SDI out basics

jonnyh1968

jonnyh1968

Well-known member
Hi, I'm about to go on a gig where the venue wants to take my SDI out, transmit it into the building (they are supplying the transmitter) and project it live on a big screen. They say all they need me to do is supply an SDI out from my camera. And that's cool and all but I've never done this before. So are there any basics you guys can tell me about SDI out on the HPX170? I'm guessing they want a SD signal. thanks.

- Is this SDI on the HPX170 a SD signal out?
- What do I set the camera to? additional settings?
- Can I record to P2 card also at the same time?
- Does SDI delivers sound?

Thanks again - the search on this topic doesn't seem to return anything "SDI".
 
HPX170's SDI output can be either HD or SD; you configure it in the menus. There's a specific menu (AV IN/OUT SETUP) that you have to go to. Be sure to turn the SDI OUT output to "on", and set the CMPNT/SDI SEL setting to AUTO if you want 720p or 1080i, or you can force it to cross-convert to 1080i even if it's in 720p mode, or you can force it to downconvert to 480i regardless of what mode it's in.

Yes you can record to P2, of course, and yes it delivers sound.
 
Barry - The HD-SDI out is 4:2:2 like the DVCPRO HD codec correct? Do you know if its post compression, or pre compression?
 
The live feed is the original, raw, uncompressed signal.

Playing back footage through the SDI port will, of course, be post-compression, since it gets compressed before being recorded.
 
Thanks Barry.

So one concern I have is sound. The projectionist crew I'm hooking up with denies that SDI carries a audio signal so they insist on using my audio out via a XLR. So rather than argue with them I'll try and do what they ask for. So...

From the manual it looks like my components will be shut off when I switch to SDI out to "on" ? So how should I go about giving them a XLR out? Could there be a synchronization issue?

thanks a ton!
 
Barry, so what you're telling me is if I capture HD-SDI from the HPX-170 in RAW on-to say, 10 15,000 rpm spindles @ 4:2:2 uncompressed it will look better than post DVC PRO HD compression?

Odd, I always thought the Codec board would down-res, compress and then output in realtime with slight latency, like it does with the HVX200 model for the component out, then hand-off to the HD-SDI-Out.

Thanks for the info.
 
Of course uncompressed raw would look better than the recorded compressed footage. The question is whether it would look good enough to justify the incredibly larger file sizes.

And the HVX200 outputs uncompressed raw over its component ports, it's just been converted to analog first (because component is an analog system).
 
Component never has audio, it's only video.

But the component video output is disabled when SDI is on. That's the whole reason to have that menu option, to choose whether you want component or SDI -- you can't have both.
 
Barry_Green said:
Of course uncompressed raw would look better than the recorded compressed footage. The question is whether it would look good enough to justify the incredibly larger file sizes.

And the HVX200 outputs uncompressed raw over its component ports, it's just been converted to analog first (because component is an analog system).
Click to expand...

I've just looked in the HVX200 service manual signal flow VIDEO BLOCK DIAGRAM (P2-CAMERA REC) - Barry, you're 100% correct. But Looking at the signal flow in P2 Record Mode confused me. As the singnal reaches the Codec board, but then gets passed right back to the Camera board, through a Scaler Chip then a DAC board and then an AMP for Component out preview, which is forwarded to the side of the camera via the top button board. - Weird stuff, travels Accross 7 different PCB's.

I wonder if you know if the singnal flow in the HPX-170 is the same, or grossly similar.


Screen-grab attached in PNG.


P.S. If you feel this Image should not be there as its from the Panasonic Service Manual, just let me know, don't nuke my girlfriends Flikr Account, I'll just take it down ASAP. Posted for Educational purposes only.

And for those who might ask, NO its not easy to swap board from HPX-170 to HVX-200 to get SDI out on the 200 model, they are different in so many ways, including fitment of the PCB in the body of the camera.
 
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I don't know the specifics of what chips the signal flows through on the 170, but I would be surprised if it's substantially different. I am 100% certain that the analog outputs and the SDI completely bypass the compression board when used during a live feed.
 
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