[FFmpeg-devel] [ANNOUNCE] New Commercial Product Using FFMPEG - Thanks To Developers.
michaelni at gmx.at
Wed Nov 28 00:27:08 CET 2012
On Mon, Nov 26, 2012 at 02:19:53AM -0600, ffmpeg-devel at ballcam.com wrote:
> Michael Niedermayer <michaelni at gmx.at> wrote:
> > On Mon, Nov 26, 2012 at 12:50:23AM +0100, Stefano Sabatini wrote:
> > > On date Friday 2012-11-23 01:59:55 -0600, ffmpeg-devel at ballcam.com encoded:
> > > [...]
> > > > libavfilter was originally considered to do the unrotating,
> > > > but as far as it is understood at this time, the rotate
> > > > filter only works in 90 degree increments. (Currently
> > > > FFMPEG-1.0 is used, and unless there is a need to use
> > > > a later commit, point-releases will be used).
> > > >
> > > > If the FFMPEG team would like to include arbitrary angular
> > > > rotation as part of the rotate libavfilter, please respond as
> > > > such to this message, and BallCam Technologies Inc. may
> > > > pursue that as part of its contribution.
> > >
> > > Check the (still flawed) vf_rotate.c filter in the archive. The
> > > rotation angle may be injected through the metadata API into each
> > > frame.
> > but make sure you do not use some nearest neighbor code, its very bad
> > quality and will be rejected if submited that way.
> > the vf_perspective code is doing proper linear and cubic interpolation
> > vf_rotate did nearest neighbor at some point IIRC, i dont know if the
> > last patch still did
> > [...]
> > --
> > Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
> > Into a blind darkness they enter who follow after the Ignorance,
> > they as if into a greater darkness enter who devote themselves
> > to the Knowledge alone. -- Isha Upanishad
> Before I go any farther, the method I use is to crop out the central area
> from a rotated frame. (The rotated framegets larger, as you can imagine.)
> Each frame that is "unrotated" may be larger than the original. You can see
> how Imagemagick, or Leptonica does it. I then crop out the common area.
> If vf_rotate.c (or perspective) rotates the image, then squeezes it into
> a bounding box the size of the original frame, that will not do.
any rotation or "perspective" code can be changed so as to output to a
larger frame than its input
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
While the State exists there can be no freedom; when there is freedom there
will be no State. -- Vladimir Lenin
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