Can someone explain SDI, please?

[MysteryMan]

Just toying with the idea of getting a Pioneer plasma and, possibly, Sky HD when I came across some references to SDI.

I have no idea what this and would be grateful if someone could either explain or point me at a source of information that would help!

[welwynnick]

SDI is serial digital interface, and it's what we had before DVI and HDMI. It's also still the best video interface , but it's not exactly widely adopted. SDI is standard definition (PAL & NTSC) but there are HD versions as well. SDI was established some time ago as the industry standard for carrying digital video in studios. this forum is probalby a good place to look - just do a few searches. Technically, SDI is digital native interlaced component video (YCbCr 4:2:2) which is as close as you can get to what is stored on a disc or broadcast by DTV/satellite. A few displays have SDI inputs, but in our context it's use is exclusively as an input for high-end video processors.

Nick

[NicolasB]

To expand slightly on welwynnick's post: very few devices like set-top-boxes or DVD players actually produce SDI output in as-sold condition, but some can be modified so that they do. This process isn't cheap (several hundred pounds, typically) and will sometimes invalidate the warranty - you need to check carefully what the terms are.

A number of video processors ("scalers") are capable of accepting SDI input. The results of doing so can sometimes be superior to other forms of digital input (although, equally well, the difference may not be detectable).

As Nick says, SDI is slightly closer to the format in which the data is actually recorded on a DVD, so there is slightly less to go wrong between the player reading the disc and the actual output. SDI is also interlaced, while some devices can only produce progressive video via a digital output. For example, if you have a Sky HD box and you're watching a standard-definition programme you have to choose between interlaced analogue output (over RGB SCART) and progressive output via HDMI. The Sky HD box does a rather poor job of deinterlacing SD material, and it would be nice to be able to take the original interlaced signal and feed it to an external video processor to be deinterlaced there.

Some scaler/deinterlacers are able to circumvent this problem: the DVDO VP50 can convert the progressive signal back to the original interlaced one, while Lumagen scalers can actually force the Sky HD box to produce interlaced output via HDMI. But other processors don't have these options. One possibility would therefore be to buy an old version 1 Sky+ box and have it SDI-modded, then use that as your digital standard-definition source, and use the Sky HD box only for high-definition output.

[Jonesthegas]

In the cirumstance you mention (SkyHD and a plasma) its probably not worth it.

You would need to get the SkyHD box modified with a HD-SDI board (£500 but do-able). Then you would need a video processor to accept the signal. The pro version of the CrystallioII (about £4k) is the only one I know of that does this although the Vantage may do it by now. Then you would output that to the plasma via HDMI and hope it does 1:1 mapping so there is no internal processing. A lot of expense for a few extra % difference.

For others (me for example) with an analogue display device, the SDI or HD-SDI route avoids the nasty HDCP protection in HDMI signals so may be worth it for that alone.

Martin

[MysteryMan]

Originally Posted by Jonesthegas

In the cirumstance you mention (SkyHD and a plasma) its probably not worth it.

You would need to get the SkyHD box modified with a HD-SDI board (£500 but do-able). Then you would need a video processor to accept the signal. The pro version of the CrystallioII (about £4k) is the only one I know of that does this although the Vantage may do it by now. Then you would output that to the plasma via HDMI and hope it does 1:1 mapping so there is no internal processing. A lot of expense for a few extra % difference.

For others (me for example) with an analogue display device, the SDI or HD-SDI route avoids the nasty HDCP protection in HDMI signals so may be worth it for that alone.

Martin

Thanks!

I have the possibility of buying a Sky+ box, already modded to provide SDI output plus a Pixel Magic PE1000 unit. It is this going to be a significant improvement on connecting the Sky+ via the Scart(RGB)?

The screen is a Pioneer PDP-427XD.

[VirusKiller]

Originally Posted by MysteryMan

It is this going to be a significant improvement on connecting the Sky+ via the Scart(RGB)?

The screen is a Pioneer PDP-427XD.

Massive improvement on a projected six foot wide screen. Presumably less improvement on a 42" plasma, but you avoid the softening of image in the Sky box D->A conversion.

Very difficult to improve low bit-rate channels though.

[Steve_B]

Originally Posted by MysteryMan

Thanks!

I have the possibility of buying a Sky+ box, already modded to provide SDI output plus a Pixel Magic PE1000 unit. It is this going to be a significant improvement on connecting the Sky+ via the Scart(RGB)?

The screen is a Pioneer PDP-427XD.

Yep SDI over RGB is a very noticable improvement and very worthwhile!

I contemplated SKY HD for a while but am sticking with SKY (SDI)...

[Jonesthegas]

Originally Posted by MysteryMan

Thanks!

I have the possibility of buying a Sky+ box, already modded to provide SDI output plus a Pixel Magic PE1000 unit. It is this going to be a significant improvement on connecting the Sky+ via the Scart(RGB)?

The screen is a Pioneer PDP-427XD.

Agree with Viruskiller, in this situation, well worth doing.

Martin

[Liam @ Prog AV]

I'd go for the SDI option Mystery Man.

[philipb]

Sky SDI is much better than RGB scart.

When I compared Sky SDI from the old box via a Lumagen HDQ, to SD output from a Sky HD box via HDMI into the HDQ, (ie forcing it to output interlaced 576), very little difference but the Sky HD box option was a bit better.

I've convinced myself that modding Sky HD to SDI is not cost effective with a good VP in the chain.

[Zax47]

Originally Posted by Jonesthegas

In the cirumstance you mention (SkyHD and a plasma) its probably not worth it.

You would need to get the SkyHD box modified with a HD-SDI board (£500 but do-able). Then you would need a video processor to accept the signal. The pro version of the CrystallioII (about £4k) is the only one I know of that does this although the Vantage may do it by now. Then you would output that to the plasma via HDMI and hope it does 1:1 mapping so there is no internal processing. A lot of expense for a few extra % difference.

For others (me for example) with an analogue display device, the SDI or HD-SDI route avoids the nasty HDCP protection in HDMI signals so may be worth it for that alone.

Martin

Regarding Vantage-HD, HD-SDI input expansion boards (dual or single input, supporting SD-SDI and HD-SDI) have been shipping since December last year. Vantage-HD is £1995 list, single SDI board is £470 list and dual is £580 list.


Cheers,


Craig

[welwynnick]

Craig, do you work for Calibre by any chance?

Nick

[Zax47]

Originally Posted by welwynnick

Craig, do you work for Calibre by any chance?

Nick

Yes, but please don't hold that against me Nick!

Maybe we need a Vantage thread on here to announce stuff like firmware updates etc.? We have one over at AVS forum.


Cheers,


Craig

[welwynnick]

Originally Posted by Zax47

Yes, but please don't hold that against me Nick!
Maybe we need a Vantage thread on here to announce stuff like firmware updates etc.? We have one over at AVS forum.
Cheers,
Craig

Quite agree; please start one up. I'd begin with legacy builds, installation instructions, and updates as and when they are issued.

A few questions, though:
Are you happy for people for people to post problems and answers here?
When are you going to add 48Hz output?
When are you going to add test patterns?

Got to say it's good to have a UK scaler manufacturer here.

Cheers, Nick