Elktrekker

Okay, I've got an audio sync question for you all. I can't go into detail about the situation, but it's an object coming into contact with a vehicle. I'm transitioning into forensic A/V work, recreation, that sort of thing. If you could help educate me, I would appreciate it. Scenario: 8 cameras multiplexing (assumed), recording 7-8fps of each camera at 2CIF. Audio is only recorded on the first camera. Using an IDIS clip player to play back the cameras. The video information says it is Timelapsed. Three questions humbly asked... 1) Is my math correct in that the frames per second is 7-8 per camera, multiplied by the 8 cameras, that it is recording approximately 60 ips? 2) If the video is multiplexed, how is the audio recorded. Separately? 3) I have determined when the audio hit the vehicle based on marks, etc., but the point of impact does not line up with the audio (examining in Premiere, looking at the audio waveform)... it seems to be a couple of frames ahead of the video). I'm assuming this is due to the missing frames of video in relation to the audio file. My question is, is there a way to know how many frames it would be off and whether it would be in front or behind the impact frame? Thanks for your help.

This information has been very helpful and time-saving. Thanks, so much.

Thanks, that does clarify things. I'll see if I can get more information about the processing chip in the camera, but your explanation seems to match what I'm experiencing. My only problem is trying to figure out if there is a definitive way of telling how many frames off the audio will be. I can only approximate. Thanks for the info.

Hello, I'm a video production specialist hoping to learn more about the CCTV world. Thanks, Elktrekker