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JVC HD100 Projection Jumps on Sky Std Def

BoeingMan

Standard Member
I wrote to Phil Hinton late last year asking amongst other things about some comparative features to do with new JVC projector models.I own an HD 100 which is short of a few desirable facilities such as Keystone correction, side blanking, focus and zoom "on the fly" and so on. I wanted to obtain an accurate opinion about the new models such as the HD 950 and 990. Thus far though, despite sending the request a further couple of times I have not yet had a reply apart from an acknowledgement that he was pretty busy and I do know that he was recently at the CES in USA. So that is fair enough!

However,there was another query I put to him, which in the absence of his considered answer, someone else out there on the AV Forum might have an answer or opinion on. Here is the verbatim gist of my query..to do with the projected picture (from the HD100) when sourced from Sky in Standard Def.

I do actually have another question. When watching some projected TV programmes,(via component from a SkyHD box) in particular BBC non-HD live-broadcasts,such as rugby, the picture keeps switching left to right by about say 4 or 5 Centimetres,when the camera changes.

You set up the picture exactly to the vertical bars of the screen ,say for the studio shots, only to find that when the camera angles, or camera positions change, so too does the picture,which shifts one way or the other. It is quite infuriating and I cannot pin down a reason for it,since it doesn't seem to happen on HD broadcasts. Regular programmes, on BBC (or whatever) seem to be stable, but its the live broadcasts which hop about. I have examined every parameter I can find,including aspect ratios in the projector, the Sky Box etc. Is there an explanation for this phenomenon? When one had gone to the trouble of tightly defining the picture edges, it is really infuriating that it will not remain stable.


So My fellow AV anoraks (;) does anyone have an answer or idea why this is happening? Would be most grateful for any thoughts. :lease:

Boeingman
 

Barcoing Mad

Active Member
Have a look at the reviews section and the relevant threads here for 750 and 950 owners!
I'm not sure what Phil could add.

With respect to picture shifts, I suppose if anything is going to hop around, then it'll be live broadcasts from several feeds. However, I tend to overlap the edges of my screen's frame by a about 2 inches left and right, and that allows for any picture shifts I've seen.
 

HDPete

Novice Member
Hi,


I don't know if this helps much, but I also have an HD100 with Sky HD (HDMI to switchbox to HD100) at 1080i in the setup of the Sky menu, but I don't see the same problem that you report.

Could it be a firmware issue? You may want to contact JVC to see if there's a later version (GaryB on AVF used to be my contact).

Regards
Pete
 

LV426

Administrator
Staff member
I'm going to hazard a guess here that you are seeing what is being broadcast.

It is a part of the Standard Definition display standard that there should if properly adjusted, be 5% overscan - meaning that 5% of the width (and height) of the broadcast signal is concealed - "off the edge" if you like - and that they (therefore) don't take too much care over what goes on at the extreme edges.

This might be compounded by the BBC's tendency to take 4x3 camera material and zoom it up to not quite fill the 16x9 frame shape for widescreen.

I'm going to guess that you aren't overscanning. If so, you should be. Now, how you go about arranging this with the kit and connection you describe........I don't know.
 

LV426

Administrator
Staff member
Overscanning is a term which is really a throwback to CRT sets but is equally applicable with any kind of screen or projection system. Basically, the picture is shown (say) 5% bigger in both directions than the screen it's on or panel on which it's displayed, etc. So the edges are truncated. This hides garbage. In a properly mastered or produced TV show, DVD, etc., there should be nothing that matters in the extreme edges of the frame; all important content should be within a "safe" area that is 95% x 95% of the total screen shape.
 
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