Draw a grid on the input image.

This filter accepts the following options:

x, y

The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.

width, w, height, h

The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the input width and height, respectively, minus thickness, so image gets framed. Default to 0.

color, c

Specify the color of the grid, it can be the name of a color (case insensitive match) or a 0xRRGGBB[AA] sequence. If the special value invert is used, the grid color is the same as the video with inverted luma. Note that you can append opacity value (in range of 0.0 - 1.0) to color name after @ sign.

thickness, t

The expression which sets the thickness of the grid line. Default value is 1.

See below for the list of accepted constants.

The parameters for x, y, w and h and t are expressions containing the following constants:

dar

The input display aspect ratio, it is the same as (w / h) * sar.

hsub, vsub

horizontal and vertical chroma subsample values. For example for the pixel format "yuv422p" hsub is 2 and vsub is 1.

in_h, ih, in_w, iw

The input grid cell width and height.

sar

The input sample aspect ratio.

x, y

The x and y coordinates of some point of grid intersection (meant to configure offset).

w, h

The width and height of the drawn cell.

t

The thickness of the drawn cell.

These constants allow the x, y, w, h and t expressions to refer to each other, so you may for example specify y=x/dar or h=w/dar.