* How do I use it?
You can derive the SAR of an image from the width, height and the
display aspect ratio (DAR) of the image as follows:
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SAR_x DAR_x * height
----- = --------------
SAR_y DAR_y * width
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for example:
width x height = 704x576, DAR = 4:3 ==> SAR = 2304:2112 or 12:11
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Please note that if your material is a digitized analog signal, you should
not use this equation to calculate the SAR. Refer to the manual of your
digitizing equipment or this link instead.
correction of aspect ratios, and there are just few exceptions. You should
even use it, if the SAR of your material is 1:1, as the default of x264 is
"SAR not defined".
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2. Overscan
------------
analog signal. Instead it refers to the "overscan" process on a display
that shows only a part of the image. What that part is depends on the
display.
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* How do I use this option?
As I'm not sure about what part of the image is shown when the display uses
an overscan process, I can't provide you with rules or examples. The safe
* What is it?
A purely informative setting, that explains what the type of your analog
video was, before you digitized it.
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* How do I use this option?
Just set it to the desired value. ( e.g. NTSC, PAL )
If you transcode from MPEG2, you may find the value for this option in the
or want to make sure that your material is played back without
oversaturation, set if to on. Please note that the default for this option
in x264 is off, which is not a safe assumption.
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* Should I use this option?
Yes, but there are few decoders/ media players that distinguish
between the two options.
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5. Color Primaries, Transfer Characteristics, Matrix Coefficients
-------------------------------------------------------------------
profile of the digitizing equipment is known, it is possible to correct the
colors and gamma of the decoded h264 stream in a way that the video stream
looks the same, regardless of the digitizing equipment used.
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* How do I use these options?
If you are able to find out which characteristics your digitizing equipment
uses, (see the equipment documentation or make reference measurements)
chroma sample location in that direction is equal to one of the luma
samples. H264 Annex E contains images that tell you how to "transform" your
Chroma Sample Location into a value of 0 to 5 that you can pass to x264.
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* Should I use this option?
Unless you are a perfectionist, don't bother. Media players ignore this
setting, and favor their own (fixed) assumed Chroma Sample Location.
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