Add ffmpeg command for media conversion

Added ffmpeg command for converting media from dark mode to light mode.

Author: danielalpizarcer-rgb

day-1.md

@@ -7,6 +7,12 @@
 
 ## Review
 
+Convert an image or video from dark mode to light mode using [ffmpeg](https://www.ffmpeg.org)
+
+```bash
+ffmpeg -i input.mp4 -vf "negate,hue=h=180,eq=contrast=1.2:saturation=1.1" output.mp4
+```
+
 
 -Item 1
 -Item 2