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57 votes
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What determines the color of every 8th pixel on the Apple II?

A nice one - and coming up every now or then. TL;DR The Apple IIs video logic produces a B&W bitstream at the right frequency to bedazzle an NTSC TV set in a way to make it 'see' colour. The ...
Raffzahn's user avatar
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53 votes

Were the classic game consoles *technically* able to play both NTSC and PAL games, if ignoring artificial region lock-in?

They were different. You probably already know that NTSC is 60 Hz and PAL is 50 Hz. The video generation hardware was much more 'bare metal' than today (the NES color palette implementation was so ...
David's user avatar
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37 votes
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Did arcade monitors have same pixel aspect ratio as TV sets?

CRTs don't have pixels, they don't work that way. Also, arcade monitors expose all the picture controls at the back so it is possible to adjust them quite extensively. Operators would have made sure ...
user's user avatar
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28 votes
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Is the only reason that my PAL NES is able to run NTSC/American games that it's doing it on an EverDrive?

The NES's region lock is implemented in hardware, not software, with the CIC chip. The NES contains a CIC, and each authentic cartridge contains an identical CIC. When the console is powered on, the ...
NobodyNada's user avatar
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22 votes
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Limitations for Color Usage in NTSC

TL;DR Any (*1) colour can be displayed. The signal is analogue and can be very fine tuned. But tuning needs time, thus not every colour can be shown beside each other (without a transition thru others)...
Raffzahn's user avatar
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20 votes
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Why not one pixel per color clock?

I think you're conflating a few issues: being in-phase with the colour subcarrier; being sampled at a rate less than or equal to the colour subcarrier; and being sampled at an integer division of the ...
Tommy's user avatar
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18 votes
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Could some 200 line displays have been pushed to 240 lines?

If the monitor’s phosphor mask is fine enough to handle the increased vertical resolution, then the rest is mostly about timing, and typical components at the time were capable of handling a 20% ...
Stephen Kitt's user avatar
17 votes
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Was PAL or NTSC encoder IC a critical component in early video games?

The PAL video encoder was not a bottleneck of any kind. It is left out because the unit is not a PAL model, but a SECAM model, which needs a different kind of encoder. So the chip is not needed and it ...
Justme's user avatar
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17 votes

Were the classic game consoles *technically* able to play both NTSC and PAL games, if ignoring artificial region lock-in?

Basically the difference between PAL and NTSC consoles is the frame rate, 50 vs 60 Hz. The consequence of that is that PAL and NTSC mostly differ in number of cycles available for the CPU per frame, ...
lvd's user avatar
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16 votes
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Ideal resolution for color computer on NTSC

The pixel clock doesn't have to be the same as the color clock. In fact, it's usually higher. Remember that in a composite video signal, the chrominance information (whose resolution depends upon the ...
mcleod_ideafix's user avatar
14 votes

Did arcade monitors have same pixel aspect ratio as TV sets?

Did arcade monitors have same pixel aspect ratio as TV sets? Short answer: No, not necessarily. Long Answer: To start with, 'Title Safe Area' is an idea to define the parts of one transmission to ...
Raffzahn's user avatar
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14 votes

Could some 200 line displays have been pushed to 240 lines?

Just to summarize, some points which people may sometimes not fully realize about analog video: The kind of analog video signals referred to in the question are based on the concept of raster scan, ...
Jukka Aho's user avatar
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14 votes

Why was the VIC-II restricted to a hard-coded palette?

We can of course only guess why, but with a fixed palette, it only needs to implement the circuits you need to get the 16 predesigned colors based on the color index. Cheaper, faster, and they were ...
Justme's user avatar
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13 votes

Why not one pixel per color clock?

The pixel clock has to be fast enough to generate the number of pixels you want to display horizontally within the 56 microsecond scan line interval. At 3.58MHz, you only get about 200 pixels. This ...
Jules's user avatar
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13 votes
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Spectrum clones 512x192 mode usable text resolution

I had two micros when I was growing up: the SAM Coupé and the Acorn Electron. The SAM Coupé has a 512x192 mode much like you discuss. The SAM's display is physically wider than a Spectrum's though, ...
Tommy's user avatar
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12 votes

Why was the VIC-II restricted to a hard-coded palette?

While I would doubt that a 16x8 ROM would be cheaper than an 8-bit register or even four of them (which is probably why the Atari 2600 allows a wide range of colors, but leaves me puzzled at the SID ...
supercat's user avatar
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12 votes
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NTSC scan lines used by 8-bit computers

I found one document which might shed some light why 192 lines was used before 200 caught on. The TI 99/4 used a TI TMS9918 VDP, which based on the document, was designed as a chip for simple low cost ...
Justme's user avatar
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11 votes

Is a normal B&W TV good enough for 80-column text?

A typical black and white television will be capable of displaying 80-column text that can be read, but such text will generally be sufficiently unpleasant to read that some other kind of display ...
supercat's user avatar
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11 votes
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Did the PAL version of the Apple II use a different clock frequency?

Yes, but only a very slightly different speed: the master crystal was around 14.238Mhz rather than 14.31818Mhz. which is only around 0.5% different, so I would expect safely within tolerance for a ...
Tommy's user avatar
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10 votes
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NTSC scan lines and vertical resolution

While nominally 241 scan lines were visible in the sense they contained video information, all TV sets hid a varying amount of scan lines on top and bottom (and left and right) by overscan and by the ...
dirkt's user avatar
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10 votes

PAL NES in USA, 50Hz vs 60Hz

Rather than convert the NES, just get a PAL monitor. The common auto backup video systems use an NTSC/PAL switchable monitor, available for not much money.Backup monitor 7" It is also possible, ...
Whit3rd's user avatar
  • 2,170
10 votes

Did the PAL version of Super Mario Bros. on the NES really have faster music, and if so, why?

Porting a game to PAL while making all actions take the same number of frames would cause the game to perform 20% slower than with NTSC. Some games did this, but other games adjusted the amount of ...
supercat's user avatar
  • 37.2k
10 votes

Were the classic game consoles *technically* able to play both NTSC and PAL games, if ignoring artificial region lock-in?

Technically, no, because usually hardware was fixed to generate the TV signal in a fixed way, instead of being programmable. Many systems had separate video chips for different TV systems, and due to ...
Justme's user avatar
  • 33.9k
10 votes

How could/can there exist NTSC->PAL converters for SNES and other classic game consoles?

These adapters do nothing else than defeat the lockout chip so that e.g. a PAL region console can be forcibly made to execute code from a cartridge whose content is originally intended to run on an ...
Justme's user avatar
  • 33.9k
10 votes

NTSC scan lines used by 8-bit computers

Older television sets used round picture tubes with a bezel to mask off the edges of the scanned area. Picture tubes were often circular, and to maximize useful areas, the image was expanded to the ...
supercat's user avatar
  • 37.2k
10 votes

NTSC scan lines used by 8-bit computers

Similar to the TI VDP answer, have a look at the Apple text mode layout described in this answer. (And keep in mind that the graphics video layout is based on the text layout). There are 40 characters ...
dirkt's user avatar
  • 28.3k
10 votes

NTSC scan lines used by 8-bit computers

Conjecture #1: NTSC title-safe area (unlikely) An NTSC video frame has 525 lines. After subtracting the 21 lines of vertical blanking, and the 20% of the visible area that was considered non-title-...
dan04's user avatar
  • 1,084
9 votes

What determines the color of every 8th pixel on the Apple II?

The simplest way to think about composite video on the Apple is to imagine that vertical colored stripes of red, blue, and green, and yellow are overlaid onto the picture. These strips are half a ...
supercat's user avatar
  • 37.2k
9 votes

Why not one pixel per color clock?

Short Answer: There is no relation. What seems like a relaiton is non related coincidence. Long Answer: First of all, there is no colour clock. The mentioned frequency of 3.58 MHz is not a colour ...
Raffzahn's user avatar
  • 226k
9 votes

Actual resolution of composite video monitors

It depends on whether the TV is color or black-and-white/monochrome. Older B&W TVs (and ordinary TV electronics and tubes converted into monochrome monitors by some el-cheapo monitor vendors), ...
hotpaw2's user avatar
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