Den 07.01.2024 23:35, skrev Andrew Randrianasulu:
пн, 8 янв. 2024 г., 01:31 Andrea paz <[email protected]>:
I don't quite understand how ffmpeg considers the various aspect
ratios. However from the site lurkertech you pointed to (and from
which I had taken some definitions put in the manual) PAR and SAR are
not the same thing: PAR is about pixel shape and size; SAR is about
frame shape and size.
To change the manual I would like to be sure that ffmpeg really
considers PAR=SAR.
lets wait until ffmpeg-users reply to just send email :)
The wikipedia article section "Confusion with display aspect ratio"
points out:
https://en.wikipedia.org/wiki/Pixel_aspect_ratio#Confusion_with_display_aspect_ratio
Pixel aspect ratio is often confused with different types of image
aspect ratios; the ratio of the image width and height. Due to
non-squareness of pixels in Standard-definition TV, there are two types
of such aspect ratios: /storage aspect ratio/ (/SAR/) and /display
aspect ratio <https://en.wikipedia.org/wiki/Display_aspect_ratio>/
(abbreviated /DAR/, also known as /image aspect ratio
<https://en.wikipedia.org/wiki/Image_aspect_ratio>/ and /picture aspect
ratio <https://en.wikipedia.org/wiki/Picture_aspect_ratio>/). Also,
/pixel aspect ratio/ (/PAR/) is also known as /sample aspect ratio/
(abbreviated /SAR/) in some industrial standards (such as H.264
<https://en.wikipedia.org/wiki/Advanced_Video_Coding>^[2]
<https://en.wikipedia.org/wiki/Pixel_aspect_ratio#cite_note-2> ) and
output of programs (such as /ffmpeg
<https://en.wikipedia.org/wiki/Ffmpeg>/^[3]
<https://en.wikipedia.org/wiki/Pixel_aspect_ratio#cite_note-3> ). Note
the reuse of the abbreviations /PAR/ and /SAR/. This article uses only
the terms pixel aspect ratio, display aspect ratio and storage aspect
ratio to avoid ambiguity.
And in Note 3
"ffprobe shows PAR as SAR" <https://trac.ffmpeg.org/ticket/1776>.
ffmpeg.org. Retrieved 2022-06-10.
https://trac.ffmpeg.org/ticket/1776
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