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Diffstat (limited to 'doc/filters.texi')
| -rw-r--r-- | doc/filters.texi | 26 |
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diff --git a/doc/filters.texi b/doc/filters.texi index 5a929960ba..abfde1b131 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -2237,6 +2237,32 @@ format=monow, pixdesctest can be used to test the monowhite pixel format descriptor definition. +@section removelogo + +Suppress a TV station logo, using an image file to determine which +pixels comprise the logo. It works by filling in the pixels that +comprise the logo with neighboring pixels. + +This filter requires one argument which specifies the filter bitmap +file, which can be any image format supported by libavformat. The +width and height of the image file must match those of the video +stream being processed. + +Pixels in the provided bitmap image with a value of zero are not +considered part of the logo, non-zero pixels are considered part of +the logo. If you use white (255) for the logo and black (0) for the +rest, you will be safe. For making the filter bitmap, it is +recommended to take a screen capture of a black frame with the logo +visible, and then using a threshold filter followed by the erode +filter once or twice. + +If needed, little splotches can be fixed manually. Remember that if +logo pixels are not covered, the filter quality will be much +reduced. Marking too many pixels as part of the logo does not hurt as +much, but it will increase the amount of blurring needed to cover over +the image and will destroy more information than necessary, and extra +pixels will slow things down on a large logo. + @section scale Scale the input video to @var{width}:@var{height}[:@var{interl}=@{1|-1@}] and/or convert the image format. |