haas@msudoc.ee.mich-state.edu (Paul R. Haas) (08/07/87)
Pardon me if this has come up before (I suspect it has).
I am trying to configure a Sun 3 (or if lucky a Sun 4) which can produce
animation for feeding to a VCR in real time. I want 30 frames a second,
but will settle for 15 or 10 if I have to. One or two seconds of video
at a shot is acceptable.
I think this will require a Sun 3 with a 384 x 512 frame buffer which
can do double buffering. At 12 bits per pixel that represents about
300k bytes per image. If the Sun has 28MBytes of real memory, that
gives 90 frames (leaving a few MBytes for the OS and such). Which is 3
seconds of video at 30 frames a second.
Does anyone make a VME bus product that can move data that fast and keep
it in sync? That is a memory to whatever copy at 8.9 MBytes per second.
I did some experiments. The best I could do was about 6 MBytes per
second, memory to memory on a half MByte copy on a Sun 3/110.
The inner loop of the test program was:
register int *count, *j, *k;
...
for(count=512*64;count;count--)
{
*j++ = *k++; *j++ = *k++; *j++ = *k++; *j++ = *k++;
}
Why does this run faster on a 3/110 than on a 3/260? Is there a faster
way of coding this?
I want as many colors as I can get. How many different colors can you
tell apart with NTSC video? I am guessing 4 bits per pixel is the
limit.
I hope to be able to do this with less than $10k (US), given that the
Sun and memory are being paid for out of a different pocket.
Am I out of mind? Does this require a Sun 4? How many years do you think
I will have to wait for < $10k, 30 frames/sec, 384x512, with 12 bits/pixel
animation? I am also calling vendors. I will post a summary of all that
I find.
--
Paul Haas, haas@eecae.ee.msu.edu, ...!ihnp4!msudoc!haas
I am going on vacation for ten days, if you want me to see it, send mail.