[MPlayer-advusers] [BUG] mencoder floating point exception with -of lavf

[Nico Sabbi]

Corey Hickey wrote:

>Michael Niedermayer wrote:
>  
>
>>i wouldnt be so sure about that, my guess would rather be that mplayer
>>extracts them from the video stream for mpeg4 and store 0x0 in the avi 
>>header, but maybe iam wrong, the only sure thing is that the dimensions
>>must be valid when av_write_header() is called
>>    
>>
>
>I'm not sure about anything, just doing my best to poke around in the
>dark. :)
>
>According to gdb both st->codec->width and st->codec->height are set to
>0 when av_write_header is called. Do you know where they should be set
>to the correct values? I'll keep looking, but I have a feeling you could
>fix this in a few seconds while it'll be a hit-and-miss process for me.
>
>-Corey
>
>
>  
>

the problem is that muxer->fix_parameters() (that calls av_write_header())
is called before video width and height are really known, parameters that
are known only after the first video frame is decoded and filtered.

So, I guess that mencoder should either
- decode and filter the first frame
- or pre-init (assuming it's possible) the video filters chain to probe 
the characteristics
of the final frame

    Nico