[FFmpeg-user] Aspect Ratios: DAR, SAR and Frame Size

[Adi Shavit]

Thanks. I think I sort-of understand what didn't.
I don't really have any command line besides the -i option as I wrote in my
first post.
Thanks,
Adi

BTW, according to
this<http://ffmpeg.org/pipermail/ffmpeg-user/2014-January/thread.html#19357>
no
one was top-posting replies (except the first question post).


On Mon, Jan 13, 2014 at 5:21 PM, Rio Kierkels <riokierkels at gmail.com> wrote:

> I think the ffmpeg command internally applies the SAR and DAR variables and
> transforms the resolution until SAR is 1:1 and DAR matches the resolution
> aspect ratio when it decodes the source footage. This way the math
> internally is easier. On output it will recompute them according to your
> given scale settings and other settings that could influence the aspect
> ratios.
> Still if you really want a good answer you should supply example input and
> output files.
>
> I have a small test dpx sequence that I often use. If you guy's like I can
> put it on an ftp server somewhere.
>
>
>
>
> On 13 January 2014 16:11, Adi Shavit <adishavit at gmail.com> wrote:
>
> > Hi Rio,
> >
> >   Thanks for the prompt reply.
> >
> > the DAR and SAR are applied on playback by the player you use. 352x240
> are
> > > the actual pixels stored in the file.
> > >
> >
> > This basically answers my last question.
> >
> >
> > > By default ffmpeg stretches you image to the dimensions you specify, no
> > > padding or cropping is done. <snip>
> >
> >
> >
> >
> > If I understand what you say, then if I didn't specify any special
> > dimensions, then ffmpeg will not do any stretching?
> >
> > But, if DAR and SAR are applied only on playback (by any respectable
> > player), wouldn't they be applied by *ffmpeg itself *when encoding to a
> new
> > file format or, say, when saving frames as JPGs?
> >
> > Thanks,
> > Adi
> > _______________________________________________
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> >
>
>
>
> --
> 42
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