αναλυση στον κινηματογράφο: μύθοι και πραγματικότητα

takisot

Μέλος Δ.Σ.
Staff member
17 June 2006
24,355
Παλλήνη
Lepton, Οπως λενε και οι Αμερικανοι "you nailed it" (χτυπησες διανα)!
Σε ευχαριστω για την ωραιοτατη αναλυση της εννοιας transfer function.
Ξαναδιαβαζοντας το κειμενο, βλεπω την λογικη χρησιμοποιησης του ορου για να περιγραψει το φαινομενο της απωλειας αναλυσης καθε φορα που μία εικόνα μεγεθύνεται μέσα από ένα φακό..
 

Κώστας Παπαγεωργίου

AVClub Addicted Member
17 June 2006
2,014
ΑΘΗΝΑ
Τάκη πολύ αξιόλογο & ενδιαφέρον θέμα.

Καλή και δυναμική έναρξη.


ΚΥΡΙΑΚΟΣ ΠΑΝΑΓΙΩΤΑΚΟΣ said:
Στό άμεσο μέλλον, στην πρώτη σύγκριση προβολικών, προτείνω να βρώ σε φίλμ 16μμ (σε 35μμ πολύ δύσκολο, θα το ψάξω όμως) υλικό που έχουμε σε 720p ή 1080 και να φέρω προβολέα να τα βάλουμε δίπλα-δίπλα, να μας φύγει η απορία. Και μήν νομίζετε οτι με 16μμ θα γελάσουμε...... θα δούμε όμως άν και εφόσον.

Κυριάκο πολύ καλή η αναφορά σου και οι διατυπώσεις σου.

Πιστεύεις ότι θα μπορούσαμε να κάνουμε εφικτή μία τέτοια αντιπαράθεση?

Εγώ μπορώ να διαθέσω τον BenQ PE 8720, εφόσον θα το οργανώσουμε σύντομα.

Επίσης αίθουσα μπορούμε να βρούμε... φιλμ και μηχανή προβολής θα μπορέσουμε να βρούμε?

Ή ακόμη καλύτερα να ψάξουμε να βρούμε άκρη να το οργανώσουμε σε μία κινηματογραφική αίθουσα?
 
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GeonX

Μέλος Σωματείου
17 June 2006
2,746
…είχα σκοπό να το ανεβάσω χώρια μια και η αναφορά είναι για την δημιουργία DVD από τα Master (ειδικά κλασικών ταινιών…) νομίζω ότι συνάφεια του θέματος το επιτρέπει… η αναφορά είναι από ένα παλιότερο άρθρο στο Laser Examiner …

It is a jungle out there. The cliché fits the DVD market perfectly at the moment; and it also seems to be applicable to the scores of authoring houses that have to combat an ever increasing (and seamlessly endless) flood of films coming their way. With errors occurring every week such as soundtracks being out of sync (albeit slightly), inaccurate color timing and color corrections, even whole sequences missing - what are the causes ? And what the remedies ?
Despite their ever increasing numbers, post houses seem to struggle when it comes to handling the everyday "onslaught". Technically, the developing trend is ironic: although encoders have improved dramatically in the last five years, have become much faster and can produce an MPEG-2 image of near perfect precision within the limitations of the format the quality on most discs is actually on the decrease. And this trend is noticeable in most studios and labels.
That makes it so aggravating to many viewers, especially those with better equipment. The knowledge that there is such a thing as better mastering has resulted in a growing number of critical comments also from the side of the "makers". By now, the effects of a more lacklustre mastering and encoding are even visible on normal screens - and thus moving into the domain of the mainstream viewer.
Technology does allow for much better quality - almost flawless releases such as "V - The Miniseries", the Japanese Editions of "The Terminator" or the "Gladiator (Superbit Edition)" presented visual excellence - and yet, so many other releases fall far short of that mark. "Gone With The Wind" was excellently scanned in 2K and mastered in the so-called "UltraDefinition process" to insure the 3-strip Technicolor elements would fit perfectly.
But the encoding to DVD was littered with artefacts, as were the releases of "Singin In The Rain" and many others. But why ? In many cases, the answer appears to lie in the massive workload, paired with a steadily declining profit margins resulting in less time for a project and less investments in the best equipment.
As we reported here before, the number of releases suffering from the "run-off-the-mill syndrome" is rising; with marketing decisions weighing heavily when it comes to the quality of the discs. Often is also a lack of good coordination and planning a cause.
With a flood of films and TV series to be marketed, making the most out of the quality of the digital source tapes when encoding to DLT (and subsequently DVD) is not only a tough job considering the limited time that is spent on each film/series - the individual title is also reduced to a mass product in every sense of the word, and very often not even big blockbusters get the attention they deserve. The reasons for this are many.

For one, the encoding of the films is very often being done way before the actual release is finalized. Extras are planned and produced later on, not rarely a long time after the mastering and encoding process - with the possibility that during that (long) planning stage some or even all of these extras are skipped, for financial or legal reasons, among others. The allotted space then just remains empty; no new encoding is made. The poor "exploitation" of the disc space is also due to limited time of preparation and testing. Very few discs are made using 2-pass methods, where the film is analyzed sequence by sequence - and the GOP structure aligned to the best way possible. A simple, default setting is all too often used instead; in which all films, black and white as well as color; video based interlaced signals @30fps as well as film-based 480p 24 or 576p 25 material is encoded the same way
MPEG encoding is literally like walking the many roads that lead to Rome. Because of the less than strict guidelines and wishy-washy interpretations of the standards of the format(ing) each manufacturer can do pretty much everything with the DVD standard and still call it correct.

The differences of encoding B/W material and highly detailed color material are just as often not taken into account as the difference between encoding film and video sources - or it is simply ignored by either using default settings in the encoder, or , even worse, using the wrong encoder all together. Sometimes, source material is encoded using the wrong field domination, or in a forced interlaced mode.

Warner Bros used forced interlaced encoding on several occasions, especially on TV shows - NIP/TUCK being the most prominent example; but the studio is not alone.
Instead of issuing the hit series in 480p 24 progressive CBS and Paramount offered forced interlaced 30fps encoded material (forced bob) of CSI and CSI Miami - except for Season 4 of CSI. MGM had the regular (!) occurance of field swaps on the R1 editions of STARGATE SG-1. On "normal TV sets" the result of forced interlaced material or the wrong field domination is less detectable; but on projection equipment it very much is. The picture, in effect, is marred by interferences such as field combing, very visible line structure and substantial loss of detail and sharpness.
We tested a number of titles regarding the mentioned "problems". Though we cannot list all the respective results individually here, what we can give you is a general idea of a trend that is continuing to develop. The results are quite interesting, as some studios seem to follow a clear pattern in planning and actual mastering of the various releases: Warner Bros, spearheading the (welcome) release of classics in form of Boxed Sets - have the mastering and encoding made completely separately from the planning of the extras. One thing all of these WB issues have in common: the maximum bitrate of the encoder is set to a very low 7.5 Mbit/s; a setting designed for saving disc space, not making the most out of it. With that in mind the fact that the newly issued collections of BETTE DAVIS, JOAN CRAWFORD, THE THIN MAN as well as THE ASTAIRE & ROGERS COLLECTION Vol 1 (putting aside the previously released single items here, these are "another matter") are all "underachievers" when it comes to disc capacity used and encoding performance should come as no surprise. Nonetheless, the results are very visible. For instance, SWING TIME, part of the ASTAIRE & ROGERS COLLECTION, must have been an enormous challenge in terms of mastering. There are countless problems with scratches and density on 35mm due to the poor state of the surviving elements - but, the harsh encoding where much of the grain was filtered, the scratches "sweetened" (i.e. softened and blurred) and artefacts are "left behind" this picture did not deserve. Even though this may be the best presentation so far on HV, we do not get to appreciate the enormous work that went into the restoration of the film elements. The cleanup was also not without mishaps; the scene at 28:32 (a single frame "rundown" here) clearly shows that two frames identical to the previous two ("leftovers" from another 35mm dupe element that is the basis of the next shot) were not cut from the digital master as they should have been, resulting in a frame jump. The DVD could have been much better with the proper treatment - and the irony is: it would have cost just the same. The used disc space is here, including almost an hour of extras, merely 6.06 GB (!!) out of 7.96; a very clear indicator that the film was encoded first, "on the fly", for a single layer - and without knowing how many extras will be put on the disc or what length these would have. The analysis of the bitrate of the extras suggests that SWING TIME, the film itself, was given less than 4 GB of the already reduced total capacity. Talk about driving on a highway in the second gear ...
SWT_2.jpg

SWT_3.jpg

SWT_4.jpg

SWT_5.jpg

Yet, there is such a thing as worse: THE GRETA GARBO SIGNATURE COLLECTION exhibits a number of titles where disc space (and quality) is thrown out of the capacity window: QUEEN CHRISTINA is encoded @ 99 Minutes for a Dual Layer with 4.88 GB out of 7.96 possible, NINOTCHKA reaches just about 5.25GB - leaving almost 3 GB of better quality capacity unused. And for ANNA CHRISTIE (for lack of a new master) a very old Standard Def 1-inch C master (!!!) was used, as was on FLESH AND THE DEVIL - where the video restoration of Kevin Brownlow dates back to 1988. Now, one of the arguments that is an evergreen when it comes to the issue of using the maximum capacity of the DVD is that maximizing and a high bitrate does not equal good quality. True - but only if the source master itself is poor or the encoder is handled wrong. Why put good space to waste, if the master is a superior one ? Warner, understandably, wants to make as much of their catalogue available as possible before the DVD craze is over - but that intention comes increasingly at a cost to the high expectations of the long waiting consumer. WB and the other studios can do better - as many other examples have shown. So, what would be the best way of coordination, mastering and presentation ? In the following, we retrace a few of the steps that lie between the best film elements and their duplication in the best way to the final, Home Entertainment, format.
discspace_comp.jpg
 
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GeonX

Μέλος Σωματείου
17 June 2006
2,746
The mastering stage of classics such as these (as opposed to newly produced films) usually begins with the inspection and density tests (and the minting of an "answer print", i.e. a test print of the negative element) of the film elements available in the film vaults. Big studios such as Warner Bros, Sony Pictures and Fox have their various 35mm, 17,5mm (magnetic sound only) and 65mm Negs "stashed away" deep underground in a salt mine where the temperature and the humidity level is constant and the degradation process is as slow as nature can provide. After viewing the materials, the best elements are used for restoration; and from the restoration negative usually a new Interpositive and a new Internegative is made for archival use and transfers.

Depending on the purpose of the planned release (DVD, HD broadcast / Disc(s), Digital Cinema, Digital Intermediate to film) the transfers/scans are made (ideally with color corrections during the scan/transfer stage) onto Harddisc/data storage tape (such as D6 @ 4:2:2/10bits) in either HD, 2K or even 4K (Columbia is working on 6K for LOA) - but mostly transfers are made in High Definition using HDCAMSR (up to 770 Mbits/s @ 4:4:4 in 10bits) or, especially in the U.S., the lower grade HD-D5 (235 Mbits/s @ 4:2:2/10bits) as a platform. In many cases, the trouble is already beginning with the transfer. Here, the choice of how much of the frame should be transferred is both grounds for a philosophical debate as well as an easy, if not sneaky, way of saving costs in post production.
The former reflects the issue of how much was really visible to audiences on the theatrical screen. That is, indeed, debatable. Regarding the latter that argumentis, however, nothing more than a fig leaf. For the complicated cleanup process, zooming in into the frame also means that splices and light emanating from the edge of the frame as well as any number of other damage (fading etc) on the edges can simply be "eliminated" without even attempting to lay a hand on it in the digital cleaning and restoration process. To make it short: it make the work a lot faster, easier and cheaper.
Ergo: "Deleting" the outer parts of the frame can save a lot of money. But, in the long run, it may turn out to be far more costly, if clients (licensees) reject the master. This is clearly a gamble.
It is a fact that the detailed reconstruction and restoration of damaged frames does cost money; and the policy of issuing DVDs at $10.99 a piece with HD masters and extras included does not help, either. Even today, many post houses work on a basis where the next, aligning frame is used for painting. This causes static grain; which is why the 4th or even 5th frames before or after the damaged frame(s) should be used, instead.

Correcting and restoring damages is getting much more difficult the bigger the size of the master gets. In the realm of NTSC or PAL the resolution of the image, and therefore that of the damages is rather minor; thus, removing them is not as problematic. Wires (also called tramlines) and even deep scratches can be removed relatively easily with the proper tools. But, in the HD or even 2K plus realm, the story becomes a different one altogether. Even the best software cannot perfectly perform such operations at this size on its own; they have to be done by hand - making it enormously - if not prohibitively, expensive. But even with very little damage or just small debris or dust in the picture frame - many studios don't even bother to attempt a proper clean up. Universal did not lay a hand on its newly transferred TV shows; WB transferred "ER" in safe light (70%) instead of best light (100%), transferred very soft and skipped the cleanup stage altogether. Columbia, Paramount, MGM - the list could go on for quite a while. And the older the movie gets the bigger the problem.

Many classics out there have problems especially on the other portions of the frame, and marketing executives do have a point when they argue that most classics would not see the light of DVD day if everything was done to perfection in the HD or even 2K realm. There are examples, but, the majority will not show the entire frame. This, however, is not or should not be a license to ruin the composition of the image. In many cases, the AR and the zoomed-in image selected for these transfers, especially of classic films is arbitrary and all too often affects the original composition severely. "Ben-Hur" is perhaps the most obvious case; although many have argued that projecting a super wide picture such as this on a small TV screen would mean detail would suffer significantly if the proper AR and image were chosen.
But, times (and most importantly, technology) have changed. In 2001, when Warner Bros issued the first DVD version of BEN-HUR the AR was about correct - 2.70 :1 - but the frame information lost on the sides, top and bottom was very substantial (see the comparison here). Ironically, it was the 1994 CAV LD (which had a lower resolution and less detail because of its analogue FBAS properties), that was mastered much more accurately using both an almost correct AR and almost the entire frame information. The new, 2005 4-Disc edition is a big improvement; the new master is (for the first time) based on a restored 65mm element scan, which contains actually slightly more of the image a 70mm projection would allow. But there are a number of negatives. For one: the incorrect color timing, at least on the DVD encoded master (DLT). At the 4K level (the most likely size this film was scanned) the result may be good, but the color correction of the Standard Definition DVD master is not entirely convincing. In many shots (not all) colors, especially reds, look overly saturated and accentuated - but most importantly seem inaccurate in registration. Reddish tones are overly pronounced and have little detail, brownish tones are far less defined; instead, shadow detail in finer textures such as sand or rock faces is more reddish. Also, greenish tones are a bit overly saturated. Yet, oddly the image looks bleached as if the gamma level was tampered with.
ben_hur_1.jpg

Comparison shot of Ben-Hur (left: 2005 edition, right: 2001 edition). Aside from the color corrections, both masters significantly lack detail & sharpness. The level of data reduction in this encoding is very evident; the soft letterbox is a "dead giveaway".
To put it simply: The various shades do not register in the way Technicolor Negative elements or positive elements of that period would, even after the reduction in size by means of digital compression; and overall, the SD master creates the impression of an image where no color really seems to fit. The word "simple" may just about hit the nail on its head.
ben-hur70mm_comp.jpg

Above: A screenshot of the 70mm image of Ben-Hur. The yellow rectangle shows the confines of the 2001 DVD edition, the blue that of the 1995
Laserdisc CAV edition. The red rectangle represents the correct size and AR of the frame's image that would be projected on a theatrical screen.
Note the accuracy of the 2005 edition compared to that, represented by the green border.
ben_hur_comp_2001_4.jpg

ben_hur_comp_2005_4.jpg

ben_hur_comp_2001_1.jpg

ben_hur_comp_2005_1.jpg
 
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GeonX

Μέλος Σωματείου
17 June 2006
2,746
ben_hur_comp_2001_2.jpg

ben_hur_comp_2005_2.jpg

ben_hur_comp_2001_3.jpg

ben_hur_comp_2005_3.jpg

Because, the MPEG 2 encoding also affects the performance of the color palette, especially the shadow detail. The encoding process is, in essence, a simplification process of the detailed data of the source master. But the devil is in the detail: the simplification of wide shots with great detail is far more complicated than with close ups.
And encoding a wide shot and superwidescreen film such as BEN-HUR requires also an individual treatment to avoid loss of detail, sharpness, and color accuracy. This was evidently not done on the new edition, as these examples show. Again, the new master may look great in 4K, but the color correction made for the SD master is not perfect. That a very good representation of a newly restored film element and new transfer is possible on DVD was very convincingly underlined by the recent classics releases by FOX. THE MAN IN THE GRAY FLANNEL SUIT is a great example.
Here, both the coordination and the supervision of the Home Entertainment/Broadcast mastering made a success on Disc possible (an almost flawless encoding, with 7.90Gb of the 7.96 GB used @ a bitrate of nearly 6 Mbit/s average for this 152 Minute movie). But FOX also sticks to that policy with movies that are merely 100 minutes long - where other studios already use a single layer. LEAVE HER TO HEAVEN is equipped with a very nice 7.78 GB total @ 110 Minutes duration. Color timing is extremely accurate as are mix & encoding of the soundtrack. Fox has - very quietly - been doing some outstanding work for quite some time; almost all of the classics series masters are at least impressive if not better. But, there is still significant room for improvement here, too - THE DIARY OF ANNE FRANK no longer features the Entr'Acte music and therfore is missing 2 minutes now on DVD (the LD version did feature the entire Alfred Newman score), the encoding of TITANIC and most notably on THE GHOST AND MRS MUIR was poor and even on the very good edition of THE MAN IN THE GRAY FLANNEL SUIT mishaps did occur: in this case in form of a high pitch noise in the 4.0 encoded soundtrack between minutes 18:21 and 19:18 that is audible in the surrounds only, and does not belong. But, very clearly, the direction FOX is going is the right one. The times where THOSE DARING YOUNG MEN IN THEIR FLYING MACHINES was reduced from a beautiful 65mm element to an unnecessarily soft and little detailed DVD, seem to be over. The very well coordinated way of production is perhaps the very element the industry needs, if it wants to increase profit at the same rate it did so far - and the costs are (ironically) the very same. Food for thought...

Όλο το άρθρο στο http://www.dvdscan.com/
 
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Mihalis S.

Supreme Member
19 June 2006
3,497
Επειδή κάποιος ανέφερε τι ποιότητα εικόνας βλέπουν οι Αμερικάνοι σε σχέση με τους δικούς μας κινηματογράφους θα ήθελα να επισημάνω από προσωπική πείρα πως εν έτη 2001 στην Αμερική, οι κινηματογράφοι τους έπαιζαν εικόνα πολύ ανώτερης ποιότητας σε σχέση με ότι βλέπουμε στους σημερινούς κινηματογράφους στην χώρα μας. Είχα δεί αρκετές ταινίες στους Αμερικάνικους κινηματογράφους και η εικόνα ήταν πεντακάθαρη, με τέλειο κάδρο, και τρισδιάστατη αίσθηση. Εχω την αίσθηση πως σήμερα πέντε χρόνια μετά η ποιότητα θα είναι ακόμη καλύτερη. Πιθανολογώ πως η διαφορά οφείλεται στις μηχανές προβολής που χρησιμοποιούν. Αν κάποιος γνωρίζει περισσότερα ας μας ενημερώσει.
 

takisot

Μέλος Δ.Σ.
Staff member
17 June 2006
24,355
Παλλήνη
Μιχάλης said:
Επειδή κάποιος ανέφερε τι ποιότητα εικόνας βλέπουν οι Αμερικάνοι σε σχέση με τους δικούς μας κινηματογράφους θα ήθελα να επισημάνω από προσωπική πείρα πως εν έτη 2001 στην Αμερική, οι κινηματογράφοι τους έπαιζαν εικόνα πολύ ανώτερης ποιότητας σε σχέση με ότι βλέπουμε στους σημερινούς κινηματογράφους στην χώρα μας. Είχα δεί αρκετές ταινίες στους Αμερικάνικους κινηματογράφους και η εικόνα ήταν πεντακάθαρη, με τέλειο κάδρο, και τρισδιάστατη αίσθηση. Εχω την αίσθηση πως σήμερα πέντε χρόνια μετά η ποιότητα θα είναι ακόμη καλύτερη. Πιθανολογώ πως η διαφορά οφείλεται στις μηχανές προβολής που χρησιμοποιούν. Αν κάποιος γνωρίζει περισσότερα ας μας ενημερώσει.

Μιχαλη, και εγω εχω δει σινεμα στην Νεα Υορκη και δεν ειχε σχεση!
Ομως ο συντακτης του εν λογω αρθρου, ειναι Αμερικανος και μαλιστα ειδικος!
 

Mihalis S.

Supreme Member
19 June 2006
3,497
Αγαπητέ Τάκη σωστή η παρατήρησή σου. Εγώ απλώς έκανα την διευκρίνηση για τον Παναγιώτη Βογιατζάκη και το Ανδρονίδη Ακη που αναρωτήθηκαν τι ποιότητα εικόνας βλέπουν τα Αμερικανάκια.
 

GeonX

Μέλος Σωματείου
17 June 2006
2,746
…να μην ξεχνάμε όμως ότι οι αμερικανοί έχουν φύγει εδώ και αρκετό καιρό από film τα καλά cinema μάλιστα διαφημίζουν ότι είναι DLP… και παίζουν με τέτοια μηχανάκια…

CP2000lr-bttmR-PR.jpg
 

GeonX

Μέλος Σωματείου
17 June 2006
2,746
Spec
-----------------------------------------------------
Brightness
(measured at screen center) Light output meets SMPTE standard 14fL (film 16fL open gate) for screens 25m (up to 82ft width)
--------------------------------------------------------------------------------
Contrast Ratio >2000:1 (full field)
>500:1 (ANSI)
--------------------------------------------------------------------------------
Brightness Uniformity >90 when displaying full white screen
--------------------------------------------------------------------------------
TI DLP Cinima™ Technology CineBlack™ Contrast Management
CineCanvas™ Image Management
CineLink™ Security Management
CinePalette™ Color Management
--------------------------------------------------------------------------------
Digital Micromirror Device™ 2K 3-chip DMD DLP Cinema™
2048 x 1080 pixels
--------------------------------------------------------------------------------
Input Line Voltage 208 VAC/60Hz, 3-phase (CP2000H/CP2000S)
400 VAC/50Hz, 3-phase (CP2000S)
--------------------------------------------------------------------------------
Color Processing (bit depth) 45 bit (3 x 15-bit resolution)
--------------------------------------------------------------------------------
Number of Colors 35 trillion
--------------------------------------------------------------------------------
Digital Video Input Two (2) SMPTE 292M; selectable dual or single
Two (2) DVI, twin or single
--------------------------------------------------------------------------------
HD Video Formats 1920 x 1080 @ 24P or 24psf (ie. MPEG-2, MXF-Interop format)
2048 x 1080 @ 24P or 48P (DCI-compliant)
A variety of alternative content formats also supported - contact your Christie sales representative for details
--------------------------------------------------------------------------------
Zoom Lenses 1.25-1.45:1
1.45-1.8:1
1.8-2.4:1
2.2-3.0:1
3.0-4.3:1
4.3-6.0:1
5.5-8.5:1
--------------------------------------------------------------------------------
Anamorphic Lenses (optional) 1.26:1 (for scope format)
--------------------------------------------------------------------------------
Screen Size Up to 82 ft/25m
--------------------------------------------------------------------------------
Xenon Lamp Type CDXL 2.0kW - 6.0kW
--------------------------------------------------------------------------------
Ballast CP2000H - 2kW - 7kW Thyristor
CP2000S - 2kW - 7kW Switching
--------------------------------------------------------------------------------
Reflector F/1.5 High Performance Compound Glass Reflector
--------------------------------------------------------------------------------
Security Locks Operator's side door, projector front top cover
--------------------------------------------------------------------------------
Safety Interlocks (3) Lamp Access Door, rear intake vent, extraction port
--------------------------------------------------------------------------------
Internal Rack Space 8RU rack space
--------------------------------------------------------------------------------
Douser Electronic douser
--------------------------------------------------------------------------------
3-Axis (X, Y + Z) Automatic Lamp Alignment Christie LampLOC™
--------------------------------------------------------------------------------
Ambient Temperature 0-35°C (32-95°F)
--------------------------------------------------------------------------------
Overall System Weight with Pedestal CP2000H - 670 lbs/305 kg
CP2000S - 505 lbs/229 kg
--------------------------------------------------------------------------------
Regulatory Approvals CAN/CSA - C22.2 No 60950-1-03 First Edition, UL 60950-1:2001, IEC 60950- 1:2001
 
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Andronidis Akis

AVClub Addicted Member
17 June 2006
2,996
Voula - Greece
>500:1 (ANSI)

Αυτο μου εκανε εντυπωση αν λαβουμε υποψη μας τα ποσα μετρα εικονα προβαλουν.

Βεβαια εκει μιλαμε για εντελως διαφορετικα "μεσα" απο αυτα που ειμαστε συνηθισμενοι απο τους home projecotrs.
 

ManosR

New member
18 June 2006
51
Crete
Μή ξεχνάτε οτι τα φίλμ που έρχονται εδώ δεν είναι κόπιες 1ης ή 2ης γενιάς, που είναι σαφώς καλύτερες. Αν έχετε δεί έργο σε Αμερική (ή ακόμα και Αγγλία) θα το έχετε προσέξει.
Πάντως το κοντράστ του σινεμά παίζει απο 150:1 μέχρι και 400:1. Κατά πολλούς όμως το μάτι δέν μπορεί να διακρίνει πάνω απο 1000:1 (και λιγότερο συνήθως).
 

Μανωλάς Βλάσης

AVClub Enthusiast
19 June 2006
781
Παιδιά, εγώ δεν ξέρω τίποτε για το θέμα, αλλά από τη στιγμή που το διάβασα, μου ήρθε στο μυαλό κάτι που είχα διαβάσει στο HiTECH. Σύμφωνα με κάποιο μηχανικό (της Lucas Films, αν θυμάμαι καλά), κατά τη μεταφορά του φιλμ στο dvd χάνεται το 98% της αρχικής πληροφορίας και μόνο ... το 2% καταλήγει στο δισκάκι!!! Δεν ξέρω αν χρησιμοποιώ τη σωστή ορολογία, αλλά, είναι δυνατόν να είναι σωστά αυτά τα ποσοστά, ρε παιδιά; Πολύ υπερβολικά μου φαίνονται!
 

takisot

Μέλος Δ.Σ.
Staff member
17 June 2006
24,355
Παλλήνη
Βλαση, αυτο που λεει το hitech μου ακουγεται ιδιαιτερα υπερβολικο (ακου το 2%!!).
 
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17 June 2006
1,443
Άλιμος
Με έναν γρήγορο (όσο αφορά την ανάλυση και μόνον) υπολογισμό το NTSC δισκάκι έχει 3456000 πίξελς ανα καρέ. Εάν υποθέσουμε οτι είναι όντως το 2% του φίλμ θα έπρεπε το φίλμ σε κάθε καρέ να έχει 345000Χ50=17280000 εικονοστοιχεία (κόκκους). Έλα που έχει παραπάνω! Άν υποθέσουμε οτι ένα μέτριο φίλμ έχει 5000Χ4000 κόκκους μας κάνει 20000000!
Εκτός αυτού όμως είναι και πολλά άλλα πράγματα που θεωρούνται πληροφορίες και εξαφανίζονται στην μεταφορά απο φίλμ σε DVD, όπως οι διαβαθμίσεις χρωμάτων που στο φίλμ σε μία συγκεκριμένη περιοχή έχουμε π.χ. 30 διαφορετικά μπλέ και στο DVD γίνονται 2 ή 5!
Δέν μου φένεται υπερβολικό το 2% αλλα μάλλον κολακευτικό για το DVD.
 

takisot

Μέλος Δ.Σ.
Staff member
17 June 2006
24,355
Παλλήνη
Κυριακο, σε θεωρητικο επιπεδο εχεις απολυτο δικιο αλλα:
1) Το mastering της ταινιας γινεται σε τουλαχιστον 2Κ αναλυση (απο το οποιο γινεται downconversion στις 480/576 γραμμες)
2) Αν διαβασεις ξανα το πρωτο μου ποστ, η θεωρια απεχει πολυ απο την πραξη οπου ειδικοι επιβεβαιωνουν οτι λογω τεχνικων προβληματων, η εν δυναμει αναλυση του φιλμ, σπανιως φτανει τελικα στο πανι μας!
Παντως, ειναι παντα επικαιρη μια "κοντρουλα" καλοσεταρισμενης 35αρας μηχανης και ενος ψηφιακου προβολεα!