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Offline Linde

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Re: Amiga audio early lead lost..
« Reply #29 on: December 26, 2012, 08:55:57 PM »
On another, somewhat related note I think the Amiga could seriously have used an additional sound chip. Four channels on an A500/A1200 setup was obviously seriously limiting when it comes to producing both music and sound effects. Something like the OPL2 or even something as simple as an YM2149 in addition to the Paula would have been very useful.
 

Offline Matt_H

Re: Amiga audio early lead lost..
« Reply #30 on: December 26, 2012, 09:11:12 PM »
Quote from: Karlos;720322
Mixing audio on the CPU, however, uses an absolutely pitiful amount of CPU time, even on any remotely accelerated Amiga (I've done 32-channel stuff in OctaMED SS on an 040), let alone a present day PC.

I can play back two dozen MP3 streams simultaneously on my current (linux) PC before I see pulseaudio lingering in the top 10 processes, and even then it's never more than a few percent of the available capacity of one core.


ChaosLord, I think the audio stuttering issues you see on your PC are more a function of the lousy performance of Windows than the underlying hardware.
 

Offline mikej

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Re: Amiga audio early lead lost..
« Reply #31 on: December 26, 2012, 09:17:02 PM »
Quote from: ChaosLord;720208
oic.  In that case he should buy a 16-bit soundcard for his Amiga. :)

Or talk FPGAreplay or Natami into adding native 16-bit Paula.


It's done. The DAC by the way is 24bit 96K and some care has been taken with the analogue layout to make sure it sounds as clean as possible.
/MikeJ
 

Offline psxphill

Re: Amiga audio early lead lost..
« Reply #32 on: December 26, 2012, 09:49:54 PM »
Quote from: Linde;720388
On another, somewhat related note I think the Amiga could seriously have used an additional sound chip.

By 1989 commodore seriously needed better graphics and sound.
To drag out pretty much the 1985 specification into 1991 was optimistic at best.
The management didn't appreciate talent and nobody in engineering had enough influence.
 
I didn't suffer too badly with windows 95, I had a gateway machine around that time. The hardware and drivers were pretty solid.
I switched to a dell a couple of years later and the hardware was so new that the windows 95 driver support wasn't great & the windows 98 beta seemed to have problems with 192mb of ram. So I switched to Windows NT4 & that was very stable.
« Last Edit: December 26, 2012, 09:59:34 PM by psxphill »
 

Offline ChaosLord

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Re: Amiga audio early lead lost..
« Reply #33 on: December 27, 2012, 01:14:31 PM »
Quote from: Karlos;720322
It has 10 24-bit DACs capable of 192kHz playback that can be multiplexed down into a single stereo stream (for instance, when using headphones). In what sense is it not capable of mixing channels?

Because it has 10 wires.
Because it does not mix the 10 audio streams.
Because it does not support any kind of useable sampling rates.
Because nobody writes 10 channel mods.
Because nobody writes mods using 100% 44.1Khz sample speed.
Of all the sample speeds used in a random mod, this sound chip supports between 0% and 1% of the required sample rates.

It only outputs what the CPU has already mixed itself into 7.1 format or into 2 channel stereo format.

Either way the sound chip does almost nothing.  Its just 10 dumb DACs sitting there waiting to be spoonfed data from the CPU.

Its not a Paula or anything of that technology level.
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Offline ChaosLord

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Re: Amiga audio early lead lost..
« Reply #34 on: December 27, 2012, 01:33:20 PM »
Quote from: Linde;720384
Did you miss the part about 10 DACs?

Did you miss the part where the CPU does all the mixing itself?

Quote

 Really, didn't the 7.1 part get through to you?

The definition of 7.1 is not mixed.  It is 7 discrete sound channels that are not mixed.  Each channel goes to a separate speaker.

If you want mixing done you must use the CPU to do it.  This sound chip is 10 dumb DACs.  They just sit there refusing to do anything until the CPU has done all the work of mixing a 64 channel mod into either A) Stereo format or B) 7.1 format.

How do you think a 12 channel mod would magically play on this sound chip?
The sound chip does not support 12 channels.
The sound chip does not support mods.
The sound chip does not support 8-bit samples. (most mods have 1 or more 8bit samples in them)
The sound chip does not support variable playback frequencies so by definition it cannot ever play a mod.

Quote

 Do you have an issue with reading comprehension?

Do u?

Quote

 That's 7 individual channels.

Exactly.  Now u r getting it.

7 individual unmixed sound channels.

7 channels is like 1980s TFMX or Okalyzer.  Your sound chip can match a 7Mhz Motorola 68000.  I am impressed.

Since nobody writes 7 channel mods for decades the sound chip can't play them.  Its up to the CPU to render your 24 channel mod down into 7.1 format and to scale all the sample rates up or down as required.  All the mixing work is done by the CPU.


Quote

 These chips are a lot more competent than you make them out to be.

No.  They are a lot less competent since I never even got started on its complete lack features.


Quote
You are naive to think that the function of modern PC sound chips is limited to CPU based software mixing.

You are naive to think otherwise.
I am sure u could somehow buy such a soundcard as u r dreaming of.
Nobody would be using it and thus nobody would support it with software so it would not be particularly relevant.
The other 99.999% of ppl with intel compatible computers would still be using lame nonmxing cpu-driven soundchip.  Somebody cut&pasted a feature list into the thread a while back.  Perhaps you missed it?

Here is a quote:
Quote

All DACs supports 44.1k/48k/96k/192kHz sample rate

Notice how it refuses to accept 99% of all existing sample rates?
Wanna play a mod?  It tells you to go screw yourself until you have the CPU do all the mixing itself and convert all samples into one of those 4 formats and convert all 64 tracks down into 7.1 format (or stereo format).

You have obviously never made a mod before or you would understand that you can't make a mod with only 4 sample rates.  Especially not those 4 particular sample rates.

Good lucking trying to make music where every note sounds exactly the same.
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Offline Linde

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Re: Amiga audio early lead lost..
« Reply #35 on: December 27, 2012, 02:56:21 PM »
Quote from: ChaosLord;720446
Did you miss the part where the CPU does all the mixing itself?


The definition of 7.1 is not mixed.  It is 7 discrete sound channels that are not mixed.  Each channel goes to a separate speaker.
Even when downmixing all the channels to two stereo channels? Did you actually read the text? You don't have any idea of what you are talking about if you think the DSPs of these chips aren't capable of internally mixing a huge amount of mixer inputs. DirectX and a lot of programs that use it make perfect use of hardware mixing and hardware resampling. The CPU doesn't have to deal with it, but since both these things are so computationally cheap, a lot of programs do it in the CPU anyway.

Quote from: ChaosLord;720446
If you want mixing done you must use the CPU to do it.  This sound chip is 10 dumb DACs.  They just sit there refusing to do anything until the CPU has done all the work of mixing a 64 channel mod into either A) Stereo format or B) 7.1 format.
Again, no idea about what you are talking about. See above.

Quote
How do you think a 12 channel mod would magically play on this sound chip?
The sound chip does not support 12 channels.
The sound chip does not support mods.
The sound chip does not support 8-bit samples. (most mods have 1 or more 8bit samples in them)
If the chip doesn't "support" mods, neither does Paula. Yes, the mod format is closely modeled after the features of the Paula, but the chip doesn't support it on chip level more than any other sound chip.

And 12 channels, are you kidding me? These sound chips frequently support 128 channels mixed by the DSP (i.e. no CPU needed) with >24 bit internal mixing depth. Mod players ran almost CPU-less already in the days of the AWE32 and GUS, the former which was able to play them back with its wavetable synthesizer, and the latter which was able to play it back on its multi-channel variable sampling rate architecture.

Quote
The sound chip does not support variable playback frequencies so by definition it cannot ever play a mod.
Maybe its firmware doesn't (and really, why would it? We don't live in the 80s where band-limited resampling could actually have been a performance hit) but neither of us know exactly what the internal DSP is capable of.

Quote from: ChaosLord;720446
Exactly.  Now u r getting it.

7 individual unmixed sound channels.

7 channels is like 1980s TFMX or Okalyzer.  Your sound chip can match a 7Mhz Motorola 68000.  I am impressed.
Wait a second, TFMX is software mixed. In that case, the whole variable sample rate rant you've got going doesn't really matter in any way, and neither does the "free mixing" rant. If we are going to compare apples to apples, PCs are capable of software mixing 7 channels, and 7 to a couple of powers of ten...

Quote
Since nobody writes 7 channel mods for decades the sound chip can't play them.  Its up to the CPU to render your 24 channel mod down into 7.1 format and to scale all the sample rates up or down as required.  All the mixing work is done by the CPU.
Not necessarily. See above.

Quote
No.  They are a lot less competent since I never even got started on its complete lack features.
Oh, please get started. It's specs are a lot unlike Paula, but are they really lacking in features? Please do a side-by-side comparison.



Quote
I am sure u could somehow buy such a soundcard as u r dreaming of.
Nobody would be using it and thus nobody would support it with software so it would not be particularly relevant.
The other 99.999% of ppl with intel compatible computers would still be using lame nonmxing cpu-driven soundchip.  Somebody cut&pasted a feature list into the thread a while back.  Perhaps you missed it?
I saw the feature list, but you obviously didn't do more than skim over it. It's not a dream sound card I'm talking about. You'll have a hard time finding a PC sound chip these days that doesn't support DirectX hardware accelerated mixing and resampling, which is all done by the DSP.

Quote
Here is a quote:

Notice how it refuses to accept 99% of all existing sample rates?
Wanna play a mod?  It tells you to go screw yourself until you have the CPU do all the mixing itself and convert all samples into one of those 4 formats and convert all 64 tracks down into 7.1 format (or stereo format).
This is an architectural difference between the Paula and modern sound chips. You are really stupid to think a modern sound chip would have anything to gain from minutely variable sample rates. But rest assured that the CPU doesn't have to deal with either resampling nor mixing.

Quote
You have obviously never made a mod before or you would understand that you can't make a mod with only 4 sample rates.  Especially not those 4 particular sample rates.
Oh, I've made quite a few mods, both on the Amiga and the PC. It's landing me live gigs every couple of months or so. I perfectly understand the differences between the variable sample rate Paula and modern fixed-rate PC soundcards. It's a difference, alright, but in no way a limitation of the latter. Variable sample rates is an artefact from a time where a dedicated DSP to handle high-quality resampling was infeasible and resampling on the CPU actually had a noticeable performance impact.  

The YM2149 is capable of playing 300 khz tones, something which the Paula (and most modern PC sound chips) is utterly incapable of. Does that make the YM2149 superior?

Quote
Good lucking trying to make music where every note sounds exactly the same.
Oh, we're talking about actual use now? Are you sure you want the discussion to head that way?
« Last Edit: December 27, 2012, 03:14:09 PM by Linde »
 

Offline Linde

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Re: Amiga audio early lead lost..
« Reply #36 on: December 27, 2012, 03:05:52 PM »
BTW, where the hell did you get the idea that the Amiga can mix 4 channels together for free?
 

Offline bloodline

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Re: Amiga audio early lead lost..
« Reply #37 on: December 27, 2012, 03:10:34 PM »
@Chaoslord I don't mean to be rude, but your rantings are just insane... I love the colour Paula's audio reproduction, but it is far from a "good" sound chip. Even in the mid 80's it was simply "good enough" (ie better than the competition) at the price point.

You go on about the fixed frequency of modern sound chips, but that is the best way to get accurate audio reproduction... The Amiga's frequencies were based on the rate the DMA could feed the chip and this only ever approximations of the required frequency... Etc... :)

Offline ChaosLord

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Re: Amiga audio early lead lost..
« Reply #38 on: December 27, 2012, 03:42:12 PM »
Quote from: Linde;720449
BTW, where the hell did you get the idea that the Amiga can mix 4 channels together for free?

It is practically free.  It uses hardware double buffering.  It uses DMA.  The Paula chip is its own processor that processes information on its own.  It does need a little supervsion from the CPU so its not 100% free, just 95% free.
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Offline ChaosLord

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Re: Amiga audio early lead lost..
« Reply #39 on: December 27, 2012, 03:45:52 PM »
Quote from: bloodline;720450
@Chaoslord I don't mean to be rude, but your rantings are just insane... I love the colour Paula's audio reproduction, but it is far from a "good" sound chip. Even in the mid 80's it was simply "good enough" (ie better than the competition) at the price point.

All u r saying is "I wish Paula had 16-bit audio output".  Well everyone wants that.  Of course it would be better.  Its a tiny tiny design change to Paula but Mehdi Ali would not allow it.  Oh well.


Quote

You go on about the fixed frequency of modern sound chips, but that is the best way to get accurate audio reproduction...

Guess what?  Paula can do fixed frequency too.
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Offline Karlos

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Re: Amiga audio early lead lost..
« Reply #40 on: December 27, 2012, 03:57:31 PM »
Quote from: ChaosLord;720443
Because it has 10 wires.
Because it does not mix the 10 audio streams.


Yes it can, actually, but never mind. I suggest you read the technical data sheets for these parts before making such statements.

Look, I love Paula's unique sound more than most and still compose for it. However, the stuff you come out with at times is just mindbogglingly messed up.

Quote
Because it does not support any kind of useable sampling rates.


In the audio industry, 11025, 22050, 24000, 32000, 44100, 48000 and so on are all standard frequencies. Any dedicated sampler (back in the days when you bought dedicated samplers) even used these frequencies. Entire professionally captured sample libraries were published in them.

However, since you raise the issue, as a musician and coder I must point out that neither does Paula. Paula doesn't even have the concept of a sampling rate; it has a sample period which is the inverse function, a physical duration of time measured in clocks between loading the sample registers. Being a 1/x function and x measured as an integer number of clocks, the error in this approximation gets worse for higher playback rates. I've tested this. Given a synthetic looped sinewave of say 64 samples, you can hear the off-pitch playback, particularly for higher notes when comparing to the same notes rendered by software into a buffer.

Also, Paula doesn't mix the four audio outputs it has, either. At least not digitally. The four channels are configured L R R L at the analogue stage and the audio filter happens after that.

Paula would have been far more useful if each of the 4 channels could be panned and if the audio filter could have been toggled per channel. Better still if the filter had more than one cut off frequency that could be selected.

Quote

Because nobody writes 10 channel mods.
Because nobody writes mods using 100% 44.1Khz sample speed.


Irrelevant. Who cares? All the Amiga mod based music I've written in the last 15 years have been OctaMED Mix Mode because as a musician it's *vastly* more useful than the old 4 channel mode. 4 channel mode is handy if all you care about is CPU time, but if you want to make music for it's own sake, no musician is going to turn down more channels and more control over them.

Quote
Of all the sample speeds used in a random mod, this sound chip supports between 0% and 1% of the required sample rates.


So what? You get a set of industry standard replay rates versus an ad-hoc set of non-standard rates that are the result of dividing your PAL/NTSC clock by some fixed integer value.

Quote
It only outputs what the CPU has already mixed itself into 7.1 format or into 2 channel stereo format.
Either way the sound chip does almost nothing.  Its just 10 dumb DACs sitting there waiting to be spoonfed data from the CPU.


Er, no. It supports all sorts of hardware DSP for channel expansion, equalisation and many other things besides. These are standard features on all modern sound chips, not just the DACs.

The driver has the responsibility of playing a potentially limitless number of input audio streams through whatever hardware configuration the chip has been programmed for, and in that it has to do whatever mixing is required. However, the chip does far more than basic DAC duty. The incoming streams can be at any of the standard audio rates. They are resampled to the configured output rate using nth-order digital filtering, equalized, companded, maybe even a bit of DSP effects depending on whatever goofy preset I select, and formatted for whatever output configuration is selected.

On all but the most unfeatured chipsets, the CPU just does upstream mixing of samples into input streams. Yes that does use CPU time, but it's absolutely insignificant on a modern CPU.

Quote
Its not a Paula or anything of that technology level.


No, it isn't.
int p; // A
 

Offline Karlos

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Re: Amiga audio early lead lost..
« Reply #41 on: December 27, 2012, 04:22:35 PM »
Quote from: ChaosLord;720453
Guess what?  Paula can do fixed frequency too.


No, it can do fixed period. They aren't quite the same. You can't play a 22050Hz stream because there's no integer value you can divide either the PAL or NTSC clock by to get that value. The closest you can get with PAL is ~22030Hz.
int p; // A
 

Offline Linde

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Re: Amiga audio early lead lost..
« Reply #42 on: December 27, 2012, 04:40:01 PM »
Quote from: ChaosLord;720452
It is practically free.  It uses hardware double buffering.  It uses DMA.  The Paula chip is its own processor that processes information on its own.  It does need a little supervsion from the CPU so its not 100% free, just 95% free.
It simply doesn't mix 4 channels together. It mixes channels together in pairs to two different outputs. I.E. sure, you could set it up to output four channels without using any CPU, but nope, it doesn't mix them all together.
« Last Edit: December 27, 2012, 04:44:54 PM by Linde »
 

Offline ChaosLord

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Re: Amiga audio early lead lost..
« Reply #43 on: December 27, 2012, 04:47:24 PM »
Quote from: Karlos;720455
No, it can do fixed period. They aren't quite the same. You can't play a 22050Hz stream because there's no integer value you can divide either the PAL or NTSC clock by to get that value. The closest you can get with PAL is ~22030Hz.


Paula does fixed frequency of 22030hz in PAL or any of a wide range of other values.

And btw: I tried to convince Gunnar that Natami Paula needs a special fix to be able to generate 44100Hz exactly.  But he repeatedly rejected the idea as unnecessary and silly and pointless.  What is your opinion on that?
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Offline ChaosLord

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Re: Amiga audio early lead lost..
« Reply #44 from previous page: December 27, 2012, 04:53:30 PM »
Quote from: Linde;720456
It simply doesn't mix 4 channels together. It mixes channels together in pairs to two different outputs. I.E. sure, you could set it up to output four channels without using any CPU, but nope, it doesn't mix them all together.
 True that it mixes 2 channels to the left and 2 to the right.  But it does not require you to use the CPU to resample all the sounds to a specific frequency.  It supports a giant range of frequencies and just mixes the different samples of different frequencies together like magic.  And it does the mixing on its own with DMA.  One DMA channel per DAC.
Wanna try a wonderfull strategy game with lots of handdrawn anims,
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