tools that are intended for relatively simple video-editing tasks

Tools that avoid the complexity of non-linear video editors:

• Handbrake
• avidemux
• vidcutter
• ffmpeg front-ends
  • LosslessCut
  • ffe [screenshots]
  • Shutter Encoder [features]
  • axiom
  • XMedia Recode [screenshots]
  • Videomass [screenshots]
  • EncodeGUI [features]

Specific tasks that I do sometimes

• Save a still frame — Use VLC > Video > Take Snapshot. The directory it's saved in can be found at Preferences > Video > Video snapshots > Directory.
  • Press E to step forward by one frame.
• Cropping black bars off of a video — Handbrake does this easily. Go to Dimensions [tab] > Cropping = "Custom", and tweak the left/top/right/bottom values.
  • Using the 'Preview' button before 'Start Encode' button can save you a lot of time, and allow you to quickly guess-and-check.
  • The left/top/right/bottom values aren't absolute pixel positions, rather they're relative to that edge. They're how many pixels you want removed from that edge.
  • Pro-tip: You don't have to guess how thick the bars are. Use VLC to save a frame, then open this still image in some image editor. If using Gimp, choose the Select Rectangle tool, and look at the bottom status bar while you're still selecting.