I would describe my level of video production in the novice category and learning as I go, so please be patient with me.
Project of producing a small music video for some friends with a prerecorded studio track and separately recorded video. My first mistake was that we recorded the video live, without the prerecorded track playing for the performers to match timing etc. This would have made the issues I am having with syncing audio to guitar playing and vocal a lot easier, as I have now found out, a mistake I will not make again. However, I am in the situation where I have matched up about 95% of the audio and video manually, it was quite a laborious task, but I am happy with most of it.
What I have left is a few short clips where the singer is slightly out of time with the audio with lip sync, they are either singing slightly slower or faster. Some of this I have corrected by slightly adjusting the clip speed to match where I can, the remaining bits left are proving trickier.
I was looking for suggestions or techniques that will help me speed up this process rather than manually adjusting the clip speed by certain percentages and if I can make use of markers (or similar) to auto stretch or shrink the time code with markers in the audio, or perhaps an entirely new way of looking at this problem.