fundamental questions on HTPC

[fnou2]

Dear Member,

I have been looking for answer for some time now and if anybody can seriously answer my questions I will be very happy.

I am trying to improve on the actual system i.e. DVD using a DLP projector.

If I was to use a HTPC can I upscale DVD movies from 480 lines to 1080 for example?
If it is possible how is the quality?
How is the quality on a very large screen (like 100 inches diagonal for example)?
Has anybody really tried that or everybody is just assuming?

If you use a movie in high def (like Terminator 3) can you actually output the whole definition or because of the difference in screen size (4/3(computer) vs 16/9(projector)) do you reduce the definition in including the black bars?

Basically apart from minor improvement in motion artifact can you really improve on a DVD player plugged in to a projector?

And if the answer is yes why manufacturers are not simply creating a computer in a box system?

Thank you in advance for any serious answers.

Frederic

[Andrew Pratt]

I'm far from the guy to talk about HTPC's but between powerstrip and Dscalar you should be able to send just about any image resolution you want to the PJ.

[JonMarsh]

The long and short of it is that an HTPC can be quite useful, depending on your goals, your display device, and your comfort level with selecting and configuring hardware.

Re some of your specific questions, playing back WM9 media is to an extent aspect ratio independent; that is, the player will use the aspect ratio of the source, and fit that as closely as possible to the display. So, for example, the T2 WM9 DVD is 1920X1080 for playback, which is widescreen; if you play it back on a 4:3 computer display, it would have black bars top and bottom, above and below the image.

Modern video cards support widescreen image sizes out of the box, including 1280X720P, and 1920X1080, but many don't support interlaced resolutions, such as the standard 1080i HD format. Some do, but the DVD software may not work right. I tend to prefer 1280X720 for widescreen PC work, though a monitor that supports 1080P will have a great image. Not all video cars support an overlay image this large; the new nVidia 5600 series does, including mpeg decoding up to 1920X1080p.

Many folks are using HTPCs with CRT or digital projectors on large screens; for widescreen, the 92" is more popular I think, because of height issues, and getting enough light output.

DVD licensing rules have prevented incorporating upscaling into players except recently on protected DVI outputs. With a PC, you can do this on ordinary RGB, and if needed, convert to component using a transcoder.

I got into HTPC's five years ago, because I wanted something for progressive scan DVD on my NEC presentation monitor and my Sony projector. No such thing as a progressive DVD player at that time, and nothing that would work with the Sony VPL-W400Q, or output RGB for my NEC monitor (which is 1280X1024, at 29") (bedroom system).

These days you do have a lot more options, including Faroudja Dcdi deinterlacing built into projectors, and a somewhat better generation of scaling chips used in projectors.

Frankly, I'd be reluctant to generalize about using an HTPC with DLP projectors, because there's a lot of variability in perfomance with those units, as regards both the optical engines and the built in electronics.

NO DLP proejctor currently available for HT use does 1080 native, so if you feed them 1080i, you're down scaling and filtering to match the projector resolution, whether it's 1280X720P, or XGA, or 1/4 HD (960X540), etc. If you ONLY plan to use the HTPC for DVD playback, and if you haven't selected your projector yet, I'd shop carefully for one that does good upsampling, but which also has DVI inputs, and can accept a 1280X720 signal on DVI (assuming you're considering a widescreen projector). This would keep your options open, both for upsampling DVD players, and for HTPC.

If there are other things you want to do with the HTPC besides DVD, such as WM9, games, etc, then a good HTPC is a relatively modest investment, compared to the rewards. Compared with projectors I've evaluated which were produced 2-3 years ago, the upscaling in good PC video cards such as ATI radeon's or nVidia GeForce is smoother, sharper, and more artifact free than I've seen in projectors. That may not be the case with the most recent chips, as they've improved substatially, due mostly to the market for flat panel LCD displays and their multi-resolution input requirements. They used to be awful when not fed their native resolution; ones available in the last year or two are vastly better.

With regards to hardware configurations for HTPC, you'll find a lot of different recommendations, and what you go with depends on your performance priorities and comfort level with different technologies.

Intel based systems with P4's may be the most broadly compatible, but I've been doing most of my own systems (especially since the introduction of the nVidia nforce chipset for Athlons with DD audio encoding) on AMD systems.

Just recently I "rebuilt" my living room HTPC, using an ASUS micro ATX board with nforce chipset, 1 GB RAM, with an Athlon running at 2 GHz actually clock (PR2400 rating), in an ATC 610GX1 case with an Antec Truepower 380 watt supply.



DVDROM drive is a Pioneer slot load, and the video board is a 5600 Ultra (which includes the most DVD support from nVidia, including full hardware MPEG decoding, 10 bit DAC's, etc). Full multichannel sound support is built into MB, including SPDIF output, and encoding of all PC audio.

Player is NVDVD, which has a natural looking, detailed, and three dimensional picture, with above average decoding of video sourced material, in addtion to great performance with film. I don't mess with FDDSHOW or using separate video filters from one player, audio from another anymore. NVDVD also includes calibration screens built in, so you can quickly get setup even if you can't find your copy of AVIA or Video Essentials. Version 3.0 is due out this fall with some further enhancements due to user feedback.

This system boots in less than 15 seconds, the power supply and CPU fan are nearly inaudible (the true power uses dual oversized variable speed fans; the CPU uses an oversized relatively slow turning fan also), and playback power works fine with HD WM9 clips, and absolutely loafs with DVD.

There's plenty of room on the Hitachi 120 GB drive to keep favorite DVD movies for reference (ripped with DVD Shrink, which is also a great backup tool).

DVD Shrink

If you're not comfortable with configuring and setting up PC's, I'd consider staying with a set top box approach, and relying on either the projectors upscaling or the new generation of players which will be offering this feature on DVD once the DVD Forum approves this. Bravo D1 and Samsung, as well as new Denon's are examples.

Me, I'm a little bit of a tweak head, only build my own PC's (excepting laptops, of course and I enjoy the ability to customize and configure and update.

And I haven't even mentioned the Immersive Technology Holograph3D board which uses Faroudja de-interlacing, accepting external 480i inputs, and uses your own PC video card for output; if I had standard satelite or NTSC, I'd get one of those. Then, there's also HDTV cards, like the MyHD series available through Digital Connection. The MyHD can output to a window, or to a dedicated HDTV input in 720P or 1080i. Some versions of the MyHD player can play VOB files, so DVD playback is possible through them, especially if you rip and re-author the media stream so you don't have unecessary materials- menu navigation isn't the MyHD player strong point! But I digress too far, as I'm sometimes wont to do

Later this week I'll try to put up a seperate post on this particular HTPC system, just for reference.

There is a dedicated section for HTPC use at the AVS Forum; you may want to check out the FAQ's over there; there's a lot of discussion about many different kinds of hardware ans software for HTPC applications.

~Jon




Earth First!
_______________________________
We'll screw up the other planets later....

[fnou2]

Thank you. very detailed reponse.

Does that mean that if you can send a film uspcaled to the native resolution of your projector through DVI than the image will be much better than a normal progressive scan player on component output?

Frederic

[JonMarsh]

Generally that is the case.

This months Widescreen review has some good articles by Greg Rogers, inlcuding a review of the Bravo D1, and a discussion re the problems with typical component outputs, versus DVI, versus wideband RGB. Especially in the case of the Bravo, the DVI is vastly better in image quality- but then, it doesn't really have a very stellar component output section. This is still an issue, to some degree or another, with getting the best out of set top DVD players. Remember, they were designed and built to work well in modest size direct view sets that don't have particularly wide input bandwidth on component signals- 6 MHz at a few dB down, typically.

OTOH, good video card RAMDACs are 350-400 MHz, and good "prosumer" video gear, like the Exetron Sync processor I used for compatibility to generate a GBR HDTV signal from a PC (combining sync on green) has a typical -3 dB bandwidth of 300 MHz.

In real terms, what this means is that the best you might do is carefully upscaled DVD to a DVI feed to a digital projector running at the same resolution. That DVI could be from a STB DVD player (VERY rare at this point), or from a PC (pretty easy at this point- both my current ones will do that, but I don't have a DVI projector).

Next best quality, and quite close, is RGBHV from a good PC video card to RGBHV input on projector. In the case of long signal runs, this may be the only practical way to go, as long DVI cables are VERY expensive and just don't work beyond a certain point. Video with good analog driver stage does; worst case, use an Exetron distribution amp.

Next would be STB DVD player with a well designed analog output stage, using 108 MHz RAMDACs.

Last would be your typical $100 to $200 DVD player, with meaurable droop at 5-6 MHz, and the possiblity (common) of timing issues between the luminance and chroma signals.

Regards,

Jon




Earth First!
_______________________________
We'll screw up the other planets later....