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3rd February 2006, 16:28 | #21 | Link | |
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Last edited by kotrtim; 3rd February 2006 at 16:36. |
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3rd February 2006, 16:41 | #22 | Link | |
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3rd February 2006, 16:47 | #23 | Link | |
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As I mentioned before, a movie with an aspect ratio of 2.35:1 can be represented as a fraction of 47/20 (ie: 47 divided by 20 equals 2.35). Which can be worked into the formula I provided. Cheers
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3rd February 2006, 16:52 | #24 | Link |
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I get the impression that you guys are trying to "run" before you can "walk".
You really must do some reading up on what "uncorrected" anamorphic images look like... What I mean be "Uncorrected" is, what the image looks like before any form of aspect ratio signalling has been applied, whether it be SAR, PAR or DAR! Cheers
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3rd February 2006, 17:06 | #25 | Link |
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I've never seen any DVD with 47/20, I've film with 2.35:1 which has added black bars to make it 4:3
Do you mean that that DVD-video standard can have any fraction of aspect ratio besides 4:3 and 16:9? Does anamorphic means the pixels are displayed rectangularly instead of squares? |
3rd February 2006, 17:24 | #26 | Link | |
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"Uncorrected" anamorphic images are 720x480 (for NTSC) with the aspect ratio of 1.5:1, right? And the DAR can be set to signal stretching to either 4:3 or 16:9 (and two others). But, going back to my example case earlier, if the source was in fact 4:3 then the DAR would be set to that, and there should be no padding borders. So why are there borders? My only conclusion is that the original source is NOT 4:3 but rather 176:135, and the borders are there to correct the aspect ration from 4:3! So it seems to me that kotrtim has the right of it, and that I should use the uncropped size for SAR calculation. Do you agree with my reasoning, SeeMore? Or ir there yet more that I don't correctly understand. Edit: Correction. Last edited by bkman; 3rd February 2006 at 17:37. |
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3rd February 2006, 18:25 | #27 | Link | ||
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The padding (borders) which can often be seen to the left and right of DVD images is (arguably) there to help reduce "over-scan". Normally when playing DVD's via a stand-alone player and viewing them via a TV, you would not see this padding but on a PC you do. But even if you crop away the left and right padding boarders, the "target" aspect ratio shape is still indended to be either 4:3 or 16:9. Cheers
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3rd February 2006, 18:59 | #28 | Link | |
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Thanks for your help with my questions, btw. |
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3rd February 2006, 20:05 | #29 | Link | |
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The level of "Aspect Ratio Signalling" (ARS) you will require will change in relation to your source "Movie's Aspect Ratio" (MAR) and your "mod16" pixel frame size (after cropping and resizing). Here's an "extreme" example of what I mean. If you had an MPEG-4 file with say, a resolution of 496x464 but you knew it should be displayed at 2.35:1 shape, you could use the following calculation: - Code:
MAR FAR ARS 47 464 21808 1363 -- x --- = ----- lowest dominator ---- Giving an ARS value of 1363:620 20 496 9920 620 Cheers
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Last edited by SeeMoreDigital; 3rd February 2006 at 22:33. |
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4th February 2006, 22:34 | #30 | Link |
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Not being the best at math, is there any easy way to work out the lowest common denominator? Is it possible to enter in 1920:2112 as the SAR in MeGUI or must I absolutely break it down further?
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4th February 2006, 22:45 | #31 | Link | |
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5th February 2006, 00:50 | #33 | Link | |
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However, this could be further converted to say: - Code:
1080 27 ---- which, in turn decimates to -- 880 22 Cheers
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Last edited by SeeMoreDigital; 5th February 2006 at 01:05. |
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5th February 2006, 18:00 | #34 | Link | |
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Is there a formula as to how to work out the lowest common den? Is it just guess work with a calculator? Give me something to go on..lol
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5th February 2006, 18:17 | #35 | Link | |
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EDIT: Here's a 2.35:1 video sample, with a pixel frame size of 704x368 and aspect ratio sigalling at 199:162. Cheers
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Last edited by SeeMoreDigital; 5th February 2006 at 22:33. |
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6th February 2006, 08:03 | #38 | Link | ||
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6th February 2006, 10:43 | #39 | Link |
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SMD likes to stick to non-standard terminology. I think his MAR is the playback AR (after cropping away the black borders). If that's the case, than in many cases you don't know the MAR in advance, unless it is specified on the box of the dvd.
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6th February 2006, 10:46 | #40 | Link | |
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