Crop/Resize PAL DVD

[CarlPig]

Hello.

What is the aspect ratio if i crop 70 in Top and Bottom??

2,35:1 or 2,40:1 or something else??

My source is a 16:9 PAL DVD with black bars in Top and Bottom.

I have searched on google but didn't get a answer.

[Groucho2004]

After cropping 70 px from top and bottom you have 720 x 436. SAR for PAL 16 x 9 is 64/45. Applying that correction you'll get 1024 x 436 resulting in an aspect ratio of ~2.35:1.

[CarlPig]

Thank You for help and fast replay.

[TheSkiller]

To make things more complicated (:D) it could also be 2.40:1 if the DVD's source picture scaling is adhering the ITU spec.
For the math you simply replace the PAR of 64/45 in Groucho2004's calculation with 16/11.

How do you know which one is correct? If you don't want to measure a round object you will never know for sure but if your DVD is quite new and fills the entire width of 720 pixels it is more likely (but not guaranteed) to be the former, 2.35:1.

[Overdrive80]

I go to explain in more details, for using directly resize with x264.

DAR=PARxSAR. You can use option of x264, --sar width:height

In your case, if source´s DAR is 16:9, and DVD is PAL:

1) Without Crooping

16/9=(720/576) x (width/height)

720/576=5/4

width/height= (16/9)/(5/4)= 64/36

In x264 would be --sar 64:36

-----------------------------------------------------

2) With Crooping

16/9= [(720-(a1+a3))/(576-(a2+a4))] x (width/height) (with crooping)

Applying crop(0,70,0,-70) --> a1=0, a2=70, a3=0, a4=abs(-70)

16/9=[(720-(0+0))/(576-(70+70))]=720/436

720/436=180/109

width/height=(16/9)/(180/109)=1744/1620=436/405

In x264 would be --sar 436:405

Regards.