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I used to work with a QCG-500 at a local TV station about twenty years ago. I can still pick out the way certain fonts looked at certain sizes on that thing. It

by LocalH 6y ago

I used to work with a QCG-500 at a local TV station about twenty years ago. I can still pick out the way certain fonts looked at certain sizes on that thing. It eventually got replaced by a Chyron Maxine. Prosumer and professional character generators are woefully underdocumented. Anyone wanna donate any old functional ones to me? I'll set up and make a Youtube series about them lol. I'd love to see them eventually be emulated in the way that classic game consoles and home computers have been. I'm 40 years old and I can still hear flyback. I actually have a Roku Express+ hooked up to a 27" Trinitron. I miss the days of CRTs, except for their weight.

ddingus 6y ago
I am 52, and it's getting tough to hear flyback. I miss CRT's too, and I have a couple. One, near my work desk, is a lightly used SONY PVM, high pitch Trinitron. I love to have movies playing on it when working. Above it, on a shelf, are a reasonable VHS that I use for capturing tapes and watching movies on as well as some not so special DVD/Blu-Ray player I should hook up via RGB, but is running S-video. Rambling aside, I would enjoy a video series on character generators. Lots of us geeked out on broadcast details. Personally, I would enjoy any tech info on how the characters were done and what trade-offs got made any why. Some of what was out there looked very good. Other gear, not so much. Bet it's a few minor details that differentiate those outcomes too.
- AnimalMuppet 6y ago
  It's been 24 years. I probably don't owe a duty of confidentiality any more. So... We had descriptions of each character of each font in a scalable, vector form. To draw a character, we'd draw it as a bitmap (1-bit depth) at 4 times the size. Then we would shrink each 4x4 cell down to one 8-bit value (weighting the center more than the edges). That 8-bit value was the alpha (transparency) value for drawing the character over whatever was already there in the frame buffer. When drawing (compositing) one thing over another with an alpha channel, we used true Porter & Duff compositing, with pre-multiplied colors. We had a custom ASIC that would do it, so it was fast. One of the trade offs was the rise time (or number of pixels, same thing) of the edge of a character. Too fast and the NTSC video signal couldn't handle it (and you'd have visually obvious stair-steps on the diagonals). Too slow and the characters looked soft rather than crisp.
  - jhallenworld 6y ago
    At VDS, there was 68000-based titler called Vidstar or Videostar, something like that. This was before the great DRAM price decline, so every effort was made to reduce the memory including the frame buffer. (on previous products they experimented with bubble memory and even shipped a product using CCD memory). So the frame buffer was compressed using run-length coding. The hardware decoded it on the fly when generating the video. Anyway, we could get very high resolution this way with a tiny fast SRAM frame buffer, it looked great. A problem was that even with the 68000, composing a page from text was quite slow: 10 seconds for single line, something like that. One of the products was a teleprompter. To make smooth slow scrolling without complex sampling we moved the screen by changing the vertical sync position. This is not so easy to do well because the vertical sync detector in the monitor is pre-charged by the nearest horz sync (this is why NTSC has the double-rate serration pulses for interlace). On the other hand, we did roll and crawl effects using fast 6809 assembly on other products. The font on this type was very crude- either fixed width characters like a terminal or semi-proportional spaced, where the width had to be a multiple of some number of pixels (so still character cells). You could get away with it on CATV bulletin board devices, but not in high quality titlers.
  - ddingus 6y ago
    Cool. Thanks. That all makes a ton of sense. It also explains some of what we would see on various systems too. If, say target frame buffer was some multiple of the color clock, it would be 320, 640, maybe as low as 160 pixels. (We had a couple of those and it was crappy obvious) That ramp seems like it needs to align with that clock too, or there would be color fringing. Avoiding it entirely is gonna be soft, or strict limits on color combos. (How many TV newscasts went with blue and white?) Going sharper would mean a potential color artifact amd or different ones, depending on the alignment between the color clock and the ramp pixel start? Say it was a blue fringe. Placing the glyph on an even pixel start might generate a bluish artifact, and a reddish one on an odd pixel. (Assuming 320 pixels for illustration) Good placement against say a blue background, maybe gradient to also mask even odd line effects... Were there placement limits per glyph to keep these things consistent? Did you guys get down to that detail? Some of the graphics seen near the end of SD were sweet! Like almost every issue woven into a nice looking, very clever package.

by LocalH 6y ago

ddingus 6y ago

I am 52, and it's getting tough to hear flyback. I miss CRT's too, and I have a couple. One, near my work desk, is a lightly used SONY PVM, high pitch Trinitron. I love to have movies playing on it when working. Above it, on a shelf, are a reasonable VHS that I use for capturing tapes and watching movies on as well as some not so special DVD/Blu-Ray player I should hook up via RGB, but is running S-video. Rambling aside, I would enjoy a video series on character generators. Lots of us geeked out on broadcast details. Personally, I would enjoy any tech info on how the characters were done and what trade-offs got made any why. Some of what was out there looked very good. Other gear, not so much. Bet it's a few minor details that differentiate those outcomes too.

AnimalMuppet 6y ago
It's been 24 years. I probably don't owe a duty of confidentiality any more. So... We had descriptions of each character of each font in a scalable, vector form. To draw a character, we'd draw it as a bitmap (1-bit depth) at 4 times the size. Then we would shrink each 4x4 cell down to one 8-bit value (weighting the center more than the edges). That 8-bit value was the alpha (transparency) value for drawing the character over whatever was already there in the frame buffer. When drawing (compositing) one thing over another with an alpha channel, we used true Porter & Duff compositing, with pre-multiplied colors. We had a custom ASIC that would do it, so it was fast. One of the trade offs was the rise time (or number of pixels, same thing) of the edge of a character. Too fast and the NTSC video signal couldn't handle it (and you'd have visually obvious stair-steps on the diagonals). Too slow and the characters looked soft rather than crisp.
- jhallenworld 6y ago
  At VDS, there was 68000-based titler called Vidstar or Videostar, something like that. This was before the great DRAM price decline, so every effort was made to reduce the memory including the frame buffer. (on previous products they experimented with bubble memory and even shipped a product using CCD memory). So the frame buffer was compressed using run-length coding. The hardware decoded it on the fly when generating the video. Anyway, we could get very high resolution this way with a tiny fast SRAM frame buffer, it looked great. A problem was that even with the 68000, composing a page from text was quite slow: 10 seconds for single line, something like that. One of the products was a teleprompter. To make smooth slow scrolling without complex sampling we moved the screen by changing the vertical sync position. This is not so easy to do well because the vertical sync detector in the monitor is pre-charged by the nearest horz sync (this is why NTSC has the double-rate serration pulses for interlace). On the other hand, we did roll and crawl effects using fast 6809 assembly on other products. The font on this type was very crude- either fixed width characters like a terminal or semi-proportional spaced, where the width had to be a multiple of some number of pixels (so still character cells). You could get away with it on CATV bulletin board devices, but not in high quality titlers.
- ddingus 6y ago
  Cool. Thanks. That all makes a ton of sense. It also explains some of what we would see on various systems too. If, say target frame buffer was some multiple of the color clock, it would be 320, 640, maybe as low as 160 pixels. (We had a couple of those and it was crappy obvious) That ramp seems like it needs to align with that clock too, or there would be color fringing. Avoiding it entirely is gonna be soft, or strict limits on color combos. (How many TV newscasts went with blue and white?) Going sharper would mean a potential color artifact amd or different ones, depending on the alignment between the color clock and the ramp pixel start? Say it was a blue fringe. Placing the glyph on an even pixel start might generate a bluish artifact, and a reddish one on an odd pixel. (Assuming 320 pixels for illustration) Good placement against say a blue background, maybe gradient to also mask even odd line effects... Were there placement limits per glyph to keep these things consistent? Did you guys get down to that detail? Some of the graphics seen near the end of SD were sweet! Like almost every issue woven into a nice looking, very clever package.