The display aspect ratio and the pixel aspect ratio you quoted can't both be correct. Your 496x384 example doesn't make sense because to display as 31:24. If the storage dimensions and the display dimensions are the same, the pixel aspect ratio must be 1.0 The pixel aspect ratio would therefore be 1024/720 = 1.422222ĭAR/SAR = PAR would give you the same result as the storage aspect ratio is 720/576, which is 1.25 Thank you! You can think of the pixel aspect ratio as being the difference between the physical width of the picture, and the width it'd be stretched or squished to in order to display with the correct aspect ratio.įor a 720x576 source (as an example) with a display aspect ratio of 16:9, the correct display width can be calculated based on the height.ĥ76*16/9 = 1024, so it'd display as 1024x576 in "square pixel" dimensions. Most of this calculations I'm doing with a calc spreadsheet from libreoffice so I can punch in the numbers and get the values I need. This is very different from PAR 10:11 we see over the internet, what I need to do to find a correspondent PAR for a 496 x 384 footage for example? Print "\t\t\tResults\n\t\t\tNumbers\n\t\t\tSource resolution: $source_res->x$source_res->Source AR: $source_arFinal resolution: $res->x$res->Final PAR: ".frac($par->, $par->)." = ".($par-> / $par->)."Final display resolution: $display_resx$display_resFinal DAR (square pixels): ".frac($res-> * $par->, $res-> * $par->)." = ".($res-> * $par-> / ($res-> * $par->)).I'm trying to understand all this SAR, PAR, DAR stuff and I'm having problem with PAR, what I've got so far?Ħ40 x 480, max common divisor of 640 and 480 is 160, so 640/160 = 4 and 480/160 = 3 or a DAR of 4:3 'pal' => ->($res, $par, $x, $y, $i)) || fail("Bad transform type in transform $i: $transform_type")
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# published by the Free Software Foundation, either version 3 of the # it under the terms of the GNU Affero General Public License as # This program is free software: you can redistribute it and/or modify In any case, for HD there do not seem to be tricky issues involving active picture regions and ITU-R B.601 PAR values, so things are pretty straightforward. Use widescreen mode for calculations with 1440x1080 stretched to 1920x1080. For "anamorphic" HD at 1440x1080 it is assumed that 4:3 is encoded without black bars, if you select fullscreen mode. This way the PAR for both fullscreen and widescreen video is 1:1.
For example, if you have a source where a widescreen movie was encoded as letterboxed fullscreen, you'll have to choose full screen as the source AR.Ībout HD: It is assumed that, in the case of full HD, 4:3 is encoded pillarboxed. Since the vast majority of professionally mastered SD material should conform to ITU-R B.601, this is the way it's supposed to be done, using correct ITU-R B.601 PAR values.Īlso note, that the correct source AR is not necessarily the AR of the movie. This means that without transforms (like cropping to the active picture region), you won't get a DAR equal to the source AR. The source AR is given with respect to the active picture region. The target size for pad must be greater than the former actual video size. Pad transforms pad the actual video resolution to the specified size. The target size for crop must be lower than former actual video size. Crop transforms crop the actual video resolution to the specified size.
Scale transforms scale the actual video resolution to the specified size. If you read and understood the linked page, know what you are doing, and think you found a bug in the calculations, please report it to: ar-calc a t ps - auxw d o t de Calculate Well, basically this is simply a calculator used to determine the correct AR data for certain types of input video under certain transformations. Not to speak of all the little details that are not quite what one'd think. There's the Sample Aspect Ratio (SAR), also called Pixel Aspect Ratio (PAR), which specifies the dimensions of each pixel, and there is the Display Aspect Ratio, which specifies the aspect ratio of the whole picture. Aspect Ratio Calculator Aspect Ratio CalculatorĪspect ratios can be a confusing business.