[MPlayer-users] BUG: mencoder segvault with -vf pullup [partial bugreport]

[D Richard Felker III]

On Sat, Sep 13, 2003 at 02:43:55PM -0700, Corey Hickey wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> D Richard Felker III wrote:
>  > The problem is your crop parameters -- they don't make sense. Granted,
> >it shouldn't segfault, but it's impossible to inverse telecine 716x374
> >video since height isn't a multiple of 4. (Chroma plane is half
> >sampled = 358x187, whereas with interlaced video you must have 2
> >fields and this even height.) If you're going to crop before passing
> >input to pullup, both height and y-offset must be multiples of 4.
> >
> >I would recommend just overcropping a little (crop=716:372:4:48, or
> >better yet crop=704:372:10:48), but if you insist on exact cropping,
> >you can wait to do the crop til after inverse-telecine.
> >
> >
> >Rich
> >
> 
> Aah, I figured it would be something like that. But I didn't think about
> multiples of 4. So, does that mean that each field has a height of 1
> chroma pixel, which is 2 luma pixels?

If your image size if WxH, each field has a height of H/2, which in
turn means the chroma height of a field is H/4.

Rich