Can Propeller Display a Human Face on the TV?
![william chan](https://forums.parallax.com/uploads/userpics/RBTCEMRWP85K/nQFR9OII9OM33.jpg)
Hi,
How difficult is it to display a human face on the TV?
Thanks.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
www.fd.com.my
www.mercedes.com.my
How difficult is it to display a human face on the TV?
Thanks.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
www.fd.com.my
www.mercedes.com.my
Comments
Maxx Headroom or Pamela Anderson?
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Don't visit my new website...
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chip Gracey
Parallax, Inc.
How many bytes of memory would be required to display a still photograph on 1/16 of the TV screen,
based on normal TV resolution?
Can the Propeller's shared memory be used for this purpose?
Is the access to the shared memory fast enough to hold the still photograph onscreen?
Thanks.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
www.fd.com.my
www.mercedes.com.my
Post Edited (william chan) : 4/21/2006 5:46:22 AM GMT
Andre LaMothe has made video drivers that can use 1 byte per pixel. These are tile and sprite engines that don't require much display RAM. You would need something like this. Andre's Hydra game console, which is based on the Propeller, will have drivers to do this sort of thing. Parallax will probably get around to making such a driver, but I don't know when. It would be neat if someone out there made it and offered it to everybody. I'm really not sure what Andre's plans are for his source code.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chip Gracey
Parallax, Inc.
Can the total number of pixels on the TV be increased, or is 256 x 192 some kind of standard?
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
www.fd.com.my
www.mercedes.com.my
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
1+1=10
Hmm, real-time JPEG decompression, anyone?
Chip Gracey
Parallax, Inc.
-Phil
Interlace flicker on the Amiga was a "personality feature". :^)
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Truly Understand the Fundamentals and the Path will be so much easier...
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chip Gracey
Parallax, Inc.
· X 7
3 5 1
I've seen some 4 level dithered images that looked pretty good. That is 256 grayscales dithered to a 4 grayscale output display.
Bean.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"SX-Video·Module"·available from Parallax for only $28.95 http://www.parallax.com/detail.asp?product_id=30012
"SX-Video OSD module"·available·for only·$49.95·www.sxvm.com
Available now! Cheap 4-digit LED display with driver IC·www.hc4led.com
"I reject your reality, and substitute my own." Mythbusters
·
Is the resolution for the VGA output 640x480? How many colours? Much better than the TV?
Can external RAM or EEPROM be used to hold a photographic still image?
Thanks.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
www.fd.com.my
www.mercedes.com.my
What kind of graphics data can be displayed with a 32k memory limitation?
Chip Gracey
Parallax, Inc.
Two questions
1.· The intent of the VGA is only to display text only?.
2·. There is a way to add external memory to display graphics?
·
Hey, does anybody know how many chars can be displayed on the TV by the propeller at any one time?
Same as the SX?
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
www.fd.com.my
www.mercedes.com.my
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Just tossing my two bits worth into the bit bucket
KK
·
Attached is a snapshot of a TV screen driven by the Propeller. The mugshot in the upper-left corner is 128 x 96 pixels and requires 6144 bytes of hub memory to store. There is no halftoning or dithering involved. The mugshot is generated in VGA mode; the rest of each line, including the syncs and colorburst are in video mode. Since vcfg is not double-buffered, I made sure that the switch was performed during a color value that displayed the same level in both modes. And even though VGA mode was used for part of the line, the resulting signal is still NTSC video. The second attachment shows a scope trace of a scan line that includes the mugshot.
It was impossible to get a true 4:3 aspect ratio for the mugshot. Eight clocks per pixel made the picture too narrow; nine, too wide. But it's closer than I was getting before with ten. Again, the grayscale data were generated from a .png file by my PC, which produced a list of longs. These were copied and pasted into the spin program that generated the output.
This technique could be extended further to get 192 (at four pixels per long) luminance levels. But the memory buffer requirements are doubled.
-Phil
four bits per color, right, for a total of 4096 colors? And three cogs would theoretically give me six bits per color? With so
many bits, the voltage divider slightly different, but it should be doable. This way there should be no need to switch to
VGA mode and back. Is there something I'm missing with this approach? I'm not too worried about the memory
consumption; that's simply a matter of appropriate compression.
And I should be able to set the frame/pixel rate so I get four pixels per VIDWAIT instruction, so I can (assuming I can
generate the raster lines fast enough) have each pixel be a completely unique color, right?
I was thinking of putting together a simple demo that just showed 4096 static colors over NTSC, but I ran out of weekend.
By the way, the Graphics_Demo is really impressive. The static pictures I've seen do not give it justice. I need to study
how it all works.
And as everyone says, the propstick is great! It was fun and easy to build; the few mistakes I made were easily corrected.
Also, synchronizing two cogs in the manner you suggest would not be easy. Andre' LaMothe has been able to do it, so that two cogs can take turns processing and displaying video; but I don't think anyone has successfully used two cogs to get better resolution. The major difficulty is getting the colorburst phases to match. There is no way to force their synchronization. It has to be done by finessing the PLL that generates the 16 x 3.57MHz internal color reference.
I'm certainly not trying to discourage experimentation. After all, the joy of hacking is why the Propeller exists! But a realistic assessment of the terrain can sometimes be helpful. The Propeller is great at what it does, and sometimes you can manipulate it in ways the designers didn't envision to do even more. But at some point, you do hit the wall.
-Phil