Romain Vimont authored Feb 04, 2020 and Jean-Baptiste Kempf committed Mar 23, 2020

The multiview mode (stereo) was applied by changing the texture
paddings to crop only the left eye.

The problem is that these texture paddings are specific to the input
picture, while the stereo mode is specific to the renderer, which should
be independent of the input picture.

To separate these concerns, apply the stereo mode using a matrix to
transform the texture coordinates from the renderer.

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>