[FFmpeg-devel] [PATCH 3/3] avutil/stereo3d: add a Stereo3D type to signal that the packing is defined by the view field

[Anton Khirnov]

Quoting James Almer (2024-06-22 04:41:11)
> 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.

I don't really see what actual problem is this supposed to address,
rather it seems to me it just muddles the situation further.

When type is AV_STEREO3D_2D, the video is monoscopic and everything else
in AVStereo3D should be ignored. In this light I also don't see the
point of patch 1.

Nontrivial values of AVStereo3DView are meaningful only for a
stereoscopic non-packed video, i.e. AV_STEREO3D_FRAMESEQUENCE.

-- 
Anton Khirnov