[vlc-devel] [PATCH 3/3] swscale: scale the aspect-ratio of the output format

[Rémi Denis-Courmont]

Le vendredi 21 février 2014, 19:49:40 Felix Abecassis a écrit :
> For instance, when using swscale after a 90 degrees rotation on 1080p,
> the transformation is 1080x1920 -> 1920x1080. The aspect-ratio must be
> modified in order to have the displayed image correctly rotated and
> not stretched.

I think conversion filters are not generally allowed to modify their input and 
output formats (This is still a bit messy in the case of video though.), 
unlike normal/proper filters. This is definitely not safe for non-zero priority 
plugins.

In other words, the aspect ought to be already correct already when entering 
swscale. If it is not, there is probably a bug somewhere else.

> Fix #10745.
> ---
>  modules/video_chroma/swscale.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/modules/video_chroma/swscale.c b/modules/video_chroma/swscale.c
> index 11a8ecb..a22e608 100644
> --- a/modules/video_chroma/swscale.c
> +++ b/modules/video_chroma/swscale.c
> @@ -441,6 +441,16 @@ static int Init( filter_t *p_filter )
>      p_sys->b_swap_uvi = cfg.b_swap_uvi;
>      p_sys->b_swap_uvo = cfg.b_swap_uvo;
> 
> +    /* Compute aspect-ratio of the output format. */
> +    p_fmto->i_sar_num *= p_fmti->i_visible_width;
> +    p_fmto->i_sar_den *= p_fmto->i_visible_width;
> +    vlc_ureduce(&p_fmto->i_sar_num, &p_fmto->i_sar_den,
> +                p_fmto->i_sar_num, p_fmto->i_sar_den, 65536);
> +    p_fmto->i_sar_num *= p_fmto->i_visible_height;
> +    p_fmto->i_sar_den *= p_fmti->i_visible_height;
> +    vlc_ureduce(&p_fmto->i_sar_num, &p_fmto->i_sar_den,
> +                p_fmto->i_sar_num, p_fmto->i_sar_den, 65536);
> +
>  #if 0
>      msg_Dbg( p_filter, "%ix%i (%ix%i) chroma: %4.4s -> %ix%i (%ix%i)
> chroma: %4.4s extend by %d", p_fmti->i_visible_width,
> p_fmti->i_visible_height, p_fmti->i_width, p_fmti->i_height, (char
> *)&p_fmti->i_chroma,

-- 
Реми Денис-Курмон
http://www.remlab.net/