On Thu, 30 May 2002, R. Michael O'Bannon, Ph.D. wrote:

>> I will check for you if that camcorder outputs SMPTE on the video. If
>it > does not, and I think it does not, because none of the consumer
>level > cameras do, then you need a LANC (Sony L control - that's right,
>SONY for > the Canon camcorder) standard wired remote control (which you
>can > implement with a PIC among other things). It reads out down to
>seconds > normally (not frames) but it is NOT accurate to the frame
>because there is > skew between the video and the LANC data stream.
>
>Peter,
>
>Thanks for the help.  I have started doing my homework on
>LANC, and it looks like a reasonable answer.  The camcorder
>does not have SMPTE.
>
>Do you by any chance know if the skew between the video and
>the LANC data is constant -- that is, could some correction
>be made after the recording?  I am currently looking into
>extracting odd/even field info from the S-video port using a
>LM1881.  Perhaps this could provide frame-by-frame sync
>along with second-by-second codes from the LANC data.

The skew is constant but not constant enough to achieve frame level sync.
If you would use the IEEE1394 data stream you would have that. Can't you
spool the material into a PC with editing capability and handle what you
need in software ? You could have an embedded PC (albeit large, to carry
the IEEE1394 infrastructure) do that.

The 'other' way to add sync to images, is to use the sound channel (one of
them). This may or may not be in perfect sync with the image.

I do not have enough details on what you are trying to do but I know that
you could buy/build a box to add SMPTE as VITC or onto a sound channel on
the signal coming out of the camcorder. Running the signal through an
editing deck with time code regen capability would do that for you. There
are boxes that do this on the fly (try www.markertek.com - but I haven't
looked in a while).

Peter

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