[FFmpeg-devel] [PATCH 2/2] ffplay: support snap to 90degree autorotation

[Michael Niedermayer]

On Sun, May 03, 2015 at 08:04:52PM +0200, wm4 wrote:
> On Sun,  3 May 2015 03:10:05 +0200
> Michael Niedermayer <michaelni at gmx.at> wrote:
> 
> > do people prefer this to be enabled or disabled by default ?
> > 
> > Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
> > ---
> >  ffplay.c |    5 +++++
> >  1 file changed, 5 insertions(+)
> > 
> > diff --git a/ffplay.c b/ffplay.c
> > index eea00e6..48b09ee 100644
> > --- a/ffplay.c
> > +++ b/ffplay.c
> > @@ -343,6 +343,7 @@ static int nb_vfilters = 0;
> >  static char *afilters = NULL;
> >  #endif
> >  static int autorotate = 1;
> > +static int snapto90 = 0;
> >  
> >  /* current context */
> >  static int is_full_screen;
> > @@ -2032,6 +2033,9 @@ static int configure_video_filters(AVFilterGraph *graph, VideoState *is, const c
> >          if (displaymatrix && !theta)
> >              theta = av_display_rotation_get((int32_t*) displaymatrix);
> >  
> > +        if (snapto90)
> > +            theta = 90 * round(theta/90);
> > +
> >          theta -= 360*floor(theta/360 + 0.9/360);
> >  
> >          if (fabs(theta - 90) < 1.0) {
> > @@ -3742,6 +3746,7 @@ static const OptionDef options[] = {
> >      { "scodec", HAS_ARG | OPT_STRING | OPT_EXPERT, { &subtitle_codec_name }, "force subtitle decoder", "decoder_name" },
> >      { "vcodec", HAS_ARG | OPT_STRING | OPT_EXPERT, {    &video_codec_name }, "force video decoder",    "decoder_name" },
> >      { "autorotate", OPT_BOOL, { &autorotate }, "automatically rotate video", "" },
> > +    { "snapto90", OPT_BOOL, { &snapto90 }, "automatically rotate to any angle or multiplies of 90°", "" },
> >      { NULL, },
> >  };
> >  
> 
> Is there an actual use-case for this? Do files like this exist?

i dont know, i just want to fix and cleanup the code
so it doesnt randomly apply snapto90 in some cases and not in others

if someone does have a file that contains an angle which is not a
multiple of 90, i would like to have that file


> (And
> why would you want to "snap" them, instead of rotating them freely.)

if you rotate a rectangle by a angle thats not a multiple of 90 then
it doesnt fit cleanly in a 90deg aligned rectangle anymore so you
either end up with black triangles, or some parts cut off


[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

It is what and why we do it that matters, not just one of them.
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