[Cin] selectable vaapi decoder device

[Andrea paz]

Good plugin; thanks.
I append manual plugins.tex, image and mirror.txt, for those who want
to read the description but don't have latex. Please propose
corrections and improvements, thank you.
-------------- next part --------------
Mirror does more than simply flip (or reflect) the frame. It divides the frame into two vertical and/or horizontal half-planes, allowing them to be translated and oriented to achieve complex reflections and compositions, which can be reminiscent of kaleidoscope.

Horizontal: composes a reflection of the right half-plane joined to the left half-plane. The axis of reflection is central and vertical (Reflection Center). It can be used together with Vertical to have 4 half-planes of reflection.
Swap LEFT-RIGHT side: Swaps the two horizontal reflection half-planes, reversing their orientation. If this option is enabled, Enable Reflection Center is disabled.
Vertical: composes a reflection of the top half-plane joined to the bottom half-plane. The axis of reflection is central and horizontal (Reflection Center). It can be used together with Horizontal to have 4 half-planes of reflection.
Swap TOP-BOTTOM side: Swaps the two vertical reflection half-planes, reversing their orientation. If this option is enabled, Enable Reflection Center is disabled.
Enable Reflection Center: allows shifting the half-plane along the X-axis and/or along the Y-axis, relative to the Reflection Center. You can enter the percentage value or act on the slider for a visual adjustment. Checking this option excludes the use of swap functions.
Reset: returns all values to the initial conditions i.e., with only the Horizontal button enabled.

An example of horizontal + vertical reflection without Swap nor shifting of the center of reflection is shown in the figure
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Plugins.tex
Type: text/x-tex
Size: 352974 bytes
Desc: not available
URL: <https://lists.cinelerra-gg.org/pipermail/cin/attachments/20230829/e3a0f50a/attachment-0001.tex>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: mirror.png
Type: image/png
Size: 51096 bytes
Desc: not available
URL: <https://lists.cinelerra-gg.org/pipermail/cin/attachments/20230829/e3a0f50a/attachment-0001.png>