Q&A # 246 - August 9, 2001

Staff

Q I live near Chicago and just want to receive over-the-air HDTV (as of this month, all of our major stations will be broadcasting in DTV/HDTV. Why doesn't anyone make a dedicated over-the-air HDTV receiver? Every unit I've looked at so far also includes satellite HDTV (which I presume adds to the cost) for $599 and above. Some even require you to purchase the satellite card in order to make the over-the-air reception work! Are the satellite providers subsidizing the building of these boxes? I have heard of a couple PC cards for about $400 that only have over-the-air built in, but then I would have to buy an extra PC. My HDTV company (Mitsubishi) says they won't have a built-in module for receiving HDTV until next summer. Any other ideas?

A The support circuitry (power supply, chassis, jacks, etc.) make it not cost effective to have just an over the air decoder. It would probably be about the same price as one that does it all, since the decoding is in a few inexpensive chips. The receiver tunes the carrier frequency to extract the program material, and that occurs whether it is an over the air frequency or a satellite frequency.

Q Do any of the PC DVD or video boards use the SIL503 de-interlacer? I have tried many boards and software for the PC, and the one I am using is the Creative Labs Encore with ATI Rage Fury as the video scalar. My dislikes on this approach are the pops in sound using DTS and the menu. I would like to see better decoding. I might get a video scalar with the SIL503 if not to expensive. I use a Lexicon MC1, NEC 6GPPlus, Newform Research Ribbons, etc.

A No PC DVD or video cards for PCs use the Silicon Image SiI503 de-interlacing solution. Software DVD players for Windows use the flags on the DVD to create the progressive image. These software decoders are doing MPEG 2 decoding in real time, which eats up a lot of CPU. They cannot do this and perform good cadence detection de-interlacing. As CPU speeds improve, this will then become possible.

There is an open source de-interlacing solution called dScaler. This requires a video capture card. It does a good job, and it is free.

Which sound card are you using? One of our contributing writers, Evan Upchurch, uses an HTPC with a Lexicon DC-2. He used the Sound Blaster Live for a year with no pops or clicks. Recently he upgraded to one of the 96/24 sounds cards, and he gets pops everytime he does anything with DVD playback. This includes just going from one DVD menu to another.

If the pops are just DTS specific, it may be DTS. DTS appears to have more than one version. There are some with flags in the stream to identify it is DTS, and others without. A decoder must listen and determine if it is or is not DTS to be 100% sure. Remember, DTS is not a required audio format for either DVD-V or DVD-A. It is merely optional.

Q I read your "DVD Shoot-out" article. I have some concerns about the Pioneer Elite DV-37. I have the ability to select between a few different models of progressive DVD players, and I would like your option (technical) about which one to pick.

1.) Pioneer Elite DV-37
2.) Denon DVD-2800
3.) Panasonic DVD-RP91K

I have already purchased the Pioneer Elite DV-37 and have the ability to trade it in. Please be aware that I have the new Panasonic 50" plasma display and I am switching component video with a Denon AVR-5800 receiver.

A The Denon and Panasonic will be included in our upcoming 2nd annual progressive shootout along with Pioneer's DV-38A, which is a DV-37 with DVD-A support. We prefer the Panasonic DVD-RP91k over the Pioneer DV-37. The details of why will be released in the shootout.

Q Some friends have asked me to write an explanation of "progressive-scan" DVD. I have read many magazine articles, books, and Internet sites concerning progressive-scan and related topics, including the excellent explanation in "Secrets..." Obviously, I want to give them correct information! However, I am quite puzzled by one aspect:

I assume that film-based (24 frames/sec) material is encoded on a DVD as "480p/24" after the MPEG-2 encoder does "reverse pulldown" to save data space on the DVD. I also assume that NTSC video is simply encoded as 30 frames (60 fields) and then output that way to the TV. Finally, I have assumed that every DVD player, even $100 cheapies, does "3/2" (or 2/3) pulldown to "re-insert" (reconstruct) the "discarded" 6 extra frames to get to the required 30 frames/sec.

If all these assumptions are right, then why is it said that certain inexpensive progressive DVD players "don't have" or "don't do" 3/2 pulldown? Even if the player is flag-reading only and not cadence-reading, it would seem that such a player still must detect 3/2 cadence for the above reasons. (As an aside, I'm not certain if some progressive players are flag-and cadence-reading in the same unit.)

There are perhaps three general answers to my own question : (A) I have a serious misunderstanding of "pulldown" and "reverse-telecine (reverse pulldown); (B) the mass-market print sources use such terms in a very sloppy and vague manner; or (C) both of the above!

A We are in the processing of updating part 5 of the DVD benchmark. We will try and clean up the confusion that you and many others have.

The short answer is that all DVD players, progressive and interlaced, perform 3-2 pulldown. As you stated, DVDs are stored at 24 fps. 3-2 pulldown converts the 24 fps back to 30 fps to be displayed on our TVs. What you are really asking is does my progressive DVD player have 3-2 pulldown "detection?" This is where a de-interlacer can detect the 3-2 pulldown cadence and properly create a progressive image. Pioneer offers a low cost progressive DVD player that does not have 3-2 pulldown "detection." We will report on how this DVD player performs in the upcoming 2nd annual progressive shootout.

Q I can't stand my Toshiba DVD hicupping anymore. ARGH! I have to get a new DVD player. I can't wait any longer for your review of the Denon 2800. But, I was hoping you could clear something up for me as I go tomorrow to pick it up.

I understand the initial release had a black dot on the box. Then the fixed one had a green dot. Now I hear there is a hollow black dot.

Which one to you your knowledge has the latest firmware? Any help would be greatly appreciated. I have no doubt that this player will be much better than my Toshiba 4109. I can't stand how the Toshiba messes with my Casa Nova with sending the digital audio out in non "red book" fashion (as Theta calls it).

A I wish we could help on the DVD player markings in regards to upgrades. We don't have a good answer for you. We would be interested in hearing more about your problems between your Toshiba DVD player and your Theta processor.

Q  I just purchased my first HDTV (Toshiba 65H80) and also have the Denon 2800 DVD player. I'm familiar with and have used "Video Essentials" in calibrating my other non-HDTV. With the Progressive Scan DVD players, you can now make setting changes at the player. The question is: Do I make the changes at the HDTV or at the DVD player? And, if at the player, how/where should the controls at the HDTV be set before calibrating at the DVD player?

A We highly recommend you leave the brightness and contrast controls on the DVD player in their default positions. The color control is not as important, but you really should adjust this on your display device.

We are currently discussing the idea of writing a series of articles to explain this all in detail. We plan to do the articles, but it is a matter of finding the time.

Q For the past year, I have been planning to buy one of the new HDTV models coming out this summer/fall (probably a Toshiba 50hx81), but am very hesitant given the upcoming digital transmission/copy protection standards. The Toshiba I mention, and most others don't have digital inputs. What is your opinion on the wisdom of buying an HDTV at this time?

A There is still a lot to be worked out with HDTV, including the copy protection standards, Firewire interfaces, other possible interfaces (see below). The fact that you can buy a good HDTV but see messages on your screen that you are not being allowed to view the HDTV program in HDTV, with it just being seen in 480p, does not encourage us to buy one at all, for now, to view programming. They are useful for viewing DVDs in progressive mode, but that does nothing for possible future incompatibilities. The industry is shooting itself in the foot with all this indecision about standards. I know of one TV company that advertises its guarantee of upgradeability when you buy one of their models. Maybe that is the way to go. The newest interface is called DVI (Digital Video Interface), and the content providers (movie companies) want this interface such that it will be the only way to view true high def video (1080i and 720p). If you don't have the interface, and current HDTVs don't have it, the incoming video signal will be down-converted to 480p. Since any adapter box would have to output analog video to the current HDTVs, you would not be able to view 1080i and 720p with the TVs that are being sold right now. Digital TVs require twice the scan rate to display any particular scan rate, so for 1080i, the digital TV has to be able to scan at 1080p. Large TVs with that capability are a couple of years away. A class action lawsuit is already being formed by consumers to put a stop to this nonsense.

Q  In your April 6, 2001, Q&A, you indicated that "there is no real advantage" to an anamorphic DVD with other than a 16:9 TV. But, don't forget, there are a few 4:3 TVs that handle anamorphic specially, by placing all the scan lines within the image area. Some Sony WEGAs do this, as does my Samsung 27". The results are outstanding . . . way better than a conventional 4:3 TV.

A There is still some down-conversion to place it within the 4:3 screen. The 1.85:1 movie anamorphic video signal on a 16:9 screen does not waste any of the scan lines, showing all 480. It stretches the image sideways to fill the 16:9 screen. With the 4:3 TV, the top and bottom scan lines of the screen are wasted, not to mention whatever losses that occur during the down-conversion process that reduces the image so that a 1.85:1 movie fits in the 4:3 screen. You end up with less scanning lines on the TV displaying the image. Some picture information is lost. That does not mean, however, that the WEGA does not do an excellent job of handling this. If you are talking about the analog TVs that actually move the raster down and include all 480 lines in the reduced picture height, then yes, anamorphic DVDs can play on these TVs with no scan line loss. However, matching the images by width is contrary to the principles of widescreen movies, where they are actually designed to be matched by height. Superimposing a 4:3 image inside the 16:9 TV screen is the correct way.

� Copyright 2001 Secrets of Home Theater & High Fidelity
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