Do you end up with periodic black frames followed by bright ones when editing video from Canon's G1X camera using Sony Vegas Movie Studio 10? If so try re-encoding the camera generated MOV files using Huffyuv (which is lossless) before editing them in Vegas.
Canon's G1X camera is capable of capturing H.264 encoded video and storing it in an MOV file. The video captured is 1920x1080 at 23.976 frames per second (you can read about this not quite 24fps if you're interested).
I had no problem opening the video files in Sony Vegas and working with them in any of the tools. For my initial test I simply stacked up a few short clips directly from the camera and started the render to H.264 process. In playback the first minute or so of the rendered video was fine but eventually a black frame was inserted into the middle of a clip, not at a transition, and bright frames followed it for a second or so before normal brightness slowly returned. Over the course of my five minute video this happened several times.
I decided to avoid using the H.264 encoded camera input by using ffmpeg to convert the camera video to Huffyuv encoded video since this would give me lossless video to experiment with. (And now a little detour getting the Huffyuv codec installed on my Windows 7 system so that it would be available for Vegas.) Once that was done I opened the Huffyuv video using Vegas in the same order that I had done before with the camera video and rendered to H.264. This time the resulting video played back without any defects.
It appears to me that Sony Vegas is not really capable of handling the 23.976 frame rate properly when working with H.264 encoded 1920x1080 input and periodically inserts a black frame during the output render. When the output is then H.264 encoded the black frame affects the compression of following frames, making them brighter.
The summary: Canon G1X video should be converted to a lossless encoding (Huffyuv works fine) before being edited on Sony Vegas 10. Other versions of Vegas may or may not need the same treatment.
