Merge remote-tracking branch 'qatar/master'

[ffmpeg] / doc / filters.texi

diff --git a/doc/filters.texi b/doc/filters.texi
index 0f82168b23478d581ee1199d2b47dc5b7d7a4c8d..e202d383d9db70f9bca9367193ec685a07b4e6bf 100644 (file)
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -79,7 +79,18 @@ display graph.png
 @end example
 
 can be used to create and display an image representing the graph
-described by the @var{GRAPH_DESCRIPTION} string.
+described by the @var{GRAPH_DESCRIPTION} string. Note that this string must be
+a complete self-contained graph, with its inputs and outputs explicitly defined.
+For example if your command line is of the form:
+@example
+ffmpeg -i infile -vf scale=640:360 outfile
+@end example
+your @var{GRAPH_DESCRIPTION} string will need to be of the form:
+@example
+nullsrc,scale=640:360,nullsink
+@end example
+you may also need to set the @var{nullsrc} parameters and add a @var{format}
+filter in order to simulate a specific input file.
 
 @c man end GRAPH2DOT
 
@@ -738,14 +749,17 @@ The filter accepts the following named parameters:
 @table @option
 
 @item compensate
-Enable stretching/squeezing the data to make it match the timestamps.
+Enable stretching/squeezing the data to make it match the timestamps. Disabled
+by default. When disabled, time gaps are covered with silence.
 
 @item min_delta
 Minimum difference between timestamps and audio data (in seconds) to trigger
-adding/dropping samples.
+adding/dropping samples. Default value is 0.1. If you get non-perfect sync with
+this filter, try setting this parameter to 0.
 
 @item max_comp
-Maximum compensation in samples per second.
+Maximum compensation in samples per second. Relevant only with compensate=1.
+Default value 500.
 
 @item first_pts
 Assume the first pts should be this value.
@@ -2318,6 +2332,26 @@ Specify the saturation in the [-10,10] range. It accepts a float number and
 defaults to 1.0.
 @end table
 
+The @var{h}, @var{H} and @var{s} parameters are expressions containing the
+following constants:
+
+@table @option
+@item n
+frame count of the input frame starting from 0
+
+@item pts
+presentation timestamp of the input frame expressed in time base units
+
+@item r
+frame rate of the input video, NAN if the input frame rate is unknown
+
+@item t
+timestamp expressed in seconds, NAN if the input timestamp is unknown
+
+@item tb
+time base of the input video
+@end table
+
 The options can also be set using the syntax: @var{hue}:@var{saturation}
 
 In this case @var{hue} is expressed in degrees.
@@ -2348,6 +2382,36 @@ h and s, so the following example will issue an error:
 @example
 hue=PI/2:1
 @end example
+
+@item
+Rotate hue and make the saturation swing between 0
+and 2 over a period of 1 second:
+@example
+hue="H=2*PI*t: s=sin(2*PI*t)+1"
+@end example
+
+@item
+Apply a 3 seconds saturation fade-in effect starting at 0:
+@example
+hue="s=min(t/3\,1)"
+@end example
+
+The general fade-in expression can be written as:
+@example
+hue="s=min(0\, max((t-START)/DURATION\, 1))"
+@end example
+
+@item
+Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
+@example
+hue="s=max(0\, min(1\, (8-t)/3))"
+@end example
+
+The general fade-out expression can be written as:
+@example
+hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
+@end example
+
 @end itemize
 
 @subsection Commands
@@ -2537,7 +2601,6 @@ The list of the currently supported filters follows:
 @item pullup
 @item qp
 @item rectangle
-@item rotate
 @item sab
 @item softpulldown
 @item softskip
@@ -2556,11 +2619,20 @@ of the corresponding MPlayer filters. For detailed instructions check
 the "VIDEO FILTERS" section in the MPlayer manual.
 
 Some examples follow:
+@itemize
+@item
+Adjust gamma, brightness, contrast:
 @example
-# adjust gamma, brightness, contrast
 mp=eq2=1.0:2:0.5
 @end example
 
+@item
+Add temporal noise to input video:
+@example
+mp=noise=20t
+@end example
+@end itemize
+
 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
 
 @section negate
@@ -4186,6 +4258,9 @@ Accept in input an expression evaluated through the eval API, which
 can contain the following constants:
 
 @table @option
+@item FRAME_RATE
+frame rate, only defined for constant frame-rate video
+
 @item PTS
 the presentation timestamp in input