[MPlayer-users] Strange results with mf://\*.png (more data)

[Matthias Goerner]

Dear list,

I had exactly the same problem with png's and figured out that it is a 
bug in mplayer/mencoders mf-driver.
I solved the problem by replacing the control function in 
libmpcodecs/vd_mpng.c by (which is actually copied from 
libmpcodecs/vd_mtga.c):

static int control(sh_video_t *sh,int cmd,void* arg,...){
   switch (cmd)
   {
    case VDCTRL_QUERY_FORMAT:
       if (*((int *) arg) == out_fmt) return CONTROL_TRUE;
       return CONTROL_FALSE;
   }
   return CONTROL_UNKNOWN;
}

This works fine for my applications. I will send a patch to 
mplayer-dev-eng at mplayerhq.hu.

Matthias Goerner

> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> Some more data on the problem (see below).
>
> 1) I'm using 1.0pre2 installed from rpm (from the official page) on 
> Linux RH 7.2
> 2) Now the command line I'm using is:
>    mencoder -ovc lavc -lavcopts vcodec=mpeg4:$opt -mf 
> type=png:w=512:h=512:fps=25 -nosound -o output.avi mf://\*.png
> 3) The problem is not affected by the dimensions of the image
> 4) The problem seems related only to the PNG format. If I use JPEG the 
> problem goes away
> 5) Seems that ImageMagick and mencoder do not love each other:
>     If I convert to TGA, here is the message from mencoder:
>         Unsupported TGA type! depth=0fps Trem:   0min   0mb  A-V:0.000 
> [0:0]
>     Else, if I convert to SGI:
>         Bad magic number in image.  0fps Trem:   0min   0mb  A-V:0.000 
> [0:0]
>
> Sure, you will ask: "why don't you use JPEG? It seem to work".
> Well, I don't want to loose quality in my frames using unneeded JPEG 
> compression. Also the
> frames are chemistry ball and sticks, not well suited to JPEG 
> compression.
>
> Any suggestion?
> Thanks a lot!
>             mario
>
>
> ------------- Here the original problem ----------------
> I'm trying to create movies from a bunch of PNG frames.
> Sometimes (with alarming frequency I must add...) also a simple MPNG 
> movie
> has wrong colors and is squeezed to the left leaving a black band on 
> the right side.
> The squeezing factor seems something like 3/4.
>
> The command used to create the movie is:
>
> mencoder -ovc copy -nosound -o tmp.avi mf://\*.png
>
> and my ~/.mplayer/mencoder file contains only:
>
> mf=type=png
>
> The same behavior happens during the real MPEG4 compression. Also once 
> happened that a movie returned
> to normal after a color change in the scene (from almost b&w to color).
>
> If you want to reproduce the problem, a set of 10 frames can be found in:
> http://www.cscs.ch/~mvalle/mencoder_bug.tar.gz
>
> Thanks a lot for your help!
>                     mario
>