Frame Rate, Bitrates ans Frame by frame comparison

[novreis]

At a C# app I want to compare tennis videos that have different properties as attached image. I want to sync frame advance to see how swings are different but I have a doubt about the speed of swing. If the frame rates are similar can I conclude that the real speed is what I see (when I advance both frames the pro swing is much much faster than the amateur one, because the racquet head is already at finish when amateur racket is making contact with the ball). At normal speed I cannot "see" that difference but I can be wrong. Bitrate or other property can mislead the speed at frame by rate comparison? Thks

[jagabo]

Bitrate has nothing to do with frame rate. Well, there is one case where it does effect frame rate. Some encoders, like WMV3, will reduce the frame rate if it thinks the resulting quality will be too low for the frame rate. For example, a 30 fps video might be reduced to 15 fps (discarding every other frame) during high action shots.