deshake: add documentation in filters.texi

Signed-off-by: Stefano Sabatini <stefasab@gmail.com>
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Paul Flinders 2011-10-20 16:10:16 +02:00 committed by Stefano Sabatini
parent ce253edf4e
commit e2c213328b
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@ -744,6 +744,76 @@ delogo=x=0:y=0:w=100:h=77:band=10
@end itemize
@section deshake
Attempt to fix small changes in horizontal and/or vertical shift. This
filter helps remove camera shake from hand-holding a camera, bumping a
tripod, moving on a vehicle, etc.
The filter accepts parameters as a string of the form
"@var{x}:@var{y}:@var{w}:@var{h}:@var{rx}:@var{ry}:@var{edge}:@var{blocksize}:@var{contrast}:@var{search}:@var{filename}"
A description of the accepted parameters follows.
@table @option
@item x, y, w, h
Specify a rectangular area where to limit the sarch for motion
vectors.
If desired the search for motion vectors can be limited to a
rectangular area of the frame defined by its top left corner, width
and height. These parameters have the same meaning as the drawbox
filter which can be used to visualise the position of the bounding
box.
This is useful when simultaneous movement of subjects within the frame
might be confused for camera motion by the motion vector search.
If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
then the full frame is used. This allows later options to be set
without specifying the bounding box for the motion vector search.
Default - search the whole frame.
@item rx, ry
Specify the maximum extent of movement in x and y directions in the
range 0-64 pixels. Default 16.
@item edge
Specify how to generate pixels to fill blanks at the edge of the
frame. An integer from 0 to 3 as follows:
@table @option
@item 0
Fill zeroes at blank locations
@item 1
Original image at blank locations
@item 2
Extruded edge value at blank locations
@item 3
Mirrored edge at blank locations
@end table
The default setting is mirror edge at blank locations.
@item blocksize
Specify the blocksize to use for motion search. Range 4-128 pixels,
default 8.
@item contrast
Specify the contrast threshold for blocks. Only blocks with more than
the specified contrast (difference between darkest and lightest
pixels) will be considered. Range 1-255, default 125.
@item search
Specify the search strategy 0 = exhaustive search, 1 = less exhaustive
search. Default - exhaustive search.
@item filename
If set then a detailed log of the motion search is written to the
specified file.
@end table
@section drawbox
Draw a colored box on the input image.