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lordofduct
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by lordofduct Tue Jul 11, 2006 1:20 pm

VGA->HDMI - not possible... DVI may have analog signals in it, but HDMI is DVI minus the analog signals and put in a different style connector. To convert analog to digital that can be used by a DVI/HDMI input is going to require some money... those converter chips come with a nice price tag (you 'could' rip one out of an LCD panel though, but then you need to know exactly what to do to wire it up... purely hypothetical as well).

VGA->Component... isn't that hard because VGA is technically RGB plus a little more. It'd be easier to do RGB to component though because it uses the same sync rate, where as VGA uses higher sync rates. It's rather simple though, you use an adder to add up the Red Green and Blue which gives you Luminance (Y) then you send that two directions, one out and the other to a polarity mixer that flips the polarity to negative. Then you combine that neg Y signal to both the Blue and Red signals giving you the Pb and Pr signals.

You can build one by hand for like 25 bucks, but it's quality is gonna be rather low. You can buy them for around that price too, but again the quality is probably gonna be kinda shotty. For a quality one that doesn't destroy all to much quality is like 100 to 200 dollars.
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Mozgus
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by Mozgus Tue Jul 11, 2006 1:28 pm

lordofduct wrote:VGA->HDMI - not possible... DVI may have analog signals in it, but HDMI is DVI minus the analog signals and put in a different style connector. To convert analog to digital that can be used by a DVI/HDMI input is going to require some money... those converter chips come with a nice price tag (you 'could' rip one out of an LCD panel though, but then you need to know exactly what to do to wire it up... purely hypothetical as well).

VGA->Component... isn't that hard because VGA is technically RGB plus a little more. It'd be easier to do RGB to component though because it uses the same sync rate, where as VGA uses higher sync rates. It's rather simple though, you use an adder to add up the Red Green and Blue which gives you Luminance (Y) then you send that two directions, one out and the other to a polarity mixer that flips the polarity to negative. Then you combine that neg Y signal to both the Blue and Red signals giving you the Pb and Pr signals.

You can build one by hand for like 25 bucks, but it's quality is gonna be rather low. You can buy them for around that price too, but again the quality is probably gonna be kinda shotty. For a quality one that doesn't destroy all to much quality is like 100 to 200 dollars.

But we are talking about 640x480 resolution. Remember that. Dreamcast is not a 1080p machine. The resolution isn't high enough to notice any clearity degration at that stage.

Also, I'm am very sure VGA to HDMI is possible, but like I said it's pointless and super expensive. It requires a device with some beefy specs to do the conversion, and there's a good chance for some lag. The current spec of HDMI at it's core, is just a DVI-D cable shrunken down, with digital audio capability thrown in to make it an idiot-proof, all in one solution. The new spec of HDMI coming out is probably a bit different though, in some form or another, considering the insane bandwidth increase. I haven't read into that too much. I'm getting tired of studying into connections for devices I can't afford.
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Clockwork
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by Clockwork Tue Jul 11, 2006 2:36 pm

Mozgus wrote: I haven't read into that too much. I'm getting tired of studying into connections for devices I can't afford.


dito :-(
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by lordofduct Tue Jul 11, 2006 7:24 pm

Mozgus wrote:
lordofduct wrote:VGA->HDMI - not possible... DVI may have analog signals in it, but HDMI is DVI minus the analog signals and put in a different style connector. To convert analog to digital that can be used by a DVI/HDMI input is going to require some money... those converter chips come with a nice price tag (you 'could' rip one out of an LCD panel though, but then you need to know exactly what to do to wire it up... purely hypothetical as well).

VGA->Component... isn't that hard because VGA is technically RGB plus a little more. It'd be easier to do RGB to component though because it uses the same sync rate, where as VGA uses higher sync rates. It's rather simple though, you use an adder to add up the Red Green and Blue which gives you Luminance (Y) then you send that two directions, one out and the other to a polarity mixer that flips the polarity to negative. Then you combine that neg Y signal to both the Blue and Red signals giving you the Pb and Pr signals.

You can build one by hand for like 25 bucks, but it's quality is gonna be rather low. You can buy them for around that price too, but again the quality is probably gonna be kinda shotty. For a quality one that doesn't destroy all to much quality is like 100 to 200 dollars.

But we are talking about 640x480 resolution. Remember that. Dreamcast is not a 1080p machine. The resolution isn't high enough to notice any clearity degration at that stage.

Also, I'm am very sure VGA to HDMI is possible, but like I said it's pointless and super expensive. It requires a device with some beefy specs to do the conversion, and there's a good chance for some lag. The current spec of HDMI at it's core, is just a DVI-D cable shrunken down, with digital audio capability thrown in to make it an idiot-proof, all in one solution. The new spec of HDMI coming out is probably a bit different though, in some form or another, considering the insane bandwidth increase. I haven't read into that too much. I'm getting tired of studying into connections for devices I can't afford.


First VGA-HDMI would require an analog to digital conversion. A microcontroller would have to do this... as I said, possible as stated by my comment of ripping one out of an LCD panel.

Second, even though it is a lower resolution. It still will suffer quality loss depending the parts used in building it. Things such as static can form in the signals due to bad shielding and at any resolution this static is a nuicance (actually a worse nuisance at lower resolutions due to the thicker scan lines being effected). Other problems are you are taking 3 signals.... mixing them to make one signal of a mononominal value then taking that mononominal value and splitting it 3 ways to create 3 different signals. This crossing of signals and spreading out it's power across 3 scales as opposed to one would create noise and signal loss. Amplifiers can be added to up this signal (which also require an external psu which will introduce more noise). Its not an aspect of picture loss, it is the addition of noise. Noise is the killer of all analog signals. Even though we call it "quality loss" it really is caused by the introduction or 'addition/gain' of new inferior outside signals caused by bad signaling and signal degregation caused by resistance. For every conversion, length of wire, gap in wire (i.e. the input port) will introduce a low amount of ohms which add and add causing more resistance.

Component also isn't as good of quality signal as RGB due to the logics required to create the true YUV signal required by the TV. It takes one extra step of converting subtracting Pr and Pb from the Luminance to solve for the missing part of Green to create a complete YUV signal. (used though over RGB because it is closer to YUV then RGB is which are two completely different color scales... Televisions unlike monitors use the YUV scale due to the better bandwidth capabilities). So inherently even a direct YPbPr signal taken directly from any source is going to be lower quality from the get go... adding in these conversion processes will degrade it even further.

With all of this said though.... RGB converted to YPbPr will still be 100 times better then S-Video which is your next option down. I mean I'm not trashing on the idea (actually I DO THIS for my HDTV as it only accepts YPbPr at max or HDMI). I'm just saying its not going to be as pretty as VGA or RGB strait into a monitor which accepts VGA or RGB (nevermind as I said before the VGA to Componenet will be harder and create even MORE noise).
Last edited by lordofduct on Tue Jul 11, 2006 8:25 pm, edited 1 time in total.
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by Clockwork Tue Jul 11, 2006 8:13 pm

did i say something different??? ;-) :-P
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by lordofduct Tue Jul 11, 2006 8:28 pm

Sorry... of all the things I've said I've yet to even answer Racketboy's question.

Yes the investment is well worth it over a composite or Svid cable. But as stated before a better investment would be an RGB to YPbPr converter because just about ALL video game consoles put out RGB (where as not many do VGA) and you can then use the same box for all your consoles saving you money over the entire spectrum of consoles... especially for someone like myself who owns 10 consoles all hooked up simultaneousily.
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Clockwork
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by Clockwork Tue Jul 11, 2006 8:36 pm

question: you`ve hooked up all your boxes simultaneousily. how? i have three 4to1-scart-switches and i hate the quality loss/noise...

i was thinking of a 15 to 20 port-switch with a comrade at my uni to loose this prob, but just as you said it would be difficult to hold the noise level low (now the construction would be about one meter long and 0.1 high to get noise reduction aso. ...).
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by racketboy Tue Jul 11, 2006 8:43 pm

lordofduct wrote:Sorry... of all the things I've said I've yet to even answer Racketboy's question.

Yes the investment is well worth it over a composite or Svid cable. But as stated before a better investment would be an RGB to YPbPr converter because just about ALL video game consoles put out RGB (where as not many do VGA) and you can then use the same box for all your consoles saving you money over the entire spectrum of consoles... especially for someone like myself who owns 10 consoles all hooked up simultaneousily.


Could you go into a bit more detail on this?
It would be cool if I could turn this into a nice, polished post to share with everyone...
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lordofduct
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by lordofduct Wed Jul 12, 2006 4:40 am

Clockwork wrote:question: you`ve hooked up all your boxes simultaneousily. how? i have three 4to1-scart-switches and i hate the quality loss/noise...

i was thinking of a 15 to 20 port-switch with a comrade at my uni to loose this prob, but just as you said it would be difficult to hold the noise level low (now the construction would be about one meter long and 0.1 high to get noise reduction aso. ...).

I have things running through multiple different inputs. I never invested or built RGB cables for some of my systems so I have those running directly into my A/V receiver that upconverts to component. Not that this gives any video gain... but the amount of loss is minimal and allows for simple switching between the consoles.

I then have a nice high quality 6 way RCA switch that I run my RGB through (the cable doesn't matter... wire is wire with the exception to gauge and shielding). This I then run into my converter box that changes it to YPbPr for the video and off to the TV... there is then another 6 way switch that handles the audio (if optical isn't available) which I then run to my receiver. If optical is available (i.e. my PS2... I run it directly to the A/V receiver on its own port). And then my Computer uses an DVI -> HDMI cable and ran directly into my television when I run windows. If I boot off of my flash drives I have a component cable that runs into the receiver (GeForce Underscan is a finicky lil' bitch so I take the quality hit for a FULL screen).

It takes some memorization to know how to use my TV of course and any joe schmoe won't know how to turn ANYTHING on unless I tell them... but then that keeps people from fucking with my shit.

There are some conversions and midways in this set up (mostly the receiver) that can create noise... but I hunted down the Receiver specifically for the fact it doesn't create that much noise. Cost me a pretty penny (700 dollars) but well fucking worth it... DTS, Dolby, THX, 7.1... OHHHHH YEAH!

The system I'm setting up in my bedroom when I move is going to be better! (just waiting until July 23rd when the Conroe is released).

picture this:

2.93Ghz Conroe Extreme Edition 1066mhz FSB
2GB DDR2
2 GeForce 7700 video cards ran SLI
80GB Raptor main drive
320GB storage drive (all sataII)
SoundBlaster 4
Dell 30inch monitor
17inch second display for my remote desktop to a linux file server/LTSP (for thin clients all around the house... music in EVERY room!)
7 channel amplifier 80W per channel (4 channels bridged to make 2 145W channels for the fronts... making a total of 5 channels)
2 front floor speakers
1 center channel
2 inwall mounted ceiling rear speakers over my bed
1 12inch woofer underneath my bed

Oh and my TV in the living is this 60inch beauty
Image
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Clockwork
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by Clockwork Wed Jul 12, 2006 2:13 pm

ugh, okay...

you must have a good income... right now i`m playin @ my 21" pc-crt, since my parents tv broke and i offered mine til they`d have a new one. right now i`m writing i realize this was two years ago :-( gonna have a word with my parents...

the problem is, most of my consoles do rgb and for that reason i naturally want to run them on it and theres no fuckin scart-switch with enough inlets, so im running three switches in a snowball system and how it looks by now thats still too less... gna...

there are remote-switches but one of these has a max of six ports and costs a hundred bucks... :-( grml...

and i want it as easy as possible to be switched (scart does all av in one).
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