Neither are for video editing. Photoshop and Gimp are both photo editors. You may want to look more at something like iMovie, Adobe Premier, or Final Cut, or if your looking for special effects Adobe After Effects.
If your talking photo editing Gimp or Photoshop would do. Or, my personal favorite is Pixelmator. Its cheap. $50 or so and its excellent. The only reason I still use photoshop is because it ties in with Maya and Unity.