Pay attention to your room. If you don't have a good room for recording in general, you cannot possibly capture good sound on video. A good room for recording eliminates outside noise and has fewer surfaces on which the sound can bounce off. If you have a studio on site, do your video recording in there.
Use an external condenser microphone. The microphone on your video camera isn't quality enough to capture good drum sound.
Use more than one microphone. Many high-end video cameras allow you to plug in more than one external microphone a time. If your camera does not allow this, you can buy a microphone adapter at an electronics store.
Place the microphones in the front and back of the drummer. Keep the mics at a 5-foot distance or as close to it as possible. Raise the boom stands to around 6 feet and angle down toward the drum set.
Use editing software. You can really clean up your sound after the video has been shot if you have a good sound editing software on your computer. With a software like Adobe Audition, you can splice separate recordings of a song together or take out any rough spots, turn the volume up or down as needed, and eliminate hiss and background noise.