vf_lavfi: add libavfilter bridge

Requires recent FFmpeg/Libav git versions. Earlier versions will not
be supported, as the API is different. (A libavfilter version that
uses AVFrame instead of AVFilterBuffer is needed.)

Note that this is sort of useless, because the option parser prevents
you from making use of the full libavfilter graph syntax. This has to be
fixed later.

Most of the filter creation code (half of the config() function) has
been taken from avplay.c.

This code is not based on MPlayer's vf_lavfi. The MPlayer code doesn't
compile as it hasn't been updated through multiple libavfilter API
changes, making it completely useless as a starting point.

1 files changed, 31 insertions, 0 deletions

diff --git a/DOCS/man/en/vf.rst b/DOCS/man/en/vf.rst
index 4e1e0b733b..1d6a8512d6 100644
--- a/DOCS/man/en/vf.rst
+++ b/DOCS/man/en/vf.rst
@@ -367,6 +367,37 @@ pp[=filter1[:option1[:option2...]]/[-]filter2...]
         Horizontal deblocking on luminance only, and switch vertical
         deblocking on or off automatically depending on available CPU time.
 
+lavfi=graph[:sws_flags]
+
+    <graph>
+        The libavfilter graph string. The filter must have a single video input
+        pad and a single video output pad.
+
+        See ``https://ffmpeg.org/ffmpeg-filters.html`` for syntax and available
+        filters.
+
+        *WARNING*: if you want to use the full filter syntax with this option,
+        you have to quote the filter graph in order to prevent mpv's syntax
+        and the filter graph syntax from clashing.
+
+        *EXAMPLE*:
+
+        ``'--vf=lavfi=graph="gradfun=20:30"'``
+            gradfun filter with non-sensical parameters. The ``'`` quotes are
+            for the shell. Otherwise, the shell would remove the ``"`` quotes.
+
+        ``'--vf=lavfi=graph="gradfun=radius=30:strength=20,vflip"'``
+            same as before, but uses named parameters. Also a vflip filter is
+            appended, demonstrating how libavfilter actually takes a graph
+            description and not a single filter.
+
+    <sws_flags>
+        If libavfilter inserts filters for pixel format conversion, this
+        option gives the flags which should be passed to libswscale. This
+        option is numeric and takes a bit-wise combination of ``SWS_`` flags.
+
+        See ``http://git.videolan.org/?p=ffmpeg.git;a=blob;f=libswscale/swscale.h``.
+
 noise[=luma[u][t|a][h][p]:chroma[u][t|a][h][p]]
     Adds noise.