[FFmpeg-user] Glossary: DAR, PAR, and SAR

[Jim DeLaHunt]

On 2020-09-30 13:09, Mark Filipak (ffmpeg) wrote:
> I seek your comments regarding the following glossary entries (that 
> have been reformatted to fit email). Kindly take your time.
>
> -Mark.
>
> DAR (display aspect ratio [1]) [noun]: 1, … as a minimized, H:V, 
> integer ratio (e.g.
>   16:9, 4:3)…
> (and similar wording for PAR and SAR):


Is the term "minimized aspect ratio" already used in this domain? If 
not, then the related mathematics term "reduced fraction" may be a 
better inspiration than "minimized". See 
<https://mathworld.wolfram.com/ReducedFraction.html>. "Reduced aspect 
ratio"? "Ratio where the two numbers have a greatest common divisor of 1"?

Also,


> SAR [noun]:…
>   [2] A standardized set of picture sizes & aspects has been
>       established:
>                  display     DAR     picture     PAR    SAR = DAR/PAR
>     16:9-2160: 3840 x 2160  16:9 : 3840 x 2160  16:9 :  1:1
>      4:3-2160: 2880 x 2160   4:3 : 2880 x 2160   4:3 :  1:1
>     16:9-1080: 1920 x 1080  16:9 : 1920 x 1080  16:9 :  1:1
>      4:3-1080: 1440 x 1080   4:3 : 1440 x 1080   4:3 :  1:1
>      16:9-576: 1024 x 576   16:9 :  720 x 576    5:4 : 64:45
>       4:3-576:  768 x 576    4:3 :  720 x 576    5:4 : 16:15
>      16:9-480:  853 x 480   16:9 :  720 x 480    3:2 : 32:27
>       4:3-480:  640 x 480    4:3 :  720 x 480    3:2 :  8:9  [3] 


The formatting of the email garbles the table [2] enough that I can't be 
sure what I'm reading. Maybe insert printable delimiters into each line?

Best regards,
         —Jim DeLaHunt