manpage: mark some filters as deprecated in favor of libavfilter

This is basically a "do not use" label. We don't remove them yet,
because we still support FFmpeg releases where we can not use
libavfilter for various reasons. Also, Libav causes pain as usual
due to the lack of ported mplayer filters in its codebase, so not
all filters will be available there.

DOCS/man/en/vf.rst

@@ -425,6 +425,9 @@ noise[=luma[u][t|a][h][p]:chroma[u][t|a][h][p]]
     :h:       high quality (slightly better looking, slightly slower)
     :p:       mix random noise with a (semi)regular pattern
 
+    *NOTE*: deprecated. Use libavfilter's ``noise`` filter through
+    ``-vf lavfi`` instead.
+
 hqdn3d[=luma_spatial:chroma_spatial:luma_tmp:chroma_tmp]
     This filter aims to reduce image noise producing smooth images and making
     still images really still (This should enhance compressibility.).
@@ -439,6 +442,9 @@ hqdn3d[=luma_spatial:chroma_spatial:luma_tmp:chroma_tmp]
         chroma temporal strength (default:
         ``luma_tmp*chroma_spatial/luma_spatial``)
 
+    *NOTE*: deprecated. Use libavfilter's ``hqdn3d`` filter through
+    ``-vf lavfi`` instead.
+
 eq[=gamma:contrast:brightness:saturation:rg:gg:bg:weight]
     Software equalizer that uses lookup tables (slow),
     allowing gamma correction in addition to simple brightness and contrast
@@ -499,9 +505,15 @@ unsharp[=l|cWxH:amount[:l|cWxH:amount]]
         :<0: blur
         :>0: sharpen
 
+    *NOTE*: deprecated. Use libavfilter's ``unsharp`` filter through
+    ``-vf lavfi`` instead.
+
 swapuv
     Swap U & V plane.
 
+    *NOTE*: deprecated. Use libavfilter's ``swapuv`` filter through
+    ``-vf lavfi`` instead.
+
 pullup[=jl:jr:jt:jb:sb:mp]
     Third-generation pulldown reversal (inverse telecine) filter, capable of
     handling mixed hard-telecine, 24000/1001 fps progressive, and 30000/1001
@@ -662,6 +674,14 @@ yadif=[mode[:enabled=yes|no]]
         :no:  Filter is not active, but can be deactivated with the ``D`` key
               (or any other key that toggles the ``deinterlace`` property).
 
+    *NOTE*: deprecated. Use libavfilter's ``yadif`` filter through
+    ``-vf lavfi`` instead.
+
+    This filter, or libavfilter's implementation if available, is automatically
+    inserted when using the ``D`` key (or any other key that toggles the
+    ``deinterlace`` property), assuming the video output does not have native
+    deinterlacing support.
+
 down3dright[=lines]
     Reposition and resize stereoscopic images. Extracts both stereo fields and
     places them side by side, resizing them to maintain the original movie
@@ -688,6 +708,9 @@ delogo[=x:y:w:h:t]
         must have a timestamp (in seconds, and in ascending order) and the
         "x:y:w:h:t" coordinates (*t* can be omitted).
 
+    *NOTE*: deprecated. Use libavfilter's ``delogo`` or ``removelogo`` filters
+    through ``-vf lavfi`` instead.
+
 screenshot
     Optional filter for screenshot support. This is only needed if the video
     output doesn't provide working direct screenshot support. Note that it is
@@ -781,6 +804,9 @@ stereo3d[=in:out]
         mr or mono_right
             mono output (right eye only)
 
+    *NOTE*: deprecated. Use libavfilter's ``stereo3d`` filter through
+    ``-vf lavfi`` instead.
+
 gradfun[=strength[:radius]]
     Fix the banding artifacts that are sometimes introduced into nearly flat
     regions by truncation to 8bit colordepth. Interpolates the gradients that
@@ -799,6 +825,9 @@ gradfun[=strength[:radius]]
         gradients, but also prevents the filter from modifying pixels near
         detailed regions (default: 16).
 
+    *NOTE*: deprecated. Use libavfilter's ``gradfun`` filter through
+    ``-vf lavfi`` instead.
+
 dlopen=dll[:a0[:a1[:a2[:a3]]]]
     Loads an external library to filter the image. The library interface
     is the vf_dlopen interface specified using libmpcodecs/vf_dlopen.h.