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Ocrana
15th October 2002, 01:18
Hello,

please dont hurt me about this topic but I have a big problem in understanding. I try to build an autocrop addonon for dvdx to solve my problems in understanding aspect ratio. Ok what I do:

I have different PAL Movies. I try to detect which width and height the movie has, and get the aspect ratio from the Ifo. In case of this, PAL is everytime 720x576 pixels. Ok thats good. I put in DVDx the picturesize of 720*576 for 4:3 Movies and 720*400 for 16:9 Movies.
Now I encode this movies to have some testmaterial. But then, after I had encoded the movies, I play my encoded movie with a aviplayer and the dvd with WinDVD to check if the frames/Pictures are equal.

NOW THE PROBLEM OCCURS. On WinDVD some Movies, like "Saving Private Ryan", "The Shawshank Redemption" and a german movie "Sieben Monde" are shown in WnDVD in a different size. Means the height of the movies are more than my encodes movie. And the faces are strechted more than the ones in my movie.

So, I take the MediaPlayer and start Playback of the DVD. And in the MEdiaPlayer, the DVD is shown extactly in the same size I encoded my Movie.

Ok, my last test was, to check the data from ifo with smartripper and vstrip. Vstrip gaves me the exact data I analyse: 16:9 and 720*576. But Smartripper says me, that the movies has a Aspect Ratio of 4:3.

So my question is: Is there a Bug in WinDVD and Smartripper, so Smartripper gets the wrong data and WinDVD shows the movies incorrect or do I a fault and the WindowsMediaPlayer has the same bug that I do?

Ocrana

mpucoder
15th October 2002, 01:25
Not a bug so much as an inconsistency. The aspect ratio is encoded in 2 different places. The video stream itself (which is all MediaPlayer looks at), and in the ifo (which standalone DVD players use). If they are both correct, then no problem. But if one is wrong, you'll see problems like this. IfoEdit can show you the value in the ifo, and VobEdit can show you the value in a vob video stream.

Emp3r0r
15th October 2002, 01:27
I believe some go by 1.778 and others go by the ITU standard (WinDVD). This is most likely the differences you are seeing. Search google for more information.

Ocrana
15th October 2002, 04:35
...Ok, first, I check all movies with vobedit. And at least, I think smartripper has a bug. It reads the aspect ratio from the Dolby(or other) Trailers from vobid 0.

Second. I really didnt understand what the ITU-R BT 601 Standard means? First the Standard ist vor 4:2:2 and 4:4:4 Movies. I thought DVDs are in 4:2:0 Format.
Second I didnt find anything about Aspect Ratio in that documents. I think that I didnt understand that document by the righ tway, so is here someone who can explain the Standard? All this make no sense??!!?!? :(

Ocrana
15th October 2002, 13:00
Hello,

its me again. I read now some internet pages and now Iam realy disorder. I also look in GordianKnot. If I compare the settings, specialy the DisplayAR in GordianKnot, and the size, WinDVD shows me, my disorder is full.
Ok, if the DisplayAR in GordianKnot and the Window in WinDVD will be the same, I will understand that ITU-r BR 601 a little bit. But GordianKnot says me that the displayAR is 1.821. But WindDVD shows the movie Bigger than 1.778. Means GordianKnot need to be around 1.70 and not 1.821?
So what is the problem with ITU-R BR 601 and normal 16:9? Why WinDVD shows the window in 720*426 (I mean 432,416 is the right choice). Why other players shows a correct 720*400 screen? Where is my understandig problem?
Is it really a missunderstanding from me or a bug in WinDVD? Specially this happens not at all movies.

Ocrana
16th October 2002, 00:28
..and other results.

Ok, I bought the:
PowerDVD
CoolDVD
VaroDVD

If I compare now:
PowerDVD
CoolDVD
VaroDVD
MS MediaplayerDVD

with

WinDVD

the result is that every player shows the movies in 720*400. So shame on me, but didnt that look as a bug in WinDVD? Why only WinDVD show 720*426 and produce EggHeads?

So please if I think wrong, please, there must be someone who can explain me the ITU-R-BR 601 Stuff.

Ocrana