[vlc-devel] [PATCH v2 14/14] picture: always copy context when cloning

[Rémi Denis-Courmont]

Le lundi 17 août 2020, 17:15:05 EEST Alexandre Janniaux a écrit :
> Yes, but on linux you could have different kind of wrapping,
> unlike D3D11 pictures. wl_buffer, direct DMA request or maybe
> some X11 object (I don't really know this part of the protocol
> for X11).

I fail to see that on Linux.

X11 only supports MIT-SHM (in semi-broken and unfixable way) and file 
descriptors. VLC uses file descriptors.

Wayland only supports file descriptors, and that's very unlikely to change, as 
pretty much nothing else can be passed over a local domain socket.

DMA-BUF is based on file descriptors as well.

It all boils down to the fact that file descriptors are the universal resource 
credential handle type on Linux. In fact, the vout display modules already 
assume that addressible pictures are based on a file descriptor anyway, be that 
a memfd or something else. Rendering breaks if picture_t.sys is not a file 
descriptor.

-- 
Rémi Denis-Courmont