Questions tagged [video]

For questions regarding hardware and drivers used for video output.

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28 votes
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How did the Atari 2600 achieve a resolution of 160 x 192 pixels with only 128 bytes of memory?

According to wikipedia, the Atari 2600 had a resolution of 160 x 192 pixels. Had it been monochrome, it would had needed 160*192 = 30,720 bits of video RAM, or 3,840 bytes. But the total memory was ...
vakvakvak's user avatar
  • 391
10 votes
5 answers
6k views

When did the PC bus start slowing access to video RAM?

The PC architecture, from the original IBM PC onward, has always been designed around the idea that video memory will be on an expansion card. This was an unusual design decision; most 80s computers ...
rwallace's user avatar
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4 votes
0 answers
324 views

How many bytes can a GameBoy copy from Work RAM into VRAM in one vblank?

How many bytes of data can be copied from work RAM into VRAM during the "safe time" while the PPU is not refreshing the LCD? I'm asking about the simplest possible case, when I am copying ...
Cactus's user avatar
  • 2,710
7 votes
2 answers
561 views

Were VGA palette's HSV math properties used in practice?

In "Why were those colors chosen to be the default palette for 256-color VGA?", we've established that 216 of its colors represent a 24x3x3 truncated HSV color space. This results in an ...
Therac's user avatar
  • 743
9 votes
4 answers
2k views

Detecting if a video mode is supported by INT 0x10

The PC BIOS uses the INT 0x10, AH=0x00 function to change the video mode. There's a big list of video modes available, but how can I be sure that the video mode I want to set is supported? For example,...
DarkAtom's user avatar
  • 2,337
1 vote
0 answers
161 views

FBAS to RGB converter available? [closed]

I am looking for a FBAS to RGB converter, small size, low cost. Background: Back in the day and until 2008 BMW used to use RGB as the video standard in its cars. Three separate wires, red green and ...
conanDrum's user avatar
  • 111
30 votes
3 answers
8k views

Why did 1990s-2000s LCD all use 60 Hz refresh?

In the CRT era, refresh rates ranged from 50 to 160 Hz. Some displays could barely do 65, high-end Mitsubishi and Sony tubes could run 120+; most people used 70-100 Hz. GPU DACs and monitor circuits ...
Therac's user avatar
  • 743
8 votes
1 answer
619 views

How did the Dragon modify 6847 video output timing for PAL?

The Motorola MC6847 Video Display Generator (VDG) generates video output with NTSC timings. (It does not do NTSC colour, however; it gives luma, R-Y and B-Y signals that need an external NTSC colour ...
cjs's user avatar
  • 25.9k
7 votes
3 answers
971 views

Did any computer systems connect "terminals" using "broadcast"-style RF to multiplex video, and some other means of multiplexing keyboards?

Rendering a screen full of text as a video signal required a substantial amount of circuitry, especially in the era before LSI semiconductors. A device to generate display signals for a moderate ...
supercat's user avatar
  • 36.2k
13 votes
2 answers
1k views

How do I stop flickering in mode 13h?

I'm making a small graphics library for MS-DOS 6.22, using mode 13h with Turbo C on VirtualBox. Recently, I was able to code a small snippet to move a sprite on the screen, using double buffering and ...
SlickSpore's user avatar
0 votes
3 answers
402 views

Toshiba laptop with Windows 98 shows corrupted characters while booting, then the system goes entirely blind

I have a Toshiba laptop and I am not sure what is going on with it. Thinking that maybe the computer was corrupted 20 plus years ago. Trying to fix it up. When the laptop boots, I can see this on ...
vintagepls's user avatar
14 votes
3 answers
5k views

Which font with slashed zero is being used in this screengrab?

Do you know which font is being used in the video here: https://www.youtube.com/watch?v=xnudvJbAgI0? A screengrab of the video that shows a lot of text: We can see that the zeros are slashed, so it ...
Lone Learner's user avatar
12 votes
5 answers
5k views

How do 80x25 characters (each with dimension 9x16 pixels) fit on a VGA display of resolution 640x480?

Due to my limited knowledge of retrocomputing and old CRT displays and graphics cards, I could be making some wrong assumptions in this question. For any wrong assumption you find in this question, I ...
Sirius Scientist's user avatar
15 votes
5 answers
4k views

Why would any "local" video signal be "interlaced" instead of progressive?

As I had understood things, "interlaced" video was nothing but a clever way to save data bandwidth by only sending every other line, swapping between starting on line 0 and 1 for every frame,...
Kyndel's user avatar
  • 151
10 votes
3 answers
2k views

How to write text in MODE 0x13?

I have read How to write directly to video memory using "debug.exe" in MS-DOS? and I know how to write text to video memory in mode 0x3 but I can't figure out how to write text to video ...
Lone Learner's user avatar
23 votes
6 answers
9k views

Why was video, audio and picture compression the poorest when storage space was the costliest?

"Full-motion video" sequences in PC and console games in the 1990s were bad-looking, in spite of taking huge amounts of storage space. Same thing with random short video clips that I ...
Romalis's user avatar
  • 281
11 votes
1 answer
481 views

On my NES, the color red displays as black. What could be the cause?

I have a NES, it is working normally, but one of the game colors appears as black. In the game Mario Bros 3, the name is in black, some blocks are black and the goombas too. What can it be?
Carlos Bueno's user avatar
3 votes
4 answers
2k views

What did game programmers and journalists mean by a "hardware trick"? [closed]

Recently, I've been hearing a good deal about hardware tricks. For instance, the YouTuber Ahoy (see A Brief History of Graphics) mentions that some game programmers resorted to "hardware tricks&...
AndrewGreen's user avatar
15 votes
6 answers
2k views

Video playback software/formats for a 386?

Wanting to have my 386DX @ 20MHz play a video (any video), just as a demo. I'd prefer it to be watchable (eg 10fps and not a tiny 10x10 pixel) as opposed to a slideshow. What player software could I ...
KERR's user avatar
  • 353
0 votes
2 answers
590 views

How did Atari RF output work?

I know that RF stands for radio frequency but what chip in the Atari handles the video output and does anybody know if something similar would work on a modern tv?
Chadley123's user avatar
14 votes
2 answers
2k views

What is the size of the border of the ZX Spectrum in scanlines/pixels/bytes?

The bitmap area of the Sinclair ZX Spectrum is exactly 256 x 192 pixels. Surrounding the bitmap is quite a wide border area which is generally just one colour but loading and saving from tape changes ...
hippietrail's user avatar
  • 6,666
2 votes
1 answer
303 views

TI-99/4a RF modulator, fuzzy video

I recently purchased a TI-99/4a. Well, 2 actually. Both work, but I only have one RF modulator. I ordered a composite adapter, but that hasn't arrived yet. Both work on the RF modulator, but the ...
Keltari's user avatar
  • 503
4 votes
1 answer
243 views

What systems had digital RGBI output at frequencies other than ~15.7 kHz?

Plenty of early '80s microcomputer systems with 16-colour graphics offered digital RGBI output: four TTL (or at least digital on/off) signals for red, green, blue and intensity. These included many ...
cjs's user avatar
  • 25.9k
14 votes
2 answers
1k views

Resources about 1980s GPCPU video controller designs

Reading about the Fujitsu Micro 7, I found out that it used a pair of 6809 microprocessors: one as main CPU and one as graphics processor. That made me remember that when running old arcade games with ...
airman's user avatar
  • 1,350
7 votes
2 answers
2k views

Why does my PlayStation RGB video cable cause the picture to be all orange-y unless pressure is applied?

In 2005, I bought an RGB cable for my old (~1996) PlayStation. It seemed to work at first. I don't remember when, but at some point, it started acting oddly. Since, whenever I plug it in, it displays ...
Vaiden's user avatar
  • 71
37 votes
1 answer
7k views

In the classic "Windows 98 crashes live on CNN" video, why does the BSOD appear so oddly?

I've been seeing this since the late 1990s: https://www.youtube.com/watch?v=eKy9fV_zX_o Was this a hoax or joke of some kind? The only reason I ask is that, when the blue screen appears, it does so in ...
Aruthur P.'s user avatar
9 votes
2 answers
609 views

Why did the COMX-35 video memory seem unreliable?

In my early days, many many years ago, one of the machines I managed to get my hands on was the COMX-35, a funky little machine based on the 1802 CPU. I remember trying to develop some games for it ...
paxdiablo's user avatar
  • 4,742
18 votes
2 answers
3k views

What made the Amiga "Genlock-able"?

Right at the moment the original Amiga A1000 was being introduced, Commodore was already advertising its ability to use a Genlock peripheral, and promising that Commodore's own Amiga 1300 Genlock ...
Brian H's user avatar
  • 60.8k
9 votes
1 answer
966 views

What causes the horizontal lines at the left of the Atari 2600 screen?

I occasionally see video captures of Atari 2600 games that have horizontal bars down most of the left-hand side of the screen, as in this video of Star Voyager by Imagic: It's not clear to me whether ...
cjs's user avatar
  • 25.9k
22 votes
4 answers
4k views

Why did the TRS-80 CPU have priority over the display?

The original TRS-80 had a separate bank of static RAM for video memory, so that there would be no interference between display and CPU when the CPU was just doing calculations in main memory. When it ...
rwallace's user avatar
  • 61k
8 votes
4 answers
4k views

Is "component video" synonymous with "RGB"?

Before asking this, I read the Wikipedia article. I've been confused about this for many, many years. I'd like to finally get it straightened out. What exactly is the difference between "RGB"...
Alexy's user avatar
  • 97
17 votes
4 answers
3k views

How were the special effects achieved for the Kraftwerk Die Roboter 1978 music video?

The following video for Kraftwerk's Die Roboter is very interesting because it features some effects which I think might require a framebuffer to achieve. Having a framebuffer in 1978 would to my ...
The Movie Man's user avatar
5 votes
2 answers
511 views

Digital to analog in an old 35mm film recorder [closed]

I'm looking at an old film recorder from 1985, the Polaroid Freeze Frame, the back of the machine pictured here: From here: https://www.radiomuseum.org/r/polaroidco_freezeframe_video_recorder.html I ...
Curiousmarble's user avatar
16 votes
2 answers
1k views

What is an XRGB video signal? (NOT the modern XRGB mini-DIN.)

I have a mid-1980s CRT monitor, a C. Itoh Chroma Pro CM1000, with an 8-pin DIN RGB input that's visually similar to the digital RGB input on a Commodore 1084. The input is selectable between "RGB,...
Willis Blackburn's user avatar
5 votes
2 answers
567 views

Is a S-VIDEO-to-RCA cable worse video signal quality than an S-VIDEO-to-SCART cable?

When I got my Sega Saturn way back, it came with a video cable that is S-VIDEO in the Saturn end and SCART in the TV end (no adapter). It has always given me very crisp and nice picture on all the TVs ...
Terreon's user avatar
  • 51
22 votes
6 answers
7k views

Why did some video games apparently use "interlaced" video modes?

I was under the impression that "interlaced" video modes was only a thing for remote television content because it saved bandwidth to only send 50% of the data to the homes, so you could fit ...
Bucky o'Hare's user avatar
7 votes
2 answers
652 views

Monitor can't display boot/DOS video mode making dual boot impossible

I have an HP ZR24w monitor connected via HDMI input to a newer custom machine running Win7, and via VGA input to an older Micron machine running Win98SE. I use the monitor's "source" setting ...
Javic's user avatar
  • 71
7 votes
1 answer
779 views

What is the name of the video signal recognized by this monitor?

I have a hobby project with an old CP/M-80 system where the monochrome monitor is showing its age as the image is flickering a lot. I was wondering if I could attach a modern monitor or tv-screen, ...
Thorbjørn Ravn Andersen's user avatar
4 votes
3 answers
628 views

Were there low-end eighties computers that used dual-ported video RAM?

Going through schematics of several home or small office computers of the era, I was wondering why almost none of them (1) used dual-ported video RAM. I understand that those chips were initaly ...
airman's user avatar
  • 1,350
12 votes
2 answers
680 views

Did any ZX Spectrum clones use a 16 bit datapath between memory and video generation?

On the Commodore 64, there is a 12 bit datapath between memory and the VIC II: the ordinary screen data, which is in DRAM, and another 4 bits which comes from another SRAM chip which may be paged into ...
Omar and Lorraine's user avatar
17 votes
5 answers
5k views

Why didn't early color TV sets accept RGB input?

Early PCs generated RF signal, and later Composite video or S-video, to use a TV set as monitor. Why didn't color TVs of those days expose a analog RGB interface for direct connection from VCR/PC or ...
Schezuk's user avatar
  • 3,752
23 votes
8 answers
4k views

Why did the VIC-20 and C64 have only 22 and 40 columns when the earlier PET had 80 column text?

When I was a kid, the "real" computers in movies looked so cool with that 80-column monochrome green text. My first computer was a VIC-20 and it always felt very "toy-like" to me ...
AvaTaylor's user avatar
  • 465
0 votes
1 answer
277 views

Workbench 3.1 Chipsets and graphics question

I have Workbench 3.1 install with Scalos and some other tweaks installed from scratch using one of numerous online guides. My machine is a CDTV with 3.1 Kickstart, TF536 030 MMU 64MB RAM. The chipsets ...
Bartek Malysz's user avatar
1 vote
1 answer
2k views

RGBI to VGA converter [duplicate]

Is there an off the shelf converter / adapter from C128 RGBI to VGA that will work with modern-ish low voltage VGA?
Bartek Malysz's user avatar
1 vote
1 answer
211 views

Operating system/hardware used for playing a video during a recorded trial that took place in 2013 [closed]

I am watching a 2013 murder trial on YouTube Jodi Arias Trial : Day 23 : 1 Of 3. There is a considerable amount of evidence involving phones and computers. The following picture briefly appears on-...
chasly - supports Monica's user avatar
6 votes
1 answer
352 views

Did the Power Macintosh 8500 have accelerated blitting?

Looking at online specifications for the Power Macintosh 8500, I was able to find few details on its graphics capabilities beyond quantity of VRAM and supported color depths, refresh rates, and ...
novice's user avatar
  • 163
7 votes
1 answer
535 views

Are there any 1980's video chips still available besides the TMS9918?

The TMS9918 is still available, which is nice. But are there any other (better) video chips still on the (after-)market in any numbers? Obviously Commodore's VIC-II is not one of them.
Gunther Schadow's user avatar
5 votes
2 answers
3k views

Sony PVM Connections / Composite Signale

I am trying to learn more about different video formats. I have a SONY PVM9044QM and want to understand the different connection options. So I understand, that Y/C equals S-Video input. But what does ...
retronexus's user avatar
3 votes
1 answer
463 views

What old version of Windows provides out-of-the-box DVD movie playback?

I bought a Playstation 2 in 2000, which famously included a DVD drive capable of playing DVD movies. I wanted the same movie playback capability on my Windows 98 PC. As I recall, I mistakenly thought ...
Brian H's user avatar
  • 60.8k
5 votes
2 answers
440 views

Vintage computer composite graphics

I am working on designing a vintage computer and I have been using the TMS9918ANL. After working with it for a month or two and not making much progress, I really want to switch to another chip. I am ...
benjamin black's user avatar