some fancy ideas for a extended (68k?) CISC-CPU

[bloodline]

Originally Posted by meynaf

We can get up to 56khz without burning the cpu. I was just stating the limit can be bypassed and you wrongly turned that into a generality. But with your SB live you're locked to 48khz, regardless of your cpu power.

Doing 56Khz on the Amiga, burns both CPU and Chipram bandwidth!! Far more than any mixing algorithm!

It's not the DAC but how it is used. 8 bit data, 6 bit volume. Count.

Ok, the Amiga’s “14bit playback” is definitely not 14bit. You need to take into account the dynamic range of the hardware and the noise floor of the DAC... but as soon as you do subranging, then you need to do the very software mixing you are so against!?

[meynaf]

Originally Posted by bloodline

I’m not sure I can even parse what you are saying here... Thomas has clearly stated, and explained why, it doesn’t matter what hardware you have installed.

If it doesn't matter, then he shouldn't constantly take his own as argument.

Originally Posted by bloodline

You are making an assertion that is demonstrably false.

Nope.

Originally Posted by bloodline

The Amiga on the other hand had very different audio characteristics between models, and even worse, different Mobo revisions and Paula batches sound distinctly different... Not to mention that running the machine in PAL or NTSC messed up the frequency of sample playback!! Amiga Audio is a mess.

That does not really matter. There is nothing here that just prevents doing acceptable audio.

Originally Posted by bloodline

I can send you a simple MOD playback routine I wrote using SDL, where the only complexity is the code to add in the deficiencies of the Amiga hardware to give a more authentic sound!

Yes, please do.

Originally Posted by bloodline

You keep going on about the fixed sample rate of modern hardware, Nyquist-Shannon is what you need to read about. The Amiga also “resamples” the audio data, in exactly the same way as a simple mix algorithm does with a simple sample and hold (more advanced resampling would use bicubic, but that only something one would only use for professional audio samplers).

Amiga has two hardware filters to handle this. It's not simple sample and hold.

Originally Posted by bloodline

Doing 56Khz on the Amiga, burns both CPU and Chipram bandwidth!! Far more than any mixing algorithm!

No it does not.

Originally Posted by bloodline

Ok, the Amiga’s “14bit playback” is definitely not 14bit. You need to take into account the dynamic range of the hardware and the noise floor of the DAC...

This is what 14 bit calibration is for. Unless pushing the volume high and using low amplitude sounds, you can't even hear the difference with 16 bit.
Try it !

Originally Posted by bloodline

but as soon as you do subranging, then you need to do the very software mixing you are so against!?

There is no mixing if we just play a wav file.
And again you're exagerating my position. I'm not against software mixing when it's necessary. The problem is that it's done when not necessary.

[Thorham]

Originally Posted by Thomas Richter

Not anytime soon

But why? You clearly hate Amiga. I've not seen you say a single positive thing about Amiga. Nothing positive at all.

[Thomas Richter]

Originally Posted by Thorham

But why? You clearly hate Amiga. I've not seen you say a single positive thing about Amiga. Nothing positive at all.

No, I don't hate the Amiga. I hate mindless fanboys and fanatics of any kind. People that close their eyes from reality and are incapable of any fair or scientiic comparison.


I'm personally used to AmigaOs, but also to other systems, and I know their limitations. But I don't pretend that AmigaOs is the "Best Operating System Ever!"(tm). None is, but AmigaOs is in multiple ways very very behind. For obvious reasons, of course.

[Thomas Richter]

Originally Posted by meynaf

I also notice you don't give a solution for anyone not having same hardware as you do (which is actually most people).

The solution is to have an abstract interface (something the Amiga is missing). This interface can be DirectSound for Windows, or alsa for Linux, or SDL for multiple platforms.

Originally Posted by meynaf

Try to play simple Protracker with that, before pretenting it's simpler.

Try to play mp3 or AAC with an Amiga. Look, what you don't understand or appreciate is that the problems people want to solve with their computer changed. If I want to play protracker on my Linux box, I use XMMS. It emulates the Amiga audio, which - given the capable hardware - it can do. The reverse - playing mp3 on the Amiga - is much harder, given the much less capable hardware.

Originally Posted by meynaf

Your version says nothing about what's not your version, and what's not your version is what nearly everybody uses.

I don't even understand what you are claiming here. What I'm claiming is that a 2020 Os can certainly run on a 2002 machine, as I demonstrate here, you just have to be a bit careful selecting the Os. There is nothing wrong with its demands, which uses paged memory, virtual memory, ... all the bells and wissles of a modern Os.

Originally Posted by meynaf

But then it is software that is unstable, not the OS.
Frankly there is nothing complicated in giving an error message and bail out.

Ehem. If it would be just so simple to do things right. Side information for you: All datatypes that came with 3.1, and 3.9 have a design bug, a race condition in its LibOpen() code that, under certain conditons, can fail in out of memory situations. You have been lucky enough not to run into them. The problem is that LibOpen() comes with a lot of complexity one wouldn't guess, complexity that is undocumented, and that is part of a design mistake in ramlib and exec. Such mistakes were left unnoticed for more than a decade, and didn't do much harm because it's hard to hit them. Yet, they are bugs in the memory management.



Every non-trivial program has bugs, and the Os should do its best to keep the system running in case they are triggered. AmigaOs cannot do that.

Originally Posted by meynaf

So you're saying Oses of today are fine, based on examples... found in third party libraries. If the OS was good to start with, there would have been no need for libraries such as ALSA. Besides, why would i care about Linux.

Alsa is an abstraction layer to play sound, a rather thin one. It just wraps library calls with human-readable names to ioctl()-calls of the corresponding kernel interface. Roughly comparable to DirectSound, which is also an abstraction layer.



Why you would care I do not know, but you seem to complain a lot on the "bloat" of windows, and confuse that with the "bloat" of any other operating system. Yet, you fail to appreciate that there are certainly choices for operating systems where you control how much services (or "bloat" in your language) run.

Originally Posted by meynaf

How many sound channels does Atari Falcon have ? It has a DSP after all, so we could pretend it has just any number.

I don't know, but the DSP alone does not define that. Rather, the (internal) bit precision limits the amount of channels you can realistically emulate.

Originally Posted by meynaf

Nah, it's working fine on my A1230/50 and i can still do other things on the machine. I can overload it 100% cpu and it never misses a buffer. I could even offer the luxury of using oversampling mixing method -- no hearable distortion then.

You should probably get some younger person to listen. People of our age have a problem with anything beyond 12Khz and high sample precision.

Originally Posted by meynaf

We can get up to 56khz without burning the cpu. I was just stating the limit can be bypassed and you wrongly turned that into a generality. But with your SB live you're locked to 48khz, regardless of your cpu power.

No, it's not locked. That's the point. That's not an AC97 codec with a fixed sampling frequency. It's input channel (does the Amiga have that? Nope) has a fixed 48Khz resolution, but not the playback.

Originally Posted by meynaf

It's not the DAC but how it is used. 8 bit data, 6 bit volume. Count.

It is the DAC. Do you seriously believed that's linear with 14 bits? "Calibration" works around the worst non-linearities, but you still get a considerable amount of non-linearity and distortion, and a higher noise-floor than any "worth its money" audio hardware you get for a PC.

Originally Posted by meynaf

Of course yes it does. Anything that's not 48khz gets resampled.

Make yourself a pleasure and read about it. The wikipedia page has a lot to say.

Originally Posted by meynaf

Browsing the internet wasn't the point.

It's a point for many.

Originally Posted by meynaf

But if you want to get there, again, ask Gunnar for how his 100mhz accelerator allows browsing the web. You might be surprised.

Not really. You still don't have a browser that can display any reasonably modern web page. Javascript, CSS... all this is only partially supported, and slloooowww.

Originally Posted by meynaf

And Unix is incredibly old, much older than the Amiga.

Absolutely. But it has a robust design. It's not the age that makes a difference, but whether it is designed properly, and maintained properly. Amiga is just locked in in its mistakes.


Not saying that Unix doesn't have some, either. But they are much less fatal for a robust service.



[QUOTE=meynaf;1449634]





And again, you're just plain 100% wrong. I don't lack experience with other systems. I coded on litterally everything ranging from pic microcontrollers to ibm c370. And of course - alas - also on the pc.
[QUOTE]
Apparently, you do. Know nothing about alsa, or linux, or xfce.

Originally Posted by meynaf

And it's by no manner something "new". It's just something old that has been dirtily expanded.

Windows? Well, MS was sane enough to through DOS overboard at some point, a non-secure, unprotected, outdated layer on top of the Bios. Right so. AmigaOs.... that step never happened.

Originally Posted by meynaf

Market success, when we have no choice ? What a joke.

You have a choice. I made my choice. I have Amigas here, and Linux boxes (like this one), and also a Windows machine. Everything has its value, and its purpose.

[meynaf]

Originally Posted by Thomas Richter

The solution is to have an abstract interface (something the Amiga is missing). This interface can be DirectSound for Windows, or alsa for Linux, or SDL for multiple platforms.

Something the Amiga is NOT missing. We have AHI. And apparently some SDL versions also work. Some music formats (like MaxTrax) use audio.device without touching the hardware. Writing a new one wouldn't be difficult either.

Originally Posted by Thomas Richter

Try to play mp3 or AAC with an Amiga.

Done. I could play mp3 on my 030 with acceptable quality after optimising mpega.library, and i can also play aac under winuae (i think vampire cards have enough power to do it too).

Originally Posted by Thomas Richter

Look, what you don't understand or appreciate is that the problems people want to solve with their computer changed. If I want to play protracker on my Linux box, I use XMMS. It emulates the Amiga audio, which - given the capable hardware - it can do. The reverse - playing mp3 on the Amiga - is much harder, given the much less capable hardware.

Playing mp3 is well within 060 reach, and within 030 reach with a few compromises. Use XMMS if you want, but it will incorrectly replay some files, like every PC player to this date except Deliplayer.

Originally Posted by Thomas Richter

I don't even understand what you are claiming here. What I'm claiming is that a 2020 Os can certainly run on a 2002 machine, as I demonstrate here, you just have to be a bit careful selecting the Os. There is nothing wrong with its demands, which uses paged memory, virtual memory, ... all the bells and wissles of a modern Os.

So an OS from 2020 runs on a 2002 machine. Big deal.

Originally Posted by Thomas Richter

Ehem. If it would be just so simple to do things right.

It is. But most programmers prefer to do complex and unwieldy things instead. Matter to satisfy their ego, maybe, i don't know.

Originally Posted by Thomas Richter

Side information for you: All datatypes that came with 3.1, and 3.9 have a design bug, a race condition in its LibOpen() code that, under certain conditons, can fail in out of memory situations. You have been lucky enough not to run into them. The problem is that LibOpen() comes with a lot of complexity one wouldn't guess, complexity that is undocumented, and that is part of a design mistake in ramlib and exec. Such mistakes were left unnoticed for more than a decade, and didn't do much harm because it's hard to hit them. Yet, they are bugs in the memory management.

I haven't been lucky, i have been prudent enough to keep my good old 3.0. Who made post-v39 changes already ?

Originally Posted by Thomas Richter

Every non-trivial program has bugs, and the Os should do its best to keep the system running in case they are triggered. AmigaOs cannot do that.

AmigaOs does not need to do that.
Bugs that are not detected at development time are for the most part harmless : program will not do what's expected or have glitches, but real crashes are rare.
On big machines I've seen programs that have run during 40 years without an error.

Originally Posted by Thomas Richter

Alsa is an abstraction layer to play sound, a rather thin one. It just wraps library calls with human-readable names to ioctl()-calls of the corresponding kernel interface. Roughly comparable to DirectSound, which is also an abstraction layer.

I have written my own abstraction layer, the problem is just to make it work on other machines. On the Amiga, implementation was so easy.

Originally Posted by Thomas Richter

Why you would care I do not know, but you seem to complain a lot on the "bloat" of windows, and confuse that with the "bloat" of any other operating system.

Linux is certainly a lot more bloat than AmigaOs. Try them on same machine. An Amiga can run linux m68k but that's useless.

Originally Posted by Thomas Richter

Yet, you fail to appreciate that there are certainly choices for operating systems where you control how much services (or "bloat" in your language) run.

Nah, sorry, if i kill processes that take time where they shouldn't, the machine won't work anymore. They are system processes. Probably not possible to even kill for most of then, actually.

Originally Posted by Thomas Richter

I don't know, but the DSP alone does not define that. Rather, the (internal) bit precision limits the amount of channels you can realistically emulate.

Having direct access to the DSP means you can do what you want. But maybe on your PC board you don't have that ?

Originally Posted by Thomas Richter

You should probably get some younger person to listen. People of our age have a problem with anything beyond 12Khz and high sample precision.

I got my A1200 at the age of 21 so i think i would have noticed something by now.

Originally Posted by Thomas Richter

No, it's not locked. That's the point. That's not an AC97 codec with a fixed sampling frequency. It's input channel (does the Amiga have that? Nope) has a fixed 48Khz resolution, but not the playback.

We can add hardware to give an input channel to an Amiga, obviously, so stop this mud slinging. Amigas could sample sounds before peecees could play them.
Now what does that mean (wikipedia extracts) :
"The SB/Live had great difficulty with resampling audio-CD source material (44.1 kHz) without introducing audible distortion."
"The DSP had an internal fixed sample rate of 48 kHz"
"the AC'97 chip provided an internal 48 kHz DAC"

Originally Posted by Thomas Richter

It is the DAC. Do you seriously believed that's linear with 14 bits? "Calibration" works around the worst non-linearities, but you still get a considerable amount of non-linearity and distortion, and a higher noise-floor than any "worth its money" audio hardware you get for a PC.

It's still better than just 8 bits, and for most uses it's good enough. Try it, really.

Originally Posted by Thomas Richter

Make yourself a pleasure and read about it. The wikipedia page has a lot to say.

The shortcoming part is indeed interesting.

Originally Posted by Thomas Richter

It's a point for many.

You can say what you want, but give it enough cpu power (with adequate software) and the Amiga will be able to do anything other platforms can do - with less resources involved.

Originally Posted by Thomas Richter

Not really. You still don't have a browser that can display any reasonably modern web page. Javascript, CSS... all this is only partially supported, and slloooowww.

Well, see where your 2002 machine goes when it comes to heavy duty javascript, or when having many pages open at once.

Originally Posted by Thomas Richter

Absolutely. But it has a robust design. It's not the age that makes a difference, but whether it is designed properly, and maintained properly. Amiga is just locked in in its mistakes.

Not saying that Unix doesn't have some, either. But they are much less fatal for a robust service.

That depends what kind of service. For gaming it's not exactly an adequate architecture.

Originally Posted by meynaf

Apparently, you do. Know nothing about alsa, or linux, or xfce.

I don't pretend to know everything. And i don't care about linux either, as already mentioned. It's not as if it had a significant desktop market share.

Originally Posted by Thomas Richter

Windows? Well, MS was sane enough to through DOS overboard at some point, a non-secure, unprotected, outdated layer on top of the Bios. Right so. AmigaOs.... that step never happened.

And obviously you don't want it to ever happen.

Originally Posted by Thomas Richter

You have a choice. I made my choice. I have Amigas here, and Linux boxes (like this one), and also a Windows machine. Everything has its value, and its purpose.

Really, i just want a machine that is fun to code on.

[bloodline]

Originally Posted by meynaf

That does not really matter. There is nothing here that just prevents doing acceptable audio.

All of what I listed make the Amiga Audio totally unacceptable in 2021.

Yes, please do.

Ok, attached... This code was written in a few hours one evening as a placeholder for a game engine I was contracted to write the audio engine, to test running the music playback in a separate thread (IIRC the in game sound effects ran in the main thread). The production code didn't use amiga tracker MODs.

Amiga has two hardware filters to handle this. It's not simple sample and hold.

All digital audio reproduction hardware has appropriately matched filters to perform the reconstruction of the waveform from the DAC signal... And as soon as you filter below 22050Hz you no longer have a high fidelity system.

You can pump the DACs as fast as you like (even 56kHz), you aren't getting any better audio fidelity.

This is what 14 bit calibration is for. Unless pushing the volume high and using low amplitude sounds, you can't even hear the difference with 16 bit.
Try it !

Ironically, the nonlinear nature of the Paula DACs probably works in their favour here providing a degree of dithering, all the calibration is going to do is reduce the DAC noise when there is supposed to be silence.

There is no mixing if we just play a wav file.
And again you're exagerating my position. I'm not against software mixing when it's necessary. The problem is that it's done when not necessary.

But you argument is about how useful the Amiga is in the 21st century. Surely you want to be doing more than one thing with your Amiga at any time?

[Bruce Abbott]

Originally Posted by Thomas Richter

No, it's not. MS-DOS is is something that operates the disk, but not the system. Don't trust the label. Trust what it does - which isn't much.

MS-DOS is an operating system, according to everyone but you. Make up your own definition if you like, but don't expect anyone else to agree with it.

After being introduced by IBM in 1981 as PC DOS, it very quickly became the OS standard for desktop computers, remaining so for the entire period of the Amiga's existence. For something that 'isn't much' its influence was enormous, so much that no other OS managed to dent the hold it had over the market.

But of course you have to dismiss MS-DOS, because if you didn't you would have to admit that Amiga OS was more sophisticated than the industry standard 'serious' OS of the time.

Not really. That's not the reason why people bought it. In fact, most people only used the boot loader of the Os.

So you went back in time and surveyed all the games 'most' people played? No, of course you didn't.

A fair proportion of Amiga games did actually use the OS while running, including famous titles that 'most people' almost certainly played at one time or another. This includes some that were bundled with the A500, so we can bet that pretty much every Amiga user used more than just the bootloader part of the OS.

And that's just games. I don't know about where you come from, but down here in New Zealand virtually all Amigas were bought by people who used their expensive purchase for more than just games. I should know, I owned and operated a computer store selling Amigas from 1991 to 2000.

AmigaOs also "needed to", but there was no business left and no customers left, so CBM went bust.

No, it didn't need to. Most Amiga users were quite happy with how the OS worked - it was hardware performance and compatibility with the 'industry standard' that the Amiga needed to improve. The vast majority of users who switched to PCs did so not because Amiga OS was lacking, but because the latest games, apps, and peripherals were only being produced for PCs. By the time PC's 'needed' a better OS Commodore was long gone and nothing could save the Amiga.

Which modern hardware is available for the Amiga today? I beg your pardon.

There you go again, redefining the word 'modern' to mean only stuff that is specific to PCs.

That's the difference between a toy and a professional application. The word "retro" already puts it - this is not about computing at all, but about memories. Nothing bad about that, but don't pretend the Amiga is anything modern or competative.

Competitive with what? There is more to life than desktop PCs and smartphones.

More and more people today are finding that 'modern' is actually not that interesting to them. They want something they can understand and create with without a lifetime of study and being told how they have to do it. A huge amount of activity in the 'toy' category is now spilling over into 'professional' areas, via the 'maker community' which is using tiny MCU boards and modules for embedded applications. There is no fundamental reason why an Amiga inspired architecture couldn't make inroads into that market, even if just as a 'toy'. Toys are actually big business.

There is no "path". The system is defined by how it was defined in 1990, essentially. If you want a "path", get a smartphone. There we have "paths" in front of us.

Nonsense. Smartphones are not a 'path', they are a mature tech and a dead end. In another 10 years they won't be significantly different from now.

That depends on "to whom" it is interesting. There are also people that ride horses, and to them horses are interesting. Yet, nobody seriously considers them as an appropriate replacement for cars, yet that's exactly by what they have been replaced.

A poor analogy. A better one would be electric motors vs internal combustion engines. The 'modern' IC engine is far more sophisticated than what we were driving 30 years ago, while electric motors haven't changed significantly over that period and (until recently) were treated as an outdated failed technology.

But today I see many people riding ebikes and scooters who would have laughed at the idea a few years ago. I still only see electric cars occasionally (apart from my own one), but the market is expanding rapidly and every major manufacturer has committed to transitioning to electric - even those who only recently considered them a joke. Why? Because some people (the 'trend setters') bought electric vehicles because they were interesting, despite having severe limitations compared to gas cars.

I get in a gas car today and think - why do I have to wait so long for it to warm up? Why does it feel like a rubber band is winding up every time I want to go? Why does it make all that noise? Why do I have to fill it up with this expensive, dangerous, polluting chemical that is only available from purpose-built 'gas stations' far from home? Why does it have to be serviced every 6 months, and why does it smell so bad?

The answer? "That's what a modern car is", they say, "and it cannot be any other way. Your Leaf is just an outdated inadequate technology that will never replace it. We laugh at you for buying a 'retro' car and thinking you will enjoy driving it more than our modern SUVs, let alone get any practical use out of it". And yet I do - just like I do from my Amiga.

I don't deny that one can be interested in Amiga (so I am), but not because it is an appropriate computer by any modern definition.

Think about where you are, and consider that perhaps people here are not so interested in turning their Amigas into 'modern' computers. If they were, they would just get a PC! Think of it more as finding ways to power our bicycles electrically so we can ride them on the same roads as 'modern' cars. And while we might be only be riding for fun, our bikes could also have 'serious' applications.

[meynaf]

Originally Posted by bloodline

All of what I listed make the Amiga Audio totally unacceptable in 2021.

What you listed is just theory. Listen to it. It is perfectly acceptable.

Originally Posted by bloodline

Ok, attached... This code was written in a few hours one evening as a placeholder for a game engine I was contracted to write the audio engine, to test running the music playback in a separate thread (IIRC the in game sound effects ran in the main thread). The production code didn't use amiga tracker MODs.

What i can see is that it uses poor quality mixing method (no interpolation or filtering of any kind). Which means, of course, that you actually had to do said mixing yourself.
So thanks. What a nice demonstration that the "abstraction layer" is indeed quite inept.
Frankly you can't decently pretend this is in any way better than an Amiga.

Originally Posted by bloodline

All digital audio reproduction hardware has appropriately matched filters to perform the reconstruction of the waveform from the DAC signal... And as soon as you filter below 22050Hz you no longer have a high fidelity system.

You can pump the DACs as fast as you like (even 56kHz), you aren't getting any better audio fidelity.

Again, this is just theory.

Originally Posted by bloodline

Ironically, the nonlinear nature of the Paula DACs probably works in their favour here providing a degree of dithering, all the calibration is going to do is reduce the DAC noise when there is supposed to be silence.

As i said, try it.

Originally Posted by bloodline

But you argument is about how useful the Amiga is in the 21st century. Surely you want to be doing more than one thing with your Amiga at any time?

And this is exactly what i can do. My A1200 just has 030 ; what it can do, on a 060 it would do with just around 25% cpu use. If still not enough, there is the V1200.

[bloodline]

Originally Posted by meynaf

What you listed is just theory. Listen to it. It is perfectly acceptable.

“Just a theory”... I suppose you don’t believe in gravity either? The quality of the Amiga audio is acceptable to people like us who want that audio character... but it is essentially useless now for the application it was designed. Poor quality and extremely limited, even back in the day is was a struggle to use in games, with sound effects panned hard left or right, and stealing a channel from the music if you used any more than three channels... not to mention that there can be no overlap of samples, and no environmental effects. All things which were becoming normal in games by the early ‘90s.

What i can see is that it uses poor quality mixing method (no interpolation or filtering of any kind). Which means, of course, that you actually had to do said mixing yourself.
So thanks. What a nice demonstration that the "abstraction layer" is indeed quite inept.
Frankly you can't decently pretend this is in any way better than an Amiga.

Do you enjoy moving the goalposts? I said it was easy it implement a tracker using the SDL audio API, I never said this code was good. I’m not going to defend ten year old code, written in an hour just to test multithreading.

I thought this code also included the low pass filter, and the nonlinear 8bit->16bit lookup table, apparently not... I think this code does use Amiga tuning, and timing... and the the software mixing, that was so I could implement the channel cross talk present on Amigas, which modern hardware doesn’t do.

As i said, try it.

I appreciate I haven’t explicitly stated it, but quite a bit of my career has been developing audio software/systems... in the 90s I tried everything to get better audio quality from the Amiga, that’s how I learned so much about the limitations of the hardware.

Back then I had to get a Roland W-30 music workstation to get professional quality audio. At the time it was really good and you could build a significant proportion of a song using it, but now it is useless for the task it was designed... I have kept it because, like the Amiga, it has some interesting audio characteristics.

And this is exactly what i can do. My A1200 just has 030 ; what it can do, on a 060 it would do with just around 25% cpu use. If still not enough, there is the V1200.

I think the problem here, is that I love using my Amiga because of its limitations, and you seem to love it in spite of them!

[meynaf]

Originally Posted by bloodline

“Just a theory”... I suppose you don’t believe in gravity either?

Don't be a fool, gravity is something we can experience every day.

Originally Posted by bloodline

The quality of the Amiga audio is acceptable to people like us who want that audio character... but it is essentially useless now for the application it was designed. Poor quality and extremely limited, even back in the day is was a struggle to use in games, with sound effects panned hard left or right, and stealing a channel from the music if you used any more than three channels... not to mention that there can be no overlap of samples, and no environmental effects. All things which were becoming normal in games by the early ‘90s.

It really depends how far you push the sound chip with more cpu use. Oh, wait. On the peecee it's a necessity to burn cpu.
What do you mean by "overlap of samples" ?
What do you mean by "environmental effects" ?
Games of early 90's had nothing special.

Originally Posted by bloodline

Do you enjoy moving the goalposts? I said it was easy it implement a tracker using the SDL audio API, I never said this code was good. I’m not going to defend ten year old code, written in an hour just to test multithreading.

You said it was easy, but you didn't actually do it. Things are always easy for people who don't really do them. I haven't moved the goalposts, you just didn't reach them.

Originally Posted by bloodline

I thought this code also included the low pass filter, and the nonlinear 8bit->16bit lookup table, apparently not... I think this code does use Amiga tuning, and timing... and the the software mixing, that was so I could implement the channel cross talk present on Amigas, which modern hardware doesn’t do.

But no lowpass filter, nothing fancy you mentioned. It's just the old cheap handwritten mixing giving the old boring pc standard of two voices and single channel at the end.
Where's the "better" here ?

Originally Posted by bloodline

I appreciate I haven’t explicitly stated it, but quite a bit of my career has been developing audio software/systems... in the 90s I tried everything to get better audio quality from the Amiga, that’s how I learned so much about the limitations of the hardware.

Back then I had to get a Roland W-30 music workstation to get professional quality audio. At the time it was really good and you could build a significant proportion of a song using it, but now it is useless for the task it was designed... I have kept it because, like the Amiga, it has some interesting audio characteristics.

This is by far not the casual use of audio, i.e. music and sound effects - for which the Amiga is still fine.

Originally Posted by bloodline

I think the problem here, is that I love using my Amiga because of its limitations, and you seem to love it in spite of them!

Isn't it wonderful ? Everyone likes their machines for different reasons.

[bloodline]

Originally Posted by meynaf

Don't be a fool, gravity is something we can experience every day.

Indeed... and that was rather my point.

It really depends how far you push the sound chip with more cpu use. Oh, wait. On the peecee it's a necessity to burn cpu.
What do you mean by "overlap of samples" ?
What do you mean by "environmental effects" ?
Games of early 90's had nothing special.

“Overlap of samples”, when a new samples plays the old one stops. Not cleanly with a fade to 0, but a hard stop, the Paula DAC might go from 127 to -128 in a single sample. It’s a good job the Amiga had such an aggressive low pass filter or a transient like that might damage some audio systems, though probably not any consumer audio equipment available in the ‘80s.

Environmental effects, like delays and reverbs... by the early ‘90s, the Amiga Audio was just about ok for games... but game developers were looking at the horizon and planning for better!

You said it was easy, but you didn't actually do it. Things are always easy for people who don't really do them. I haven't moved the goalposts, you just didn't reach them.

You claim was that it was easier to set up and use the Amiga Audio system than SDL, you suggested it would be difficult to write a tracker in using SDL... Frankly, it was trivial, I think I wrote this on my laptop while watching Family Guy!

But no lowpass filter, nothing fancy you mentioned. It's just the old cheap handwritten mixing giving the old boring pc standard of two voices and single channel at the end.
Where's the "better" here ?

Now I have had a chance to look over the code, it’s quite convoluted because I wanted to be able to add such things to make the audio more like the Amiga (certainly not better)... for example I clearly wanted the ability to cut off a playing sample, as I’ve made quite an effort to allow that to happen outside of the tracker playback routine!

This code never went in production, which is why I still own the rights to it and can share it. If it were for serious work, I would always use 32bit float audio, not 16bit

It would be even simpler if I just used the audio device raw, opened 4 8bit channels etc (you can read how the SDL API works... and half the code is just structure definitions and byte swapping! I also seem to have wanted the ability to “O’Scope” the individual channels (I have no idea what my plan was for that, but that has made the code more convoluted too...

Why not add an LP filter and whatever else you like, you might find it fun.

This is by far not the casual use of audio, i.e. music and sound effects - for which the Amiga is still fine.

For nostalgia junkies like us, but that wasn’t the original intention of the machine, and certainly it would not be of any use to most people now who want to game/produce music/enjoy music! All things that one can easily do on a cheap laptop now!

Isn't it wonderful ? Everyone likes their machines for different reasons.

But why do you deny the characteristics which made it interesting? Had the Amiga produced perfectly good high fidelity audio, I definitely wouldn’t still have one in my studio!! There just wouldn’t be any point!

[Bruce Abbott]

Originally Posted by bloodline

I think the problem here, is that I love using my Amiga because of its limitations, and you seem to love it in spite of them!

I love using my Amiga without worrying about limitations that aren't a big deal.

My high frequency hearing is so shot that I can hardly tell the difference between 8 bit and 16 bit sound, or 16kHz and 44kHz. I am amazed by how good those old 8 bit 4 channel Mods sound, blasting out of my stereo with huge speakers producing enough sound to drown out the constant tinnitus I am afflicted with. I prefer standard 640x256 resolution in composite video because my eyes can't handle pin sharp high resolution screens for long. My Amiga may be old and incapable of the performance people expect today, but it suits my old body perfectly.

Modern PCs may be far more capable, but they still seem to suffer from unexplained delays and poor response at random times. I can turn on my A1200, fire up a Mod player and have continuous music playing in seconds with no noticeable effect on performance, unlike my PC which takes an age to start up, constantly runs into virtual memory and thrashes around for no good reason.

On my Amiga I often have several programs running on their own screens, each totally independent and instantly accessible when I need them. I can drag screens down or flick between them to see something on one while typing into another, whereas on the PC I am forever minimizing and expanding windows in an attempt to do the same.

The Amiga is slower at doing some things for sure, but compared to the PC it is far more consistent. In general operation it feels responsive, solid, and reliable - almost like pure hardware - whereas the PC is frustratingly vague and often makes me feel like I am the lowest priority to it.

Yes, the Amiga has limitations, but they often aren't a big deal, and can sometimes even be an advantage. No virtual memory means programs can't allocate Gigabytes and then slow the computer down to a crawl. Not powerful enough to play streaming video so I don't struggle trying to shut them down in the web browser before it locks up trying to do too much. Not quite powerful enough to play mp3s without sucking up all the CPU time, so I am 'forced' to play - and appreciate - those wonderful Mods instead!

[Bruce Abbott]

Originally Posted by bloodline

All things that one can easily do on a cheap laptop now!

That's great for people who already have a cheap laptop, I guess. But if I had the money to buy a reasonable laptop, I would have the money to buy a CD32 so...

[meynaf]

Originally Posted by bloodline

Indeed... and that was rather my point.

But mine is that your analogy isn't valid.

Originally Posted by bloodline

“Overlap of samples”, when a new samples plays the old one stops. Not cleanly with a fade to 0, but a hard stop, the Paula DAC might go from 127 to -128 in a single sample. It’s a good job the Amiga had such an aggressive low pass filter or a transient like that might damage some audio systems, though probably not any consumer audio equipment available in the ‘80s.

If this annoys you that much, it's possible to do that in software... just like peecees.

Originally Posted by bloodline

Environmental effects, like delays and reverbs... by the early ‘90s, the Amiga Audio was just about ok for games... but game developers were looking at the horizon and planning for better!

Not in early 90's, no. And Amiga can of course do that too.

Originally Posted by bloodline

You claim was that it was easier to set up and use the Amiga Audio system than SDL, you suggested it would be difficult to write a tracker in using SDL... Frankly, it was trivial, I think I wrote this on my laptop while watching Family Guy!

As i said, you didn't actually do it. Do not take as base something that has not been agreed with.

Originally Posted by bloodline

Now I have had a chance to look over the code, it’s quite convoluted because I wanted to be able to add such things to make the audio more like the Amiga (certainly not better)... for example I clearly wanted the ability to cut off a playing sample, as I’ve made quite an effort to allow that to happen outside of the tracker playback routine!

This code never went in production, which is why I still own the rights to it and can share it. If it were for serious work, I would always use 32bit float audio, not 16bit

It would be even simpler if I just used the audio device raw, opened 4 8bit channels etc (you can read how the SDL API works... and half the code is just structure definitions and byte swapping! I also seem to have wanted the ability to “O’Scope” the individual channels (I have no idea what my plan was for that, but that has made the code more convoluted too...

Last time i've looked at SDL API, i haven't seen something like ability to open 4 8bit channels. At least, not with independent frequency and volume (aka "totally useless").

Originally Posted by bloodline

Why not add an LP filter and whatever else you like, you might find it fun.

What ? The so much marvellous hardware abstraction doesn't do this ?
No, really, i wouldn't find it fun. However, would you find it fun to implement the audio API i want to have in my VM ? As it's so easy according to you.

Originally Posted by bloodline

For nostalgia junkies like us, but that wasn’t the original intention of the machine, and certainly it would not be of any use to most people now who want to game/produce music/enjoy music! All things that one can easily do on a cheap laptop now!

Your cheap laptop must still be connected to something better than its internal speakers to have a good enough sound, so it's not that cheap at the end.

Originally Posted by bloodline

But why do you deny the characteristics which made it interesting? Had the Amiga produced perfectly good high fidelity audio, I definitely wouldn’t still have one in my studio!! There just wouldn’t be any point!

You have chosen the characteristics you find interesting, i have chosen mine. They just differ.

[Thorham]

Originally Posted by bloodline

For nostalgia junkies like us

I'm as nostalgic as a pile of bricks! No, really. I never stopped using my A1200.

Originally Posted by bloodline

But why do you deny the characteristics which made it interesting? Had the Amiga produced perfectly good high fidelity audio, I definitely wouldn’t still have one in my studio!! There just wouldn’t be any point!

The A1200 doesn't have any interesting characteristics when you turn the audio filter off and can sound quite good for WAV files made from CDs. This character you speak off comes from the filter and low fidelity samples. Other Amigas have some filter crap going on, and on the A1200 you get similarly shitty sound if you turn the filter on.

[bloodline]

Originally Posted by meynaf

But mine is that your analogy isn't valid.

I feel like I’m being trolled. Perhaps my use of langue is an issue? But, I’m sorry to say my French is abysmal, so I have to use English, and I’m honestly embarrassed by this fact.

If this annoys you that much, it's possible to do that in software... just like peecees.

I’m not sure you have understood me. The Amiga only has 4 DMA channels, and that’s it. There can only be one buffer played at any time. If you change the buffer, like one would with a tracker, the output doesn’t neatly cross fade, it hard cuts between them. This is a very serious limitation, hence the need for an aggressive (read fidelity crushing) low pass filter.

Not in early 90's, no. And Amiga can of course do that too.

No, not without our using serious amounts of CPU, and definitely needing to use a mix buffer... you simply couldn’t do that in an Amiga game.

As i said, you didn't actually do it. Do not take as base something that has not been agreed with.

I’ve just compiled it with Clang, the code only needs the SDL2 headers... it definitely still works... though I apparently didn’t bother to implement many of the track commands.

Last time i've looked at SDL API, i haven't seen something like ability to open 4 8bit channels. At least, not with independent frequency and volume (aka "totally useless").

I’ve already explained this, the “independent frequency” of each channel is just the DMA fetch period. It’s impossible to get equal temperament frequency steps with the Amiga’s DMA... all music made this way on the Amiga is out of tune. This is a serious limitation (and one that I have recreated in my tracker code).

The Amiga DACs just get fed a value by the DMA, and will hold that value until next sample. This is how the Amiga resamples its audio buffers. I have used this same technique in my tracker code, as it introduces harmonics via aliasing, which would be better filtered out, but again that’s a limitation of the way the Amiga produces audio.

If memory serves the actual DACs in paula are a couple of 1bit 3.5Mhz PDMs, which is why they need the reconstruction filter stages. The model exposed to the programmer doesn’t really match the reality of what is going on. So it’s probably time to move away that particular point.

If it helps, think of the audio callback as the DMA... the model is much the same.

What ? The so much marvellous hardware abstraction doesn't do this ?
No, really, i wouldn't find it fun. However, would you find it fun to implement the audio API i want to have in my VM ? As it's so easy according to you.

The SDL abstraction is meant for cross platform games, it exposes everything needed to, as simply as possible to meet those requirements without vendor lock in which is what the Amiga does.

Also if you have a high fidelity (16bit, 44.1kHz or better) playback device, like you will find on a modern computer, you don’t need an aggressive low pass filter to try and hide all the distortion and noise in the audio signal!

Your cheap laptop must still be connected to something better than its internal speakers to have a good enough sound, so it's not that cheap at the end.

The poor quality of the Amiga’s audio is apparent even using crappy speakers... garbage in, garbage out.

You have chosen the characteristics you find interesting, i have chosen mine. They just differ.

You seem to make great pains to deny that the Amiga has any characteristics!

[Thorham]

Originally Posted by bloodline

This is a very serious limitation, hence the need for an aggressive (read fidelity crushing) low pass filter.

A1200 doesn't have this except for the software controllable filter.

Originally Posted by bloodline

No, not without our using serious amounts of CPU, and definitely needing to use a mix buffer... you simply couldn’t do that in an Amiga game.

68030

Originally Posted by bloodline

Also if you have a high fidelity (16bit, 44.1kHz or better) playback device, like you will find on a modern computer, you don’t need an aggressive low pass filter to try and hide all the distortion and noise in the audio signal!

A1200 can do ~14bit ~44.1khz WITHOUT this stupid filter. Lookup audio filter mods.

Originally Posted by bloodline

The poor quality of the Amiga’s audio is apparent even using crappy speakers... garbage in, garbage out.

Again, NOT on the A1200 because of the lack of this shitty default filter.

Originally Posted by bloodline

You seem to make great pains to deny that the Amiga has any characteristics!

They come from the shitty filter that's part of the analog parts of the audio circuitry. The A1200 doesn't have this problem, and other models can be easily modded.

It's the fukken filter

Anyway, CD style audio sounds similar to my peecee on my A1200, except for softer passages in music.

[meynaf]

Originally Posted by bloodline

I feel like I’m being trolled. Perhaps my use of langue is an issue? But, I’m sorry to say my French is abysmal, so I have to use English, and I’m honestly embarrassed by this fact.

You're not trolled, but indeed language barriers don't help. While my English isn't abysmal (in its written form), it's clearly not the right tool.

Originally Posted by bloodline

I’m not sure you have understood me. The Amiga only has 4 DMA channels, and that’s it. There can only be one buffer played at any time. If you change the buffer, like one would with a tracker, the output doesn’t neatly cross fade, it hard cuts between them. This is a very serious limitation, hence the need for an aggressive (read fidelity crushing) low pass filter.

And you think peecees, which (unless using special sound board) are single DMA channel (regardless of number of voices) do better ?
Everyone has single buffer played at any time !
But you can "program" next buffer, if it's what you mean, to seamlessly continue playing.

Originally Posted by bloodline

No, not without our using serious amounts of CPU, and definitely needing to use a mix buffer... you simply couldn’t do that in an Amiga game.

With default 68EC020 of A1200 SuperStardust already manages to play multichannel s3m during the menu. So Thorham is right : 68030 !

Originally Posted by bloodline

I’ve just compiled it with Clang, the code only needs the SDL2 headers... it definitely still works... though I apparently didn’t bother to implement many of the track commands.

The ability to compile and run without errors are not my definition of "working".

Originally Posted by bloodline

I’ve already explained this, the “independent frequency” of each channel is just the DMA fetch period. It’s impossible to get equal temperament frequency steps with the Amiga’s DMA... all music made this way on the Amiga is out of tune. This is a serious limitation (and one that I have recreated in my tracker code).

Oh no. You really seem to have absolutey no idea of how the Amiga plays sounds...
Please let me explain.
The period isn't just the DMA fetch period. It is actually the real speed at which the AUDxDAT (audio data registers) are fed to the DAC. Whenever AUDxDAT is empty (it contains two samples), the DMA refills it.
You can also feed these registers with CPU to remove DMA speed limits.
And the time between two samples is of course constant.

Originally Posted by bloodline

The Amiga DACs just get fed a value by the DMA, and will hold that value until next sample. This is how the Amiga resamples its audio buffers. I have used this same technique in my tracker code, as it introduces harmonics via aliasing, which would be better filtered out, but again that’s a limitation of the way the Amiga produces audio.

It is of course filtered out, there are no aliasing harmonics.

Originally Posted by bloodline

If memory serves the actual DACs in paula are a couple of 1bit 3.5Mhz PDMs, which is why they need the reconstruction filter stages. The model exposed to the programmer doesn’t really match the reality of what is going on. So it’s probably time to move away that particular point.

Your memory doesn't serve
The DACs are true 8-bit, using PWM for volume.

Originally Posted by bloodline

If it helps, think of the audio callback as the DMA... the model is much the same.

Except that the DMA doesn't miss in case of system overload.

Originally Posted by bloodline

The SDL abstraction is meant for cross platform games, it exposes everything needed to, as simply as possible to meet those requirements without vendor lock in which is what the Amiga does.

This does not in any manner make it better than the Amiga, far not.

Originally Posted by bloodline

Also if you have a high fidelity (16bit, 44.1kHz or better) playback device, like you will find on a modern computer, you don’t need an aggressive low pass filter to try and hide all the distortion and noise in the audio signal!

Thorham was faster

Originally Posted by bloodline

The poor quality of the Amiga’s audio is apparent even using crappy speakers... garbage in, garbage out.

No, my A1200 has always sounded great.

Originally Posted by bloodline

You seem to make great pains to deny that the Amiga has any characteristics!

You seem to not understand what i write...

[bloodline]

Originally Posted by Thorham

A1200 doesn't have this except for the software controllable filter.

AFAIK paula is essentially using a Sigma-delta DAC technique... so you will need a reconstruction filter regardless

A1200 can do ~14bit ~44.1khz WITHOUT this stupid filter. Lookup audio filter mods.

It’s not 14bit... it’s going to have a better dynamic range than the normal 8bit, but as soon as you do this two channels are locked together, making you have to do the very mixing Meynaf is so against...

You aren’t doing 44.1kHz unless you have shutdown the video DMA... that’s not a practical for most situations.

Again, NOT on the A1200 because of the lack of this shitty default filter.


They come from the shitty filter that's part of the analog parts of the audio circuitry. The A1200 doesn't have this problem, and other models can be easily modded.

It's the fukken filter

It’s the filter than turns Paula’s square wave output into an analog signal...

Anyway, CD style audio sounds similar to my peecee on my A1200, except for softer passages in music.

If you want to use your Amiga as a Dedicated CD player, which sounds almost as good as a real one, all power to you! I prefer to use my Amiga for something it’s good at doing