Build Your Own Arcade Controls Forum
Main => Monitor/Video Forum => Topic started by: Blanka on February 01, 2010, 05:58:36 am
-
Does anyone know a cheap/easy way to connect a composite output to a PC monitor? The monitor has VGA and RGB inputs.
-
Short answer NO.
long answer, it could be done, but unless your an electronics expert with video you'd be better off just using a tv.
you would have to build a circuit to separate the mashed together composite signal to it's seperate Red green blue and sync signals to feed into the monitor. a ready made unit could be had for about $200 if one feels so inclined to do so....http://www.hdtvsupply.com/s-video-to-component-video-converter-scaler.html (http://www.hdtvsupply.com/s-video-to-component-video-converter-scaler.html)
for what it would cost in parts and headaches....use a tv.
-
This is a several part process:
0) You will probably need to DC restore the incoming video since it's probably AC coupled.
1) You need to demodulate the analog QAM modulated chroma information to recover the I and Q channels of the YIQ video.
2) You need to convert colorspaces from YIQ (roughly YPbPr or YUV - how far off it is varies with whether you're running PAL, "true" NTSC, or "fake" NTSC which is more common than "true" NTSC).
3) You need to recover the sync information from the incoming composite video.
4) (optional) You may want to separate the sync as PC monitors generally expect separate sync but often work with composite, but see step 5 since it may need one or the other
5) You need to scale the video from 480i to 480p (or 576i to 576p in 50Hz land) as PC monitors cannot display 15kHz scanrate video
6) Output to the PC monitor
Step 5 has to be done digitally to be practical and is usually done with a dedicated scaler chip or a DSP. You could also use an FPGA. There are chips out there that combine steps 0-3 for you from companies like TI or Analog Devices. You want what is commonly called a "video decoder". Step 6 would then be a video DAC and possibly an output buffer to drive the 75ohm input impedance of the PC monitor.
All in all, not generally a feasible hobbyist project. It's probably cheaper to just buy a box that'll do it for you or use an actual television.
If you happen to have a PC monitor capable of displaying 15kHz scanrates (rare, but they do exist), and you're OK with black and white video, just hook the composite video up to all three inputs and put the monitor in SoG mode. If the monitor can't handle SoG, use an LM1881 or similar to recover a discrete composite sync signal.
If you have a PC you can dedicate to this, you could use a TV tuner card. However, even in overlay mode, these exhibit some latency.
-
^ what he said^ - only with less words :P
-
OK. Got it. CRAP :D
-
There are plenty of composite to VGA boxes floating around the net. You can probably find a cheap one for $40-50.
-
26 euro for a multi-source (component/svid/composite) to HD VGA converter. New. Not bad. Might come in handy for hooking up my consoles over the next years.
-
The one thing to be careful of is that it might introduce input-delay due to the de-interlacing involved. Try to see if reviews mention it.