Fix exposure, tonality and color the easy way, using Lightroom 4
Step 2 
Since you can’t work on video in Develop mode, sneak in some editing by capturing a still frame and then bringing it into Develop. Drag the playhead (the line that indicates where exactly you are in your clip) to a frame that represents the clip’s color and tone. Then click on the rectangular screen symbol and choose Capture Frame. Note that you won’t see the frame if you’re in the Previous Import folder.