vf_vapoursynth: add standalone Lua scripting

1 files changed, 25 insertions, 0 deletions

diff --git a/DOCS/man/vf.rst b/DOCS/man/vf.rst
index b8a258bbd9..6e7418c0c3 100644
--- a/DOCS/man/vf.rst
+++ b/DOCS/man/vf.rst
@@ -910,6 +910,31 @@ Available filters are:
         making it higher than the number of cores can actually make it
         slower.
 
+``vapoursynth-lazy``
+    The same as ``vapoursynth``, but doesn't load Python scripts. Instead, a
+    custom backend using Lua and the raw VapourSynth API is used. The syntax
+    is completely different, and absolutely no conveniencve features are
+    provided. There's no type checking either, and you can trigger crashes.
+
+    .. admonition:: Example:
+
+        ::
+
+            video_out = invoke("morpho", "Open", {clip = video_in})
+
+    The special variable ``video_in`` is the mpv video source, while the
+    special variable ``video_out`` is used to read video from. The 1st argument
+    is the plugin (queried with ``getPluginByNs``), the 2nd is the filter name,
+    and the 3rd argument is a table with the arguments. Positional arguments
+    are not supported. The types must match exactly. Since Lua is terrible and
+    can't distinguish integers and floats, integer arguments must be prefixed
+    with ``i_``, in which case the prefix is removed and the argument is cast
+    to an integer. Should the argument's name start with ``i_``, you're out of
+    luck.
+
+    Clips (VSNodeRef) are passed as light userdata, so trying to pass any
+    other userdata type will result in hard crashes.
+
 ``vavpp``
     VA-AP-API video post processing. Works with ``--vo=vaapi`` and ``--vo=opengl``
     only. Currently deinterlaces. This filter is automatically inserted if