Thank you for replying. Well, this is not good. I need to make fine adjustments to the speed of my video. I have a video with a band playing and it turned out that the video has a slightly different speed than the audio, so after 1/2 minutes the movements of the musicians are already noticable not in sync with what I hear. The audio is pitch-perfect, so I want to adjust only the speed of the video to match it the audio again.
How this happened? I recorded with Quicktime player using my phone as an external camera and microphone with a program called iriun webcam. (dumb idea, i know) Well, I just need to be able to finely adjust the video speed to match the audio again.