diff options
| -rw-r--r-- | doc/filters.texi | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/doc/filters.texi b/doc/filters.texi index 872afc6ca1..00a954ca84 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -789,6 +789,36 @@ ratio of the input image. The default value of @var{width} and @var{height} is 0. +@anchor{setdar} +@section setdar + +Set the Display Aspect Ratio for the filter output video. + +This is done by changing the specified Sample (aka Pixel) Aspect +Ratio, according to the following equation: +@math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR} + +Keep in mind that this filter does not modify the pixel dimensions of +the video frame. Also the display aspect ratio set by this filter may +be changed by later filters in the filterchain, e.g. in case of +scaling or if another "setdar" or a "setsar" filter is applied. + +The filter accepts a parameter string which represents the wanted +display aspect ratio. +The parameter can be a floating point number string, or an expression +of the form @var{num}:@var{den}, where @var{num} and @var{den} are the +numerator and denominator of the aspect ratio. +If the parameter is not specified, it is assumed the value "0:1". + +For example to change the display aspect ratio to 16:9, specify: +@example +setdar=16:9 +# the above is equivalent to +setdar=1.77777 +@end example + +See also the "setsar" filter documentation (@pxref{setsar}). + @section setpts Change the PTS (presentation timestamp) of the input video frames. @@ -849,6 +879,32 @@ setpts=N/(25*TB) setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))' @end example +@anchor{setsar} +@section setsar + +Set the Sample (aka Pixel) Aspect Ratio for the filter output video. + +Note that as a consequence of the application of this filter, the +output display aspect ratio will change according to the following +equation: +@math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR} + +Keep in mind that the sample aspect ratio set by this filter may be +changed by later filters in the filterchain, e.g. if another "setsar" +or a "setdar" filter is applied. + +The filter accepts a parameter string which represents the wanted +sample aspect ratio. +The parameter can be a floating point number string, or an expression +of the form @var{num}:@var{den}, where @var{num} and @var{den} are the +numerator and denominator of the aspect ratio. +If the parameter is not specified, it is assumed the value "0:1". + +For example to change the sample aspect ratio to 10:11, specify: +@example +setsar=10:11 +@end example + @section settb Set the timebase to use for the output frames timestamps. |