Sure, what I meant is (I thought it was obvious) the control that would look like the "Adjust Volume" control or similar and it would have at least these options:
- Normal Speed (default) - the video plays at normal speed
- Double or 2x speed - the video plays at double speed (sound pitch should remain the same)
Well based on that it could be just checkbox but even better would be slider that would have more options (though probably that means also more performance issues).
Edit: Reason? Speed learning - time is money - double speed double money ;). Some parts of the video can be pretty basic and there you'd have e.g. double speed and when more complicated things came up you'd set it back to normal.