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-   -   SVideo & BNC Output (https://www.dvinfo.net/forum/canon-xl-gl-series-dv-camcorders/54342-svideo-bnc-output.html)

Declan Smith November 14th, 2005 04:52 AM

SVideo & BNC Output
I am trying to simultaneously connect a monitor & and an LCD monitor to the XL2. The LCD is mounted on top of the XL2 to assist in framing , whilst the monitor is for the director to view. I tried doing this with a BNC T-adapter, but as expected, with both devices connected, the brightness level dropped on the CRT.

So two, questions.
1. Is the S-video output separate from the BNC/RCA output, and can it be run simultaneously ?
2. How do I make an S-Video to RCA adapter (as S Video has both Y & C outputs).

(I know that was really three questions).

It's not a burning issue, as I am quite happy to frame with the viewfinder, but it would be nice to have the option as it's not always easy on certain camera moves to be stooped over the eyepiece!

Steve House November 14th, 2005 12:36 PM

I'll let someone who knows for sure answer the first part but you can get an sVideo to RCA adapter at Radio Shack (or the UK equivalent) for a couple of bucks.

A. J. deLange November 14th, 2005 01:43 PM

1. Yes, I believe it can.
2. You can't make one unless you have circuit design experience. To convert the S video signal to composite requires modulating the chroma signal onto a subcarrier. The job can doubtless be done by a single chip but if you haven't any experience with such things you chances of quick success are small. You can probably buy an adapter. You can probably also buy devices that take a single S or composite video input and put out several copies. These are trivial designs. Most studio monitors incorporate features which allow them to be daisy chained e.g. the little Sony monitor I use has an S-video out port which just copies whatever goes into the S-video in port and a composite (BNC) out port which just replicates whatever goes into the composite in BNC.

Declan Smith November 14th, 2005 05:29 PM


Done a bit more of digging around, and looks like the following does work:

Y-Ground >-----++-----> RCA Composite Ground
C-Ground >-----+

Y >------------++-----> RCA Composite Video
C >-----||-----+
470pF Ceramic

Now I have made the adapter I can confirm that the S-Video is on all the time and is independant of the BNC/RCA output switch combo.

Karl Heiner November 14th, 2005 09:41 PM

hello declan,

i run a rca to the monitor, and a rca from the monitor (out) to the lcd monitor


A. J. deLange November 15th, 2005 07:10 AM

My dumb. The chroma is already on a subcarrier (how else would we be able to extract phase?). In fact the two components of S video if summed give a legitimate PAL or NTSC composite signal. The trick is to do the summing without loading the source. A simple OP-amp should do the trick and simply connecting the two channels together might even work in some cases. There is one additional little twist. If the chroma signal is at 0 DC offset the video is 4:3 aspect ratio. If the offset is +2.3V it is letterbox (16:9) and if the offset is +5V it is widescreen 16:9. Thus a blocking capacitor will be required as you have shown. Looking into an S-video cable the pin at 1 o'clock is chroma signal and the one at 3 chroma ground. The one at 11 is Y' signal and the remaining pin is Y' ground.

Steven Digges November 18th, 2005 10:55 AM

Avoid adapters and loops whenever possible, especially home made ones. Do yourself a favor and buy a long s-cable to run to the directors’ monitor, he should be looking at a quality image. Don’t worry about the “12’ foot rule of thumb” for this purpose. Go as short as possible but I have them up to 75’. There is an image shift (mostly saturation) at that distance but the signal in clean. Also, if you are doing an iso record, always take the signal into the deck first and use the monitor out (best, most show display info) or video out to feed the monitor. All to often I see signals fed to a monitor and looped out to the deck. All loops cause some degradation and you are not monitoring the signal from the heads on the deck.


Declan Smith November 18th, 2005 05:48 PM


Originally Posted by Steven Digges
Do yourself a favor and buy a long s-cable to run to the directors’ monitor, he should be looking at a quality image.

I normally run the 'directors' monitor off the BNC output. Is there much difference between the two, quality wise ? The main reason for the "2nd" monitor, was just as a framing aid (LCD monitor on top of the XL2), which doesn't have to be high quality as the FU-1000 is my main framing/focus tool. Thus I wanted to take the output from the S-video and convert to RCA.

Thinking about it though, I guess it would be better to swap the two around as BNC to RCA adapters are pure mechanical as it is still a composite signal, except I don't have a long s-video, just a long BNC.

Steven Digges November 18th, 2005 06:21 PM

Use the RCA video out to run the preview monitor on the camera and run BNC to the director’s monitor.

Yes there is a quality difference between s-video and BNC cable but it wont matter for what your doing. The director’s monitor will look fine.

Steve Maller October 18th, 2006 06:29 AM

OK, just tried this at a shoot yesterday, and it appears EITHER the BNC OR RCA outputs are live, but not both. Is there any way to get any combination of two video outputs (S-Video and BNC, for example) live simultaneously?

Karl Heiner October 18th, 2006 06:38 AM

i run this like so:

s-video out to field monitor, if needed rca out to lcd on board monitor

or bnc video out, when ma-200 is mounted, and s-vidoe out to field monitor
(or bnc to field monitor) s-video to deck

ps sorry: xl1-s

Steve Maller October 18th, 2006 06:50 AM

I'll bring my other LCD next time, which does have an SVideo in. Sigh.

Thanks for the quick response!


Jarrod Whaley October 18th, 2006 04:15 PM


Originally Posted by Steven Digges
Use the RCA video out to run the preview monitor on the camera and run BNC to the director’s monitor.

Just wanted to point out that you can't use both the BNC and RCA outputs at the same time on the XL2. There's a small switch that chooses which of the two is active, therefore both cannot be active at once.

Karl Heiner October 18th, 2006 04:40 PM

my xl1-s does not have bnc out, only rca, s-video, and dv.

like it said. when using my ma-200, i loose the rca, since the ma-200 plugs into that. but i gain one bnc.

don't know the xl2 in/ out

Mark Sasahara October 19th, 2006 07:58 AM

As stated, on the XL2 you have the choice of BNC, or RCA. I haven't tried it, but you may be able to do BNC and S-Video out simultaneously.

My onboard monitor has a loop through, so I go from camera to onboard monitor, then to the director's monitor. Most of the cheaper monitors don't have loop through. Marshall, Transvideo and Nebtek have models with loop through. Though they are more expensive than Glidecam, or Varizoom, you get more features such as choice of power supply, switchable 4:4/16x9, loop through, multiple ins/outs, mounting options, flip/reverse images, etc.

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