Compare HMDI & Genlock ?

[Ing Poh Hii]

** Thanks for Chris for correcting my title mistake as I originally compare HMDI to Genlock ;p **

Can anyone help to explain the different between HMDI & SDI ?

Please don't tell me one is for consumer-HD and another one is professional-HD. Something more could be useful.

This is nothing about buying Sony V1 or Canon G1 (as it is surely out of my budget), but just want to gain some basic knowledge of these output.

Many thanks in advanced. :-).

[Chris Hurd]

HDMI and Genlock are two different things intended for two different purposes.

HDMI is a video / audio output connection. It provides a way to send an uncompressed High Definition video signal together with multi-channel audio to another device such as an HDTV display or a personal home computer.

Genlock, on the other hand, is an input connection which accepts a synchronizing signal from a device called a pulse generator. This commonly is used in the broadcast video realm to insure that multiple cameras in a live-switching environment are in perfect lock-step with each other, so that their individual frames of video are being generated at the exact same time among all cameras.

So I guess you can see how HDMI and Genlock are totally unrelated to each other! Hope this helps,

[Ing Poh Hii]

Thank you Chris,

blind me ;p, sorry for the stupid question, I was actually mean "HMDI vs SDI" the HD output provided by XH-G1.

Are there any significant different especially for post-editing ?

many thanks again :-).

[Chris Hurd]

Okay, so you're looking for a comparison of HDMI to HD-SDI that goes beyond the simple statement that HDMI is a consumer interface while SDI is a professional interface. I guess an easy cop-out answer is that it's harder to yank out an SDI cable than it is an HDMI cable. I'll let somebody else go into the specifics, but suffice to say that you'll run into SDI in the broadcast realm much more frequently than HDMI. If you're working for yourself out of your home, HDMI might be all you need. If you're planning to interact with other shooting professionals in a broadcast environment, especially where long to very long caqble runs are concerned, then you're better off with SDI.

http://www.hdmi.org/

http://www.hdmi.org/consumer/faq.asp

http://en.wikipedia.org/wiki/Serial_Digital_Interface

[Douglas Spotted Eagle]

HDMI is "poor-man's HD/SDI" but it is not as flexible as SDI, and more importantly, can't run long cable runs to a truck, as Chris mentions.
Additionally, the connectors are not designed to be tugged on; they'll either break or simply pull out. Audio is SPDIF, and even though current implementations of HDMI can carry higher bitrates, only 8 bit is passed with 2bits set to null.

[Ing Poh Hii]

Thank you Chris &

Thank you Douglas.

I am not capable to invest in broadcast equipment so I can forget SDI.

ta~ : ).

[Marcus Marchesseault]

I can say this for HDMI: it is a huge step in the right direction for consumer HD. I plugged my V1 into some screens with HDMI and the picture is fantastic. The setup is as simple as can be. If I get the HDMI to DVI issues worked out, it will mean $200 HD monitors available at the local electronics store in the form of LCD computer monitors. It won't plug into a production truck, but for the typical indie-film and event video shooter, compatibility with affordable monitors is probably more beneficial.

[Dave F. Nelson]

Originally Posted by Douglas Spotted Eagle

HDMI is "poor-man's HD/SDI" but it is not as flexible as SDI, and more importantly, can't run long cable runs to a truck, as Chris mentions.
Additionally, the connectors are not designed to be tugged on; they'll either break or simply pull out. Audio is SPDIF, and even though current implementations of HDMI can carry higher bitrates, only 8 bit is passed with 2bits set to null.

Are you absolutely sure that the statement "only 8 bit is passed with 2bits set to null." is true?

When I was at the DV Expo show in LA on Nov 15/16, I spoke to 3 different Sony representatives, none of whom knew what I was takling about. I'm not sure if HDMI output is incorporated into Sony's sales briefings or talking points. After speaking with these 3, I asked to speak with someone that had more technical knowlege about the V1U. I was referred to someone who should know the answers. This individual assured me that Sony implemented the HDMI 1.3 spec into the V1U. I didn't get the name of the representative.

But when I asked him about details of color space and bit depth, his eyes glazed over, and I realized I was getting nowhere. I left the show wondering if anyone at Sony actually knew anything about the V1U. In all fairness, Sony's employees were mainly prepared for presentations and simple questions. Most of them had never seen a V1U before the show.

However, I didn't feel like I got a satisfactory answer to my question.

I would appreciate it if you would ask your connections at Sony if the V1U impliments the HDMI 1.3 spec or something earlier. If 1.3 were true, the HDMI port would output 1080i60 4:2:2 10 bit or higher "deep color." This would allow full 10 bit output to an adaptor such as the Convergent HD Connect MI, HDMI -> HD SDI converter. You could then output directly to HD SDI with deck control (over 1394), etc., and could integrate the V1U, or any camcorder with HDMI output, directly into your HD SDI workflow with no disadantages except for TC. This is not much of a disadvantage and the Canon XL-H1 does not provide TC either.

The Convergent adaptor generates time code though which is fine, at least for me.

Black Magic also makes a big deal of 10 bit color on their Intensity web page. And while it is true that they used the Sony HDR-HC3 as their HDMI camcorder specimen, since that was all that was available for testing before the HDR-SR1 and HDR-UX1 came out, Black Magic maintains that the HC3 outputs 10 bit color. And if the HC3 outputs 10 bit, it is likely the the V1U outputs 10 bit or greater also.

Could you use some of your contacts at Sony to get a definitive answer to the V1U's 8 bit, 10 bit HDMI output question?

Thanks, in advance, Dave.

[Douglas Spotted Eagle]

It's a 10bit signal with the last two bits set to null, according to Sony engineers at both the press conference and subsequent commentary.

I believe Convergent Design's manual also mentions this. I don't have a Black Magic Design product with HDMI, so don't know what their manual says the camcorder offers.

[Dave F. Nelson]

Originally Posted by Douglas Spotted Eagle

It's a 10bit signal with the last two bits set to null, according to Sony engineers at both the press conference and subsequent commentary.

I believe Convergent Design's manual also mentions this. I don't have a Black Magic Design product with HDMI, so don't know what their manual says the camcorder offers.

Thank you very much for your response, Dave.

[Giroud Francois]

you should have guessed that by these days (cost compression, greedy companies, false advertising, hard competition).
today everything is like this. Big numbers, small results.
I think it started with cheap Hi-fi amplifier. They started to state any funny number as output power. Today you can buy a car amplifier for 20$ that output an incredible power of 4x 480W, while 15 years ago it would have been sold like a 4x25 W system.
same with HD, now everything is HD , even if the sensor is 640x480 pixel.
that is the magic of business.