Amiga Animation and CHIP RAM versus FAST RAM

[bloodline]

shoggoth wrote:

bloodline wrote:
And the addition of 2 PCM audio channels isn't really much of an improvement over the original ST... Certainly nothing on the Amiga's 4 PCMs :-)

Most true, no offence, didn't you sort of miss the point with the original post?

Ok, then... on topic...

The Original poster states, from memory, he felt that the Amiga seemed to only play at 30fps when the Atari ST appeared to play at 60fps.


First off, this statement is based on apparent observation, not a testable examination, of an event that happened 18 years or more in the past.

Secondly, no one seems to be able to test this... are there really that few Atari ST's around? Does no one have the software in question?

Thirdly, in answer to the OP question... Yes the Amiga can display animations at 60fps with out problems. In fact, these animations can even be in HAM-6 mode and use very little CPU time. I or in fact anyone with a modicum of programming ability can easily write a program to prove this, if need be.

Fourthly, The ST used an alternate bus cycle design, to share the memory between the CPU and the Display chips. This means that on a 16Mhz bus, each chip only gets access to the memory half the time, ie 8MHz. On the Amiga the GFX chips could steal (dynamically allocate) cycles from the CPU if needed (beneficial since the GFX chip do most of the work on the Amiga). On a related note the Atari Scanline Interrupt trick, to increase the effective number of colours displayable (essentially a new 16 colour palette every scanline) was also available on the Amiga (and probably every other 68k based machine of the time), but it uses a huge amount of CPU time, leaving nothing left for any other code to run.

I hope that sums everything up.

[shoggoth]

bloodline wrote:
Ok, then... on topic...

The Original poster states, from memory, he felt that the Amiga seemed to only play at 30fps when the Atari ST appeared to play at 60fps.


First off, this statement is based on apparent observation, not a testable examination, of an event that happened 18 years or more in the past.

Secondly, no one seems to be able to test this... are there really that few Atari ST's around? Does no one have the software in question?

Well, my bad. I replied to your post before having read all of his posts. I tend to agree with you in this case. The topic in itself is off topic. The whole discussion is silly imo.

[amigaksi]

>Isn't that what I said "a fresh 16 colors every line" plus hold and modify? Well if not, that's what I meant. Still even so- I could do some things in Spectrum 512 that would still cause even SHAM problems. But obviously, the reverse is possible as well- even more so with SHAM. And like I said, by the time SHAM was available (I'm not sure if paint programs supported it?) I know the demo world was even pushing the ST with more colors on scan lines and overscan etc.

Even Spectrum 512 is allowing only 48 unique colors for 320 possible pixels.  And there's a half-bright mode that does 64 unique colors and I'm sure you can toggle between half-bright and HAM-6 using the Copper list as well as change palette colors every scanline.  Everything the Spectrum 512 does with producing more colors can be done with the Amiga as well along with having more shades.

And comments about more shades are pertinent to the topic since the animation that uses more shades compresses less and thus requires greater processor power to display.  That's why I was asking whether the animation was compressed?  If they were uncompressed, a 1040ST only would hold 32 frames in memory (half a second of ST video at 60 fps since 32K*32=1Meg) assuming the application is highly optimized and does not hog up memory.

[amigaksi]

>Thirdly, in answer to the OP question... Yes the Amiga can display animations at 60fps with out problems. In fact, these animations can even be in HAM-6 mode and use very little CPU time. I or in fact anyone with a modicum of programming ability can easily write a program to prove this, if need be.

He's talking about minimum of 320*200*16 frames.  He can't be talking just about changing pointers of the display memory since that would only allow for 32 frames even on a 1040ST.  Perhaps, if you have an animation running at 60fps on an Amiga 500, you can give him a link.

[amigaksi]

>The whole discussion is silly imo.

He does a valid point that 8Mhz vs 7.16Mhz and given that ST videos would compress better and produce smaller files given less shades at 320*200*16 that decompressing from RAM to display buffer would be faster on ST.  But the question becomes is that sufficient to prevent the Amiga from displaying 60fps and is the ST actually doing 60fps?

[Britelite]

He's talking about minimum of 320*200*16 frames.  He can't be talking just about changing pointers of the display memory since that would only allow for 32 frames even on a 1040ST.  Perhaps, if you have an animation running at 60fps on an Amiga 500, you can give him a link.

No, he IS talking about pageflipping animations, which IS just changing the pointers in memory.

[amigaksi]

We are trying to understand him not pick on some word he used-- "page flipping".  You do see that he claimed 320*200*16 frames and on an A500 and Atari 1040ST?  Let him speak for himself as to how many seconds was the animation.

[Britelite]

amigaksi wrote:
We are trying to understand him not pick on some word he used-- "page flipping".  You do see that he claimed 320*200*16 frames and on an A500 and Atari 1040ST?  Let him speak for himself as to how many seconds was the animation.

Well, he was mentioning Spectrum 512 animations as an example of stuff running at 60fps on his ST, and somehow I doubt those are done by any other method than pageflipping + a tight loop for the colorswitches. He also mentioned running animations on a 4MB machine, which can fit quite a lot of frames (as it can be used as gfxmem, in contrast to the 512/1024kB limit on the OCS-amigas).

And finally, I'm giving him the benefit of the doubt and assuming he actually has a clue, and therefore if he talks about pageflipping, I assume he knows what it means

[Rowbeartoe]

WOW- I'm sorry for doubting the Ability of the Amiga- but again all I have is what I saw as a computer salesman and tons of magazines with software reviews never mentioning doing more than 30fps.  Understand I'm in the states, so we had the 60hz monitors for 60fps.  

Spectrum 512 was NOT 16 colors per scan line.  That would be very limiting graphicly as is evident from Apple IIGS pictures.  To clarify and understand Spectrum 512.  Every scan line was interupted 3 times- meaning 16 colors about every 100 pixels PER scan line.  I have a link to a picture I made in Spectrum 512 that gave HAM-6 a hell of a time.  The reason- well the picture has 33 colors on a scan line with the color black between each one.  That will give Ham-6 hell.  The other link is just an example of what Spectrum 512 pictures could do, including converting 2 famous 256 color GIF pictures and 1 Amiga HAM-6 and 1 Amiga SHAM or DHAM picture.  Followed by some BMP pictures and 2 pictures I made displaying the colors.  I included both links.  Overall- they are impressive and comparable to 320x200 HAM-6 in my opinion.

http://upload.wikimedia.org/wikipedia/en/b/b8/ST_versus_Amiga.png

http://upload.wikimedia.org/wikipedia/en/0/0c/Spectrum_512_power.png

Now I hope that clarifys the 16 colors per scan line misunderstanding of Spectrum 512.  

Spectrum 512 included at slideshow program and a simple script editor that allowed me to type in each picture in what ever order and then page flip them using the functions keys- 60fps being the fastest.  What many Atarians did was take some Amiga HAM-6 demos and run them on the ST up to 60fps.  The juggler for example was on the ST and would run faster with the spectrum 512 slideshow program-  as was the Scult 3D raytrace demo of that 5 ball thing bouncing under a lamp.  Again the ST could run this demo faster.  

So, every demo I saw on the Amiga was not going at 60fps.  Every magazine review of animation never mentioned they could.  That's why I question and could never honestly tell people if the Amiga could at that time.  

My ST still works- I'd love to just show people what I'm talking about here.  I wish I also had an Amiga 500 with some HAM-6 demos runing at 60fps.  Perhaps an improved juggler with that feature would be satisfying enough to me?  

I have a hard time just accepting people saying it could.  But I'll just take the word of everyone here.  The Amiga could, the software demos just sucked at achieving 60fps, and move on.  

O and yes my MegaST4 was a blast at home, because I could have 60 or more 500 color pictures displaying at 60fps (the pictures were compressed SPC- because SPU files took up 50K versus about 20-30K).  But most demos, would have about 10-30 frames like the juggler just repeating.  The juggler demo is below.  I paid $1800 for my 4 megabyte Atari ST in 1988.  I had to sell my 520ST to help pay for it then.  But 4 megabytes was great to digitize music and page flip large animations.  

http://home.comcast.net/~erniew/juggler.html

Thanks everyone.  

[Rowbeartoe]

shoggoth wrote:

JetRacer wrote:
Fun fact: even modern PC's have major difficulties working under similar conditions (read: massive MB 320x200 raw animation replayed with flawless 60hz fps). It's ofcourse the OS of Win/Linux/Mac that bogs down performance and nothing else.

I beg to differ. Having programmed low level VGA stuff, I can assure you that this is not an issue. Maybe if you're running XP with little memory and virus scanners and {bleep}, but well... that's not a proper comparison.

Not to get sidetracked, but my Dad was a PC guy, and around 1990 when 256 color VGA was afforadable and common along with 16MHz 80286 clones, he had demos doing 60fps page flipping as well.  This was the DOS days, and the program used GL files I believe.  I remember a 256 color jolt can spinning around.  But by this time, Amiga and Atari have been doing these kinds of demos for almost half a decade.  =)  The PC was very slow in catching up.  Prior to 1990 you had to pay over $5,000 to use a Mouse, 3.5" disket, Soundblaster card, VGA, and a 16-Bit 80286 with a megabyte of RAM.  All about 5 years after the ST and Amiga.  

[shoggoth]

Rowbeartoe wrote:
I have a hard time just accepting people saying it could.  But I'll just take the word of everyone here. The Amiga could, the software demos just sucked at achieving 60fps, and move on.  

Dude, why ask a question if you don't want to trust the answers you get anyway?

[bloodline]

If you link to me 30 frames of an animation, I will write a program to play back in HAM6 at a user selectable speed on an A500. Will that help?

[bloodline]

I just fired up DPaint4... you can set the frame rate in that... I can happily run an animation 60fps.

[Rowbeartoe]

shoggoth wrote:

Rowbeartoe wrote:
I have a hard time just accepting people saying it could.  But I'll just take the word of everyone here. The Amiga could, the software demos just sucked at achieving 60fps, and move on.  

Dude, why ask a question if you don't want to trust the answers you get anyway?

Because I'm a skeptic, and must be convinced. Some people are just so biased, that they will say it can.  I know you understand that.  I was hoping to hear someone say, for example, that old ANIM players were limited to 30fps then improved.  

[bloodline]

Rowbeartoe wrote:

shoggoth wrote:

Rowbeartoe wrote:
I have a hard time just accepting people saying it could.  But I'll just take the word of everyone here. The Amiga could, the software demos just sucked at achieving 60fps, and move on.  

Dude, why ask a question if you don't want to trust the answers you get anyway?

Because I'm a skeptic, and must be convinced.

No you are not. A true skeptic would not have made the original post without a fully testable example or at least some evidence to support the initial theory.

Some people are just so biased, that they will say it can.  I know you understand that.  I was hoping to hear someone say, for example, that old ANIM players were limited to 30fps then improved.  

When I opened up DPaintIV, it defaulted to 30fps, but was more than able to run the Animation at 60fps...

[Homer]

WOW- I'm sorry for doubting the Ability of the Amiga- but again all I have is what I saw as a computer salesman and tons of magazines with software reviews never mentioning doing more than 30fps. Understand I'm in the states, so we had the 60hz monitors for 60fps.

I'm no supertec, but I thought US was 29 fps with NTSC (Mains supply frequency 60Hz) and UK is 25 fps with PAL (Mains supply frequency 50Hz). Am I missing the point here  :-?

I must admit, I thought this thread was flamebait from the start, but please prove me wrong  :-D