[FFmpeg-devel] [PATCH] Document slice ordering assumption done by sws_scale()

[Ramiro Polla]

On Mon, Oct 26, 2009 at 9:01 PM, Stefano Sabatini
<stefano.sabatini-lala at poste.it> wrote:
> as in subject.

> Index: libswscale/swscale.h
> ===================================================================
> --- libswscale/swscale.h	(revision 29797)
> +++ libswscale/swscale.h	(working copy)
> @@ -137,6 +137,12 @@
>   * slice in the image in dst. A slice is a sequence of consecutive
>   * rows in an image. Slices can be bottom to top or top to bottom.
>   *
> + * Slices have to be provided in sequential order,

> either in
> + * top-bottom or bottom-top order.

This is already written right above it.

> The assumed direction for the whole
> + * image

IMO this should better be "for each image"

> depends on the value of srcSliceY provided when drawing the
> + * first slice, if it is 0 it is assumed top-bottom order, otherwise
> + * bottom-top order.

That's not entirely right. It is assumed top-bottom if srcSliceY is 0,
and bottom-top if srcSliceY + slice height == image height or
something like that.

Anyways I think this is a hack, and instead of documenting the hack we
should let the user specify the slice direction somehow.

Ramiro Polla