Technical Issues and Questions

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

#1576 Post by knives » Fri May 12, 2017 9:53 pm

Sometimes it is easier to hard encode the subtitles rather than giving the option to switch it on and off.

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Re: Technical Issues and Questions

#1577 Post by MichaelB » Sat May 13, 2017 4:03 am

knives wrote:Sometimes it is easier to hard encode the subtitles rather than giving the option to switch it on and off.
That doesn't make much sense to me, unless you're talking about making it easier for dimwitted projectionists.

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Re: Technical Issues and Questions

#1578 Post by knives » Sun May 14, 2017 12:05 am

Yes.

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Banasa
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Re: Technical Issues and Questions

#1579 Post by Banasa » Sun May 14, 2017 9:39 am

If I recall, in my town there have been people using older digital projectors that no longer can be upgrade their software.This has lead to subtitles not being displayed if certain presenters have chosen a less typical font for subtitles because the system can not recognise them in their current digital format.

Not sure how many instances of this there is, but it has happened.

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Survivability of blu-rays in heat?

#1580 Post by Morbii » Sun Jul 16, 2017 6:51 am

Hopefully this is the right place for this:

I was wondering if anyone knew anything about the survivability of blu-rays in heat?

I was excited today about getting 9 separate packages from Barnes & Noble (because fuck software that notices everything is shipping to one address from the same warehouse at the same time). I get to my lockbox to find: 0 packages. Ok, I figured that even though the post office had them yesterday, maybe they still didn't come today. So, I check the tracking, only to find they've all been delivered. I troll around my house/backyard in the usual places where other carriers will leave things and don't find it. I don't know why, but something told me to look behind some bushes in my front yard, which, if you see them, you'd note they are a PERFECT place to put packages if you want to hide them from the recipient for long periods of time. Sure enough, there's a huge stack of packages. Only, there's 10 packages, not 9. 2 1/2 months ago, I had ordered a Bride of Re-Animator BD from amazon.co.uk. They eventually sent me a new one as I never got it. Well, that package was the 10th one. A snail (at some point) had started eating through it (but didn't make it to the BD itself), and it probably even got rained on.

TLDR: A BD in a shipping package (that that is still sealed and in perfect shape) probably sat out there for roughly 2 months, possibly got rained on, and certainly saw multiple days of 100+ temperatures. It most likely did not get any direct sunlight, though. What are the odds that this BD has survived so I can sell it (amazon told me I can do what I want with it if I ever found it)?

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tenia
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Re: Technical Issues and Questions

#1581 Post by tenia » Sun Jul 16, 2017 8:37 am

I believe it needs to be lower than minus 20°C or more than 50°C, or an insanely fast change in temperature. So you should be fine.

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Re: Technical Issues and Questions

#1582 Post by Morbii » Sun Jul 16, 2017 8:55 am

Thanks.

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Re: Technical Issues and Questions

#1583 Post by kekid » Tue Jul 18, 2017 3:09 pm

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.

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Re: Technical Issues and Questions

#1584 Post by Drucker » Tue Jul 18, 2017 3:27 pm

I will try to be helpful though I am not one of the experts here:

A restoration is creating a brand new master copy of a film. A company or foundation will take the best available elements (the original camera negative or something as close to it as possible), scan those elements, and then use technology to get the film looking "brand new." If done right, in most cases, the film will look and sound as good as if not better than a brand new copy would have looked theatrically upon release. Nowadays, most things are scanned and uploaded digitally, but in the past this would have been done with photo chemical restoration. A combination of both still occurs frequently I believe.

Check out this trailer on the restoration of The Apu Trilogy which shows how much work it can take.

A transfer and encode are essentially the same thing. Encoding a disc is essentially transferring the "master" on to physical media. The restoration house that does the work described above is often different than the company distributing the film on home video. The former can be done exquisitely and perfectly, but to make sure the restoration looks accurate on home video requires essentially a transcription process to get the video on disc. Sometimes this is done well (like with the above Apu Trilogy) and sometimes it's done poorly.

If I'm way off the mark I will delete.
Last edited by Drucker on Tue Jul 18, 2017 4:01 pm, edited 1 time in total.

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Re: Technical Issues and Questions

#1585 Post by swo17 » Tue Jul 18, 2017 3:42 pm

I believe the big issue with encoding is how to optimally compress a master that's hundreds of GBs large down to 30-50GB so it will fit on a Blu-ray disc.

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Re: Technical Issues and Questions

#1586 Post by MichaelB » Tue Jul 18, 2017 4:28 pm

swo17 wrote:I believe the big issue with encoding is how to optimally compress a master that's hundreds of GBs large down to 30-50GB so it will fit on a Blu-ray disc.
Indeed. And a lot of people get hung up on the numbers, but a good manual encode at, say, 30MB/sec may well look noticeably better than an automatic one at 35.

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Re: Technical Issues and Questions

#1587 Post by kekid » Tue Jul 18, 2017 6:24 pm

Thank you Drucker, swo17 and MichaelB for your responses. Do I understand from these that if Kino and Arrow were to use the same encode of a film, the Blu Rays will be essentially identical in quality? Or is there some aspect of manufacture that can differentiate the two?

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?

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Re: Technical Issues and Questions

#1588 Post by swo17 » Tue Jul 18, 2017 6:35 pm

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?

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Re: Technical Issues and Questions

#1589 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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Re: Technical Issues and Questions

#1590 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?

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Re: Technical Issues and Questions

#1591 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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Re: Technical Issues and Questions

#1592 Post by swo17 » Tue Jul 18, 2017 11:12 pm

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

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Re: Technical Issues and Questions

#1593 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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Re: Technical Issues and Questions

#1594 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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Re: Technical Issues and Questions

#1595 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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Re: Technical Issues and Questions

#1596 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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Re: Technical Issues and Questions

#1597 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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Re: Technical Issues and Questions

#1598 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.

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Re: Technical Issues and Questions

#1599 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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Re: Technical Issues and Questions

#1600 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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