On Wed, Nov 16, 2016 at 05:38:20PM -0500, Vittorio Giovara wrote: > On Tue, Nov 15, 2016 at 8:52 PM, James Almer <jamr...@gmail.com> wrote: > > On 11/15/2016 10:39 PM, Michael Niedermayer wrote: > >> On Tue, Nov 15, 2016 at 11:56:48AM -0500, Vittorio Giovara wrote: > >> [...] > >>> +/** > >>> + * This structure describes how to handle spherical videos, outlining > >>> + * information about projection, initial layout, and any other view > >>> modifier. > >>> + * > >>> + * @note The struct must be allocated with av_spherical_alloc() and > >>> + * its size is not a part of the public ABI. > >>> + */ > >>> +typedef struct AVSphericalMapping { > >>> + /** > >>> + * Projection type. > >>> + */ > >>> + enum AVSphericalProjection projection; > >>> + > >>> + /** > >>> + * @name Initial orientation > >>> + * @{ > >>> + * These fields represent the pose values that measure the rotation > >>> + * transformation (in degrees) to be applied to the projection. > >> > >>> + * They are exported as 16.16 fixed point. > >> > >> why waste 7 bits of precission ? > > > > 16.16 seems to be part of the spec > > > > https://github.com/google/spatial-media/blob/master/docs/spherical-video-v2-rfc.md > > Correct, there is no point in adding more precision that the > underlying layer can withhold.
if people prefer storing angle * 180 * (1<<16) / PI (using about 25bits of 32bits) instead of angle * (1<<31 - 1) / PI (using 32bits) than iam happy with that too, ive a slight preferrance for using the full 32bits though to me the "underlying layer" for rotations is not some spec but reality [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB The greatest way to live with honor in this world is to be what we pretend to be. -- Socrates
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