how to smoothly combine two sence

[KK]

I want to ask that if i cut out two sence from a video and how can i smoothly combine the two together without noticng it has been modified. I tried before with TMpg econ with but at the point of combining it lag for 1 or half second and there is also a beep in the audio. how can i avoid that?

and also is there a way i can increase the frame speed for a sence, i mean if i there is a part in the sence i wanted it to play faster is there a way to do that ?

thank you.

[Tommyknocker]

Yes, AviSynth to both questions.