Perhaps you’ve noticed that your videos on YouTube are a pale version of what you saw on your camcorder’s LCD screen. Whether you’re exporting your movies to QuickTime first or uploading directly from iMovie, the colors appear less saturated, blacks a dark gray. Below is a comparison between the original .MTS file and the same image uploaded to YouTube, with the resulting loss of color.
There is a way to preserve the original colors you saw, and that is by encoding with x264. The resulting files will have a lower bit rate than H.264 with no loss of quality, meaning they take up less space on your precious hard drive. Below is a screenshot of the same frame encoded with x264.