Jack Pack - How does it work?

[Philip Brubaker]

My film school professors never talked to me about time code. Now I'm having a devil of a time synching audio to different cameras in post. Can someone tell me how a jack pack works, and if its possible to use time code with a plain ol HDV camera, sans jack pack?

[Steve House]

Originally Posted by Philip Brubaker

My film school professors never talked to me about time code. Now I'm having a devil of a time synching audio to different cameras in post. Can someone tell me how a jack pack works, and if its possible to use time code with a plain ol HDV camera, sans jack pack?

That's kind of a tall order as the workflows for timecode are very dependent on the camera, sound recorder, and the NLE software you plan to use. Wolf Seeburg has a couple of excellent books out on timecode for digital video that have a wealth of practical information you won't find anywhere else that I know of and I can highly recommend them to you.

A 'jackpak' is simply Canon's marketing term for timecode input and output and genlock input terminals. Virtually all truly professional broadcast grade cameras have had those I/O ports for years while virtually none of the consumer/prosumer camcorders have 'em, so when Canon introduced them on the XL2 they made a big deal about it, including inventing a marketing buzzword that has continued with their present G1 and H1 HDV cameras.

You can use timecode without a TC out from the camera, sure, but not for many of the purposes TC is normally used for in video production and only with a lot of workarounds in the workflow. For example, one can do it the way film has done it for years. Timecode is generated by a Master Clock or in the audio recorder itself and a smartslate is slaved to it (jammed to it). At the start of each take, audio rolls and the timecode is recorded as a timestamp in the file header or continuously as an extra audio track (depends on the type of recorder). The slate shows the same numbers that are being recorded with the audio so when it's photographed by the camera, the frames in the picture can be readily matched to the same location in the audio based on the matching timecode numbers. And that's just one of many possible workflows.

Another workflow has the audio recorder generating continuous LinearTC and sending it to the camera where it's recorded on one of the audio tracks as well as using it to stamp the tracks recorded back in the audio recorder. Some software (Avid?) can read the code in the audio tracks and position clips on the timeline so the numbers in the in-camera audio (aligned to picture) and alongside the separate audio can match up.

As you might guess from the above, this is all a highly convoluted subject with a lot of possibilities. If you can come with some more specific questions you should get a lot of food for thought in return.