[MPlayer-users] [UPDATE]Re: Strange problem with expand filter and rmvb files

[陆然]

Hi,

> I use the expand filter to enlarge the video window to a 4:3 aspect with
> "-vf expand=:::::3/4", this option is ok for most files, but when I try to
> expand a rmvb file, which is not a 4:3 video, the epanded part below the
> video, which is expected to be blank, have some duplicated images, and the
> color of the video messed up, then I test it with many other rmvb files,
> they all suffer from the same problem, and it seems the bug happens only
> when I set the aspect argument of the expand filter. otherwise it will be
> ok.

It's a little bit frustrated that I'm the only one bother with this bug, but 
I'm make progress, I found that if I expand the video large enough (KEEP the 
width, just expand the height), I will see 5 pictures, the first big picture, 
with the same height and width of the 'correct' video, but only black and 
white, below the big picture is four small picture, half width and 1/4 height 
of the original video, they are grey image too,  and the picture in the same 
row looks identical. so it looks like this.

 ----------------------------------------------------------------------------
 |                                                                          |
 |                                                                          |
 |                                                                          |
 |                                     I                                    |
 |                               Big grey image                             |
 |                                                                          |
 |                                                                          |
 |                                                                          |
 ----------------------------------------------------------------------------
 |                 II                  |               III                  |
 |                                     |            same as II              |
 ----------------------------------------------------------------------------
 |                 IV                  |                 V                  |
 |                                     |            same as IV              |
 ----------------------------------------------------------------------------

And I think this may have some relation with the misinterpretation of 
colorspace, maybe the big one is the Y plane, and others are the U and V 
plane, but I still cannot figure out why there are two identical small 
picture with 1/4 height instead of one bigger picture with half height.

And this seems have something to do with a bug I reported before, some real 
video, made by merge two real video with different resolution together, will 
messed up when the resolution changes, I checked these video again, the image 
also split to the five block I mentioned before, but most video also have 
some distortion, which I still don't know why. maybe because the width 
changes too.

Here is how you can check this bug yourselves, find a rm/rmvb file, try to 
play it with -vf expand=:height, height should be larger than the height of 
the video, increasing the height, you will see different color distortion. 
finally, the video split to five, and all pictures are black and white.

NOTE, somehow if you expand the width too, -vf expand=800:1000 e.g. the 
problem disappears, don't know why though.

-- 
Best Regards,
LR