I have a bizarre sound synchronization problem which I am really puzzled with.
I recently recorded an interview with the video camera capturing the sound of the interviewed and an external sound capture for the interviewer.
When editing it with
Adobe Premiere CS6 I started by synchronizing the start of the interview since both recordings started a few seconds apart. So far so good.
Then, one of the recordings was lagging and at the end of the recording (lasting around 25 minutes) where I found a delay of more than one second on one of the sound tracks. So I found a sync point and used the
rate stretch tool to adjust one of the tracks to match the other and since beginning and ending were synchronized (I checked) all was fine... Or at least so I thought.
When I started editing further I realised that towards the middle of the recordings there was further de-synchronization. It is like the lagging and speed-up of sound is non linear; like an accordion...
Has anyone experienced this before? What causes it? How can it be corrected other than cutting everything in smaller chunks and adjusting them one by one?
Thanks in advance for any help.
PS: I had posted this same question on Video Production beta but decided to repost it here since it relates more to sound than to video.