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Restoration tips: Andrea’s Corollary to the Kush Gauge™ |
Posted by: spoRv - 2015-01-04, 03:44 PM - Forum: Restoration guides
- No Replies
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prologue: DON’T (always) TRUST COMPANIES!
Following many HDTV and internet broadcaster advice, a “studio quality” transmission for an H.264 1080p transmission could be achieved with a bitrate of a mere 6mbps; if we use the Kush Gauge formula, we can see that this is true only if the motion factor is lower than average… for example, a 16/9 sport material at 29.97fps needs a 17.4mbps bitrate!
The Kush Gauge™ formula:
width x height x FPS x motion rank x constant = final bitrate in bps
(where constant is 0.07 for H.264/MPEG-4 part 10, or AVC)
Read more here: Restoration tips: Kush Gauge™
ANDREA’S COROLLARY TO THE KUSH GAUGE™
To calculate video bitrate for a codec different from H.264, the Kush Gauge costant value should be changed accordingly to the codec used.
Other lossy video codecs (apart H.264/MPEG-4 part 10, or AVC)
Even if AVC is widely used, also thanks to the x.264 open source encoder, there are many other codecs still in use nowadays; the main ones are: - MPEG-2 – used in many DTV and HDTV broadcasting, in DVD and sometimes in BD
- VC-1 – used sometimes in BD; once used in HD-DVD
- H.265, or HEVC – new codec, used in particular for 4K/UHD
There are also many other ones – H.263 (divx/xvid), MPEG-1 (VCD), WMV9 – that are slowly replaced by newer (or better) ones; so, let’s focus on the main three alternative codecs to AVC.
VC-1
Quality is really similar to AVC; but it has some technical features missing or worst than AVC; the constant will therefore be set at 0.075 - sligthly worse than AVC.
HEVC
New codec, still in development; few serious comparisons were made, and it seems that bitrate gain could vary from 35% to over 70%; based on past studies, it could be difficult to believe that; if an AVC encoded video had a bitrate factor of 100, HEVC could achieve the same video quality at 30… so, to be fair, I’ll put it at 60 – 40% gain – so the constant will be set for the moment at 0.042; this is obviously a value that will change in time, whenever more deep comparisons will be conducted, and newer encoders will be developed.
MPEG-2
This is the most known and valid alternative to AVC; widely used aroud the globe thanks mostly to DVD and DVB, it will be used for many years to come.
And it’s the most difficult to rate in comparison to AVC… According to many, AVC have the same quality of MPEG-2 at half the bitrate; so, if MPEG-2 bitrate factor is 100, AVC should be 50 – setting the constant at 0.14.
Is it true? Well, probably in many cases it could be, but there are so many variables that plays against or in favour of this, that a simple, unique value is difficult to set at the moment.
Comparison papers state that average AVC bitrate gain is around 55.4%; this value is mainly calculated using PSNR as main video quality valutation. But it’s known now that modern video codecs (including MPEG-2) rely on the fact that human vision could be “tricked” more easily than measurement; therefore, this value should not be taken as an absolute truth; infact, following test results that used SSIM, when MPEG-2 and AVC have the same subjective quality, AVC gain is lower.
Some HDTV stations claims that their MPEG-2 1080i broadcasting have a perfect quality at 6/8mpbs; obviously it’s not true; even if in some cases this bitrate is more than enough – news, weather reports, soap operas, studio transmissions – it is not the case for movies, or worst for sport!
In their defense, there were great improvements in the latest years in MPEG-2 encoders, gaining more than 30% in bitrate Vs. the first encoders; plus, some technique “borrowed” from the H.264 format helped to achieve extraordinary results – in comparison to old MPEG-2 encoders, of course.
Speaking about software encoders, these is not always true; despite the fact that there were improvements, they were not so outstanding as hardware encoders of broadcast level…
So, at the end, I think it’s fair to set the constant for MPEG-2 at 0.136 - considering AVC bitrate gain between 40 and 55%: this constant could be lowered to 0.116 – setting the AVC gain at 40% – only for evaluating existing encoded material that was produced with industry level hardware encoders, like DVD, BD or HDTV material, as it’s a matter of fact that those kind of encoders work better than available software ones that we could use at home.
FINAL NOTES:
As the Kush Gauge is a “rule of thumb” and not a law, of course also these constants are approximate; nevertheless, this rule should be used with the most part of video sources, but must still be used with a grain of salt!
ANDREA’S COROLLARY TO THE KUSH GAUGE™
To calculate video bitrate for a codec different from H.264, the Kush Gauge costant value should be changed accordingly to the codec used.
To obtain a good quality video, this is the formula:
width x height x FPS x motion rank x constant = final bitrate in bps
where the constant should be equal or higher* than
- 0.045 for HEVC
- 0.075 for VC-1
- 0.136 for MPEG-2 (software encoders)
- 0.116 for MPEG-2 (hardware encoders)
*CBR or VBR average bitrate
and the motion rank is equal to
- 1 for low motion (e.g. news)
- 2 for medium motion (e.g. movie)
- 4 for high motion (e.g. sport)
Note: I think that for action movies a motion rank of 3 could be a good value to use.
CHECKING QUALITY OF A GIVEN VIDEO MPEG-2 ENCODED SOURCE:
HD-NET is known to have a fairly good quality; let’s take “Escape from New York”: its actual resolution is 1920×804, FPS is 29.97fps and motion factor could be set at 2, so:
1920 x 804 x 29.97 x 2 x 0.116 = 10,733,268 = ~10.73mbps
or, according to higher constant value,
1920 x 804 x 29.97 x 2 x 0.136 = 12,583,832 = ~12.58mbps
as its bitrate is 17.2mbps, its quality could be considered very good!
***
Also WOWOW, a japanese HDTV station, has a good quality; “Indiana Jones and the Temple of Doom” has an actual resolution of 1920×816, FPS is 23.976fps and motion factor could be set at 2, so:
1920 x 816 x 23.976 x 2 x 0.116 = 8,714,773 = ~8.71mbps
or, according to higher constant value,
1920 x 816 x 23.976 x 2 x 0.136 = 10,217,320 = ~10.22mbps
as its bitrate is 19.9mbps, its quality could be considered really high!
***
“Matrix Reloaded” is a movie full of action; so a motion factor of 4 is considered – even if probably a 3 should be quite good.
NTSC DVD:
720 x 480 x 29.97 x 4 x 0.136 = 5,634,551 = ~5.63mbps
average bitrate is 6.34mbps, so its quality is good.
PAL DVD:
720 x 576 x 25 x 4 x 0.136 = 5,640,192 = ~5.64mbps
average bitrate is 6.5mbps, so its quality is slightly better than the NTSC DVD.
Comments, improvements, corrections are welcome!
References:
PDF documents
The Kush Gauge – H.264 FOR THE REST OF US (page 21)
SUBJECTIVE QUALITY ASSESSMENT OF THE EMERGING AVC/H.264 VIDEO CODING STANDARD
EBU Technical Report 008 – HDTV Contribution Codecs
Using AVC/H.264 and H.265 expertise to boost MPEG-2 efficiency
BBC Guidelines – Technical and Delivery Standards for Worldwide
Comparison of the Coding Efficiency of Video Coding Standards
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Restoration tips: the Slice Technique™ |
Posted by: spoRv - 2015-01-04, 02:22 PM - Forum: Restoration guides
- Replies (1)
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THE SLICE TECHNIQUE™
What’s about this so-called “Slice Technique™”?
In few words: achieve the widest (highest) image possible adding a “slice” of another video clip.
Be more specific…
Well, sometimes there are two editions of the same movie, where one has more image on one side, while less on the other side, and vice versa. So I thought to use the missing “slice” of one joined together with all the other, to obtain the widest image possible. Indeed, it could be only (e.g.) 3% wider than any each version, but I much prefer a 100% wide image Vs a “mere” 97%… (^^,)
Of course, it’s quite difficult – sometimes impossible – to use this technique with every movie, because what must be taken in account are the dimensions (eventual image rotation, width and heigth of sources and chosen slice, eventual resizing and cropping, exact point of matching), colors (both versions should have the same color grading, or one should color match the other), video quality (grain, resolution/definition, different compression used in the sources, frame whobbling in a version not present in the other – in particular at the beginning and ending of a shot), etc.
In these examples, I used a vertical slice and two sources, but it’s possible to use an horizontal slice, or even multiple slices from various sources – obviously, in this case, a good result will be astonishingly difficult…
Hint: best results are from two versions with same resolution – like 2 Blu-rays, 2 DVDs, 1 Blu-ray and 1 HDTV.
EXAMPLE:
“Escape from New York” examples (attention: only preliminary tests, not used for final project)
comparison screenshots:
[Image: EFNY_test_201311190111_000001.jpg]
[Image: EFNY_test_201311190111_000143.jpg]
[Image: EFNY_test_201311190111_000774.jpg]
[Image: EFNY_test_201311190111_001152.jpg]
[Image: EFNY_test_201311190111_001747.jpg]
[Image: EFNY_test_201311222331_000156.jpg]
[Image: EFNY_test_201311222331_000333.jpg]
[Image: EFNY_test_201311222331_000451.jpg]
[Image: EFNY_test_201311222331_000816.jpg]
It looks like there’s more image at the bottom in some shots on the XXX Vs. YYY. It is possible to adjust that too?
It is not possible to use it, as the small “slice” on the bottom of the YYY is missing… like the following example:
see the missing piece at the bottom right? Unless there is some method to “invent” the missing piece using surrounding images… and I’m afraid, there is not (yet)! EDIT: if the corner is small enough, inpaint could be used; result may vary from quite noticeable to perfect, depending on source and size.
How about using XXX as the main source and just adjusting the colors, instead of using the YYY?
It depends… if XXX color matched with YYY as color reference is better, then use XXX; if not, then use YYY – I must add that sometimes the best solution is to use XXX for some scenes and YYY for others… your mileage can vary!
Comments, improvements, corrections are welcome!
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Restoration tips: Overlap matching |
Posted by: spoRv - 2015-01-04, 02:00 PM - Forum: Restoration guides
- Replies (14)
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OVERLAP MATCHING
What is the Overlap matching?
When two images of different sizes are used to improve the final result.
Could you be more specific?
Usually this is used when two different versions of the same movie are available at different aspect ratios.
Let’s say you want to restore a movie that is not available in high definition, and you want to upscale a DVD or a laserdisc capture. If you are lucky, an anamorphic DVD is available, so a theoretical 720×576 (PAL) or 720×480 (NTSC) max resolution could be achievable. But, if the original aspect ratio of the movie is 2.35:1, then you have only 720×432 (PAL) or 720×360 (NTSC). Well, enough resolution left to do a decent upscale. However, if the DVD is not anamorphically enhanced, actual resolution drops to 720×324 (PAL) or 720×252 (NTSC).
But what if the only (or the best) available low definition sources are analog? In this case, a 2.35:1 original resolution in laserdisc could be at maximum 576×324 (PAL) or 576×262 (NTSC), while VHS could be 328×324 (PAL) or 328×262 (NTSC)… pretty poor…
So, how it’s possible to improve the quality of such low resolution sources? It’s easy! Overlap a pan&scan version of the same movie over the letterbox version! The P&S version of a laserdisc could be 576×576 (PAL) or 576×480 (NTSC), while VHS could be 328×576 (PAL) or 328×480 (NTSC). Can you see the differences?
EXAMPLE:
here you can see how a P&S version overlapped to a letterbox version, upscaled, have a better resolution than the latter; this will lead to better details in the center of the image, leaving less detailed image at the borders. It is also possible to use two letterboxed versions (like 1.66:1 and 2.35:1) – even if difference in details will be less than using a P&S version, it nevertheless improve definition a lot.
A lower difference in aspect ratios between sources makes the final resolution only slightly better, but often this avoids all the image cropping and variations that lie in the pan&scan version.
Can I use an open matte version instead of pan& scan?
It is often futile to use an open matte version with a letterboxed version both from the same format, as active image have the same effective vertical resolution; however, it is possible to use an open matte version of an higher resolution source overlapped to a lower resolution source.
So, for example, an open matte DVD (with higher horizontal resolution) overlapped to a letterbox laserdisc; or an open matte laserdisc or DVD (both with higher horizontal resolution) overlapped to a letterboxed VHS, will increase the details clarity of the final upscaled version.
What about high definition formats, like Blu-ray and HDTV sources?
in some rare cases, the open matte version of the same (or comparable) format of the letterbox version has a better resolution – due to several factors like different masters, encoding, bitrates etc. – in such cases, it’s possible to use the Overlap matching method, although usually with lower quality improvement in comparison to previous cases.
NOTE: consider that pan&scan cropping vary usually everytime between shots, and often during a single shot; so this method is really really hard to follow, much more than the “Slice technique”…
Top, upscaled DVD, bottom, upscaled DVD with HDTV overlapped:
[Image: matrix_083217.jpg]
http://s27.postimg.cc/fwskn8q8x/matrix_083217.jpg
same image as the previous second one, not cropped:
[Image: matrix_PLUS.jpg]
http://s22.postimg.cc/3ucfmeuj3/matrix_PLUS.jpg
WARNING: this is a very difficult technique, and could be really hard and time consuming to find out the perfect settings; I did this simple match in an hour, and both previous and next shots have completely different setting… be aware!
Comments, improvements, corrections are welcome!
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Restoration tips: UAR - Ultimate Aspect Ratio |
Posted by: spoRv - 2015-01-04, 01:42 PM - Forum: Restoration guides
- Replies (42)
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UAR - ULTIMATE ASPECT RATIO™
What is the UAR - Ultimate Aspect Ratio™?
It is an unconventional aspect ratio to represent a motion picture, using sources taken from different media, in an axis-aligned polygon enclosed inside a conventional aspect ratio screen.
How does it work?
If a motion picture is displayed in a screen with a different aspect ratio than the original – e.g. a film on tv, a 4:3 show on a 16:9 tv – there are different methods to do it. Of course, if the aspect ratio of both screens are the same, nothing will (should) be done, and the motion picture will be displayed “as is”.
Letterbox
Display A/R: 1.78:1 (or 16:9) < Source A/R: 2.35:1 If the display A/R value is lower than the source A/R, black bars will be added on top and bottom sides of the picture. This method preserves the whole image AND the original intended aspect ratio.
Pillarbox
Display A/R: 1.78:1 (or 16:9) > Source A/R: 1.33:1 (or 4:3) If the display A/R value is higher than the source A/R, black bars will be added on the left and right sides of the picture. This method preserves the whole image AND the original intended aspect ratio.
Pan & Scan
Display A/R: 1.33:1 (or 4:3) < Source A/R: 2.35:1 If the display A/R value is lower than the source A/R, the only way to avoid black bars is to choose the most important part of the actual shot, and discard the rest. This method does NOT preserve the whole image NOR the intended aspect ratio – as you can see in the bottom picture…
Open Matte (or Full Screen)
Display A/R: 1.33:1 (or 4:3) < Source A/R: 1.85:1
Display A/R: 1.78:1 (or 16:9) < Source A/R: 2.35:1
If the display A/R value is lower than the source intended A/R, but a full frame version exists, is it possible to show the whole picture to “fill” the screen. This method preserves the whole image BUT NOT the original intended aspect ratio. Sometimes the full frame version is not available in the consumer market, but only at production level; with it, it could be possible for example to produce several versions with different aspect ratios; if someone would like to see as much picture as possible, there are two possibilities:
- Obtain the original full frame version – if still exist, and is possible to obtain it
- Make a “patchwork” using different versions that exist in the consumer market.
This is the aim of the UAR - Ultimate Aspect Ratio.
Theoretical examples
“Ideal” UAR – both versions fill the horizontal and vertical space:
More real example – one source fills the vertical space, while the other leaves black space on the left and right sides:
Here one source fill the horizontal space, and the other leaves black space on top and bottom of the image:
Wrong application of the UAR method; all four sides have black spaces, while only one axis should have them:
Practical examples:
It is possible to get UAR using not only two, but also three different sources!
(all images are 640 pixel wide only to be visually uniform, but some have the wrong UAR)
More examples here: http://ultimateaspectratio.ga/comparisons
Conclusion
Albeit there is any movie released in UAR, there are many fan projects in progress using this fascinating new aspect ratio; main problem is that the aspect ratio of each source is not fixed, but variable, and it will be really hard to adjust a whole movie scene by scene or shot by shot or, in the worst cases, frame by frame!
(note: of course, colored thin lines will not appear in the final version of a movie release in UAR...)
A “good reason” to use this technique:
http://www.avsforum.com/forum/34-hdtv-pr...ost3926009
EDIT: From the end of February 2018, I'll stick with the UAR acronym instead AAP-AR (but it's just the same thing, of course), because it's shorter and easier to remember - I decided that "U" stands for Ultimate, but can stand also for Unified, Unhortodox, Unreliable and so on...
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Restoration, Preservation, Fan Edit – definitions |
Posted by: spoRv - 2015-01-04, 03:37 AM - Forum: Announcements
- Replies (4)
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Definition of fan restoration categories:
1) Fan Restoration
Attempts to restore a film version, that had a full retail BROAD digital release*, to be as closest as possible to its original theatrical release, using best sources available.
This may include video taken from commercial releases, or TV broadcasts, and may consist of one or several of the following works: color regrading, frames/scenes replacing, aspect ratio correction, removal of scratches, tears, spots and dust, sounds/dialogs replacing/correction, entire soundtracks replacing etc.
It could also include restoring theatrical or director’s cut where the BROAD digital release* includes only the extended edition, or viceversa.
2) Fan Preservation
A fan-made release of a film version that has never had a full retail BROAD digital release*.
This is sourced from analog formats such as VHS, laserdisc or film print, but sometimes they can be sourced from captured TV broadcasts (both analog and digital) or NICHE digital releases**.
2b) Fan Enhanced Preservation
The same as fan preservation, but with some sort of enhancement (noise reduction, conversion from letterbox to anamorphic) not as extensive as a restoration.
2c) Fan Restored Preservation
The same as fan preservation, but with extensive enhancement, the same level of a fan restoration – the only difference is the fact that the film has not a BROAD digital release* (yet)
3) Fan Recreation
The most meticolous kind of restoration; it attempts to restore a film version closest to its original theatrical release, using various video sources (also different from the film itself like trailers, documentaries, and even other films), applying every kind of restoration work, and more, to obtain the best restoration ever possible.
For example, where a restoration will use a one-for-all technique for the whole movie, the reconstruction will use the best technique for each scene or eventually single frames.
4) Fan Extended Edition
It adds additional scenes where they fit, to have a new extended edition not available on BROAD digital release*.
If the additions require a few movie alterations for plot reasons, it still counts as an extended edition, for example if an alternate ending replaces the original one.
4b) Fan Restored Extended Edition
The same as fan extended edition, but the restoration is applied to the main features and extended scenes as well.
5) Fan reMux
A multiplexing of video and/or audio and/or subtitles taken from analog and/or digital releases, to obtain the best version possible.
This involves NO restoration at all, just a selection of the best/correct/alternative audio/video/subtitles streams from different sources.
6) Fan Edit
A fan-made alternative version for an existing film, made by the insertion, deletion or re-ordering of scenes within the film, or taken from different films, or a fusion of different films/TV episodes in a coherent version.
7) Workprints and Bootlegs
Low quality cams/telecines/television/VHS captures of alternative workprint versions or lost theatrical cuts.
8) Filmumentary™
"A format where the viewer can watch a film whilst additional material appears on screen including: deleted scenes, alternate takes, on set audio, text facts and information, audio commentary from cast and crew etc. The intention is to draw these resources from archival and contemporary interviews, documentaries, tv spots etc. to make the ultimate “making of” experience for the viewer." (Jamie Benning, http://filmumentaries.com)
9) Fan bonus disc
A collection of extras, like trailers, interviews, deleted scenes, storyboards etc. not available in a disc of its own; so the extra material, if from bonus BD or DVD, should be from different discs, or if just from one bonus BD or DVD it should have some material from another source like VHS, LD, web etc. in a consistent number; one fan bonus disc made using all the material from a retail bonus disc plus just one trailer from the web could be NOT considered a fan bonus disc...
10) Fan Mod
Modified version of a film; could include one of more of the following:
- aspect ratio different from theater release - like open matte, full screen, UAR, hybrid, VAR etc
- modified color grading - with incomplete reference like trailer or film cells, or custom
- modified audio track - using elements from music soundtrack
10b) Fan Mod Edit
The same as before, but adding extended/deleted scenes and shots, even from trailers, documentaries etc.
* BROAD digital release = DVD, BD, digital download
** NICHE digital release = VCD, HD-DVD, D-VHS, UMD…
These are only initial guidelines, but could be a good start to look at when deciding how to categorize your project.
NOTE: it is always nice to state which kind of project you are working on, listing what you are doing!
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FanRes.com first impressions - feedback wanted |
Posted by: spoRv - 2015-01-03, 09:44 PM - Forum: Everything else...
- Replies (18)
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Hi folks, what do you think of the site? Do you like the name? fanres stands mainly for fan restoration, but res could be also used for resolution, and some other words... http://www.scrabblefinder.com/starts-with/res/
What about the overall look? I know it's the usual, classic theme, but after I tested a lot (and I mean it!) everyone had some problem... so, should I continue to search for a better theme, or it's good as is? Of course, I could always change the color, which one do you prefer?
Logo: do you like it?
Thanks for the feedbacks!
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[proposal] Jurassic Park: The Lost World (1997) - extended version |
Posted by: spoRv - 2015-01-03, 09:33 PM - Forum: Requests, proposals, help
- Replies (29)
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I own the JP trilogy on DVD, and, even if I was aware of the two deleted scenes on JP2, I haven't thought about to use them to make an extended version, until yesterday, when I discovered there is a TV version with those scenes reinstated... at least, now it's possible to know where those scenes should excactely be positioned!
I wonder if the JP2 BD has those scenes in HD or not; if not, I thought it's always possible to PaNup the NTSC DVD (or BD, as they should be the same) and the PAL DVD to obtain a better quality upscales for them, to be mixed with the BD.
Opinions?
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