Draw a colored box on the input image.

It accepts the following parameters:

x, y

The expressions which specify the top left corner coordinates of the box. It defaults to 0.

width, w, height, h

The expressions which specify the width and height of the box; if 0 they are interpreted as the input width and height. It defaults to 0.

color, c

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

thickness, t

The expression which sets the thickness of the box edge. A value of fill will create a filled box. Default value is 3.

See below for the list of accepted constants.

replace

Applicable if the input has alpha. With value 1, the pixels of the painted box will overwrite the video’s color and alpha pixels. Default is 0, which composites the box 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 width and height.

sar

The input sample aspect ratio.

x, y

The x and y offset coordinates where the box is drawn.

w, h

The width and height of the drawn box.

t

The thickness of the drawn box.

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.