<div dir="auto"><div><br><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">пн, 8 янв. 2024 г., 01:52 Terje J. Hanssen <<a href="mailto:terjejhanssen@gmail.com">terjejhanssen@gmail.com</a>>:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><u></u>
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<div>Den 07.01.2024 23:35, skrev Andrew
Randrianasulu:<br>
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<div dir="ltr" class="gmail_attr">пн, 8 янв. 2024 г., 01:31
Andrea paz <<a href="mailto:gamberucci.andrea@gmail.com" target="_blank" rel="noreferrer">gamberucci.andrea@gmail.com</a>>:<br>
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don't quite understand how ffmpeg considers the various
aspect<br>
ratios. However from the site lurkertech you pointed to
(and from<br>
which I had taken some definitions put in the manual) PAR
and SAR are<br>
not the same thing: PAR is about pixel shape and size; SAR
is about<br>
frame shape and size.<br>
<br>
To change the manual I would like to be sure that ffmpeg
really<br>
considers PAR=SAR.<br>
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<div dir="auto">lets wait until ffmpeg-users reply to just send
email :)</div>
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<br>
The wikipedia article section "Confusion with display aspect ratio"
points out:<br>
<a href="https://en.wikipedia.org/wiki/Pixel_aspect_ratio#Confusion_with_display_aspect_ratio" target="_blank" rel="noreferrer">https://en.wikipedia.org/wiki/Pixel_aspect_ratio#Confusion_with_display_aspect_ratio</a><br>
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: <i>storage aspect ratio</i> (<i>SAR</i>)
and <i><a href="https://en.wikipedia.org/wiki/Display_aspect_ratio" title="Display aspect ratio" target="_blank" rel="noreferrer">display aspect ratio</a></i>
(abbreviated <i>DAR</i>, also known as <i><a href="https://en.wikipedia.org/wiki/Image_aspect_ratio" title="Image aspect ratio" target="_blank" rel="noreferrer">image aspect
ratio</a></i> and <i><a href="https://en.wikipedia.org/wiki/Picture_aspect_ratio" title="Picture aspect ratio" target="_blank" rel="noreferrer">picture aspect
ratio</a></i>). Also, <i>pixel aspect ratio</i> (<i>PAR</i>) is
also known as <i>sample aspect ratio</i> (abbreviated <i>SAR</i>)
in some industrial standards (such as <a href="https://en.wikipedia.org/wiki/Advanced_Video_Coding" title="Advanced Video Coding" target="_blank" rel="noreferrer">H.264</a><sup id="m_-345566080737687439cite_ref-2"><a href="https://en.wikipedia.org/wiki/Pixel_aspect_ratio#cite_note-2" target="_blank" rel="noreferrer">[2]</a></sup>)
and output of programs (such as <i><a href="https://en.wikipedia.org/wiki/Ffmpeg" title="Ffmpeg" target="_blank" rel="noreferrer">ffmpeg</a></i><sup id="m_-345566080737687439cite_ref-3"><a href="https://en.wikipedia.org/wiki/Pixel_aspect_ratio#cite_note-3" target="_blank" rel="noreferrer">[3]</a></sup>).
Note the reuse of the abbreviations <i>PAR</i> and <i>SAR</i>.
This article uses only the terms pixel aspect ratio, display aspect
ratio and storage aspect ratio to avoid ambiguity.<br>
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And in Note 3<br>
<span><cite><a rel="nofollow noreferrer" href="https://trac.ffmpeg.org/ticket/1776" target="_blank">"ffprobe shows PAR
as SAR"</a>. <a href="http://ffmpeg.org" target="_blank" rel="noreferrer">ffmpeg.org</a><span>.
Retrieved <span>2022-06-10</span></span>.<br>
<a href="https://trac.ffmpeg.org/ticket/1776" target="_blank" rel="noreferrer">https://trac.ffmpeg.org/ticket/1776</a></cite></span></div></blockquote></div></div><div dir="auto"><br></div><div dir="auto">well, both cingg and ffmpeg can interface with digitizing boards, but after another pass at reading</div><div dir="auto"><br></div><div dir="auto"><a href="https://lurkertech.com/lg/video-systems/#sqnonsq">https://lurkertech.com/lg/video-systems/#sqnonsq</a><br></div><div dir="auto"><br></div><div dir="auto">I hopefully hope that only DEVICE DRIVERS for analog input cards must deal with picture aspect ratio, as they deal with sampling of analog video.</div><div dir="auto"><br></div><div dir="auto">One can also hope that modern smartphone cameras also follow square pixels convention, because they typically do not send video over SDI but hand it into system-on-chip shared memory where encoder/display blocks deal with it directly.</div><div dir="auto"><br></div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><span><cite><br>
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