Composite Video over Cat5 Ethernet |
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justamadman
Registered User Joined: 13 May 2007 Location: United Kingdom Status: Offline Points: 1118 |
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Posted: 25 August 2009 at 8:39pm |
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Found an article on Instructbles.com about using Cat5 to send AV signals.
i did some digging and found found pre-made CAT5 to composite adaptors, But I'm unsure how exactly how it works, would it be a case of some sort of streaming via the Ethernet port? Cheers, Ian. |
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in front of the bass bins baby
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odc04r
Old Croc Joined: 12 July 2006 Location: Sarfampton Status: Offline Points: 5482 |
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A CAT5 to composite would be pretty pointless, a composite video signal is just signal and ground, 2 wires.
Do you mean component video or RGB+sync (VGA) over CAT5 as I have made up a few of these cables. Component takes 3 pairs of the CAT5 cable whilst VGA (RGB) takes 3 or 4 depending on whether the sync signal is combined with green or not. Got one component over CAT5 cable in my loung right now between the xbox and the projector, 25m or so long and works like a charm. This is the way I would use CAT5 to transfer video anyway, if you mean digitising video and transferring over TCP/IP then thats obviously a different kettle of fish. No experience with that. |
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justamadman
Registered User Joined: 13 May 2007 Location: United Kingdom Status: Offline Points: 1118 |
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Typo, it should have been component red, white, yellow.
I think I'm probably misunderstanding the concept. The way i'd looked at it was that one end of the CAT5e plugged into the Laptop/PC ethernet port and the other into the component adaptor allowing me to play video/ audio from my laptop to my tv. I'd now imagine that both ends of the CAT5 need to terminate with an adaptor allowing a signal to be sent from an A/V output such as a DVD to a TV or projector over long runs without amplification. |
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in front of the bass bins baby
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Sinfinity
Old Croc Joined: 06 July 2008 Status: Offline Points: 1632 |
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Yep, nice way of getting a decent length lead for the transmission of video signal. Got a friend using a component run over 20 meters and its great.
The red, white and yellow is a mixture of video and sound. Red and white carrying left and right channel, yellow carrying composite video. If you can get an AV source that will output component ( on red / green / blue ) from DVD players etc, that would get you a better quality signal. If you running from you laptop you should be able to make an adapter to run from the vga output and send that down a decent length of CAT5. What video source are you trying to get to which output device, and over which length ? |
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Matt at ukamp dot co dot uk
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ceharden
The 10,000 Points Club Joined: 05 June 2005 Location: Southampton Status: Offline Points: 11776 |
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It's very simple,
You put a transformer at each end to convert from unbalanced screened cable to balanced twisted pair. They are thus called BalUns. You can then use CAT5 cable for the video. It's nothing to do with using networking, just the twisted pair cable. Have just done it in an install to do security cameras. You need something with a good strong video output or ideally a line driver for it to work well. Security cameras have fairly weak video outputs not designed for long cables. |
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shagnasty
Old Croc Joined: 30 July 2007 Location: Guildford, UK Status: Offline Points: 7685 |
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Composite wouldn't be point less as you need to get from 75 >120ohm>75 so it is still a project, but CPC sell every type of composite, Component and RGB cat-5 jiz you can imagine......
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jamwa
Young Croc Joined: 10 February 2009 Location: Southwest Status: Offline Points: 1060 |
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Component is RGV or YUV using the Green as the sync - then yes you can run this over cat 5 but bare in mind that the cheap converters are only good for upto around 30-40 meters if oyu go for
companies like Extron or Moave etc then you would be good for 100mtrs plus - we have been using them for a few years now running up to projectors on trusses etc but not the best way to do it - oh and get screened Cat5 cable not the real cheap stuff thats used for networking - reduces signal loss and ghosting and hmm etc...
you can get all types of converters with and with out audio - CPC or Maplins for Budget or talk to the Guys at truecolours...
everything now has gone over to either DVi or fibre which is great we ran out a fibre 2kms from an OB truck to the LED Screens and looked super crisp and clean...
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Sound, Light, Projection, Display, Cameras and production support
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odc04r
Old Croc Joined: 12 July 2006 Location: Sarfampton Status: Offline Points: 5482 |
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As someone else said this is right audio, left audio, composite video. Hence why phono plugs for turntables/CDJs etc are red and white too. Component cables are usually 3 phono plugs too (red/green/blue YPbPr) but they carry no audio.
Yeah I think you are misunderstanding it a bit. The only way you could get a video signal out of a PC like that would be to use the second monitor connection which is usually analog on most modern laptops still (VGA). Connect that to a VGA port on your TV or convert it into component video and then connect that depending on whats available. Both methods will offer you all HD resolutions if your TV and laptop support them. I'm sure it is possible to convert video over TCP/IP but you would have to encode it on the source PC, send it over a network, and then decode it at the destination. I'm sure it could have its advantages in a one to many distribution system. As to transmitting component/VGA over Cat5, I don't think transformers are really necessary unless you have a very weak output signal or a very long run of cable. Impedance of a typical video connection is 75Ohm and a twsited pair is 110Ohm I believe so it's not a ridiculous mismatch. Or put it this way, I don't use transformers with quite a long run of cable at the moment and it looks fine with no ghosting etc - your mileage may vary of course. Edited by odc04r - 27 August 2009 at 10:16am |
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justamadman
Registered User Joined: 13 May 2007 Location: United Kingdom Status: Offline Points: 1118 |
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so cuold i run Video over the cat5 from VGA to composite and audio from 3.5mm jack to stereo phono?
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in front of the bass bins baby
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odc04r
Old Croc Joined: 12 July 2006 Location: Sarfampton Status: Offline Points: 5482 |
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Not really, VGA is a video signal carried by 4 pairs of wire. Red, blue, green, and syncs. Composite is one wire pair that contains all of that. You would need a VGA->composite converter.
To get any real benefit out of connecting a laptop to a TV you will need a TV with a component or VGA input. Some desktop 3d cards have a TV out signal that is composite or s-video which would be of more use to you perhaps. It's worth noting that if your TV has a scart input, then it may potentially be wired for VGA or component through the scart socket as they have 21 pins to play with, this is pretty unlikely though. Have a read of the TV manual. You are correct about the audio however! Edited by odc04r - 27 August 2009 at 5:47pm |
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justamadman
Registered User Joined: 13 May 2007 Location: United Kingdom Status: Offline Points: 1118 |
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I got the TV off a mate and don't have a manual.
Looking at it though, the TV has component, S-Video and Dual Scart inputs. My laptop only has VGA out so i think some sort of vga and 3.5mm jack to component and stereo phono or to scart is my best bet. No luck finding any online yet though |
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odc04r
Old Croc Joined: 12 July 2006 Location: Sarfampton Status: Offline Points: 5482 |
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Yeah, not many people are going to be interested in converting VGA to composite, its a significant downgrade.
Desktop with a graphics card that has a TV out composite signal is your best bet. |
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