How to calculate aspect ratio for different sources

[turbo71113]

Quite often i face problems in calculating the aspect ratio.
When i rip the movie sometimes i feel that its stretched horizontally and vertically sometimes.

can anyone guide me how to calculate perfectly the AR for various sources or post some guide on AR

[JEEB]

Don't know if this is the right section of Doom9 for your question, but here goes:

With DVDs: It's a pain, and is related a lot to analog video. Basically, read over this text (http://lipas.uwasa.fi/~f76998/video/conversion/) a couple of times and then proceed to using this calculator (http://ps-auxw.de/cgi-bin/ar-calc.pl) for aspect ratios. Of course, always remember to check the output - most DVDs should be made correctly by the standard, but nothing wins over your eyes and some round object on the screen. I usually set the correct aspect ratio / output resolution when muxing into mkv/mp4, but you may use whatever way works for you.

With HDTV material: Usually much easier here. 1440x1080 gets stretched to 1920x1080 or kept as-is, therefore you keep in mind the final resolution and make needed aspect ratio changes if needed. End of story. Still, you'll always have to check things with your eyes in the end.

[roozhou]

With HDTV material: Usually much easier here. 1440x1080 gets stretched to 1920x1080 or kept as-is

I have a sample from BBC-HD which is 1440x1080 ==> 1964x1080, quite similar to 720x480 ==> 872x480 on DVDs.

[JEEB]

As I wrote, there will probably always be exceptions. Thank Hanyuu most of the blu-ray / ISDB-T / DVB-C streams I've seen have been pretty much default-like. Do note the "usually" I wrote first of all.