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2nd September 2014, 23:10 | #1 | Link |
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DAR of "2.40:1"
There used to be this great online resize tool, but it seems gone.
So, on a PAL DVD, at "720x576", with a DAR of "2.40:1", should I upscale to 1920x800? That feels too wide, but is really what my calculations keep telling me. Or did I forget to factor something in?
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3rd September 2014, 00:18 | #3 | Link |
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Crop the borders first since DVD only allows 4:3 or 16:9 flags, but yeah. 2.39:1 and 2.35:1* work out to 1920x800 and 1920x816 (accounting for mod), respectively.
*deprecated since 1970 but still occasionally shows up |
3rd September 2014, 01:21 | #6 | Link |
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No cropping.
Different players are playing it differently, though (often at ca. 1920x1040), which actually looks more natural. Although the DVD VOB container pegs it at 2.40:1, other sites list the same PAL DVD ("Cherry 2000") at 1.85:1, which would, indeed, come down to 1037p. And that *does* indeed make it far more natural. Hence, my confusion. EDIT: I just checked, it actually says 1.85:1 on the cover of my box too, LOL. Guess the VOB had it wrong. :P
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Gorgeous, delicious, deculture! Last edited by asarian; 3rd September 2014 at 01:30. |
3rd September 2014, 02:21 | #7 | Link |
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Try this. I'm not sure where it gets it's ITU pixel aspect ratios. They're slightly different to the ratios most other programs use, although the difference is very tiny. Most 16:9 DVDs would probably use straight 16:9 resizing anyway, so you'd uncheck the ITU resizing option. It's an exe, but it's safe.
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5th September 2014, 08:30 | #8 | Link | |
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There are two approaches on how the movie is stored. One is to put the movie inside a fullframe (or 4:3). In this case you'll have some 300 pixels for the whole vertical field. This is the worst solution, and therefore found mainly on budget movies/studios/countries. The other one is to have the DAR of 16:9. This will give you another 100 pixels. Sensibly better image. This is usually found with better editions (premium, collector, platinum etc). All values must be corrected for overscan, in particular the horisontal one. Either way, the final resolution for upscaling would be 1920 x 800. While the horizontal definition is not greatly affected by the upscaling (it's only ~2x) the vertical ranges from ~3x to ~2x, accordingly. Non-integer ratios yield more artefacts. And either way, the upscaling algorithm must be good, as you'll have to live with the result. Meanwhile the hardware scalers, as found in BD players and TV sets, improved a lot and became incredibly cheaper, thus available even in budget gear. Like creaothceann I'd leave this to the player-TV combination. Unless one has to edit sequences from old movies into a HD project.
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5th September 2014, 15:59 | #9 | Link |
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Am I not correct in saying that there is a 3rd DAR (Full frame) for DVD, 2.21:1 or something like that,
although I have never seen one like that ?
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5th September 2014, 16:31 | #10 | Link | ||
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Gorgeous, delicious, deculture! Last edited by asarian; 5th September 2014 at 20:02. Reason: I wrote 1337, instead of 1037 |
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5th September 2014, 16:39 | #11 | Link | |
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5th September 2014, 18:16 | #12 | Link | |
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2.21:1 is not a valid DVD aspect ratio flag (DVD only allows 4:3 and 16:9 flagging), but all the MPEG-2 encoders I've ever seen have a setting for doing 2.21:1. Which makes me think it's defined as an 'official' ratio in the MPEG-2 spec (and the aspect ratio listing above confirms it was in the MPEG-2 part), but since it's not used very much at all day-to-day, it was left out of the DVD specifications. I mean, to my knowledge, no widescreen TV ever had a 2.21:1 ratio, since (as per that link) it was developed as a film ratio in the 1950s but was still rarely used. Most, if not all, widescreen televisions and monitors are 16:9 or 16:10, although I'd imagine some ultra-widescreen models exist that are 2.39:1 to match the common film ratio.
Case in point, if you try to make HCenc use 2.21:1, it tells you it's not DVD compliant. Quote:
*which also includes mod8, mod4, and mod2, but going 5 pixels down makes less sense when using the others because they can get closer to 853 than mod16 can. With mod16, you can use 848 or 864, and 848 is closer. 1.85:1 at 480p is 888x480, which is compatible with mod8, 4, and 2, but not 16 (which needs 880 or 896). |
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5th September 2014, 20:01 | #13 | Link | |
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Besides, I took a still of the DVD, scaled it properly (1.85:1), and it gave me exactly 1040p; so I figured I would just use the same.
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5th September 2014, 20:31 | #14 | Link | |
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PAL DVD flagged as 16:9. 720x576 -> 1024x576 Crop off the letterboxing/pillarboxing. Scale up based on 1.85:1, getting 1920x1040 when accounting for mod16. |
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5th September 2014, 20:41 | #15 | Link | |
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Last edited by Wilbert; 5th September 2014 at 20:46. |
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5th September 2014, 22:53 | #16 | Link | |||
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8th September 2014, 09:24 | #18 | Link | |
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MPEG-2 on the other hand is a generic algorithm. It can be used on computers, cellphones, whatever. The problem with digital (one of them) is that the display is fixed, ie it has a finite and exact number of pixels. Any pixel costs money, so one would not make screens of eg 123x71 pixels, because no application would use it.
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8th September 2014, 10:14 | #19 | Link |
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when I'm dealing with ntsc dvds, I would add 6 pixels blackborders at vertical direction first, then resize them to 720*540 then crop all blackborders, it's a reverse process of how dvds were made from broadcast ntsc mastertapes
Last edited by feisty2; 8th September 2014 at 10:19. |
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