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THX needs some feedback


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60 replies to this topic

#1 of 61 OFFLINE   Parker Clack

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Posted May 24 2005 - 07:05 PM

The guys at THX are wanting some feedback from you on wide screen displays to text DVD playback quality.

Here the information in question they are looking for:

Quote:
THX is doing R&D on wide screen displays to test DVD playback quality. The intent is to find potential problems that may occur in the conversion processes and determine solutions for improving DVD quality when displayed in the wide screen format. We welcome HTF members' comments and experiences. We are also working to establish an industry standard for the Home Theater Mix in an effort to duplicate the theater experience with DVD. So we also welcome comments about sound.

Please post your responses and any questions you have for THX here in this thread. They will be reading it daily. Believe me when I say that the guys at THX pay attention to what the consumer wants and will definitely appreciate any feedback you can offer.

Parker

"I tried to get my medical records from the company but they say they

are confidential and can only be released to other insurance companies,

pharmaceutical​ reps, suppliers of medical equipment and for some

reason the RNC."
 


#2 of 61 OFFLINE   Parker Clack

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Posted May 24 2005 - 07:08 PM

Steve: (This is the guy with THX that will be following and responding to posts in this thread)

I have a Mitsubishi WD-62725 and a newly aquired HTPC from 2 Parts Fusion. (My review will be posted later on this weeek). It has a DVDR built in and the picture from DVD is nothing short of amazing.

I can hardly wait for HiDef DVD to see what they look like on the set.

Parker

"I tried to get my medical records from the company but they say they

are confidential and can only be released to other insurance companies,

pharmaceutical​ reps, suppliers of medical equipment and for some

reason the RNC."
 


#3 of 61 OFFLINE   Vince Maskeeper

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Posted May 25 2005 - 03:03 AM

I'm interested in taking part, although I'm not sure exactly what they're asking here. There doesn't seem to be a question.

?

I have several widescreen displays and would be happy to offer input.

-V
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#4 of 61 OFFLINE   John S

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Posted May 25 2005 - 03:24 AM

I agree with Vince about "What are they looking for?"

I'd just be happy if on an anamorphic DVD, that the entire DVD including bonus/special features would also be in anamorphic, most times they are in 4:3 it seems. UUHHGG

#5 of 61 OFFLINE   ElAhrai

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Posted May 25 2005 - 05:12 AM

I'd be interested in helping too, but again, there doesn't seem to be a question.

So if there is some clarification on what they need, count me in.


#6 of 61 OFFLINE   Carlo Medina

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Posted May 25 2005 - 05:21 AM

Yeah, I too am not sure what they're looking for based on the quote that Parker has, but I'll definitely be interested in giving my $.02 Posted Image

With regards to what I can make out as questions from that quote, here's my attempt at feedback:
Quote:
The intent is to find potential problems that may occur in the conversion processes and determine solutions for improving DVD quality when displayed in the wide screen format.
As posted above: all extras enhanced for 16x9 TVs is a great place to start. Oh, and a no-brainer, all transfers of 1.66:1 or wider should be enhanced for 16x9 TVs as well (I remember the early THX DVD releases that weren't 16x9 but hopefully those days are long gone).

Also: selectable placement of subtitles (i.e. 2 subtitle tracks) for 2.35:1 movies.
i.e.
1) the subtitles close to the bottom of the screen, towards or completely in the "black bars" for those of us who are watching on a regular TV, RPTV or projector w/o mattes. That way the subtitles can be out of the picture.

2) the subtitles completely within the picture border (not in the black bars at all) for all those who do have mattes that hide the black bars.

Currently most subtitles on 2.35 movies are part on the movie, part in the black bars, which makes watching foreign 2.35 films with a matte setup partially unreadable.

Quote:
We are also working to establish an industry standard for the Home Theater Mix in an effort to duplicate the theater experience with DVD.
This is somewhat trickier. Since most movie soundtracks are mixed for large halls (500+ seated venues) I would guess that some sort of near-field mixing happens on home theater releases? If so, the trick is to find the "sweet spot" in the theater and make the home version sound like that.

XBox Live: TheL1brarian (let's play Destiny on XB1)


#7 of 61 OFFLINE   Parker Clack

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Posted May 25 2005 - 05:28 AM

Its not really a question. I took it as they are wanting your own observations about DVD and how it is displayed on the monitors that you have viewed it on.

I will send them the link to this thread to see if they can be a bit more specific in what they are looking for.

"I tried to get my medical records from the company but they say they

are confidential and can only be released to other insurance companies,

pharmaceutical​ reps, suppliers of medical equipment and for some

reason the RNC."
 


#8 of 61 OFFLINE   James Phung

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Posted May 25 2005 - 09:20 AM

THX Optimizer results seem to differ from different THX dvds. I'm guessing the optimizer is meant for that particular dvd. Why not make it the same for each dvd so we can always use one setting without having to change it each time?

#9 of 61 OFFLINE   Parker Clack

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Posted May 25 2005 - 09:59 AM

I heard back from Steve at THX and he said basically the same thing that I said and that is they are just wanting to know of any problems with DVD playback on your widescreen display.

Here is a general idea of what they are wanting.

Quote:
Are you having any performance issues or technical problems when you play DVDs on your widescreen display? THX is interested in hearing about any complaints that specially relate to picture quality (or lack thereof.) As an example, you may have noticed artifacts or some sort of
picture distortion compared with a CRT display. THX is looking for any perceivable (even minuscule) recurring problems that viewers experience with their wide screen playback of DVDs. (Positive experiences aren't needed.) The next step for THX is to analyze the members' experiences (along with controlled research) and create solutions that improve quality and set higher standards for the industry.

"I tried to get my medical records from the company but they say they

are confidential and can only be released to other insurance companies,

pharmaceutical​ reps, suppliers of medical equipment and for some

reason the RNC."
 


#10 of 61 OFFLINE   James Phung

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Posted May 25 2005 - 11:50 AM

There's the macroblocking issue found on dvds that people have problems with. These macroblocks are found on many dvds (including THX certified movies like Finding Nemo), when played with certain display and dvd player combinations, will make it worse. There seems to be many complaints about it right now on high quality dvd players that use faroudja deinterlacing. Faroudja seems to enhance the macros making the picture very much unwatchable on their display. Even on non faroudja based players, people still see the macroblocking, it's noticeable, just not enhanced. Though some displays will not show the macroblocks, others will, it is display dependent and it seems to affect plasmas the most. I'm using the Faroudja based Oppo dvd player and I haven't seen any of these macroblocks on my Infocus 4805 DLP projector.

There's also an issue with audio sync. We have dvd players processing video to our display and then the display processing the video again, for some, this will give lip sync issues, which is why you find many people requiring lip sync delay in their receiver so that they can fix the sync.

#11 of 61 OFFLINE   Matt*B

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Posted May 25 2005 - 11:56 PM

THX,

It would be nice for Discs that are only in 16x9 to have menus that are in 16x9 as well. This way the user won't have to switch display formats on the fly to view the menus in the OAR. Perhaps seperate menus for DVD's with both screen formats, if possible. I suppose this would be a good idea to apply to the bonus material as well, but that may not be a practical idea.... But the menus in 16x9 screen format would be a nice feature.

Thanks,

Matt
(magicianstalk@hotmail.com)

#12 of 61 OFFLINE   PhilBoy

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Posted May 26 2005 - 12:41 AM

Use the maximum bitrate possible for all mpeg2 compression (fill the disc) both layers.

Use only anamorphic transfers for widescreen features.

Put the 'extras' on a second disc.

Clean the prints/negatives before transfer.

I seriously would not object to paying more for a quality transfer.

If the Optimizer is calibrated to each release, then always include it.
simplicity is genius...

#13 of 61 OFFLINE   Gabriel.H

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Posted May 26 2005 - 01:30 AM

I agree with Philboy here, much like the Superbit titles, all dvd's should use one disc for the movie and make use of all its capacity for higher quality video, and the inclusion of DTS is more than welcome Posted Image. Bonus features can be on a 2nd disc. Superbit dvd's are what I use to show off my TV to people who come over.

#14 of 61 OFFLINE   Kevin_Wadsworth

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Posted May 26 2005 - 02:34 AM

Similar to the requests for the aspect ratio on the menu and extras to be the same as the movie, I’d request that the audio signal for these portions also be the same. Many of today’s movies are enoced in DD or DTS but still have the menus in stereo. Fro those of us with receivers that take a second or two to lock onto a new audio signal when it changes types, this can be irritating

#15 of 61 OFFLINE   Kwang Suh

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Posted May 28 2005 - 11:13 AM

Stop applying edge enhancement...

#16 of 61 OFFLINE   George_W_K

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Posted May 28 2005 - 12:19 PM

I second the elimination of edge enhancement.

I also agree that if the DVD is 16 X 9 or greater, it should be anamorphic. The special features also.

And I agree that the movie should use the maximum bit rate possible, with the special features on a second disc.

Use the best source possible when encoding the Dolby Digital and/or DTS audio tracks.

Use the same high standards for every THX disc so the Optimizer only has to be set once.

More THX trailers?:wink:

#17 of 61 OFFLINE   ChrisWiggles

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Posted May 29 2005 - 05:48 AM

I have quite a few things that are general, and a couple that are THX-specific. FYI: my system is CRT front-projection at 720p 72hz, so I'm viewing on a very revealing system. However, there will be more and more viewers using large-screen displays, and these issues will become more important. In any case, as THX strives for the best performance, I feel these are totally appropriate requests that should be done right regardless of the rarity (or not) of high-end large-screen playback systems.

1) as mentioned: high bitrates please!

2) second the NO edge enhancement. None. EVER. Totally unecessary. Users can apply sharpening in their own systems if they wish to degrade their performance. Please don't force this garbage on me.

3) make sure that colorspace is properly encoded in 601 for SD (presumably DVD)material, and 709 for any HD material or future formats.

4) And for THX very specifically: please, please, PLEASE figure out your optimode system. I cannot fathom how it ended up as convoluted as it has. If you want to discuss specifics please contact me privately, but having individualized test patterns for each transfer was a terrible idea if you weren't utilizing them to correct your mastering chain. ALL the patterns should be reference-correct when finalized. If they were inserted before the mastering stage and they came out off-standard, that means your chain is off. Fix your chain. Don't have consumers compensate by calibrating to individual titles. I have not heard specifics as to whether the patterns are now correct, but it still doesn't shed light on whether your mastering chains are still off a bit. This is why I *always* recommend that users NOT use the THX patterns, because they are unreliable. Please figure this mess out! Optimode patterns should be reference and on-standard, and your video should hopefully be the same. If you are gonna insert the patterns before the mastering chain, use them to make sure they come out correct in the end. If they don't, fix your chain until they do.

5) THX certified DVD players NEED to pass the full range of values including blacker-than-black, AND peak whites for analog outputs at both 0 and 7.5IRE. Further, digital outputs should be correctly aligned, and no expansion to PC levels should be applied in default settings. Options for these settings should be clearly labeled. Options like "enhanced black" are very misleading. You should definitley suggest to manufacturers that the IRE setting is just a clear selection between 0 and 7.5, and the digital output is between Video and PC levels. Avoid this "enhanced black" or "expanded" language. It is misleading. Too many unassuming users mess up their video because of this. Lastly, PLEASE make sure that the IRE setup option does *not* affect the digital outputs and is implemented only on the analog outputs. Cost-cutting player designs have screwed this up terribly by trying to do this digitally.

6) upscaling DVD players: should twist the colorspace to 709 before outputting an HD signal for YPbPr and YCbCr output. Some professionals disagree with me here, but since many displays do not have the ability to alter the decode, and I don't see any sources utilizing the colorspace flag, if the upscaling DVD player leaves the output in 601, it's gonna get decoded 709 by the display and the colors will be all wrong. At the very least make this clear in the literature as to what the player is doing/not doing to the colorspace. An option to select this is ok.

7) My last request: when you master a title, please take care to view it critically on a large-screen reference display system, something like 1080p LCOS, or high-end CRT on a system that is carefully designed to eliminate banding. There are a lot of films out there with banding problems, probably because of banding problems in the mastering chain. This is almost impossible to see on small monitors so while it is unacceptable, it is understandable. The R1 Finding nemo is an example of an otherwise awesome transfer that has this banding problem. Other masters of this film do not: it is evidence of a mastering chain limitation of this particular version.

My goal is the best possible video, and when the limitation is outside of my control it is frustrating. On the whole THX titles are very high-quality, but there is always room for improvement. If you strive for having your titles consistently be very high-quality, and near or among "reference" titles, there are still things to be done. There is perhaps more work to be done on the playback side of THX-certified sources as well, because even with reference titles if the sources are not doing things correctly there's still an obstacle to the best performance.

Thanks!
--Chris

#18 of 61 OFFLINE   Adam Barratt

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Posted May 30 2005 - 06:56 PM

Quote:
Also: selectable placement of subtitles (i.e. 2 subtitle tracks) for 2.35:1 movies.
i.e.
1) the subtitles close to the bottom of the screen, towards or completely in the "black bars" for those of us who are watching on a regular TV, RPTV or projector w/o mattes. That way the subtitles can be out of the picture.

2) the subtitles completely within the picture border (not in the black bars at all) for all those who do have mattes that hide the black bars.

Currently most subtitles on 2.35 movies are part on the movie, part in the black bars, which makes watching foreign 2.35 films with a matte setup partially unreadable.

I'll second that. Using mattes and subtitles can be a nightmare, but this idea would solve the problem of 'lost' subtitles, and the cost in time and bandwidth would be negligible.

It would also be nice if there was more standardisation of subtitles. Everyone seems to use their own colours, sizes and fonts and I've seen more than a few important pieces of dialogue lost in the image (white font over white background, for example).

As far as recurring problems on widescreen displays, I often notice a very narrow (~2 pixels) white horizontal line between the active picture area and black bars on 1.77:1+ DVD images, even when zoomed in on a PC. Maybe a result of edge enhancement, but distracting in dark scenes.

Adam

#19 of 61 OFFLINE   Shad R

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Posted June 01 2005 - 05:18 PM

I think each THX disc has it's own optimizer on purpose. I think (and this is just a guess) that each movie is intended to be shown differently. Example: Finding Nemo is probably a brighter movie than Fight Club. The fight club dvd probably has you optimize to bring out the blacks, and finding nemo to bring out the brighter colors. Just a thought.

THX: Higher bit-rate...definately. Honestly, I would sacrifice DTS if the Dolby track was done right, to make the picture better.

#20 of 61 OFFLINE   ChrisWiggles

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Posted June 01 2005 - 07:10 PM

Example: Finding Nemo is probably a brighter movie than Fight Club. The fight club dvd probably has you optimize to bring out the blacks, and finding nemo to bring out the brighter colors. Just a thought.


There are standards in use. In an ideal world there would be one calibration, and all DVDs would be correctly authored to standard and viewed correctly. Per-DVD calibration has never been an appropriate goal. I will fight tooth and nail against any such a disastrous idea!

The larger explanations behind the original goals of the optimode system, and the current iteration have not come to me directly from THX, so I'd rather leave them off the table at the moment, because they cause me a more profound concern about the original thought behind the whole idea. In any case the variation is a problem. That current patterns seem to be coming out correctly still leaves me pause because the underlying glitches that caused patterns to vary earlier on may not have been rectified completely. I would like to know where the patterns are being inserted in the chain now, and where they were inserted in the past. This is something that has never been clarified from anyone at THX that I've ever seen...


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