AVS Forum banner

Status
Not open for further replies.
1 - 10 of 10 Posts

·
Registered
Joined
·
10,201 Posts
Discussion Starter · #1 ·
Hi folks,

I thought that this might make a worthwhile thread in its own right. When paulgas and I went to a G150CL / DVHS demo awhile back, we asked the JVC rep some questions that frankly he couldn't answer satisfactorily. But, at least he was willing to look at it. In particular he didn't seem to have any sort of handle on digital copy protection issues.

I thought I'd post my email exchange with him in this thread as it develops.

To protect the rep from an impractical flood of emails I'm not including his contact info here. Of course, I can certainly ask him if I can give you his info if you're considering a G150CL.

I hope this proves useful!

Michael
 

·
Registered
Joined
·
10,201 Posts
Discussion Starter · #2 ·
First, concerning copy-protected high-definition content. It is still my understanding that there is an effort in the video community to move to an all-digital, encrypted format to deliver HD video to display devices. I suppose that the current choices being bandied about are DVI/HDCP, DVI/HDMI, and some encrypted Firewire protocol.


Once this copy protection system has been agreed upon and put in place, all future high-definition players (such as D-VHS) will be prevented from sending high-definition signals out without encrypting them---and that includes the analog component outputs. The highest resolution available unencrypted, in fact, I believe is set at 480p.


Now in case you still think I'm making this up---here is a quote from Tom Stites in BizDev for JVC Pro:


"The current D-VHS machine does allow output of 1080i material via the Analog Component output so it is useable with today's projectors. At some point, this capability will cease to exist in new products...two years if I recall correctly. Not good news but likely the price of having higher quality source material." (March 19, 2002)


This is exactly the kind of talk that is the source of fear among us HT enthusiasts. Yes, we'll be happy for a couple of years with a D-VHS deck, for sure. But we really don't want our projector to be prevented from reproducing the new high-definition material coming down the pike in a couple of years. Now it is my understanding that the JVC G150CL's DVI input is HDCP compatable, or at least upgradable, which has a real possibility of rendering this issue moot.


Now it is my understanding that the G150CL's DVI input is indeed HDCP compatible. But you commented on Tuesday that companies are now settling on Firewire as the exclusive encrypted digital interconnect medium. If that's the case, the G150CL will eventually be obsolete just like it's analog-only bretheren. I would definitely appreciate any clarification you can bring to this issue.


---

Secondly, will the G150CL support perfect pixel-for-pixel resolutions over DVI? More detail:


According to the manual, the DVI input can support the standard VESA resolutions of [email protected] and [email protected] So from purely a timing and bandwidth standpoint, there seems to be no reason that the DVI input couldn't handle [email protected] as well.


The manual says that other resolutions such as these are 'possible': but for us home theater nuts 'possible' isn't enough assurance.


What I would like to know, very specifically, is this: can the DVI input be configured to perfectly map a [email protected] video signal to the panel? I would also like to know if these resolutions can be handled as well

--- [email protected], with 5 columns of black pixels

--- [email protected], with 3 columns of pixels 'cut off' from the image

These last two are also important since many video cards only support horizontal resolutions that are multiples of 8.


Just to be crystal clear, please note that when I'm asking about perfect mapping, I'm talking about bypassing the internal scaler. I know, for example, that you can have the projector display 640x480, 800x600, 1024x768, 1280x1024, etc. without scaling---obviously using only a fraction of the panel. So we'd like to be able to do the same with 1360x1024, 1365x1024, and 1368x1024.


----

Finally, I asked if you knew what the resolution of the A/D converters on the RGB and/or component inputs were. If you can track down that information, I'd appreciate it.
 

·
Registered
Joined
·
10,201 Posts
Discussion Starter · #3 ·
Michael,

You have certainly stumped the panel with your questions! I have forwarded your e-mail to the "brain trust" and it may be necessary to involve engineering in Japan so please be patient.

I, for one, cannot understand why the need for double encryption as it seems you are saying. Currently, the encryption or copy protection process involves the signal material which is then decoded by the playback device. Though we can see the resulting video on a display device we cannot copy it because of this process. It strikes me as very odd we would encrypt a program, then decrypt it not in the machine but in the display device. This implies there could only be one method of encryption in perpetuity! I can only imagine the likelihood of that happening! As you point out, ANY display device - TV set, monitor, plasma or projector sold up to the time of implementation of such a program would become obsolete.

On top of this, every network program and satellite delivered HD movie would have to follow suit. It makes more sense to leave the encryption to an outboard device such as a set-top box for over-the-air delivered programming and the VCR for pre-recorded material.

This is why there are standards bodies such as the Consumer Electronics Association.

I have no information concerning the removal of component analog outputs from the D-VHS machines but perhaps Tom has information which has not been shared with the rest of us. As I understand the D-Theatre version of D-VHS, all outputs - digital and analog - will carry the encryption signal to prevent unauthorized recordings.

I can sympathize with you "HT enthusiasts". But is this not typical of the electronics industry? Three years ago had someone suggested Betacam ( a production videotape format) would be discontinued or that most S-VHS equipment, the most widely used production format in the world, would be dropped (except by JVC) that person would have been considered certifiable! The electronics beat goes on!

I look forward to hearing from the "experts".
 

·
Registered
Joined
·
10,201 Posts
Discussion Starter · #4 ·
Thank you very much for the response! Here is some more information for you. I'm sure that it will help JVC sell projectors to come up with a solid response to these copy protection issues.


Information about HDCP, one of the first digital copy protection schemes to be overlaid on DVI, can be found here:

http://www.digital-cp.com/


According to Tom Stites, the JVC G150CL implements HDCP---not so much because of any perceived need for it, but simply because the DVI chipset used happened to support it already.


You might also look at the Focus Enhancements CenterStage video scalers:

http://www.focusinfo.com/products/ce...enterstage.htm


These units have HDCP-enabled DVI as both an input and output. So, if you supply these scalers a copy-protected digital video signal, it will be able to decrypt, scale, and re-encrypt it, preserving copy protection while implementing scaling functonality. (If it did not re-encrypt it, they would be in violation of the HDCP license.)


From the web site: "High-bandwidth Digital Content Protection (HDCP) is a content protection scheme used with DVI to prevent unauthorized copying and redistribution of digitally perfect content. Original content via computer display cards or game consoles, and video from standard definition DVD players will not likely be content protected. High-definition set-top boxes are expected to be HDCP enabled to protect high-definition movies and pay-per-view programming. DVI with HDCP is standard on CenterStage CS-2, and optional on CenterStage CS-1, so both are fully compatible with any HDTV installation."


Frankly, Brian, the idea of a new copy protection scheme for high-definition video shouldn't be that much of a surprise. Copy protection is an incredibly hot issue right now in the media industry:

--- Compact discs are being copied and distributed en masse over the Internet; in response, the music industry is testing various methods for copy protecting their CD's (in many cases preventing them from being played on legal CD players!)

--- Entire movies are now available for download on the Internet. In fact, illegal copies of Star Trek II were released on the Internet before the movie was available in theaters! That's not causing as much of a panic yet, because the copies are highly compressed from several gigabytes to a few hundred megabytes, so the quality is not as high as that of the orignal DVD.

--- Several lawsuits erupted over the publishing of code which allows encrypted DVDs to be decrypted and copied. Thanks to that code, I can rent a video at Blockbuster and make a perfect digital copy of it on my hard disk and burn it to a DVD-ROM.

--- The Digital Millenium Copyright Act made such code illegal, or for that manner any software or hardware that is designed to circumvent an encryption or copy protectecion system.

--- If Senator Fritz Hollings' SSSCA bill were to pass, your company could actually be forced to accept and implement digital copy protection schemes in devices like your D-Theater.


Many people are holding off on projector purchases for precisely this reason. There's a big difference between your Betacam example and HD copy protection. With Betacam, you said that people had no reason to believe that the format would be end-of-lifed so soon. But with high-definition video, people do have reason to believe a new, incompatible format is coming. So why buy any equipment now---at the price level of the G150CL---that you'd like to use for years to come, if it will not work with whatever new is coming down the pike?


I am definitely interested in what your experts might have to say about this and my other two questions as well. (DVI resolutions, A/D converter resolutions).


Thank you very much for the response!
 

·
Registered
Joined
·
3,335 Posts
Michael,

Great thread ... thanks for trying to get answers from JVC and sharing the results!


I've been trying to get a response from JVC on the following:
Quote:
Taken from TVInsite
D-Theater encryption carries instructions on how content may be used, such as which outputs will be permitted to carry the signal to the television monitor. That way, if the D-Theater encoding allowed for component video outputs (as found on the JVC deck), the decrypted signal is transmitted through those terminals. Signals permitted to be sent over IEEE-1394/5C or DVI/HDCP could further protect the interfaces.


Asked before CES why Mitsubishi elected to omit the D-Theater system, Mitsubishi marketing VP Bob Perry said: "It is our belief that D-Theater is still a proprietary encryption system, that it creates confusion in the marketplace and it creates a situation where a consumer can buy a tape and not be sure whether it will play or not."
The user manual does provide some interesting error messages, such as:
Quote:
Taken from the User Manual
202 - COPY RESTRICTED PROG OUTPUT 480I VIDEO

When playing back a program that was copy protected in 1080i,

720p, or 480p mode, the VCR down-converts to 480i mode for output.


203 - COPY RESTRICTED PROG CAN NOT PLAY BACK

An attempt was made to play back a tape containing a copy protected

program.
Taken together, I believe this indicates that content providers can decide what outputs a given tape will support, and at what resolution (full or 480I) for each output. For examples, studios could release tapes now of older movies that allow for full resolution via analog. But, future releases of newer movies could be made that only allow full resolution on a protected connection (1394/DTCP or DVI/HDCP) while only allowing limited resolution via analog.


My questions are:

1. Does D-Theater allow content providers to decide what outputs a given tape will support, and at what resolution (full or 480I) for each output?

2. If not, then what exactly are the "instructions on how content may be used" mentioned in the TVInsite article?


If the D-Theater copy-protection scheme is not as draconian as the TVInsite article presents, I hope JVC can make steps to correct this information. My conclusion (above) is the only reason why I have not yet purchased a D-Theater deck.


Micheal, again thanks for sharing this information. If my questions on D-Theater fall outside the scope of what you are trying to get answered, I'll understand if you don't forward these questions.


Thanks!
 

·
Registered
Joined
·
821 Posts
I once encountered a WAV file of chirping crickets, as part of some desktop theme. It occurs to me that JVC correspondents would be fully as informative if they were to reply to all G150CL DVI-related questions by forwarding this WAV file as an attachment.


Seriously, the JVC rep with whom Michael is conducting his email correspondence skirted the subject like a pro. It reminded me of the manual for the projector.
 

·
Premium Member
Joined
·
7,212 Posts
Jvc invented the copy protection on D-vhs and is putting connectors on their televisions sets for these D-theater movies but a rep doesn't know anything about copy protection? Where the F&^I are my hip boots!!
 

·
Registered
Joined
·
27,143 Posts
This is an interesting thread, but relative to todays media, how much (if any) improvement does a DVI signal on a G-150 improve, let's say, have over a calibrated G-15? I'm not talkin' test pattern differences but real world differences.


My understanding of DVI is that is for playback only and has no means to carry a signal to copy, hence, it is not an output on any of JVC's new D-VHS machines.


Though both of their D-VHS machines have firewire input / outputs.


Jeff
 
1 - 10 of 10 Posts
Status
Not open for further replies.
Top