Technical Issues and Questions

Discuss North American DVDs and Blu-rays or other DVD and Blu-ray-related topics.
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kekid
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Re: Technical Issues and Questions

#1526 Post by kekid » Tue Jul 18, 2017 7:40 pm

swo17 wrote:If it really is the same encode being used by different companies, I don't believe there should be a difference. I don't know how commonly this happens though (other than cases where it's advertised, like when Cohen collaborates with one of the UK labels).

Modern films typically run at 24 frames per second, whereas many silents run at slower speeds. If you showed each silent frame once, it would run at 24fps. If the correct speed is, say, 20fps, then you would need to include 4 duplicate frames along with the 20 intended for that second so that it takes one whole second to see them all.

A separate issue is that something like Colossal Youth was shot in PAL video, as opposed to film. This is much lower than Blu-ray quality, but higher quality than DVD (more lines of resolution). PAL also runs at 25fps instead of 24. So when MoC issued that film on a PAL DVD, you're seeing it just as it was shot. In contrast, when Criterion issued it on NTSC DVD, the frame rate was slowed down, and it was also presented with fewer lines of resolution. Does that make sense?
Yes, it does. Thank you for clearing it up.

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Zinoviev
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Re: Technical Issues and Questions

#1527 Post by Zinoviev » Tue Jul 18, 2017 8:17 pm

While we're talking restoration, I've always wondered why restorers choose to keep the occasional stray hair in the frame even as they're cleaning up years of scratches and all manner of deterioration. Sure, the offending hair was there "from the beginning" (I guess?) but it certainly wasn't meant to be there. The technology certainly exists to remove it, but do restoration teams feel that doing so would cross the line from restoration to reinvention?

artfilmfan
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Re: Technical Issues and Questions

#1528 Post by artfilmfan » Tue Jul 18, 2017 9:11 pm

Talking about stray hair, the one in La Notte is really annoying.

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swo17
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Re: Technical Issues and Questions

#1529 Post by swo17 » Tue Jul 18, 2017 11:12 pm

Those are probably harder to remove than you'd think.

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tenia
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Re: Technical Issues and Questions

#1530 Post by tenia » Wed Jul 19, 2017 1:30 am

They're also sometimes considered as a definite part of the movie and left as is because of it.

As for the encode, it is the on-disc end-result.

To sum up roughly the workflow :
Physical elements (camera negative, interpositive, etc) are scanned.
The digital scan is cleaned up and restored to obtain the digital restoration. That's the source (the "master" / the restoration) which is often shared by different companies.
This restoration is compressed to obtain the encode that is the digital file on the BD disc.

If 2 BD releases share the same video encode, it means the picture on both discs will be 100% identical. It's rare, but it happens. Sometimes, it's easier / quicker (/ cheaper ?) for companies who licence a movie to get straight-away an encode than getting the uncompressed master and have to get an authoring house to compress it again.

That's the case for instance with the French and UK release of A Touch of Zen.

Most of the time though, because labels are used to work with this or that person or authoring house, encodes are different from one label to another (for instance between Arrow and Criterion, typically). Also, in some cases, some labels can do additional clean up (like Arrow on My Darling Clementine) or choose to re-do the color grading (like Koch Media on What Have You Done to Solange or Subkultur on Wake Up and Kill). In both cases, the encodes can't be identical.

kekid wrote:Separately, there has been occasional reference to "skipping/repeating every nth frame" to account for the film speed in ft per second of the original. I recall some discussion (I think) about the Blu Rays of Griffith's Intolerance as done by MoC being superior to that done by Cohen, and it was suggested that Pedro Costa's Colossal Youth will inherently be better in the MoC version than the Criterion version due to some such technical detail. Could you please clarify the basic issue(s) underpinning these situations? Are decisions to account for these issues part of the encode process?
These are 2 different technical specificities.

In the first case, it's linked to how early movies weren't shot and made for projections at 24 frames per second (but rather 18, 20, 21 or whatever). However, Blu-ray specifications don't allow playback at these native speeds. It's usually either 24 fps or 25 fps, which means frames have to be duplicated to fill in the blank, and they have to be cleverly spaced to avoid any jerkiness. Here is a very good article about this.

The other case (Pedro Costa) is linked to how some recent movies are shot at 25fps (like Colossal Youth).
European players are compatible with 25fps but US players are not so there is no way to reproduce easily 25fps movies, so the easiest way is usually to simply slow down the movie to 24 fps. It's what Criterion did with Colossal Youth, but also with Berlin Alexanderplatz.
This is the case for both DVDs and BDs, so that's why Criterion also had to slow down the Dekalog to 24fps.

This choice usually is part of the encode process (and sometimes "forced" onto the process due to compatibility issues).
Last edited by tenia on Wed Jul 19, 2017 4:08 am, edited 1 time in total.

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MichaelB
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Re: Technical Issues and Questions

#1531 Post by MichaelB » Wed Jul 19, 2017 4:02 am

swo17 wrote:Those are probably harder to remove than you'd think.
Yes, some things are much, much harder to remove than others. Vertical tramlines are the bane of film restorers' lives, and that notorious white speck on The Long Goodbye that's onscreen for something like thirty seconds is also pretty much impossible to remove because the camera is moving constantly under it, as of course is the grain structure of the film. A skilled digital artist might be able to reduce it, but eliminating it entirely seems a forlorn hope, and the former is an expensive proposition.

(I assume it was introduced back in 1972 during postproduction when dirt got into the optical printer, and unfortunately the dissolve being created involved one very long take. If those separate film elements still survive, the dissolve could be recreated and the blemish eliminated, but I bet they don't.)

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Morbii
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Re: Technical Issues and Questions

#1532 Post by Morbii » Wed Jul 19, 2017 5:12 am

On a related note to this, something I was just thinking about asking a day or two ago:

When they say "original film negative", do they mean the reel that was edited and spliced together, or the "raw" negative that then needs to be re-edited(/duplicated as necessary) to be exactly like the original film? Or something else entirely?

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JSC
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Re: Technical Issues and Questions

#1533 Post by JSC » Wed Jul 19, 2017 10:12 am

When they say "original film negative", do they mean the reel that was edited and spliced
together, or the "raw" negative that then needs to be re-edited(/duplicated as necessary) to be
exactly like the original film? Or something else entirely?
My understanding is that it refers to an edited negative. After the editor receives a print
struck from the raw materials they create a work print. The negative cutter than uses that
editor's print as reference. Excised material is either destroyed or separately stored.

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jedgeco
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Re: Technical Issues and Questions

#1534 Post by jedgeco » Wed Jul 19, 2017 11:35 am

Drucker wrote:A transfer and encode are essentially the same thing.
Yes. Based on my understanding, although "transfer" is still widely used, it's a bit of a misnomer for modern technology.

Back in the SD analog days, a film would be literally "transferred" from the film elements into magnetic video using a telecine machine. With the advent of digital workflow, the film elements are scanned to 2K or 4K; because the final product to the customer will be digital, all work can be done in the digital realm, which is finally encoded (compressed) on to disc or other media. Criterion tends to use "transfer" now to refer to the entire soup-to-nuts workflow of getting film elements onto disc.

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movielocke
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Re: Technical Issues and Questions

#1535 Post by movielocke » Wed Jul 19, 2017 3:14 pm

kekid wrote:I am not knowledgeable about the technical jargon pertaining to the production of a Blu Ray disc starting from the original film source. Specifically, what is the precise meaning of terms like restoration, transfer, encode, etc. (I am not sure I know all relevant terms to make a comprehensive list). As a result, I have sometimes posted questions using a wrong term, and people corrected me before answering the question. It will be helpful to me if someone could explain in simple language what these terms mean (please feel free to add additional terms: for example, how can discs produced by different companies from the same encode look different; what is the name of the process that makes them different? etc.). Thank you.

With film elements and digital elements there is the camera original--the element captured by the camera.

For digital, that is the hard drive and backup harddrive recording the camera raw files, handled by DIT individuals or a post house which "develop" the camera raw into various formats for dailies viewing, for assembly editing, and eventually for final grading.

For film, that is the reels of original negative, exposed in camera, developed at a lab, printed at a lab, and film element dailies returned for viewing and assembly editing and eventually the reels of negative are cut together into a single element to conform to the final edit. This creates what is commonly called the 'original' negative. This is the element from which all further elements will derive. the cut negative will be put into a printing machine and a contact print will be made from it, this contact print is called an interpositive. From this interpositive, several duplicate negatives will be made via contact print. The process can repeat and expand until many printing elements (duplicate internegatives) have been created, perhaps four or five generations away from the cut negative. From these late generation elements, release prints (often six generations away from the cut negative) will be created by contact print, and each internegative will be used used hundreds of times before being discarded.

When going back to restore a film, sometimes the original cut negative has not survived. Sometimes the best element they can find is an interpositive. Sometimes the best element they can find will be an duplicate internegative. Sometimes the best element they can find will be a release print.

(note that for films shot on film today, it is commonly the case to never cut and assemble a final negative, an interpositive will be be made from uncut reels, making it the first assembled element in the chain rather than the second, this is so that the negative experiences the most non-destructive workflow possible to devise, but it also means we don't have a cut negative for many modern studio films, potentially raising extremely difficult restoration problems in the future).

Any of these elements can be scanned digitally into a computer. Most commonly, scans are done as a telecine, meaning the data is stored in very high quality to magnetic tape. It can also be stored on harddrives, but it is probably going to wind up on magnetic tape at some point, whether as long term storage or as a mastered element. Once a digital scan has been made, that becomes a digital camera original not unlike modern digital workflows. From those high resolution camera raw files a post house will "develop" the format into computer friendly elements for assembly, restoration, grading within the various software environments.

When final digital elements have been finished, they can be "printed" to a variety of master formats, you could print back out individual files for every frame and store the data on harddrives or magnetic tape or even printed back to film as a print or as a new negative element, you could have a DCP created, you could have an HDCAMSR (also magnetic tape) created etc etc, all of these elements could be called a "master"

When criterion receives a "master" they almost always receive either an HDCAMSR, or a harddrive with the equivalent master fiels. They can then ingest these master tapes or files into various software (they may do additional grading or restoration) and from their final files they will use software to then compress the master file to create an encode, VOB files for a DVD, for example. And this encoded VOB file is what can then be used to create a DVD, as it is what is burned (or pressed) into the physical DVD structure.

your dvd player then decodes the VOB as it plays it back, and displays the decoded image to your TV.

kekid
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Re: Technical Issues and Questions

#1536 Post by kekid » Wed Jul 19, 2017 11:55 pm

tenia wrote:They're also sometimes considered as a definite part of the movie and left as is because of it.

As for the encode, it is the on-disc end-result.

To sum up roughly the workflow :
Physical elements (camera negative, interpositive, etc) are scanned.
The digital scan is cleaned up and restored to obtain the digital restoration. That's the source (the "master" / the restoration) which is often shared by different companies.
This restoration is compressed to obtain the encode that is the digital file on the BD disc.

If 2 BD releases share the same video encode, it means the picture on both discs will be 100% identical. It's rare, but it happens. Sometimes, it's easier / quicker (/ cheaper ?) for companies who licence a movie to get straight-away an encode than getting the uncompressed master and have to get an authoring house to compress it again.

That's the case for instance with the French and UK release of A Touch of Zen.

Most of the time though, because labels are used to work with this or that person or authoring house, encodes are different from one label to another (for instance between Arrow and Criterion, typically). Also, in some cases, some labels can do additional clean up (like Arrow on My Darling Clementine) or choose to re-do the color grading (like Koch Media on What Have You Done to Solange or Subkultur on Wake Up and Kill). In both cases, the encodes can't be identical.

kekid wrote:Separately, there has been occasional reference to "skipping/repeating every nth frame" to account for the film speed in ft per second of the original. I recall some discussion (I think) about the Blu Rays of Griffith's Intolerance as done by MoC being superior to that done by Cohen, and it was suggested that Pedro Costa's Colossal Youth will inherently be better in the MoC version than the Criterion version due to some such technical detail. Could you please clarify the basic issue(s) underpinning these situations? Are decisions to account for these issues part of the encode process?
These are 2 different technical specificities.

In the first case, it's linked to how early movies weren't shot and made for projections at 24 frames per second (but rather 18, 20, 21 or whatever). However, Blu-ray specifications don't allow playback at these native speeds. It's usually either 24 fps or 25 fps, which means frames have to be duplicated to fill in the blank, and they have to be cleverly spaced to avoid any jerkiness. Here is a very good article about this.

The other case (Pedro Costa) is linked to how some recent movies are shot at 25fps (like Colossal Youth).
European players are compatible with 25fps but US players are not so there is no way to reproduce easily 25fps movies, so the easiest way is usually to simply slow down the movie to 24 fps. It's what Criterion did with Colossal Youth, but also with Berlin Alexanderplatz.
This is the case for both DVDs and BDs, so that's why Criterion also had to slow down the Dekalog to 24fps.

This choice usually is part of the encode process (and sometimes "forced" onto the process due to compatibility issues).
Very helpful. Thank you.
Does your last comment imply that if the BD of Berlin Alexanderplatz was issued by both Second Sight and Criterion, Second Sight will be preferable (all other factors being equal), similar to the Colossal Youth situation?

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swo17
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Re: Technical Issues and Questions

#1537 Post by swo17 » Thu Jul 20, 2017 12:22 am

The NTSC/PAL issue goes away with Blu-ray, which is 24fps for the whole world. Berlin Alexanderplatz would presumably require some kind of workaround to present it as intended, but theoretically any label would have it in their power to release it in the best way possible.

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andyli
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Re: Technical Issues and Questions

#1538 Post by andyli » Thu Jul 20, 2017 1:00 am

Actually it does not go away. Native 25fps material can be preferably presented in 1080i50, as demonstrated by Arrow's Dekalog Blu-ray. So basically 24p is not the only option in Blu-ray and the PAL/NTSC issue remains.

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MichaelB
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Technical Issues and Questions

#1539 Post by MichaelB » Thu Jul 20, 2017 3:05 am

Similarly - and correctly - the BFI presented its Alan Clarke, Ken Russell and Peter Watkins BBC Blu-rays at 25fps. And Second Sight confirmed on Facebook yesterday that they'll be doing the same with Berlin Alexanderplatz and Heimat (the latter also shot for German television at 25fps).

Note that the "i50" in "1080i50" is deceptive - to all practical intents and purposes, these are progressive transfers at 25fps in terms of what the player serves up.

A US label generally has to slow these down to 24fps, as Criterion was forced to do with Dekalog.

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andyli
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Re: Technical Issues and Questions

#1540 Post by andyli » Thu Jul 20, 2017 3:27 am

MichaelB wrote:Note that the "i50" in "1080i50" is deceptive - to all practical intents and purposes, these are progressive transfers at 25fps in terms of what the player serves up.
Exactly. As I understand it it is only nominally interlaced, for the two adjacent fields actually come from and compose the same frame and will not cause any visual anomalies.

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MichaelB
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Re: Technical Issues and Questions

#1541 Post by MichaelB » Thu Jul 20, 2017 3:29 am

Yes, that's correct. Because of the limitations of the Blu-ray specs such transfers have to run at 50fps, but all this means is that the same film frame is duplicated across two BD "frames". The end result is indistinguishable from watching an actual 25fps transfer, because to all intents and purposes that's what it is.

kekid
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Re: Technical Issues and Questions

#1542 Post by kekid » Sat Jul 22, 2017 4:33 pm

[quote="tenia"]

The other case (Pedro Costa) is linked to how some recent movies are shot at 25fps (like Colossal Youth).
European players are compatible with 25fps but US players are not so there is no way to reproduce easily 25fps movies, so the easiest way is usually to simply slow down the movie to 24 fps. It's what Criterion did with Colossal Youth, but also with Berlin Alexanderplatz.
This is the case for both DVDs and BDs, so that's why Criterion also had to slow down the Dekalog to 24fps.

I am still trying to understand what this means. Please correct me if any of the following statements are inaccurate.
The Blu Ray standard permits a disc to have 24 or 25 fps speed.
(further clarification: faster than 25 fps is ok, but slower than 24 fps is not - is this true?).
The USA Blu Ray players are made to play back discs at only 24 fps, while the European players can play them back at either 24 or 25 fps.
(How is this actually accomplished? Do 24 fps discs get spun in the player at a different rpm than the 25 fps disc?)
Therefore, European players can play discs made to play at 25fps at correct speed, but US players cannot.
1080i50 notation implies discs made with 50 fps (or interlaced with 25fps speed) - is this true?
If this is true, why is my OPPO player, meant for US consumer, able to play some of the Eric Rohmer discs made with 1080i50?
All this is not nuclear science but, for a layman like me, it is close!
Thank all of you, who have patiently tried to answer my questions.

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Morbii
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Re: Technical Issues and Questions

#1543 Post by Morbii » Sat Jul 22, 2017 11:34 pm

Kekid,

My understanding is that most BD players can handle this frame rate. It's American TVs that can't (or have it disabled). American BD players generally have it disabled too, but a region free player will either have a chip or a setting changed that can do a conversion. Your oppo will do a local conversion before sending it to the TV.

As far as disk rotation speed, it shouldn't increase specifically due to frame rate. It just means more data is used in the same time frame (assuming an encode that is identical to a 24fps one, minus that one frame). I could be wrong on this part, but the disc should have a max "bandwidth", which is the most data that can be read in a specific period of time. I suppose it may spin faster or slower depending on the read request (unsure), but it won't be directly related to the frame rate.

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TMDaines
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Re: Technical Issues and Questions

#1544 Post by TMDaines » Wed Aug 02, 2017 8:59 am

Is it wrong to devoid your device of all its colour saturation when watching black and white films? Were black and white films truly devoid of any hue or did the film stock ever have a slight colour tint in one direction?

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tenia
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Re: Technical Issues and Questions

#1545 Post by tenia » Wed Aug 02, 2017 9:29 am

I asked such a question when our French Tokyo Story BD release turned out to be slightly brown-ish and was answered that B&W stock was really without hue so should be pure B&W.

But then, maybe the person who answered me could have been wrong.

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Re: Technical Issues and Questions

#1546 Post by David M. » Wed Aug 02, 2017 12:18 pm

TMDaines wrote:Is it wrong to devoid your device of all its colour saturation when watching black and white films? Were black and white films truly devoid of any hue or did the film stock ever have a slight colour tint in one direction?
It's not wrong, but there's also not much point. B&W content should have no chroma data whatsoever (not always the case, sometimes small tints creep in).

The color you end up seeing with a truly B&W piece of video depends on the color temperature of your display. D65 (x=.313, y=.329) is the standard white point for all NTSC, PAL, and HDTV, and gives a fairly neutral tone (most TVs have something insanely blue-tinted in their so-called "Neutral" color temperature, but that's besides the point).

Some people do like to have a D55 white point set up on their display for B&W movies, since it's thought to emulate what projection would have looked like back in the day.

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TMDaines
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Re: Technical Issues and Questions

#1547 Post by TMDaines » Wed Aug 02, 2017 9:15 pm

I got into the habit of doing as they are a few earlier DVDs that have a slight purple hue and old VHS and TV rips can be susceptible to going greenish.

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Re: Technical Issues and Questions

#1548 Post by GTO » Thu Aug 17, 2017 3:37 pm

I recently watched my first b&w 4K transfer on my new 4K TV, specifically 12 Angry Men. Especially in the darker scenes the film grain looks like silver beetles crawling all over the place. There's one close up of Henry Fonda's face where this makes it look like a horror movie. Is this typical for b&w movies in 4K? Not sure I want to buy any more if that is the case.

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Ribs
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Re: Technical Issues and Questions

#1549 Post by Ribs » Thu Aug 17, 2017 3:42 pm

Black and white has no impact on the amount of grain, it's dependent on the stock used for the film. 12 Angry Men is especially grainy, as is (just as a simple comparison of a film from around that same time) On the Waterfront. That said, I'd first advise you to make sure you've got the sharpness setting as low as possible without blurring - grain's one of those weird things that makes a picture just look absolutely fantastic but if the sharpness is even a little bit off it can make it look horrid. Similarly, a 4K transfer will not necessarily be a good transfer, nor does a 2K (or HD) transfer mean that there won't be a great picture with lots of good, thick grain (again, dependent on the movie). It also depends on what player and TV you are using, as one of them might be upscaling the disc (which is in 1080p, despite being from a 4K source) improperly.
Last edited by Ribs on Thu Aug 17, 2017 3:56 pm, edited 1 time in total.

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fdm
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Re: Technical Issues and Questions

#1550 Post by fdm » Thu Aug 17, 2017 3:53 pm

Also look for the movie mode setting on your tv. If you're not using it, it will be a lot closer to what you want than the typical default torch mode setting.

(I usually tweak my tvs with a calibration disc, though this last time after I did that I also grabbed some settings from the internet for it which gave me a pretty decent picture, so decent that even though I keep meaning to re-calibrate it with the disc to check my settings, I never seem to get around to it - too busy watching. I got the tv back in 2013...)

(Also, I pretty much turn off every special setting that is on by default, and stick with the basics.)

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