Understand video inputs on RPTV

[BraeBrae]

I am trying to better understand the inputs on my 65" Diamond (907). When
looking at the panel (which is also in the manual, including the PDF that is
online at Mits' website) there are the following inputs:

STB (RCA L/R-Audio, S-Video)
Input 1/2/3 (RCA L/R-Audio, S-Video or RCA Yellow Video)
VGA (RCA L/R-Audio, 15-Pin Dsub) for 640x480 @ 60Hz
Component 1/2 (RCA L/R-Audio, RCA Y/Pr/Pb) for 480i/480p
DTV (RCA L/R-Audio, RCA Green/Red/Blue, RCA Horizontal/Vertical Sync) for
480i/480p/1080i

1.) Are all inputs analog interfaces with the exception of the DTV input?
2.) Which inputs only take interlaced sources, which only take progressive (non-interlaced), and which both?
3.) Is sync control for the component inputs carried on Green?
4.) How are the sync rates determine, or the range of sync rates determined?
5.) For my 16:9 unit, a 1080i DTV input 'should' be capable of a 1920x1080 [vertual] resolution while the VGA it is explicitly stated to be 640x480 (4:3), but what about the component inputs? Would it be 850x480?

From the five (5) above questions you can imagine two things: 1.) I know very little about broadcasting and video as a whole, and 2.) I must be asking these questions to map out boundaries of what can and cannot be fed into the various inputs in terms of interlacing, signaling, sync and the such.

 

[Superdoopercooper]

I'll give you the quick few word answers. If you need to know more, let me know.

1) All the inputs are analog... even the DTV (I believe... I don't think it is a digital signal). However, those are higher bandwith inputs, and probably head to a line doubler or something.

2) Everything is an interlaced source, EXCEPT 480P (progressive scan DVD player) and the VGA. VGA is inherently a progressive signal. The DTV input will accept both progressive and interlaced -- thus the 480*i* and 480*p* specs. Actually... the 480p Component will also accept progressive (the DTV inputs and component inputs are really BOTH component inputs. Like I said, the DTV is probably channeled to some additional hardware in the TV).

3) Sync is carried on the green input I think. Either that... or the horizontal sync is on one color (red maybe) and the vertical on another (green). I don't think any sycn is on the Y, but then again, I'm not the master, and it really doesn't matter for practical usage.

4) Sync rates...?? You mean scan rates? For 480i, the scan rate is 15.75kHz... whereas for 480p, the scan rate is 31.5kHz. At 1080i, I think you are also at 31.5kHz... and then 720p (which your TV doesn't support... it is probably up converted to 1080i)... scan rate is 39kHz or something.

5) Using components (the DTV component inputs)... a 1080i signal will have an on screen res. of 1920x1080. I beleive that is the "definition" of 1080i format. VGA is limited to 640x480 because the... **480**... that is the number of vertical lines... and its a progressive signal. So, the 480 VGA has a scan rate at 31.5kHz, which is probably the limit of the TV's scan converter or scan gun or whatever it's called. So, any higher res, and it TV wouldn't be able to keep up. 480P drawas 480 lines at one time, every 1/30th of a second (Maybe 1/60th, can't remember). 480i draws 240 lines every 1/60th of a second, and then the other 240 lines every 1/60th of a second. That is why Progressive uses double the bandwith of interlaced, for the same number of lines.

Well... these were longer than few word answers. Hope they help. Sorry I could'nt recall exactly every little detail I was trying to convey.. I think the main points will get across, though.

 

[BraeBrae]

Cool. I could not get a response on a home-theater specific forum even though their are Mitsubishi fanatics that could not answer these questions relating to my Mits 907. Anyways, i would like to connect my PC, driven by a GF2MX200, on this RPTV, but the tought of using VGA is depressing me.

Thus, I am looking at the other inputs. What disturbs me is the lack of correlated information on using the component and or DTV inputs. The RPTV explicitly states what its limits are (640x480 and 60 Hertz), but the information for the component say less. Thus, my concern about over-driving the RPTV is connected to not know what NOT to set my PC's refresh rate to and just be limited to 60Hz.

It is going to be another two years before I consider a front projector with DVI inputs and minimally based DLP of WXGA/SXGA, but experimenting, safely, now is problem.

 

[Superdoopercooper]

Brae,

I would suggest not hooking a PC up to it.

Oh yeah... you must have some sort of scan limit, which limits you to a 480p or 1080i. Unfortunately, the HTPC thing just won't get you very far. You'll end up with a picture comparable to a progressive scan DVD. Which isn't bad, but not sounding like what you had envisioned. I'm thinking that the TV will upconvert it to 1080i... which won't improve the resolution any... just telling you that FYI.

 

[miguel]

Just a suggestion: save up for a plasma tv. These can get pretty high resolutions and are perfect for PC use as well. Nowadays you can get for about $100/inch. In two years, should be a little less.

I agree with coop - the quality of display coming from PC won't be any better than a progressive DVD player. THe good part with HTPC is you get an inexpensive scaler, provided you have the right hardware/software.

 

[Kartman]

Superdoopercooper, actually I am not really planning on this endeavor for the purpose of making an HTPC for progressive DVD sourcing. A run of the mill DVD player will automatically upconvert to progressive via the RPTV's internal line doubler. This unit is going to become a secondary viewing display in about 18-24 months. I am replacing the RPTV with a SXGA or UXGA fixed pixel front DLP projector unless the prices for D-ILA drop significantly while increasing their fixed-pixel resolution.

I know the 1080i spec calls for a [virtual] resolution of 1920x1080(i), but this is only on the DTV input, and I am not sure how to interface this input. Some say a [hardware] transcoder is needed, but I'm still looking for something that will do it in software--PowerStrip?

miguel, I am trying to stay as far away from phosphor-based display systems for my media displaying needs as possable. Thus, CRTs (front or rear) and plasma are out of the picture. I am strongly leaning towards DLP (Texas Instruments) and maybe JVC's version of LCOS. Although DLP and DILA both are just as scarry as plasma and LCD in potential fixed-pixel weaknesses (pixel-death), they will allow me to use the disply system for more than conventional DVD presentations (logo populated satellite broadcasting and PC stuff). Besides, I can get a grey-market Sharp 9000 front projector that is SXGA for $5K and for another grand place it on a 120" screen. A plasma half that diagonal would cost me double (and for only one-quarter the viewing area).

 

[Superdoopercooper]

Kartman, you really are looking for that magical display device that does NOT exist. Every technology has some downside, unless you have OOODLES of cash to just throw around, and even then... there is a downside --> cash wastage.

I have a Sony VPL-VW10HT displayed on a 1.3 gain 16:9 106" screen. No dead pixels, and I've had it for 2 years (about 340 hours on it). I have ZERO complaints... except that the black level on really dark screens isn't spectacular. If you set it up well and use AVIA and some other methods that the dudes at http://www.thebigpicturedvd.com have come up with... the black levels can get pretty good. Plus, if I projected on a 0.8 gain (Steward GreyHawk or equivalent), the Black levels would get even better.

And, 2 years ago, I paidl $5400. The same projector now can be had for about $4300. Pretty inexpensive by today's standards.

If you were buying a projector today, I'd say don't rule out LCD. In 2 years, if those stupid TI snots don't lower the prices for the DLP chips and offer at least 1366x768 devices... then they should be shot. And, there really is no reason that a DLP machine should be more expensive than and LCD. I doubt the electronics to drive each are that much different. NOTE... eventually one of those little DLP mirrors will break or not move anymore... so I bet there can be a type of stuck pixel on the DLP's at some point (speculation). So, 2 years from now... DLP should be kickin' tail... D-ILA... not sure about that one.

 

[iocon]

This could get quite involved...

You will want to use the RGBHV input (Analog VGA) with a custom resolution which can be made using powerstrip.

Rather than try and stuff all that info here, I will direct you to a forum with gobs of searchable posts on the subject, including a FAQ:

AVS HTPC Forum

The answer is there, tested and ready to go. You can also check out the other sections on digital projectors, HD... everything.