user17189: I have a background image that I'm trying to fade to specific color values using this filter: lutrgb=enable='gte(t,3)':'r=0.3*val:g=0.3*val:b=0.3*val'
This almost works, but it changes the values instantly.  How do I get it to fade to those values gradually over time?

user1871: The lut filter expressions don't work with time. geq does.
geq=r='(1-0.7*min((T-S)/D,1))*p(X,Y)':g={the same as r}:b={the same}:enable='gte(t,S)'

S should be your start time in second. D is duration for the change in colours. T and p(X,Y) are variables and should be kept as is.  

17189: <p>I have a background image that I'm trying to fade to specific color values using this filter: <code>lutrgb=enable='gte(t,3)':'r=0.3*val:g=0.3*val:b=0.3*val'</code></p>

<p>This almost works, but it changes the values instantly.  How do I get it to fade to those values gradually over time?</p>
 1871: <p>The <code>lut</code> filter expressions don't work with time. <code>geq</code> does.</p>

<pre><code>geq=r='(1-0.7*min((T-S)/D,1))*p(X,Y)':g={the same as r}:b={the same}:enable='gte(t,S)'
</code></pre>

<p><code>S</code> should be your start time in second. <code>D</code> is duration for the change in colours. <code>T</code> and <code>p(X,Y)</code> are variables and should be kept as is.  </p>
