[MPlayer-dev-eng] vd_libmpeg2: change in video parameters causes mencoder to core-dump

[Michael Niedermayer]

Hi

On Monday 15 September 2003 16:42, Peter Niemayer wrote:
> Hi,
>
> I just noticed that unlike mencoder 0.9, which silently ignored
> changes of video parameters in mpeg-2 streams, mencoder 1.00pre1
> will core dump.
>
> In libmpcodecs/vd_libmpeg2.c there is a piece of code like this...
>
>          case STATE_SEQUENCE:
>             // video parameters inited/changed, (re)init libvo:
>             if(!mpcodecs_config_vo(sh,
>                 info->sequence->width,
>                 info->sequence->height, IMGFMT_YV12)) return 0;
>             break;
>
> ... that might be helpful to change aspect-ratios and alike during
> replays with mplayer, but which causes mencoder to dump core if
> it encounters such an event (at least when -ovc lavc is chosen).
>
> It would be nice if either the encoder would be able to handle the
> reconfig request or - much simpler - if a re-init would just be
> avoided when the code is for mencoder, not mplayer.
reiniting the encoder is problematic, for example it will break 2pass rc, and 
changing aspect / resolution / whatever in the middle of a video will 
probably break many players and is probably not allowed in many video 
standards, furthermore for formats which use a global header to store the 
res/aspect, or which dont encode the aspect / res at all in the video stream 
it simply wont work, so this would probably only work for MPEG-1/2, for 
MPEG-4 we would need 2 different video streams which get played sequencially 
as its not allowed to change stuff midway IIRC

[...]
-- 
Michael
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