doc/filters: update documentation.

doc/filters.texi

@@ -17,10 +17,11 @@ output pads is called a "sink".
 @anchor{Filtergraph syntax}
 @section Filtergraph syntax
 
-A filtergraph can be represented using a textual representation, which
-is recognized by the @code{-vf} and @code{-af} options in @command{avconv}
-and @command{avplay}, and by the @code{av_parse_graph()} function defined in
-@file{libavfilter/avfiltergraph}.
+A filtergraph can be represented using a textual representation, which is
+recognized by the @option{-filter}/@option{-vf} and @option{-filter_complex}
+options in @command{avconv} and @option{-vf} in @command{avplay}, and by the
+@code{avfilter_graph_parse()}/@code{avfilter_graph_parse2()} function defined in
+@file{libavfilter/avfiltergraph.h}.
 
 A filterchain consists of a sequence of connected filters, each one
 connected to the previous one in the sequence. A filterchain is
@@ -1125,15 +1126,12 @@ Follow some examples:
 overlay=main_w-overlay_w-10:main_h-overlay_h-10
 
 # insert a transparent PNG logo in the bottom left corner of the input
-movie=logo.png [logo];
-[in][logo] overlay=10:main_h-overlay_h-10 [out]
+avconv -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
 
 # insert 2 different transparent PNG logos (second logo on bottom
 # right corner):
-movie=logo1.png [logo1];
-movie=logo2.png [logo2];
-[in][logo1]       overlay=10:H-h-10 [in+logo1];
-[in+logo1][logo2] overlay=W-w-10:H-h-10 [out]
+avconv -i input -i logo1 -i logo2 -filter_complex
+'overlay=10:H-h-10,overlay=W-w-10:H-h-10' output
 
 # add a transparent color layer on top of the main video,
 # WxH specifies the size of the main input to the overlay filter