eq

Set brightness, contrast, saturation and approximate gamma adjustment.

The filter accepts the following options:

'contrast'

Set the contrast expression. The value must be a float value in range -2.0 to 2.0. The default value is "1".

'brightness'

Set the brightness expression. The value must be a float value in range -1.0 to 1.0. The default value is "0".

'saturation'

Set the saturation expression. The value must be a float in range 0.0 to 3.0. The default value is "1".

'gamma'

Set the gamma expression. The value must be a float in range 0.1 to 10.0. The default value is "1".

'gamma_r'

Set the gamma expression for red. The value must be a float in range 0.1 to 10.0. The default value is "1".

'gamma_g'

Set the gamma expression for green. The value must be a float in range 0.1 to 10.0. The default value is "1".

'gamma_b'

Set the gamma expression for blue. The value must be a float in range 0.1 to 10.0. The default value is "1".

'gamma_weight'

Set the gamma weight expression. It can be used to reduce the effect of a high gamma value on bright image areas, e.g. keep them from getting overamplified and just plain white. The value must be a float in range 0.0 to 1.0. A value of 0.0 turns the gamma correction all the way down while 1.0 leaves it at its full strength. Default is "1".

'eval'

Set when the expressions for brightness, contrast, saturation and gamma expressions are evaluated.

It accepts the following values:

'init'

only evaluate expressions once during the filter initialization or when a command is processed

'frame'

evaluate expressions for each incoming frame

Default value is 'init'.

The expressions accept the following parameters:

'n'

frame count of the input frame starting from 0

'pos'

byte position of the corresponding packet in the input file, NAN if unspecified

'r'

frame rate of the input video, NAN if the input frame rate is unknown

't'

timestamp expressed in seconds, NAN if the input timestamp is unknown

Commands

The filter supports the following commands:

'contrast'

Set the contrast expression.

'brightness'

Set the brightness expression.

'saturation'

Set the saturation expression.

'gamma'

Set the gamma expression.

'gamma_r'

Set the gamma_r expression.

'gamma_g'

Set gamma_g expression.

'gamma_b'

Set gamma_b expression.

'gamma_weight'

Set gamma_weight expression.

The command accepts the same syntax of the corresponding option.

If the specified expression is not valid, it is kept at its current value.