On 9/12/19, Michael Koch <[email protected]> wrote: > Am 12.09.2019 um 14:05 schrieb Paul B Mahol: >> On 9/12/19, Michael Koch <[email protected]> wrote: >>> Paul, >>> >>>>>> Make this correction: >>>>>> >>>>>> new_fov = 180 * tan(fov/4) >>>>>> >>>>>> where fov the the field of view you get from the command line, and >>>>>> fov_new is the value that you use for the filter. >>>>>> You must exclude values too close to 360°, because 360° stereographic >>>>>> projection is impossible. >>>>>> >>>>> P.S. of course fov must be converted to radians before using tan(): >>>>> >>>>> new_fov = 180 * tan(fov * pi / 720) >>>> Thanks, that cleared some stuff. >>>> Should be fixed. >>> Converting from equirectangular to stereographic is working fine now. >>> Field of view is correct. >>> But in the other direction from stereographic to equirectangular the >>> output is wrong. >>> The output doesn't contain any no-data areas. I mean those areas that >>> aren't visible in the stereographic input. These areas should be filled >>> with black (or better a user-defined color). >> That is not doable by design. > > What about fisheye input and output? > Fisheye (180°) input is almost the same as already implemented as > dfisheye, and if the second hemisphere doesn't exist it can be replaced > by a color. > Fisheye input and output is important. For example I've made a long-time > timelapse from many fisheye images, but some of the images require a few > degrees tilting. That means the fisheye image must be converted to > equirectangular, tilted, and then converted back to fisheye.
I'm working on dual fisheye output.... > >> >>> Also, the default output size should be width/height=2, but it is >>> quadratic. >> output size for what? > > The equirectangular output image should have width/height=2 by default. Will try to fix it. > > Question: > If the input format is stereographic and the output format is > equirectangular, what's then the meaning of the h_fov and v_fov parameters? > Do they define the field of view of the stereographic input (that would > make sense), > or do they define the field of view of the equirectangular output (that > makes no sense, because equirectangular should always be 360° x 180°). They are always used only for output when they make sense, for flat and stereographic currently. > > Michael > > _______________________________________________ > ffmpeg-user mailing list > [email protected] > https://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email > [email protected] with subject "unsubscribe". _______________________________________________ ffmpeg-user mailing list [email protected] https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
