[FFmpeg-devel] [PATCH 2/8 v2] avutil/stereo3d: add a Stereo3D type to signal that the packing is defined by the view field

[James Almer]

Given that a video stream/frame may have only one view coded, or both packed in
an undefined way, and as the values of AVStereo3DView and AVStereo3DType may
clash (namely if type is AV_STEREO3D_2D, then AV_STEREO3D_VIEW_PACKED would be
invalid, and if it's anything other than it, then only AV_STEREO3D_VIEW_PACKED
would be valid), this commit adds a new type value AV_STEREO3D_VIEW that
signals the user that AVStereo3D.view contains information about the nature of
the stream, with the added constrain that AVStereo3D.view should be ignored if
AVStereo3D.type is anything other than AV_STEREO3D_VIEW.

Signed-off-by: James Almer <jamrial at gmail.com>
---
This is the only way i could think of to work around the fact AVStereo3DType
and AVStereo3DView just can't work well together if we want to keep AVStereo
backwards compatible.

 libavutil/stereo3d.c |  1 +
 libavutil/stereo3d.h | 11 ++++++++++-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/libavutil/stereo3d.c b/libavutil/stereo3d.c
index 0c0cad127c..e8e5030db9 100644
--- a/libavutil/stereo3d.c
+++ b/libavutil/stereo3d.c
@@ -65,6 +65,7 @@ static const char * const stereo3d_type_names[] = {
     [AV_STEREO3D_SIDEBYSIDE_QUINCUNX] = "side by side (quincunx subsampling)",
     [AV_STEREO3D_LINES]               = "interleaved lines",
     [AV_STEREO3D_COLUMNS]             = "interleaved columns",
+    [AV_STEREO3D_VIEW]                = "view defined",
 };
 
 static const char * const stereo3d_view_names[] = {
diff --git a/libavutil/stereo3d.h b/libavutil/stereo3d.h
index 77340f72b2..e3af519e03 100644
--- a/libavutil/stereo3d.h
+++ b/libavutil/stereo3d.h
@@ -136,6 +136,14 @@ enum AVStereo3DType {
      * @endcode
      */
     AV_STEREO3D_COLUMNS,
+
+    /**
+     * Video may be monoscopic, or stereoscopic where either the
+     * packing is unknown or only one view is present.
+     *
+     * @see AVStereo3DView
+     */
+    AV_STEREO3D_VIEW,
 };
 
 /**
@@ -207,7 +215,8 @@ typedef struct AVStereo3D {
     int flags;
 
     /**
-     * Determines which views are packed.
+     * Determines which views are packed. This field should be ignored when
+     * @ref type is set to anything other than AV_STEREO3D_VIEW.
      */
     enum AVStereo3DView view;
 
-- 
2.45.2