Correct Aspect-Ratio in x264?

[lenouch]

Is PARanoia a freeware ? If yes, anyone got a link to download it? It looks nice, but google always give me results concering the "true" word paranoia

thanks :)

[SeeMoreDigital]

If you had used the forums search facility you would have found this: -

http://forum.doom9.org/showthread.php?t=101070&highlight=PARanoia

[Rash]

Look, I have just one question that may seem very stupid after all this great discussion. :) I've read it all but I couldn't extract my question out of it.

Let's see if I can make this simple. I have a 720x480 video from a DVD. The video is flagged as anamorphic so the real video is DAR 16:9. The DVD player would then display the video as 853x480 (forget about mod16 just for now), correct so far?

So this video has black bars, and I crop it. The cropped resolution is 720x352. My question is: which DAR do I use to calculate SAR for this cropped resolution? 4:3 from the source video (720x480), 16:9 that is the real DAR for the source video (853x480) or the cropped resolution DAR 2.05:1 (720x352)?

Thank you a lot for your attention. ;)

[SeeMoreDigital]

...So this video has black bars, and I crop it. The cropped resolution is 720x352. My question is: which DAR do I use to calculate SAR for this cropped resolution? 4:3 from the source video (720x480), 16:9 that is the real DAR for the source video (853x480) or the cropped resolution DAR 2.05:1 (720x352)?Try: -

68:75 - If the "Movies" AR is 1.85:1

54:47 - If the "Movies" AR is 2.35:1

88:75 - If the "Movies" AR is 2.40:1

EDIT: By-the-way.... what is the movies" aspect ratio. It should tell you somewhere on the DVD case. If you have not got the case you should be able to check it over on Amazon.com


Cheers

[Inc]

The video is flagged as anamorphic so the real video is DAR 16:9. No thats just the flag in the streams header so the SAP knows if letterboxing is needed if a 4:3 TV set is the target device. ;)
The DVD player would then display the video as 853x480 (forget about mod16 just for now), correct so far?
The DVD Player just sends a Signal @13.5Mhz wich equals 720x480px
On a "16:9" Tv it would be displayed as this:

NTSC_D1_PAR = 4320/4739

So 720*(4320/4739) x 480 = 656,341 x 480 (still anamorph, means squeezed)
Lets do take the anamorph factor into account:
656,341*(1,33333) x 480 = 875 x 480 ... so not 853x480 ;)
So your 720x480's real DAR is 875/480 = 1,823
So your cropped stream results in 875 x 352 = a real DAR of 2,486 ... use this one to calculate the SAR

[akupenguin]

Why so complicated? You do not need to recalculate SAR after cropping.
The 720x480 "16:9" has SAR=5760/4739 or 40/33 or 32/27 depending on how standards-compliant the DVD is.
The 720x352 still has SAR=5760/4739.

[SeeMoreDigital]

Those calculations are okay if you want to follow the ITU specification "to the letter". But if you want to follow a more logical approach, try the following methods...

If your movies aspect ratio (MAR) is 1.85:1, then this can be represented as a fraction of 37/20 (because 37 divided by 20 equals 1.85). Meaning it can be placed in an calculation, this way: -

37 352 13024 407
-- x --- = ----- lowest dominator --- giving a PAR of 407:450
20 720 14400 450

Which "could" be further simplifieid to say: -
708 68
--- = --
450 75


But like I mentioned before.... You need to know the "aspect ratio" of your source movie :)


Cheers

[Rash]

Right, OK. Thank you. ;)