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: 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 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 above is equivalent to
setdar=1.77777

See also the "setsar" filter documentation (setsar).