Amiga Animation and CHIP RAM versus FAST RAM

[amigaksi]

>Well, this wasn't rocket science. For one, the software on the ST said it was 60fps, and for proof all I would have to do is load 30 frames and play it as 60fps and I'd see all of them displayed twice every second- id notice if it went only once...

It may skip frames while attempting to play at 60fps.  Given the fact that ST is 8Mhz and Amiga 500/1000 are at 7.16Mhz simple processor-based memory transfers would be slightly faster on ST but not 30fps vs 60fps and this is also assuming the RAM chips are not the bottleneck.  The code I gave before was running from Chip RAM and copying to Chip RAM the slowest RAM in the Amiga.

>...funntion key did. with that knowledge, and placing the two computers side-by-side with 3 of the same animation demos, I was shocked to notice the ST was page flipping at least twice as fast- ableit once again with graphic pictures that took up less memory- (well Spectrum 512 pictures uncompressed took up 50kilobytes- versus uncompressed 16 color 32 kilobyte files on the ST).

There could be a software limitation on the application used.  What's the format of the 50Kb of Spectrum 512-- is that also 320*200*16 with palette changes every scan line?  50Kb per frame at 60fps would be 3Megabytes/second.

>I hope that is proof enough- as for the interlaced issue, I spent days drawing pictures with my eyeball pressed up against my Atari 12" RGB monitor- it was not flickering.

I wasn't asking about interlaced stuff since you can always enable/disable interlace with one bit in register mentioned before (one that was poked with 4204h) without affecting performance.

[Rowbeartoe]

"There could be a software limitation on the application used. What's the format of the 50Kb of Spectrum 512-- is that also 320*200*16 with palette changes every scan line? 50Kb per frame at 60fps would be 3Megabytes/second."


Spectrum 512- well believe it or not this graphic program gave the Atari ST some advantages over Amiga HAM-6.  Spectrum 512 wasn't the standard way (Apple IIGS like) to achieve lots of colors 16 per scan line.  

The enginneers hooked an oscilloscope to teh Atari ST MMU chip and reverse-enginneered its timers.  Using this information, they designed a method to manipulate those times and stuff more colors into extra simlulated bit planes, before the signal even gets to that Atari ST's graphic Shifter chip.  In short- in 1987 Spectrum 512 allowed the ST to display 48 colors every scan line.  Quick math translates into 16 colors about every 100 pixels per scan line.  This gave some advantages over HAM-6- but then again HAM-6 could also put 320 colors on a line- it's just HAM-6 allowed you only to modify 1 of the 3 RGB colors at a time.  

Now I'm not a programmer, but the files took up 50 kilobytes per file uncompressed.  I'm not sure why or how- I understand 4-bit (16 colors) pictures on the ST took only 32 kilobytes uncompressed.  The ST was able to page flip these files 60 times per second as well as it's 16 color picture formats with software back in 1987.  I purchased a 4 megabyte MEGA ST4 at that time, so I could make large page fliping animations at that time.  

Still, I feel I'm getting side tracked.  I'm not arguing about graphic quality- surely the Amiga offered way more versatiltiy- especially with it's highres overscan color pictures mixed with other resolutions (nice!).  And even though I'm an Atarian, to me the Amiga is more of an Atari than the ST was, since it was the evoluation of the Atari 8-bit computers.  

O- to understand the memory in the Atari ST- I read that the engineers gave the ST 16 MHz unified RAM- giving 8-MHz to Video, and 8-MHz to the 68000.  The ST didn't have anything fancing like CHIP RAM and FAST RAM.

Thanks everyone for still trying to resolve this.  I'm starting to accept that perhaps software engineers didn't feel pressed to push the Amiga to 60fps with there animation software.  They appeared to be more focused on graphic quality?  (I'm still speculating).  To bad I just couldn't buy all the animation software, Scult 3D, zoetrope, etc- purchase an Amiga 2000 or an Amiga 500 with a megabyte expansion and benchmark it's software.  I'm still leaning towards Chip RAM, and 7.1 MHz clock speed

[Britelite]

Page-flipping is perfectly possible at full framerate on both machines (well, any machine really), only limit is of course the available memory. I'd say the piece of Amiga-software you tried was limited or badly coded, because there's no reason for page-flipped animations to be less than full framerate.

So no reason to blame chip-ram or the clockspeed, a page-flip takes a few cycles and therefore doesn't require any CPU-power at all.

[xeron]

I suspect that the juggler animation is running at 30FPS because its a 30FPS animation, not because the amiga can't run it faster.

[Rowbeartoe]

I have the May/June Magazine of Amiga World about the Juggler.  It's a very in depth interview with how it was made and how HAM-6 works.  Sadly the article doesn't discuss why his animation program was set to 30fps.  Great article about Ray-Tracing etc though.  This is what bothers me though-  I have several magazines dealing the Amiga including Info which was my favorite for Amiga- but none of the graphic animation reviews even in 1989 said any of the programs allowed up to 60fps animation.  That and my personal experience as a Computer Saleman in 1988 and 1989- really bothers me.  Didn't Juggler let you select speeds up to 30fps or was it just one speed only- I can't remember now.  The conversion on the ST, like all animations, let me select speeds from frame by frame to 60fps.  =(

I loved that Amiga demo- my favoriote next to Fuji Boink from Xanth on the Atari ST.

[Rowbeartoe]

xeron wrote:
I suspect that the juggler animation is running at 30FPS because its a 30FPS animation, not because the amiga can't run it faster.

Below is part of the readme file from the juggler program I just found on the internet..



 " Juggler
  (c 1986 by Eric Graham, All Rights Reserved.
 
  Controls:
  Juggling speed is set by typing 0-9 on the numeric keypad.  Speed is   only changed once per complete juggling pass, so it may seem to take   a bit of time before the Juggler responds to your speed change command.  ESC exits the program.


  This program is being made available by Commodore for use on the   Amiga Computer.  We encourage you to copy it for your friends who   own Amigas.  Have fun."

Notice the control speeds- this is much like the Atari ST programs I used.  So why would the Amiga need to stop at 30fps?  The article from the 1987 Amiga World magazine claimed the program ran at 30fps, and that is what I remembered when it was side by side the Atari ST.  I realize this is just one demo- but this along with two others I had from CAD programs (Anitic CAD-3D 2.0 and Cyber Scult) had animations up to "only" 30fps.  

Thanks everyone again for trying to help me.

[Rowbeartoe]

Britelite wrote:
Page-flipping is perfectly possible at full framerate on both machines (well, any machine really), only limit is of course the available memory. I'd say the piece of Amiga-software you tried was limited or badly coded, because there's no reason for page-flipped animations to be less than full framerate.

So no reason to blame chip-ram or the clockspeed, a page-flip takes a few cycles and therefore doesn't require any CPU-power at all.

I was reading a 1988 issue of Amazing Computing and it's review of Videoscape 2.0.  Again nothing about Video speed playback BUT thar article did tell me it's viewers.  

"The technique for saving has been improved: a VideoScape 2.0 animation takes up half as much space as a 1.0 animation.  These new ANIM files can be played back with version 4.0 of ShowANIM or 4.2 of PlayANIM."

Now VideoScape 2.0 allowed Hold and Modify- these animations could be 4,096 pictures.  I wonder did Scult 3D using ShowANIM or PlayANIM?  and did these programs offer 0-9 speed selections as the juggler animation- and most important- how fast for the top speed of these programs.  And if it was limited to 30fps- WHY?

Thanks everyone again-  I'll keep digging thru all more magazines and internet to get more answers if I can find them.

Robert.  =)

[Zac67]

Actually, there's no sense in running any anim with >30 fps - your eyes wouldn't see the difference anyway (60 fps vs 30 fps with every other frame skipped). That's the exact reason why cinema/PAL/NTSC work with 24/25/30 fps: their designers wouldn't waste film/bandwidth.

The Amiga programmers were obviously aware of this and just coded that way.

[Rowbeartoe]

 

Zac67 wrote:
Actually, there's no sense in running any anim with >30 fps - your eyes wouldn't see the difference anyway (60 fps vs 30 fps with every other frame skipped). That's the exact reason why cinema/PAL/NTSC work with 24/25/30 fps: their designers wouldn't waste film/bandwidth.

The Amiga programmers were obviously aware of this and just coded that way.

No disrespt, but I so strongly disagree- ever play video games that play at 30fps versus 60fps?- try car games, you'll notice the differnece.  In short, especially back in those days, I could see a differnce simply becuase motion blur wasn't working- a trick that works real good with "low" frame rates. Movies drive me crazy at 24 fps when they pan left and right quickly- but this isn't my question- this is a whole entire differn't argument or opinion.  I used to make lots of animations on my Atari ST, and 60fps was clearly better when lots of frames where included.  Boing on the Amiga, would be smoother for example at 60 verus 30fps.

 

[tonyp12]

If all the frames in raw format would been able to fit on chip ram:

Then 60fps would be not problem and would only use
1% cpu power as just simple changing the mem pointer in the copper list.

But if you use delta compression such as IFF anim when the cpu would have to go to work

And if you have to copy from fast ram to chip ram you could not use the blitter.

[Zac67]

With the frames in raw format, you could end up with 0% CPU load: let the copper handle all the page flipping (rather lengthy list, but with only a few frames to play).

But: if you have no fast RAM and use HAM (6 planes) you end up with 50% less bandwidth during bitplane DMA. Depending on overscan width, you'd get 25-45% speed penalty for the CPU.

In addition (with fast RAM), you would probably store the ANIM data in fast and decompress directly from fast to chip, so you could use the remaining 55-75% of chipram speed to fill the frames; with few enough bytes to change you could just about get away with full 60 fps.

The Atari STs could only do 16 colors, and with only 4 bitplanes you'd have no speed penalty on the Amiga, so 60 fps would be a piece of cake (with or without fast RAM).

[Rowbeartoe]

tonyp12 wrote:
If all the frames in raw format would been able to fit on chip ram:

Then 60fps would be not problem and would only use
1% cpu power as just simple changing the mem pointer in the copper list.

But if you use delta compression such as IFF anim when the cpu would have to go to work

And if you have to copy from fast ram to chip ram you could not use the blitter.

I was watching these demos at my work on an Amiga 500- that translates to all Chip RAM.  Again, I keep reading the Amiga can, or the Amiga should have no problem, or the Amiga has no need too, but the reality is, in my visual experience at the time, the Amiga animation demos, as with Sculpt 3D, or Antics Cad 3D 2.0, or the Juggler Demo, these animation programs stopped at no greater than 30fps.  My question again is, why? And is everyone that says it can, better programmers than the software makers of these programs, or is it because of other reasons?  I'm just curious, because the Atari ST was pounded for being inferior by experts all the time, and i really don't care what was better- to me it was a win win, because Amiga to be is an Atari computer (sorry if that upsets Amiga fans), and I enjoyed my Atari ST software very much as well.  I keep reading all my old magazines reviewing animation software or demos, and none mention 60fps as was bragged about with Atari ST's Cad 3D and shown all the time with Spectrum 512 page flipping.  Again, if the Amiga was limited to this page flipping, was it just the software, the speed of Chip RAM, the 7.1 MHz clock speed, the more memory intense files?  I duno.  sigh.

Thanks again everyone for trying to help.

[Zac67]

To repeat my theory: The programmers coded that way to allow non-interlaced as well as interlaced anims - you usually program as universally as reasonable. They regarded 30 fps as sufficient (which it usually is, at least if the frames are made for it (video captured / motion blurred).

The Atari programmers didn't have to watch for non-/interlace differences since the STs can't output the former (only with tricks).

[Rowbeartoe]

Zac67 wrote:
To repeat my theory: The programmers coded that way to allow non-interlaced as well as interlaced anims - you usually program as universally as reasonable. They regarded 30 fps as sufficient (which it usually is, at least if the frames are made for it (video captured / motion blurred).

The Atari programmers didn't have to watch for non-/interlace differences since the STs can't output the former (only with tricks).

So is this a confirmation that the software writen for all these animation programs by 1989 never let the users to 60fps?

Thanks again everyone.

[stefcep2]

An important thing to consider here is the critical flicker fusion frequency
http://en.wikipedia.org/wiki/Flicker_fusion_threshold

For the average person under low light levels this about 60 Hz and under bright light this is about 30 hz ( thats why using a  refresh of 50 hz ie pal or DBLpal flickers at night and not so much in daytime).  Its also why NTSC flickers less than PAL.

[amigaksi]

>So is this a confirmation that the software writen for all these animation programs by 1989 never let the users to 60fps?

You need to make it clear whether you want to compare what frame rates the softwares written for both machines can accomplish or what the hardware is capable of doing.  My Atari ST disk drive is down right now-- perhaps someone can write code or port the one I wrote previously to see what frame rates they get on the ST at 4bits/pixel.  I guess on the ST everything is fast RAM or everything is chip RAM.

Sorry for delay in replying-- was too busy discussing death here: http://www.atariage.com/forums/index.php?showtopic=123710