Composite displays better than s-video?!

mashley

Standard Member
A little while ago I bought a USB video capture device for archiving recordings from my Sky satellite box. The capture device has composite and s-video inputs. Naturally I wanted to use s-video, but I found that the quality over s-video was very poor compared to composite. I assumed there was either a fault with the Sky box or with the capture card.

Recently I got an s-video cable for my Super Nintendo and connected that to the capture device. The s-video signal was again very poor compared to composite, so I thought I had confirmed that the problem was with the capture device.

However, when I then connected the Super Nintendo directly to my Epson EH-TW3200 with the s-video cable, the signal was just as bad as it was through the capture device. So now I'm really confused. I though s-video was supposed to be better quality than composite, but with two different sources (the Sky box and the Super Nintendo) going to two different display devices (the projector and the USB capture device), composite looked better than s-video.

I have attached two pictures. The first one is the Super Nintendo displaying via the composite signal on the USB capture device. The second picture is the same thing but displayed over s-video. As you will see, the composite is significantly better quality.

An advice would be much appreciated.

Mark
 

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MTech535

Active Member
I always found s video better on old crt tv's, but composite better on my LCD, might be something to do with the way the upscaling works?
 

mashley

Standard Member
Thanks for the reply. Good to know it's not just me ;) I wonder whether the projector has any settings to improve the up scaling? I'll have a look through the menus later.
 

MTech535

Active Member
Mine looks just like yours, washed out colours and like watching through some kind of mesh.

I never got anywhere with mine. Best of Luck.
 

mashley

Standard Member
Hmm, I wonder if converting the s-video signal to a different format rather than connecting it directly to the s-video port would make any difference?
 

MTech535

Active Member
Mine was with a Profigold cable, pretty decent with gold plated connectors into a Sony TV. I think it was with a PlayStation 2???

The picture was sharper, but colours were washed out and there was this (hexagonal?) mesh effect.
 

mashley

Standard Member
Hi Gordon

Thanks for the reply. To be honest I can't remember if the s-video output from the Sky box had the same display problems as the SNES. It was connected using a different cable.

I think there must be two separate problems here, as I seem to be having issues with different sources (Sky/console), different cables (s-video cable/console av cable) and different displays (USB capture/projector).

Putting aside the Sky box and video capture device for now, my problem is that two different consoles (SNES/n64) each with its own av cable looks better in composite than in s-video on the projector. Would a scaling s-video to hdmi converter like the one I linked above help by scaling the image before it gets to the projector?

Thanks,
Mark
 

mashley

Standard Member
Thanks Aclass. I realise that s-video is supposed to surpass composite in quality which is why I was confused by what is happening. I have just ordered the s-video to hdmi converter I linked to above and hope that this will better upscale the s-video signal. I'll post again with an update once it arrives.
 

Gordon @ Convergent AV

Distinguished Member
AVForums Sponsor
Thanks Aclass. I realise that s-video is supposed to surpass composite in quality which is why I was confused by what is happening. I have just ordered the s-video to hdmi converter I linked to above and hope that this will better upscale the s-video signal. I'll post again with an update once it arrives.

OK...Lets step back.

svideo is not always better than composite. It depends on how the original content was created and distributed. I am not a gamer. I expect than old games consoles will have composite video as their native game content. If this is the case then outputting svideo is really just meaning that the console is doing the composite to svideo conversion instead of the display...it still needs to end up as rgb for the display to work though. The images you posted looked like a hardware fault to me. Some sort of earth loop, which is why i asked about the cable.

Sky content is broadcast as digital component video. So with a skybox you should get best results using hdmi..and if you can't then either svideo or RGB scart. Composite should look worse. If you put up the sky guide and swap between composite and svideo/rgb outputs you should see the crawling dot tell tale composite artefacts when you are watching in that lowly manner. You may get different artefacts with the other formats due to colour channel delays (ie ghosting and shadows on some colours)

You may find an external svideo to hdmi convertor is better of course but as i say, if the original content encoded in the games discs/carts etc is pal,composite video then i wouldn't waste money and i'd just use composite.
 

mashley

Standard Member
Well, I don't really know anything about the video hardware in Nintendo consoles, but I'm prepared to give the converter a try. At the very least, it will allow me to connect the consoles through my Yamaha amp using hdmi which will mean the amp will switch the audio and video simultaneously. I'll report back on quality once it arrives!
 

mashley

Standard Member
Hi guys

The av-hdmi adapter arrived this morning and I've just given it a try. The bad news is that s-video looks just as bad as it did when I connected the SNES directly to the projector. It looked marginally better when I set the converter to output 720p instead of 1080p, which leads me to believe that it is something about the scaling which is causing the problem.

The good news is that composite looks much better going through the adapter. For some reason the colours are more vibrant and the image looks sharper. I can also switch audio and video simultaneously between my iMac and my av sources using the hdmi adapter and my Yamaha amp, so all is good :)

I still don't really understand why s-video looks so bad, but I going to have to put it down to a peculiarity of using old analogue av equipment with shiny new digital equipment ;)
 

bigpapi007

Novice Member
My 2 cents is the composite is a basic signal, unprocessed and thus is handle as if its raw data while the s-video has already been processed and further processing corrupts the signal. Similar to audio where some receivers or processors reverse the already converted signals back to analog and then d/a s again
 

noiseboy72

Distinguished Member
Shall we consider how the signals are created and what they consist of? This will give some insight into the issues you are seeing.

The mesh is caused by colour information appearing on the Luminance channel (black and white image) of the S-Video cable. S-Video transmits the colour and black/white information separately, while composite mixes them together.

My guess would be that either the s-video output is being derived from the composite by filtering rather than from a dedicated processed output from the graphics processor or that a setting is incorrect on the console. Games consoles generally create the graphics in RGB, as this is easier to re-code to PAL or NTSC, and can also give an RGB output for better monitors and displays. The old C64s and BBC micros did this. I am not sure what system the games console or Sky box uses, but I would guess it is similar to the above, albeit the Sky box will work from a component YUV signal.

I would check settings, as it may be you need to set the output to S-Video for it to turn off the colour information on the S-video output.
 

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