Video Byte

[Hydrophilic]

I just got a Video Byte from eBay.  In case of you haven't heard of this thing, it's a video digitizer for the C64/128 from around 1988.

Since it interfaces to high bandwidth video signals, I assumed it was a cartridge.  Wrong!  It plugs into the User Port 

I tried it out and it works pretty good (if you consider 160x200 image at 4-level grayscale good).  It takes about 2.5 seconds to capture a frame.  So you're video source better be very still or better have a good pause / freeze-frame.

It takes about a minute to save the frame to disk as a Koala file.  I am not using JiffyDOS, so that part could be improved.

Another suprise is how it captures the image.  I imaged it would capture 200 rasters sequentialy from top-to-bottom.  However, the thing captures video horizontally from left to right.

I would love to investigate this blast from the past some more, but I'm swamped in projects now.  If anybody has some insights into this gadget, or links they want to share, I would appreciate it!

[RobertB]

I just got a Video Byte from eBay.

Congrats!

Since it interfaces to high bandwidth video signals, I assumed it was a cartridge.  Wrong!  It plugs into the User Port 

I have the Video Byte II, which is a cartridge that plugs into the user port. 

It takes about 2.5 seconds to capture a frame.  So you're video source better be very still or better have a good pause / freeze-frame.

If you move, the image will have all kinds of strange "shearing" effects. 

It takes about a minute to save the frame to disk as a Koala file.  I am not using JiffyDOS, so that part could be improved.

It works quite well with its companion cartridge, Super Explode III, in the expansion port.

I would love to investigate this blast from the past some more, but I'm swamped in projects now.

I've always imagined what an improved Video Byte developed today would be able to do.

              Maybe I should cue a hardware hacker friend,
              Robert Bernardo
              Fresno Commodore User Group
              http://videocam.net.au/fcug
              The Other Group of Amigoids
              http://www.calweb.com/~rabel1/
              Southern California Commodore & Amiga Network
              http://www.sccaners.org

[polishedball]

Lifted from  http://moogle-tech.com/blog/?tag=computers  I just got one and was curious as well,  this turned up from a buddy that works on MESS.


Take A Byte
Sunday, November 30th, 2008
I recently purchased a Commodore 64 off of Craigslist. One of the interesting things that came with it was a Video Byte II cartridge - a still, black-and-white frame grabber that plugs into the User Port.

Fascinated, I cracked open the case and found it to be rather devoid of parts - only four ICS: An LM324N (quad op-amp), a CD4066BCN (quad bilateral switch), and two 555 timers.  This was even more impressive, since it uses no ASICs, FPGAs, or anything else traditionally associated with video capturing.  In addition to the ICs, there were some transistors, resistors and capacitors, of course.  After completing a partial schematic of the device based on PCB scans, I decided to try a different tack: reverse-engineering the software itself by using VICE.

It turned out to be a very simple loop utilizing CIA #2’s ability to time the duration that CNT2 is held high on the User Port by decrementing Timer B each time Timer A underflows. The loop reads pixels in column-by-column by performing a dummy read off of CIA #2 Data Port B, which in turn causes a pulse on the /PC2 handshaking line. This triggers the Video Byte 2 to pull CNT2 high for a duration corresponding to the brightness level of the upcoming pixel. The loop then checks the value in Timer B; 0xDC is Dark Gray, 0xDA is Medium Gray, 0xD8 is Light Gray, and 0xD6 is White.

Simple. Elegant.

My changes to VICE’s source tree are available on request; my implementation is currently highly deficient in that it simply reads in raw pixel data from an image in a hard-coded path with a hard-coded name. However, the actual CIA-related changes and functionality should be there. For what it’s worth, VICE did not actually have proper support for the Timer B mode that is used by the Video Byte. Mode 0×60 should decrement Timer B when Timer A underflows only if the CNT line (attached to the User Port) is held high; by contrast, VICE treats it the same as mode 0×40, which always decrements Timer B when Timer A underflows.

[RobertB]

Take A Byte
Sunday, November 30th, 2008
I recently purchased a Commodore 64 off of Craigslist. One of the interesting things that came with it was a Video Byte II cartridge - a still, black-and-white frame grabber that plugs into the User Port.

Fascinated, I cracked open the case and found it to be rather devoid of parts - only four ICS: An LM324N (quad op-amp), a CD4066BCN (quad bilateral switch), and two 555 timers.  This was even more impressive, since it uses no ASICs, FPGAs, or anything else traditionally associated with video capturing.  In addition to the ICs, there were some transistors, resistors and capacitors, of course.

Hmm, thanks for passing along the info.  I've never opened up my video capture carts, like video Byte and ComputerEyes.

              Truly,
              Robert Bernardo
              Fresno Commodore User Group
              http://videocam.net.au/fcug
              July 24-25 CommVEx v6 2010 - http://www.commodore.ca/forum and click on ComVEX

[polishedball]

Still looking for my computer eyes,  missing it a set of paddles and a datasette unit from my youth.  Hopefully it will turn up.  How do the two compare?

[RobertB]

How do the two compare?

If you mean a comparison between Video Byte II and ComputerEyes, I like VBII, because it scans faster, makes use of the Super Explode cart, and gives you the option of colorizing the captured image in 4 colors.

            Truly,
            Robert Bernardo
            Fresno Commodore User Group
            http://videocam.net.au/fcug
            July 24-25 CommVEx v6 2010 - http://www.commodore.ca/forum
            and click on ComVEX

[RobertB]

A goal of mine is to one day have the Scanntronik Digifox (Video-Digitizer).  With the use of a color wheel, you'd scan the image once for each primary color, and then with the software, you'd combine all three images to form one colored image.

Very much like Digiview on the Amiga,
Robert Bernardo
Fresno Commodore User Group
http://videocam.net.au/fcug
July 24-25 CommVEx v6 2010 - http://www.commodore.ca/forum
and click on ComVEX

[polishedball]

That sounds pretty interesting had never heard of that one....

Now I need to find that super explode cart looks like I just missed one on ebay and i believe  the one listed on ioffer was the same one

[RobertB]

That sounds pretty interesting had never heard of that one....

Yeah, I've asked a German friend from the Dienstagstreff.de club to dig out one for me, but I guess he doesn't consider it a priority.

          One day... one day...
          Robert Bernardo
          Fresno Commodore User Group
          http://videocam.net.au/fcug
          July 24-25 CommVEx v6 2010 - http://www.commodore.ca/forum
          and click on ComVEX

[destined]

Robert,

Would this be a similar idea?

http://starbase.globalpc.net/~ezekowitz/vanessa/hobbies/projects.html  skip down to "quickscan."

[RobertB]

Would this be a similar idea?

http://starbase.globalpc.net/~ezekowitz/vanessa/hobbies/projects.html  skip down to "quickscan."

Quickscan doesn't do color, as does Digifox.  Also Quickscan is dependent on an old webcam which cannot be found anymore.

          FCUG celebrating 30 years,
          Robert Bernardo
          Fresno Commodore User Group
          http://videocam.net.au/fcug