow

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PC Engine behaves differently
« on: September 16, 2016, 07:55:24 PM »
So I downloaded the latest pre-release of DefleMask.

Then I opened Go Straight, and then, umm, it sounds kind of different.

So, the volume curve/mixing algorithm seems to have changed. Plus seems like sample changes cut off adjacent channels (may need headphones to be audible).

Steps to Reproduce:

  • Open DefleMask.
  • Load Go Straight (both NTSC and PAL versions reproduce).
  • To reproduce first bug, play from the first order.
  • To reproduce second bug, go to any order between 10 and 1F, and then mute all channels but Channel 4.

Additional Information:

The first bug might not be a bug...................

Proof:


Offline Delek

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PC Engine behaves differently
« Reply #1 on: September 16, 2016, 08:53:10 PM »
I updated the emulation core to a more recent version. We should test this vs the actual hw to conclude it is a bug

Offline Fragmare

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PC Engine behaves differently
« Reply #2 on: January 06, 2017, 02:31:34 PM »
I updated the emulation core to a more recent version. We should test this vs the actual hw to conclude it is a bug

I think I recently ran into this bug, or something similarly related.  Ironically enough, it was while working on a cover of Fighting In The Street for the PC-Engine.  It seems to happen when switching from Note Mode to Sample Mode.  At least on channel 5 or 6.  I can confirm this occurs on real hardware, and occurs in Ootake and Mednafen, but sounds fine in Deflemask playback.  You can hear it happen in the WIP DMF/HES I've attached here at row [10], Channel 6 of the pattern.  I snuck in a square wave note there because there was room for it, but when the samples resume playing after [1000][08FF][1701] are set, they are DRASTICALLY reduced in volume.  Like 25% of their original volume.  I'm not sure if this is an issue with how the HuC6280 handles note>sample mode switching or if it is some sort of bug, but it happens, for sure.

Oh, and Go Straight also does this on real hardware and Mednafen.  You'll notice the samples are extraordinarily quiet.  You'll also notice the sample channel was switched to note mode at the very beginning of the song.  Also, you'll notice Speedy turned on the Noise Mode toggle but never turned it off when playing samples.  On real hardware and any recent version of Mednafen, the HuC6280 then seems to assume that channel is in noise mode all the time and plays nothing but noise (no samples)... technically, I guess this is a problem with the sequencing, but it's another thing that sounds fine in Deflemask but not on real hardware.

I find loading up the HES in Mednafen is a good way to quickly get a feel for how it sounds on real hardware.  It's not perfect sound emulation, nothing is, but it's awfully close.


In the included DMF file @ Row [10] / CHN6 / Tick 012, you will see:

D#4 - 4  1001  08CC  1700  <------- Square note.  All samples prior to this play at normal volume.
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C#4 - -  1000  08FF  1701 <--------- This sample and all the rest play at drastically reduced volume.  Even when forced with [08FF]
« Last Edit: January 06, 2017, 03:39:29 PM by Fragmare »

Offline Delek

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PC Engine behaves differently
« Reply #3 on: February 11, 2017, 02:54:41 PM »
I corrected some stuff about the emulation in the PCE. Please grab the latest 0.12.1 pre-release.

Offline tildearrow

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PC Engine behaves differently
« Reply #4 on: April 03, 2017, 10:41:20 PM »
Sorry for not replying. I have been busy with other things.

Thank you Delek for the changes!