The setdar
filter sets 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:
DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR
Keep in mind that the setdar
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 setsar
filter sets 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 equation above.
Keep in mind that the sample aspect ratio set by the setsar
filter may be changed by later filters in the filterchain, e.g. if
another "setsar" or a "setdar" filter is applied.
The setdar
and setsar
filters accept a parameter string
which represents the wanted aspect ratio. The parameter can
be a floating point number string, an expression, or a string of the form
num:den, where num and 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:
setdar=16:9
The example above is equivalent to:
setdar=1.77777
To change the sample aspect ratio to 10:11, specify:
setsar=10:11