avfilter/vf_v360: implement stereo 3D support

doc/filters.texi

@@ -18080,6 +18080,21 @@ Set the output video resolution.
 
 Default resolution depends on formats.
 
+@item in_stereo
+@item out_stereo
+Set the input/output stereo format.
+
+@table @samp
+@item 2d
+2D mono
+@item sbs
+Side by side
+@item tb
+Top bottom
+@end table
+
+Default value is @b{@samp{2d}} for input and output format.
+
 @item yaw
 @item pitch
 @item roll

libavfilter/v360.h

@@ -22,6 +22,13 @@
 #define AVFILTER_V360_H
 #include "avfilter.h"
 
+enum StereoFormats {
+    STEREO_2D,
+    STEREO_SBS,
+    STEREO_TB,
+    NB_STEREO_FMTS,
+};
+
 enum Projections {
     EQUIRECTANGULAR,
     CUBEMAP_3_2,
@@ -95,6 +102,8 @@ typedef struct V360Context {
     int out_cubemap_face_rotation[6];
     int rotation_order[3];
 
+    int in_stereo, out_stereo;
+
     float in_pad, out_pad;
 
     float yaw, pitch, roll;
@@ -108,6 +117,11 @@ typedef struct V360Context {
 
     float input_mirror_modifier[2];
 
+    int pr_width[4], pr_height[4];
+
+    int in_offset_w[4], in_offset_h[4];
+    int out_offset_w[4], out_offset_h[4];
+
     int planewidth[4], planeheight[4];
     int inplanewidth[4], inplaneheight[4];
     int uv_linesize[4];