[FFmpeg-cvslog] avfilter/vf_v360: fix hfov/vfov calculation from dfov for sg projection

[Paul B Mahol]

ffmpeg | branch: master | Paul B Mahol <onemda at gmail.com> | Wed Mar 25 13:38:01 2020 +0100| [0b4389753035c9a69116ea4a4a8caee213ed7c24] | committer: Paul B Mahol

avfilter/vf_v360: fix hfov/vfov calculation from dfov for sg projection

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=0b4389753035c9a69116ea4a4a8caee213ed7c24
---

 libavfilter/vf_v360.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/libavfilter/vf_v360.c b/libavfilter/vf_v360.c
index ae94354212..fe0c9f3c4d 100644
--- a/libavfilter/vf_v360.c
+++ b/libavfilter/vf_v360.c
@@ -3542,6 +3542,15 @@ static int allocate_plane(V360Context *s, int sizeof_uv, int sizeof_ker, int siz
 static void fov_from_dfov(int format, float d_fov, float w, float h, float *h_fov, float *v_fov)
 {
     switch (format) {
+    case STEREOGRAPHIC:
+        {
+            const float d = 0.5f * hypotf(w, h);
+            const float l = d / (tanf(d_fov * M_PI / 720.f));
+
+            *h_fov = 2.f * atan2f(w * 0.5f, l) * 360.f / M_PI;
+            *v_fov = 2.f * atan2f(h * 0.5f, l) * 360.f / M_PI;
+        }
+        break;
     case FISHEYE:
         {
             const float d = 0.5f * hypotf(w, h);