I want to edit the audio part of a video (.mov) file. I open it in sound forge (v9.0e). The payback is a little fast. I need to change the "playback rate" to about 0,93. Then it is "almost" normal. The sampling rate of the movie is 7.875 Hz. If I change this to about 7.300 Hz, again the audio sounds almost normal. But WHY is this happening?