aspect ratio confusion

[graysky]

If I look at a DVD that has an advertised aspect ratio of 2.35:1.00 which is 720x480. Shouldn't that mean that the black bars should take up 174 pixels of the 480? This is not the case. With the DVD I am looking at right now. I can crop out 114 pixels of black bars to leave a 720x366 video which is not even close to 2.35:1.00 as an aspect ratio... it divides out to about 1.97:1.00 which isn't right.

Can someone explain this?

[Baldrick]

DVDs has two aspect ratios, 4:3 or 16:9. If 2.35 black borders will be added.

So a letterboxed 4:3 movie with 2.35:1 video, 720x480 to 4:3 = 640x480 to 2.35 = 640x272 pixels, so the 720x480 should has 480-272 = 208 pixels black borders.

A 16:9 anamorphic movie 2.35, 720x480 to 16:9 = 854x480 to 2.35 = 854x364, 480-364 = 116 pixels black borders.

I'm not sure if I calculating correct here...but it seems to be correct....

[Cornucopia]

A well-done DVD with an original AR of 2.35:1 ought to have been authored as an Anamorphic title.

This means, it will have dimensions of 720x480, but with a complete screen-filling AR (including letterbox bars) of 16:9. Remember, the DVD-Video format only NATIVELY supports 4:3 (1.333:1) and 16:9 (1.78:1). So 2.35:1 means 720(640)x272 active image with 44 pixel letterboxing on top & bottom, to give an equivalent (square pixel PAR) image of 720(640)x360, stretched out to 720x480 for anamorphic encoding.

Scott

>>>>>>>>>
edit: Baldrick got to it before me! It may look confusing, but I think we're both arriving at the same dimension #'s from 2 different perspectives.
...Yup, I got 116 or 117.

[j1d10t]

Check out this guide/article: https://forum.videohelp.com/viewtopic.php?t=174200

[Pinstripes23]

graysky:

You can't look at the 720x480 as square pixel, because as stated above the display AR can either be 16:9 or 4:3. Although when determining how much are black borders I use Baldrick's calculations. 480 is the vertical resolution and you will usually see borders only on the top and bottom, so I leave that unchanged. 4:3 = 640x480, 16:9 = 854x480.

[graysky]

Thanks for all the replies... this whole issue gives me a headache. I found that if I simply crop out the black borders with a null transform without resizing AND use the -aspect 235:100 command, I get a pleasing result.

Alternatively, I found that using mpeg-4 modifier mentioned by Baldrick in this post and forcing the display AR to 2.35:1.00 with that software also works and I don't have to use the -aspect 235:100 switch with mplayer in that case.

I'm stuff totally confused by this using mplayerc however. It just plays what it's given (in this case 720x366) which doesn't look right... guess I have to resize it to 720x306 but then it gets messed-up in mplayer (looks too long).

This is quite maddening!