Draw a grid on the input image.

It accepts the following parameters:

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. For the general syntax of this option, check the "Color" section in the ffmpeg-utils manual. If the special value invert is used, the grid color is the same as the video with inverted luma.

thickness, t

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

See below for the list of accepted constants.

replace

Applicable if the input has alpha. With 1 the pixels of the painted grid will overwrite the video’s color and alpha pixels. Default is 0, which composites the grid onto the input, leaving the video’s alpha intact.

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.