@cdimauro

Quote:

The point was: what a PC did at the Amiga time.

Difference between 800 USD Amiga and 2500 USD PC may be great.

Quote:

Doom for sure, because it's quite well known.

Used yes, but in 360x480 resolution? I don´t think so.

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We should take a look at magazines of the time, if we want to clarify it. But now I'm going to sleep, because it's too late and I'm tired.

I have extensive price lists since 1981, in this regard, you can simply trust me.

Good night!

@All

You all are missing in the specs and totally decontextualized. Amiga always have been better than the sum of their parts. Back in 1993 when i wanted to purchase an Amiga i was undecided because the commodore situation so i doubt between an A1200 or a PC. For the price of A1200 there was 386 that were at the end of the line,Pentiums just arrived and were more expensive than Amiga 4000. So the only alternative were 486. What made me decant for the Amiga? Precisely see in action a friend's 486. It was worse than my other friend's A500 so i thought if the A500 is more or less a bit better than 486 then the A1200 that is even better than A500 would be even better that the 486

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@cdimauro

Quote:

One question: why video playback was faster on AGA?

A few personal views regarding the subject, feel free to prove any of them wrong

Generally for uncompressed / custom compressed video, the "target format" (chunky/planar) shouldn't make much difference. If you got chunky display, just copy pixel data as-is. If you have planar instead, store the actual bitplanes instead, and copy them directly. One (minor) advantage for planar here is, reducing the amount of colors directly reduces the amount of data that has to be copied over / stored in game data.

With planar, you basically have a bunch of "1-bit images", more images resulting in more colors. With chunky, you generally have series of... bytes (or at least values, that fit single byte evenly, such as 4 bytes). If you f.ex. have 7 bits per pixel, it's probably faster to just copy (and store) bunch of 8 bit values at once instead (with highest bit always 0), which doesn't really have any benefit, so most probably just used all 8 bits.

If you need lots of colors, either use HAM6 or HAM8. With properly "pre-optimized" data, they can deliver better looking results than you would normally get with exact same amount of bits-per-pixel. Like previously mentioned, there's less data to store / copy with HAM6.

You could do some "shadow effects" by having few bitplanes assigned with constant value. This definitely was used in many 2D games, but I don't think it was used that much in videos.

@pavlor

Quote:

pavlor wrote: @cdimauro Quote: The point was: what a PC did at the Amiga time. Difference between 800 USD Amiga and 2500 USD PC may be great.

Sure, but they hadn't similar hardware features.

A PC had a more powerful CPU, more RAM, an hard disk, a SVGA, and a SVGA monitor.
Quote:

Quote: Doom for sure, because it's quite well known. Used yes, but in 360x480 resolution? I don´t think so.

No, Doom used 320x240 (to have 4:3 aspect ratio). Unfortunately it's very difficult to know the real resolution used by a game, because rarely they are publicly available.
Quote:

Quote: We should take a look at magazines of the time, if we want to clarify it. But now I'm going to sleep, because it's too late and I'm tired. I have extensive price lists since 1981, in this regard, you can simply trust me.

Good. I think it's interesting to see the prices for Amiga 2000 and 500, and some low-end PCs at the end of 1987, and the same for Amiga 4000 and 1200 at the end of 1992. Please, can you report some data?
Quote:

Good night!

Danke. :)

@Fransexy

Quote:

Fransexy wrote: @All You all are missing in the specs and totally decontextualized. Amiga always have been better than the sum of their parts. Back in 1993 when i wanted to purchase an Amiga i was undecided because the commodore situation so i doubt between an A1200 or a PC. For the price of A1200 there was 386 that were at the end of the line,Pentiums just arrived and were more expensive than Amiga 4000. So the only alternative were 486. What made me decant for the Amiga? Precisely see in action a friend's 486. It was worse than my other friend's A500 so i thought if the A500 is more or less a bit better than 486 then the A1200 that is even better than A500 would be even better that the 486

Yes, I think that contextualizing is important. I don't know how you can say that on 1993 a PC with a 486 was worse than an Amiga 500.

Regarding my situation, I can say that I bought an Amiga 1200 on 1992 because it was cheap. I bought an hard disk only after one year, because it was expensive (albeit I got a normal 3.5" PC hard-disk, which a friend was able to fit on my 1200).

If we take a look at real data, the Amiga 1200 was a good machine due to its low price. That's it. But with a single floppy was really hard to be productive, and not even good for games which usually required more floppies (at the time it was normal to use more of them to store all data; adventures were a nightmare with A LOT of floppies!).

So, yes, it was affordable because it was economic. But you also got a mediocre hardware (and AGA really sucked a lot, since ONLY the display subsystem was changed, with an horrible patch over the ECS).

How about fast bumping the version number to AmigaDOS 11? Then you will lead over Windows 10, not that I think OS4a deserve it but neither does Firefox 38 and Google Chrome 44...

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@Jupp3

Quote:

Jupp3 wrote: @cdimauro Quote: One question: why video playback was faster on AGA? A few personal views regarding the subject, feel free to prove any of them wrong

We are just discussing.
Quote:

Generally for uncompressed / custom compressed video, the "target format" (chunky/planar) shouldn't make much difference. If you got chunky display, just copy pixel data as-is. If you have planar instead, store the actual bitplanes instead, and copy them directly. One (minor) advantage for planar here is, reducing the amount of colors directly reduces the amount of data that has to be copied over / stored in game data. With planar, you basically have a bunch of "1-bit images", more images resulting in more colors. With chunky, you generally have series of... bytes (or at least values, that fit single byte evenly, such as 4 bytes). If you f.ex. have 7 bits per pixel, it's probably faster to just copy (and store) bunch of 8 bit values at once instead (with highest bit always 0), which doesn't really have any benefit, so most probably just used all 8 bits.

The problem is that reducing the depth of the screen reduces a lot the quality of the output. 8 bitplanes instead of 7 isn't that much: it's just 14% more space and bandwidth, but the difference between 256 and 128 bit colors is huge, especially for videos.

A VGA had not problem for 8-bit packed (commonly referred as chunky) pixels. Even a 286 had bandwidth for rewriting the entire 320x200 screen 60 times per seconds (it required 3.66MB/s for writing it; of course you have to read also data from memory using another 3.66MB/s), but it wasn't the case because at the time (end of 1992) 486s were more common, and 386 were disappearing.

So, the problem was only about the AGA Amiga, which had a very limited bandwidth for accessing the chip RAM. The problem here is that the display logic stolen 8 accesses (slots) every 32 for each displayed line; fortunately the horizontal blanking gave some free slots, and the vertical blanking was a bigger chance (no displayed data at all).

Fortunately the AGA machines allowed 32-bit access to the chip RAM (the Amiga 3000 with ECS also, if I remember correctly), so counting the 24 free slots every 32 per displayed lines + all slots on the blanking period, it roughly has the bandwidth to read and write a 320x200@60FPS (NTSC) or 320x256@50FPS (PAL) screen.

But that's the only thing that you can do, because you're using all the processing power for this task. An Amiga 1200 hadn't enough power to even think about using some form of data compression.

Fortunately videos don't require a whole rewriting of the screen for every frame. So you ends-up with some little rectangle regions to be updated every frame: something which is affordable, and you can also use some form of data compression.

The problem here is that with bitplanes you can do very little of data compression. You can achieve something only for the top bitplanes, whereas the mid-low bitplanes are basically "noise" and have to be stored as-is.

A packed format, instead, allows to better use RLE or some lightweight LZ, maybe with some prediction algorithm.

Another huge disadvantage of bitplanes, is that they had a 16-bit or 32-bit granularity & alignment. It means you can only update rectangles with are located at multiples of 16 ore 32 pixels, and you have to store 16 or 32 pixels at the time. Usually you use 16-bit stores with very short rectangles (less or equal 16 pixels width) AND on 16-bit/pixel boundaries. Otherwise (wider rectangles) it's better to use 32-bit stores.

In short, it means that bitplanes are much worse of packed formats, because require more bandwidth (because you need to store at least 16 bits at the time, multiplied by the number of bitplanes, even for updating a SINGLE pixel) and space (because of the same alignment & size restrictions, you have to store even data which hasn't changed from the previous frame).

Last but not least, when you update something on the screen, you have to repeat the operation by the number of bitplanes.

So, even for video playback AGA & bitplanes were/are much worse performers.
Quote:

If you need lots of colors, either use HAM6 or HAM8. With properly "pre-optimized" data, they can deliver better looking results than you would normally get with exact same amount of bits-per-pixel. Like previously mentioned, there's less data to store / copy with HAM6.

Yes, but that's mostly for static images. Unfortunately for videos HAM modes generate visual artifacts.
Quote:

You could do some "shadow effects" by having few bitplanes assigned with constant value. This definitely was used in many 2D games, but I don't think it was used that much in videos.

Exactly. We used it also for Fightin' Spirit.

But it's not usable for videos, as you stated.

@cdimauro

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Sure, but they hadn't similar hardware features.

Of course.

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No, Doom used 320x240 (to have 4:3 aspect ratio).

It is 320x200!

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Good. I think it's interesting to see the prices for Amiga 2000 and 500, and some low-end PCs at the end of 1987, and the same for Amiga 4000 and 1200 at the end of 1992. Please, can you report some data?

June 1987 (in original Swedish Krona, used then Exchange rate to USD, all taxes included):
A500: 1011 USD
A2000: 2497 USD
A1081: 671 USD (monitor)

Atari 1040STF: 1011 USD
Atari SM124: 310 USD (monochrome monitor)
Atari SC1224: 621 USD (color monitor)
Bundles Atari ST + monitor are little bit cheaper
Atari SH205: 777 USD (slow 20 MB HDD)

October 1987 (in original USD, all taxes EXCLUDED):
8088 10 MHz + 640 kB RAM + 360 kB Floppy + Mono GFX card and monitor: 699 USD
8088 10 MHz + 640 kB RAM + 360 kB Floppy + EGA GFX card and monitor: 1099 USD (another cca 300 USD for 20 MB MiniScribe HDD)
80286 10 MHz (1 wait state?) + 512 kB RAM + 1.2 MB Floppy + Mono GFX card and monitor: 1199 USD
80286 10 MHz (1 wait state?) + 512 kB RAM + 1.2 MB Floppy + EGA GFX card and monitor: 1599 USD

March 1993 (I have separate prices form 1992 for PCs/Amiga, but here it is in one place, so better comparable; in original Czech koruna, used then Exchange rate to USD; all taxes included):
A1200: 718 USD (another cca 275 USD for 2.5" 40 MB HDD)
A4000/040: 3083 USD
C1085: 359 USD (RGB monitor)

80286 25 MHz + 1 MB RAM + 40 MB HDD + 1.2 MB Floppy + SVGA mono monitor: 818 USD
80386SX 33 MHz + 2 MB RAM + 40 MB HDD + 1.2 MB Floppy + 1.44 MB Floppy + Paradise VGA + SVGA color monitor: 1203 USD
80486DX/2 66 MHz + 4 MB RAM + 40 MB HDD + 1.2 MB Floppy + 1.44 MB Floppy + Paradise VGA+ SVGA color monitor: 2836 USD

(prices may vary among vendors/configurations)

Last edited by pavlor on 20-Jun-2015 at 09:43 AM.
Last edited by pavlor on 20-Jun-2015 at 09:43 AM.

@Hillbillylitre

Quote:

How about fast bumping the version number to AmigaDOS 11?

I think dos.library is at 50 something it may even be 60.x. I can't check at the moment.

@cdimauro

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Yes, but that's mostly for static images. Unfortunately for videos HAM modes generate visual artifacts.

AFAIK, HAM modes behave exactly same as images do. The only clear benefit for images is that they can be higher resolutions (especially X, which doesn't even cause flicker), which tends to hide artifacts.

Sure, many mpg video players produce quite nasty artifacts. Why? Because they need to balance between "good looking video" and "fast enough remapping of incoming image data". With game videos, all this information is precalculated, and it doesn't really matter "how long it took".

IIRC, HAM8 has 64 "normal" colors, which already is more than enough for "bearable" animation quality. Then, the trick is to find the optimal 64 color palette, either for the entire video or each frame separately, assign colors that exactly match one from the 64 color palette, and then for the rest, decide whether you should modify the previous pixel color, or assign one from the 64 color palette, that's "not too far away".

Quote:

Quote: You could do some "shadow effects" by having few bitplanes assigned with constant value. This definitely was used in many 2D games, but I don't think it was used that much in videos. Exactly. We used it also for Fightin' Spirit. But it's not usable for videos, as you stated.

It's perfectly usable - no-one just has yet figured out a perfect usecase for that!

Last edited by Jupp3 on 20-Jun-2015 at 10:34 AM.

For example quake released in 1996 still used VGA. So AGA from y1993 was really vs vga in games.

Normal 486sx and dx33 sold in july1994 had SVGA ISA cards with 512kb, no audio or cdrom as standard. Year before that, 386 was common. Year after that dx2,dx4 were common, half year later p1.

etc.

_________________
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// For freedom, for honor, for AMIGA
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@pavlor

Quote:

pavlor wrote: @cdimauro Quote: Sure, but they hadn't similar hardware features. Of course. Quote: No, Doom used 320x240 (to have 4:3 aspect ratio). It is 320x200!

No it used the 320x240 unchained 256 color mode also commonly called mode-x. Look at the released source code to see the optimized blitting solution used to lessen the overheads of unchained modes.

O.T: simplified description how the VGA graphics mode are addressed:

VGA graphics modes are commonly accessed via a 64kiB window into the framebuffer. The standard way is that the window accesses a single bitplane out of four with a total of 4x64kiB=256kiB accessible.

The standard 320x200 256 color mode uses a variant called "chained" addressing were the first pixel is in bitplane 0 address 0, the second in bitplane 1 address 1 etc. The problem with this is that the addressable memory is reduced to 64kiB out of the 256kiB available. This also means that there is no option of using double-buffering.

What the mode-x and other "unchained" modes do is simply removing the chain mechanism so that the pixel 0 is in bitplane 0 address 0, pixel 1 is in bitplane 1 address 0 etc. This makes all 256kiB of memory usable but requires switching between which bitplanes are visible in the memory window, something that can have huge performance impacts if done wrong.

DOOM uses an optimized routine that takes pixels from a linear buffer and does the specialized chunky-2-planar conversion required for the unchained modes utilizing the cache of the processor to reduce the amount of plane switches required.

It is also possible to do a chained 320x200 graphics mode on a 320x240 screen (with the upper and lower 20 pixels showing the border color) which have the advantage of square pixels. That is however rarely used.

Edit: remove -> lessen

Last edited by megol on 20-Jun-2015 at 11:35 AM.

@Fransexy

Quote:

Fransexy wrote: @All You all are missing in the specs and totally decontextualized. Amiga always have been better than the sum of their parts. Back in 1993 when i wanted to purchase an Amiga i was undecided because the commodore situation so i doubt between an A1200 or a PC. For the price of A1200 there was 386 that were at the end of the line,Pentiums just arrived and were more expensive than Amiga 4000. So the only alternative were 486. What made me decant for the Amiga? Precisely see in action a friend's 486. It was worse than my other friend's A500 so i thought if the A500 is more or less a bit better than 486 then the A1200 that is even better than A500 would be even better that the 486

Didn't this pretty much stop being valid towards the end of the Commodore era already? My point is, how is that "Amiga always have been better than the sum of their parts" relevant in 2015 with a €3000 AmigaOne running OS4 that's (relatively speaking) only slightly better than the Commodore Workbench (relatively as in "the world has turned 20 times around the sun since the death of Commodore, and the world outside Amiga has come an enormous way since then while the Amiga has been pretty much on halt the whole time, relatively speaking")?

@megol

Quote:

No it used the 320x240 unchained 256 color mode also commonly called mode-x. Look at the released source code to see the optimized blitting solution used to remove the overheads of unchained modes.

Doom GFX is 320x200. No visible border.

@pavlor

True, it was Quake that supported unchained graphics modes so I had a memory error. Thanks for acting as my ECC ;)

@KimmoK

Quote:

For example quake released in 1996 still used VGA. So AGA from y1993 was really vs vga in games.

Yes, it definitely supported VGA too. However, I'm quite sure it also supported higher resolutions as well, although perhaps not in the very first versions (by the time it became popular in Finland, there probably were already quite a few updates)

Sure, many people definitely played it in VGA resolutions. Why? Because most computers at that time definitely couldn't handle anything higher in even remotely playable framerate.

On the other hand, games like The Settlers (1993), SimCity 2000 (1994) and Warcraft II (1995) don't hurt so badly with slower framerate & don't need to update the whole image at each frame, so they ran quite playable on common hardware of the day, even in SVGA resolutions.

@pavlor

Quote:

pavlor wrote: @cdimauro Quote: Sure, but they hadn't similar hardware features. Of course.

So comparing them isn't useful. Unless we compare an Amiga with similar equipment.
Quote:

Quote: No, Doom used 320x240 (to have 4:3 aspect ratio). It is 320x200!

ECC error as well.
Quote:

Quote: Good. I think it's interesting to see the prices for Amiga 2000 and 500, and some low-end PCs at the end of 1987, and the same for Amiga 4000 and 1200 at the end of 1992. Please, can you report some data? June 1987 (in original Swedish Krona, used then Exchange rate to USD, all taxes included): A500: 1011 USD A2000: 2497 USD A1081: 671 USD (monitor) Atari 1040STF: 1011 USD Atari SM124: 310 USD (monochrome monitor) Atari SC1224: 621 USD (color monitor) Bundles Atari ST + monitor are little bit cheaper Atari SH205: 777 USD (slow 20 MB HDD) October 1987 (in original USD, all taxes EXCLUDED): 8088 10 MHz + 640 kB RAM + 360 kB Floppy + Mono GFX card and monitor: 699 USD 8088 10 MHz + 640 kB RAM + 360 kB Floppy + EGA GFX card and monitor: 1099 USD (another cca 300 USD for 20 MB MiniScribe HDD) 80286 10 MHz (1 wait state?) + 512 kB RAM + 1.2 MB Floppy + Mono GFX card and monitor: 1199 USD 80286 10 MHz (1 wait state?) + 512 kB RAM + 1.2 MB Floppy + EGA GFX card and monitor: 1599 USD

Thanks for the data. I suppose that the A500 was equipped with the common 512KB expansion card.

Unfortunately there's no PC with a VGA, but looking at what you reported it would have been very costly, maybe around $2000.

Personally I consider a VGA the bare minimum for talking about good quality games. An ECS with 16 colors (out of 64) was too much limited, albeit some nice (to play) games were made.

Atari ST also had only 16 colors, but the palette had 512 colors, so it nicer compared to an EGA. The prices were also interesting.
Quote:

March 1993 (I have separate prices form 1992 for PCs/Amiga, but here it is in one place, so better comparable; in original Czech koruna, used then Exchange rate to USD; all taxes included): A1200: 718 USD (another cca 275 USD for 2.5" 40 MB HDD) A4000/040: 3083 USD C1085: 359 USD (RGB monitor) 80286 25 MHz + 1 MB RAM + 40 MB HDD + 1.2 MB Floppy + SVGA mono monitor: 818 USD 80386SX 33 MHz + 2 MB RAM + 40 MB HDD + 1.2 MB Floppy + 1.44 MB Floppy + Paradise VGA + SVGA color monitor: 1203 USD 80486DX/2 66 MHz + 4 MB RAM + 40 MB HDD + 1.2 MB Floppy + 1.44 MB Floppy + Paradise VGA+ SVGA color monitor: 2836 USD (prices may vary among vendors/configurations)

That's more interesting. An Amiga 1200 + C1085 was $1077, and $1352 adding the HD: even more than the 386SX PC, which had a better hardware.

Honestly my thought was that a similar PC was more expensive. Again, ECC error.

@Jupp3

Quote:

Jupp3 wrote: @cdimauro Quote: Yes, but that's mostly for static images. Unfortunately for videos HAM modes generate visual artifacts. AFAIK, HAM modes behave exactly same as images do. The only clear benefit for images is that they can be higher resolutions (especially X, which doesn't even cause flicker), which tends to hide artifacts. Sure, many mpg video players produce quite nasty artifacts. Why? Because they need to balance between "good looking video" and "fast enough remapping of incoming image data". With game videos, all this information is precalculated, and it doesn't really matter "how long it took". IIRC, HAM8 has 64 "normal" colors, which already is more than enough for "bearable" animation quality. Then, the trick is to find the optimal 64 color palette, either for the entire video or each frame separately, assign colors that exactly match one from the 64 color palette, and then for the rest, decide whether you should modify the previous pixel color, or assign one from the 64 color palette, that's "not too far away".

You can change the palette only if you rewrite the whole frame.

But that wasn't the important thing. The problem with HAM and HAM8 was that inserting a new rectangle on an (existing) image required a proper "transition phase", which can take up to 3 (horizontal) pixels to get the expected color (the following ones will be fine), and this can produce some horizontal bends (the artifacts which I was talking about).

However I took a look at some HAM and HAM8 videos on YouTube, and I saw that (given the quality of the video, of course, which wasn't perfect) such artifacts are barely noticeable in the latter, thanks to bigger (quadruple) base palette. So, at least HAM8 deserved for reproducing videos with very good quality (in low-res: 320x200 or 320x256; high resolution is not recommended, due to lack of chip RAM bandwidth).
Quote:

Quote: [quote]You could do some "shadow effects" by having few bitplanes assigned with constant value. This definitely was used in many 2D games, but I don't think it was used that much in videos. Exactly. We used it also for Fightin' Spirit. But it's not usable for videos, as you stated.

It's perfectly usable - no-one just has yet figured out a perfect usecase for that! [/quote]
The problem here is to create an algorithm that scans the image looking at shadows which can make use of the bitplane(s) trick (only updating one or two bitplanes in this case). But it's quite hard to find a region where only the intensity of the pixels changed.

@KimmoK

Quote:

KimmoK wrote: For example quake released in 1996 still used VGA. So AGA from y1993 was really vs vga in games.

Again, I quote yourself:

"Do not start to mix up things"

Quake was a 3D game, and it was also the first which introduced graphic acceleration through OpenGL.

AGA games were mostly 2D, because it lacked packed/chunky pixels which are a requirement for 3D games.

But for 2D games PC used also SVGA graphic modes. Take a look at the other comments.
Quote:

Normal 486sx and dx33 sold in july1994 had SVGA ISA cards with 512kb, no audio or cdrom as standard. Year before that, 386 was common. Year after that dx2,dx4 were common, half year later p1. etc.

Here, instead, take a look at the data reported by pavlor, which are very interesting.

BTW, on 1994 there were already SVGA with VESA Local Bus available.

Anyway, a VGA using a 16-bit ISA slot had enough bandwidth to refresh the whole VGA screen and even more. And on PC usualy you do NOT directly use the video memory, as Amiga did. You had a framebuffer on system memory, which is MUCH faster to access, and you create the next frame using it, copying the final result on the VGA memory.

Of course, using bigger resolutions than the stock VGA required more bandwidth, and that's where VLB was useful.

>386SX PC, which had a better hardware.

You have no clue.


+no os, no plug and play, 640k limit, 16bit ram, no photo capability, no audio.

Last edited by KimmoK on 20-Jun-2015 at 03:41 PM.

_________________
- KimmoK
// For freedom, for honor, for AMIGA
//
// Thing that I should find more time for: CC64 - 64bit Community Computer?