Questions tagged [video]

For questions regarding hardware and drivers used for video output.

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78
votes
9answers
13k views

Why were CLIs typically light text on dark background, whereas GUIs typically use(d) dark text on light background?

My experience is that CLIs were typically shown with light text on a darker background. For example, the IBM PC would use white/light gray (depending on your point of view), amber or green (the latter ...
65
votes
3answers
13k views

What character is the MS-DOS cursor?

The cursor used on my 486 (and Pentium 3) in MS-DOS 6/7 has a thick underlined character. I cannot find that in code page 437. The underscore character is the closest to it, but is thinner. Where ...
58
votes
6answers
8k views

Reason for the Amiga clock speed

The Amiga used a CPU rated for 8 megahertz, but clocked at 7.14 megahertz. What was the reason for this number? I remember it was something to do with a multiple of the frequency of the video ...
55
votes
6answers
13k views

How did old MS-DOS games utilize various graphic cards?

Nowadays each graphic card has some driver in operating system that translates some (typically) standard API such as OpenGL, so that programmers use some standardized API code to tell graphics cards ...
45
votes
4answers
33k views

Commodore 64 to modern TV

I've been thinking about getting a Commodore 64 machine. However, I realise there's obviously no video cables I have that will work. But when I looked online there are many people using S-Video to VGA ...
43
votes
2answers
9k views

Why were some early PC 3D cards unsuitable for 2D graphics?

Some of the early PC 3D graphics cards such as the 3dfx Voodoo Graphics cards had a passthrough port to enable them to switch to a secondary card to display 2D graphics. I am curious to know why these ...
37
votes
8answers
12k views

Why did computer video outputs go from digital to analog, then back to digital?

While early microcomputers used analog video outputs (often to use a television as a display), higher end machines such as the BBC Micro or Commodore 128 supported a digital RGB (or RGBI) video output....
36
votes
4answers
7k views

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

On the Apple II there's an interesting way to add a little color to the bitmap, since the high bit select the palette used for the three-and-a-half pixels represented by the byte. Like this: 0: Black,...
35
votes
2answers
3k views

What mid-1970s to mid-1980s home computers had their graphics characters added to Unicode 13?

The Unicode 13.0.0 release notes mention among the symbol additions: 214 graphic characters that provide compatibility with various home computers from the mid-1970s to the mid-1980s and with early ...
33
votes
1answer
2k views

How did the Amiga DCTV work

This is an unusual question since I'll answer it right away because it was a truly unique device and there is absolutely nothing about the technology it used on the internet. I spoke with the hardware ...
31
votes
3answers
10k views

Why do PCs boot in 720x400 resolution?

Using my 21" Trinitron OSD, I can see that the resolution at boot is 720x400. From memory, this weird resolution is extremely uncommon if ever to be seen as a choice on software that supports ...
28
votes
3answers
2k views

What are the differences between a PAL and NTSC C64?

A lot of programs released for the Commodore 64 contained different software for the PAL or NTSC computer. Why did they have different versions of the hardware? Did the software have to be different ...
26
votes
10answers
7k views

Graphics chips in 1980

Suppose you were trying to build a computer with a color graphics display in 1980, you have limited engineering resources and time to market is critical, so you want to get as many of the parts off ...
21
votes
1answer
1k views

When does the VIC-II read the sprite data?

This question is about the Commodore 64 and its graphics chip, the VIC-II. Imagine that on a particular scanline, the VIC-II needs to fetch 40 bytes (the background tiles) and since it's a badline ...
20
votes
1answer
2k views

Can I hook up an Atari 8-bit computer to a flat-screen tv

I'm interested in getting an Atari 8-bit (like I had 30 years ago), but have only LCD TVs (and computer monitors). Can I hook this Atari to a flat screen TV, or do I need an analog CRT?
19
votes
7answers
4k views

What video connections were common in Europe?

What video connections were common on European TVs and monitors during the "retro" era? In the USA, first there were none on TVs (RF screw terminals only) and monitors had composite (yellow RCA, CVBS)...
19
votes
3answers
2k views

Do all VGA cards implicitly support CGA and EGA?

Practically speaking, if I buy an ISA VGA card, will it implicitly support CGA and EGA games?
19
votes
6answers
2k views

Limiting factor on sprite sizes

Early consoles and home computers that were optimized for games, tended to provide sprites. From a game programmer's viewpoint, these were good to have. Of course, one always wanted more and larger ...
18
votes
2answers
3k views

How did the Sega CD decompress video?

In the early nineties, Sega released the Sega CD, a.k.a. Mega CD, an add-on that attached a CD-ROM drive to the Mega Drive a.k.a. Genesis. Its primary or at least most conspicuous use was for full-...
18
votes
7answers
3k views

Cost of unrestricted sprites

All the game consoles of the second through fourth generations, and several early home computers, had sprites, which were valuable though costly, e.g. the VIC-II spent 2/3 to 3/4 of its area on ...
16
votes
5answers
3k views

Can the wrong sync frequency really destroy a CRT monitor?

I've read in various places that an incorrect signal of the wrong refresh rate can cause physical damage to a CRT monitor, but I've never found an adequate explanation of why this is so. Is this true? ...
16
votes
5answers
2k views

What specific technical advance(s) allowed PCs to play “Full-screen full-motion” video?

In the early 1990s, the new buzzword for PCs was "Multimedia", and the gold standard for multimedia performance usually talked about was "full-screen full-motion" video playback. Many will remember ...
16
votes
6answers
2k views

Did scanlines appear on the ZX Spectrum screen?

I used played Spectrum games as a child. According http://scanlines.hazard-city.de/ and http://www.zxdesign.info/vidresearch.shtml, the Spectrum 48K emitted 50Hz half-resolution full frames, instead ...
16
votes
1answer
801 views

Did the Macintosh Classic series use DMA to display video?

I'm learning more and more on how the original Macintosh series worked. I can't, however, find information in my research on how the Mac's video generator accessed the video RAM. My assumption is ...
15
votes
3answers
2k views

What graphical effects can be created by changing the VIC-II settings?

I read in this answer that one could create graphics effects outside the usual specifications of the hardware by changing the settings of the machine's VIC-II at specific cycles during the video ...
15
votes
3answers
4k views

With a 15 kHz video signal (240p or 480i), does VGA have any real-world advantage over S-Video?

It's difficult to find a modern LCD monitor that can display a 15 kHz signal through VGA, so I'm wondering if S-Video is just as good when displaying 240p and 480i? I've looked at screenshot and video ...
15
votes
1answer
741 views

How do Amiga “Monitor” drivers work?

A "Monitor" driver for an Amiga is a file which, when placed in DEVS:Monitors, enables additional screenmodes. The standard PAL or NTSC driver, which provides screenmodes compatible with consumer TV ...
14
votes
2answers
642 views

Atari ST DRAM timing puzzle

From the Atari SM124 Monochrome Monitor Service Manual, I get that the video signal timing for one line is 20µs. With the horizontal resolution of 640 pixels, this gives a 31.25ns pixel clock. Using ...
13
votes
7answers
3k views

Z80 and video chip contending for random access

Back in the 8-bit days, I used 6502 computers, where the story about memory access was easy to understand. RAM chips of the late seventies and early eighties could do 2 MHz (or a bit more e.g. 2.6 in ...
13
votes
3answers
2k views

What is going on in the overscan area of Sega Genesis games?

What is going on in the overscan area of Sega Genesis games? I noticed that different games display different things in the overscan area. I understand this was never intended to be seen. However, I ...
13
votes
1answer
176 views

Videoprocessor with custom horizontal sampling

I have a variety of videoprocessors (Micomsoft Framemeister, Micomsoft SC-512N1-L/DVI, Sync Strike) to help me get the best possible RGB picture out of my retro computers/consoles. However one issue ...
12
votes
9answers
2k views

Did any machines alternate between two video memory banks?

If a home computer or console has two banks of memory, A and B, then the following design is possible: The video chip only connects to bank A. The CPU connects to both. During active scan line, CPU ...
12
votes
2answers
1k views

Acorn Electron to VGA/HDMI?

I am aware that there are answers regarding this but they do not seem to answer it for me. A few years back I got a Acorn Electron and it works using the arial for video fine, but I would like to ...
12
votes
1answer
584 views

How did the Apple 1 video circuit work?

One of the major innovations of the Apple 1 when it was released in April 1976 was that instead of using a serial interface requiring an expensive external terminal it had a built-in 40×24 text video ...
12
votes
3answers
684 views

What are the Ultra-Highres registers in ECS and AGA for?

The Amiga custom chip set, in its ECS and AGA versions, seems to contain some registers for what is called an "Ultra-HighRes/DUAL" mode: DFF078 SPRHDAT W Ext. logic UHRES sprite pointer and ...
11
votes
3answers
4k views

Visible resolution of C64 video output, including borders

The VIC-II in the C64 outputs 320x200 pixels inside the borders. What is the full visible resolution including the borders? To clarify, I am interested in the full screen size in units of normal ...
11
votes
4answers
1k views

Video chip for hypothetical 1988 arcade game

I have a project where I aim to create a retro arcade game cabinet, the technology would be ~1988. For now I am planning to only simulate the system on my PC in order to develop the game. The ...
11
votes
2answers
538 views

Amiga Video Toaster support

What features of the Amiga chipset architecture and/or Amiga OS made it possible to design the Video Toaster for the Amiga? Why weren't there similar (cost-effective) video products for the PC or Mac?...
11
votes
3answers
3k views

Were video chips specific to the CPU?

Modern graphics cards are essentially miniature supercomputers in their own right, with their own memory and instruction sets, but in the eighties and late seventies, a very common kind of personal ...
11
votes
1answer
871 views

Can the BBC be programmed to a half-size mode 1 screen mode with 16 colours instead of 4?

Screen Mode 2 on the BBC micro is 160 x 256 with "16"* colours. This uses up 20Kb of memory. Horizontal-rectangular pixels ( 2 x squares each). 4 bits per pixel (0-15 values for 16 colours) Screen ...
11
votes
1answer
2k views

Recommendations for high quality cheap RF demodulator

Does anyone have recommendations for a specific inexpensive RF demodulator that's higher quality than your standard VCR (and maybe a little bit smaller)? Like any old equipment floating around that ...
11
votes
2answers
166 views

Which addresses does the Motorola 6845 CRTC output during retrace?

I'm trying to understand how the video hardware (CRTC and Gate Array) in Amstrad CPCs works. Specifically, I have a question about the behavior of the refresh memory addresses and row adresses output ...
11
votes
1answer
667 views

Possible cause for C128 A/V output containing faintly coloured columns and failing shortly after?

I recently acquired a Commodore 128. It worked fine for about an hour, in both C64 and C128 mode, at the exception of some coloured bars, before displaying garbage and not booting anymore into any ...
10
votes
4answers
3k views

Is it possible to swap the Apple IIc's monochrome CRT tube for a color one?

I just love the Snow White industrial design language of the Apple IIc, especially when paired with the Monitor IIc. It is a classic design that doesn't show its age. I've even recently seen them ...
10
votes
7answers
4k views

What Video Chips/Video generation techniques are usable for the Z80?

I'm building a Z80 home computer and I need color graphics for it similar to other home computers such as the C64. I thought that, like Motorola or MOS, Zilog would have a peripheral chip dedicated ...
10
votes
2answers
1k views

Atari Centipede Video and the GBS-8200 didn't seem to work - looking for ideas

So I ordered the GBS-8200 (It's a v4.0) and tried to use it to convert the 15KHz RGBHV monitor output to VGA. I did a direct connect to P11 with Red, Green, Blue and Hsync and Vsync and Video return ...
10
votes
1answer
654 views

How can I hook up my Acorn RISC PC 600 to a LCD monitor?

I own an Acorn RiscPC 600 which I picked up from Ebay years ago which apparently works but did not come with a monitor. I purchased a VGA to DVI connector to hook up the computer to my PC desktop ...
10
votes
1answer
582 views

VIC-II transistor count

I'm curious about the transistor count of the VIC-II, the video chip in the Commodore 64. According to http://visual6502.org/wiki/index.php?title=Chips_in_our_collection the Atari 2600 TIA chip has ...
10
votes
1answer
603 views

Why CPC464 display is less stable while reading from cassette?

Context The Amstrad CPC 464 has a very stable RGB video output. By "stable" I mean that the image on the CRT monitor does not move, wiggle, shake in any way. The electron beam draws every pixel ...
10
votes
1answer
457 views

What was the difference between the original Video Toaster and the 4000 version?

There were two versions of the Video Toaster hardware: an original one designed for the A2000 and a later one designed for the A4000 which was suitably called the Video Toaster 4000. While I can ...