capturing desktop, can VLC detect screen activity?

[grandpixel]

I am capturing my desktop to H.264 for a screencast, and the video is running for several hours at a time, for several days. Often there is no movement on the desktop because I am either thinking / discussing / slow progress bar / using restroom / whatever. Is there a filter that will only record during screen activity? Or perhaps a way to later trim my videos in this way? Thanks for your input!

[Rémi Denis-Courmont]

No.