[FFmpeg-devel] [PATCH 2/2] doc/faq: explain DAR/SAR preserving.

[Michael Niedermayer]

On Mon, Feb 16, 2015 at 07:49:50PM +0100, Nicolas George wrote:
> L'octidi 28 pluviôse, an CCXXIII, Clement Boesch a écrit :
> > A lot of users will want to know how to avoid the transcode.
> 
> True. New patch attached.
> 
> Regards,
> 
> -- 
>   Nicolas George

>  faq.texi |   34 ++++++++++++++++++++++++++++++++++
>  1 file changed, 34 insertions(+)
> 5193c6d2bce98c5addcc246e311c29e7af2d837d  0001-doc-faq-explain-DAR-SAR-preserving.patch
> From db3ed4560061be5cbfad5547ef7a2d9af7ccb874 Mon Sep 17 00:00:00 2001
> From: Nicolas George <george at nsup.org>
> Date: Mon, 9 Feb 2015 16:17:22 +0100
> Subject: [PATCH] doc/faq: explain DAR/SAR preserving.
> 
> Signed-off-by: Nicolas George <george at nsup.org>
> ---
>  doc/faq.texi | 34 ++++++++++++++++++++++++++++++++++
>  1 file changed, 34 insertions(+)
> 
> diff --git a/doc/faq.texi b/doc/faq.texi
> index 494da86..c3db720 100644
> --- a/doc/faq.texi
> +++ b/doc/faq.texi
> @@ -467,6 +467,40 @@ point acceptable for your tastes. The most common options to do that are
>  @option{-qscale} and @option{-qmax}, but you should peruse the documentation
>  of the encoder you chose.
>  
> + at section I have a stretched video, why does scaling does not fix it?
> +
> +A lot of video codecs and formats can store the @emph{aspect ratio} of the
> +video: this is the ratio between the width and the height of either the full
> +image (DAR, display aspect ratio) or individual pixels (SAR, sample aspect

> +ratio). For example, EGA screens at resolution 640×350 had 4:3 DAR and 35:48

this x looks strange, and we had problems with these in the past
and removed them: 1afbb4c226203c1a0853c9ad469cd9ef337080e4

patch LGTM otherwise

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

It is dangerous to be right in matters on which the established authorities
are wrong. -- Voltaire
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