Resize/Upscale questions

[Selur]

I thought there cannot be another PAR value, sine I know the 720x576 and 4:3. PAR should follow that ratio SAR * PAR = DAR ?

you might want to read http://web.archive.org/web/2011122800541...onversion/

If I open file with Hybrid by default Input PAR is set to 1:1.
Using preview the circle in the video has correct shape, but the Input DAR 1:1 definitely is not correct.

If the Vapoursynth Preview shows the circle correctly the values Hybrid uses are correct.
And a PAR of 1 would mean that the DAR is the same as the SAR (=sample aspect ration = 720/576).
Do not use the normal Preview for this!

Does it mean that correct PAR is 12:11 and Input PAR has to be manual changed from default 1:1 to 12:11 ?

I doubt that 12:11 is correct more likely 1150:1053 (ITU-R 601 - common for analog content).
see: https://forum.selur.net/showthread.php?tid=597 and read the linked sites.

Playing encoded video a circle has correct shape, frame dimensions measured on PC screen as ~1.333 ratio.
But Target Resolution 984x720 has slightly different ratio of 1.3666, not the same as 4:3. It is difficult to measure on the screen a circle shape object to understand if it is distorted.

Problem is: There is tons of content that does not abide to any standards and processing often also messes with the par.
Also on old analog content the PAR does not refer to the active pixels, but the pixels you have after the overscan of the TV was applied.
So inside the overscan you can have active pixels,...
Now you got to choose: either keep the active pixels (this is what I usually prefer) or crop the content.
Then there is the problem with digitalizing content, if capture at a different resolution than the active pixels you change the content.
-> I would not care that much to be too accurate and always prefer to:
a. keep the proportions correct
b. keep all the active pixels I can get

Cu Selur