Path: utzoo!news-server.csri.toronto.edu!rutgers!apple!tahoe!tucker From: tucker@tahoe.unr.edu (Aaron Tucker) Newsgroups: comp.sys.amiga.graphics Subject: Re: Colorburst and Animation Message-ID: <5739@tahoe.unr.edu> Date: 13 Mar 91 22:15:08 GMT References: <13948@life.ai.mit.edu> Reply-To: tucker@tahoe.unr.edu (Aaron Tucker) Organization: University of Nevada - Reno Lines: 46 People have been wondering about how the video DMA contention will lock out Amiga CPU access to chip ram and therefore reduce access speed by the CPU to chip ram. If you consider a High resolution 4 bitplane Amiga screen, (the size screen required to pass 8 bits to ColorBurst) you will find that the CPU is locked out during the Screen DMA fetching for about 80% of the time. DCTV and HAM-E all have this bottle-neck as well. BUT - With ColorBurst you can still display the full 24 bit Picture with Amiga DMA TURNED OFF! This means that you can have 100% access speed to Amiga chip ram and still display your last frame. Then after operating on your chip memory, then turn DMA back on and update that bank of ColorBurst Video RAM. Also, a different trick you could use would be to use a 3 bitplane Hi-res screen which would give 6 bits each for RED, GREEN and BLUE. you would then be shifting less data, have less display DMA contention (only about 33 % lockout) and still be displaying your Animation in TRUE 18 bit video (still pretty smooth). Remember also that ColorBurst supports full double buffered animation, Allowing you to display 1 bank while updating the other. The ColorBursts custom PROCESSOR can also be used to scroll and move 24 bit objects around at 60 fps and also page flip animate at the same time with virtually NO Amiga proc essing. A good example of this is a cute little ColorBurst demo that replaces the Amiga system mouse pointer with a 24 bit sprite (that can be as large as the whole screen) and move it at 60 fps working with ANY intuition software (eg DPAINT, WORKBENCH, DTP, WORD PROCESSORS). With the Firecracker, the Amiga CPU can only access its display memory during ] Horizontal and vertical blank (80 % lockout) also. The only way around this with video cards is to use Dual Port Video RAM on a card. But you cannot double buffer animate or scroll with firecracker. You cannot expect to be able to animate with uncompromised 24 bit at the same speed as speed as units that only shift 8 bits of data (DCTV and HAM-E) but the quality is far superior with true 24 bits. As a service to ALL ColorBurst owners, MAST is installing a full single frame edit Bureau onto Laser disk (then onto tape if desired) and unbelievably in- expensive rates. You will be able to Render your 24 bit frames and send the files to MAST and they will Put them to laser disk in RGB (Yes the laser disk recorder accepts RGB) at 30 frames a second in pure hi-res overscan 24 bit! This is a service MAST calculates to be yet another competetive edge! You may be wondering, How will I get my files to MAST if I have a 100 megabyte Animation ? MAST will supply you free of charge with an encoder to encode 300 megabytes of Data onto a standard 3 hour VCR tape with a standard VCR. You then just send us the VCR tape with the Data on it and we will send you back a laser disk or Tape. For a true 24 bit card, ColorBurst's animation is about as fast as 24 bit comes. And the quality is so much higher than DCTV or HAM-E. Gary Rayner Colorburst Designer You cannot reply to me via the INTERNET, but you can leave me a message on the MAST BBS at (702) 359-0132. Thank you for your responses and inquiries. D D D D The Firecracker also has the same problem of DMA lockout about 80%