[FFmpeg-devel] [PATCH] Zoom & Pan filter

[João Bernardo]

On Thu, Oct 31, 2013 at 8:04 AM, Paul B Mahol <onemda at gmail.com> wrote:

> Signed-off-by: Paul B Mahol <onemda at gmail.com>
> ---
>  doc/filters.texi         |  83 +++++++++++++
>  libavfilter/Makefile     |   1 +
>  libavfilter/allfilters.c |   1 +
>  libavfilter/vf_zopan.c   | 301
> +++++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 386 insertions(+)
>  create mode 100644 libavfilter/vf_zopan.c
>
> diff --git a/doc/filters.texi b/doc/filters.texi
> index 14692a2..9ddf26e 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -8195,6 +8195,89 @@ only deinterlace frames marked as interlaced
>  Default value is @code{all}.
>  @end table
>
> + at section zopan
> +
> +This filter accepts the following options:
> +
> + at table @option
> + at item z
> +Set the zoom expression, Default is 1.
> +
> + at item x
> + at item y
> +Set the x and y expression. Default is 0.
> +
> + at item d
> +Set the duration expression in number of frames.
> +This sets for how many number of frames effect will last for
> +single input image.
> +
> + at item s
> +Set the output image size, default is 'hd720'.
> + at end table
>

I'm interested in this filter, but why is it necessary to set the default
image size to hd720 instead of the original size?