misere Posted January 14, 2004 Posted January 14, 2004 I was wondering if someone could tell me if I will see a big difference if I connect my DVD player to a plasma TV using a SCART RGB cable versus using a s-video cable? Is it right that DVDs are SD and therefore I will not get a meaningfully better picture from the SCART RGB over the s-video? Any help is much appreciated.
Pierre42 Posted January 14, 2004 Posted January 14, 2004 It all depends, does your DVD player output RGB over the SCART socket, does your display take RGB input on the SCART? Do you have a quality fully-wired SCART cable? My Personal Experience: I have a Grundig Elegance 82cm TV with SCART connectors which accepts either RGB or S-Video input. My DVD player (NAD) has a SCART socket, and will talk RGB or S-Video signalling over said SCART socket. RGB from DVD across quality fully-wired SCART cable to TV in RGB input mode is immediately and significantly visible better picture quality. Specifically, in my setup the S-Video over SCART showed (really) bad "warble" on high-contrast vertical edges. (?? sync issues ??) RGB over SCART shows a crystal clear picture. I have no hesitation recommending SCART+RGB with quality cable over S-Video. Apparently, if you have component in and out, it's even better. I don't, so I can't really comment.
misere Posted January 14, 2004 Author Posted January 14, 2004 Thanks very much for your thoughts. Very helpful indeed.
gclark8 Posted January 14, 2004 Posted January 14, 2004 I recently bought a DVD player for my son, it has the lot. He gets best PQ from SCART-RGB. He has a SCART TV. See below for best to worst. RGBHV, (15 pin D-Sub) = 5 cable connection SCART-RGB = 4 cable connection Component YUV (YCpCr)= 3 cable connection S-Video = 2 cable connection Composite = 1 cable connection
Pierre42 Posted January 14, 2004 Posted January 14, 2004 Just to be clear to those who're even less in-the-know than I am.... (the few, the proud) RGBHV is where the video signal is actually sent across 5 seperate pathways (for want of a better term, not really "wires"because each will actually be two wires [??plus/minus or signal/ground??] ). (Red / Green / Blue / Horizontal Sync / Vertical Sync) These all go out across seperate connectors. (usually sold as seperate cables? or one cable with many heads?) Amongst other things, SCART carries seperate wires for Red / Green / Blue / Combined Sync (aka "RGB"). Wiring within the cable is optimized to minimize interference and crosstalk. SCART connectors also have pinouts for audio, s-video, and control signals. Not all SCART cables are "fully wired", often for the purposes of penny-pinching, cable manufactures do not wire up the RGB signalling wires - caveat emptor. A SCART cable is one (relatively thick) cable with a bulky rectangular (21 pin?) connector at each end. Component is Y/Pb/Pr or Y/Cb/Cr (physically 3 x RCA connectors) Pb/Cb and Pr/Cr are 'color difference' signals, so they consume less bandwidth than a full RGB signal. (effectively ~50% of the bandwidth used for Green from RGB is saved) S-Video is also often known as Y/C (Y = Luminance ie black and white ie 'brightness', C = Chrominance ie color) [sync is mixed in how?] S-Video is a single cable, with a round connector with 4 pins (2 are ground). Composite is a single RCA connector. All signalling munged together. RF is what your antenna pulls out of the air, raw and unconverted. The main image quality gains (RGB/Component > S-Video > Composite > RF) come from better signal seperation and less interference. Also I read (URL below) that DVD is a digitised recording of a component signal, which is then MPEG compressed. (ie Component out from DVD is merely the uncompressed analog equivalent of the digital recording that is on the DVD - no analog-domain signal/format conversions) Technically Component->RGB is an 'upconvert' although in practice any conversion has potential for loss (Physics 101), but ->SVideo or ->Composite involves actual loss of (some) information as part of the conversion. Taming the Composite, S-Video, Component and RGB Jungle (images of connectors) Video Primer Video Signal StandardsVideo Cabling Standards (includes images showing picture quality differences RF/Composite/S-Video/Component) Dans Data - Digital Video Decoded
Winno1503559512 Posted January 17, 2004 Posted January 17, 2004 A SCART cable is one (relatively thick) cable with a bulky rectangular (21 pin?) connector at each end.Component is Y/Pb/Pr or Y/Cb/Cr (physically 3 x RCA connectors) Pb/Cb and Pr/Cr are 'color difference' signals, so they consume less bandwidth than a full RGB signal. (effectively ~50% of the bandwidth used for Green from RGB is saved) S-Video is also often known as Y/C (Y = Luminance ie black and white ie 'brightness', C = Chrominance ie color) [sync is mixed in how?] S-Video is a single cable, with a round connector with 4 pins (2 are ground). Composite is a single RCA connector. All signalling munged together. RF is what your antenna pulls out of the air, raw and unconverted. Yes, SCART plugs (fully wired ones) are 21-pin. Component YPP/YCC, S-video and composite carry sync information down the 'Y' channel. In fact, the 'Y' channel appears to be identical in all three cases, however in composite it is intermingled with the 'P'/'C' channels. This can be demonstrated by hooking the 'Y' connector from a component out to a composite in (or the 'Y' cable of S-video). You should get a black and white image.
gyoung00 Posted January 17, 2004 Posted January 17, 2004 A point to note in response to the first post re connection via Scart to PLasma monitor. If your plasma doesnt have a Scart input socket, its unlikely the scart ouput signal from the DVD (or other component) will work into the VGA input (obviuosly with appropriate cable) the reason for this is that Scart outputs RGB & composite sync signal (per earlier post), HOWEVER it ouputs traditional composite video sync level of only 0.3Vpp - which is insufficient to drive the VGA input on a plasma (or at least a Pioneer - confirmed via the tech spec). A plasma/projector VGA input usually requires TTL sync levels, which typically need to be 1Vpp of higher. The scart sync output is simply to low & the plasma will fail to lock the sync & display zip! Also to note in addition to the earlier post - a SCART has more than one pinout & also cannot output RGB, Svideo & composite (PAL) simultaneous - it electrically switches some of the outputs - hence why on the DVD or component there will be in the setup menu an option to select (usually between Svide & RGB/composite) - because the latter 2 can co-exist. If your plasma (like my Pioneer CMX503) has teh above challenge (& like me you have a component that has SCART) - the solution is to use a sync separator circuit that separates & regenerates the snc (from the composite video signal) & then outputs TTL based sync levels for the VGA input on the plasma. A search on the internet will find a simple circuit using a LM1881 IC (these are about $9 from farnell) plus a few other components that can be built into the cable (self powered from the 5V line that is also present on scart) If you live in UK - I found a retailer on line that sells the cable with the above convertor circuit "built in" for STG77 (yeah right !!) I am yet to acquire the LM1881 (on order) - but the mfr datasheet confirms the circuit that appears popular on the internet for achieiving this. Hope this helps save you mths of frustration that I have been thru - with no one locally able to solve this problem.
gyoung00 Posted January 17, 2004 Posted January 17, 2004 and here is the link that has a lot more detail than my post, as well as the circuit that I am planning to use. http://www.hut.fi/Misc/Electronics/faq/vga2rgb/scart.html
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