Controlling Lan-C/Control-L-capable VCR With Linux?

An unnamed assailant writes: "I want to do a real nerdy project: My VCR has a plug in the back for a LAN-C/Control-L cable which connects to a serial port on a computer as well as a LAN-C connection on a camcorder. The VCR also came with some simple software to control a VCR and a camera through the cable. This was obviously before nonlinear editing was as common as it is now. Anyway, I want to see if there's any way to figure out what the codes are that the protocol uses so I can talk to the VCR using perl. Any suggestions?" Now this would be a great project, even (or especially?) without the whiz-bang eyecandy of B2K. There are a lot of middle- and high-schools with LAN-C equipped VCRs (most of which probably never get used that way), and it would be nice to be able to control them this way.

Comments

Basic Research

[MrChuck]

Golly! Why waste 10 minutes on Google and Yahoo when I can Ask Slashdot (tm)?

Okay, background, SMTPE, described before, tosses timecode onto the tape (in video blanking interval?). Critical to professional editing.

There are consumer versions of time code. Not as locked down to the frame, but for most purposes, enough.

Professional editing:
2 or more VCRs playing to one recording VCR. (actually in modern times, VCRs are replaced by these computer things - loaded from 1" digital tape for holding the volumes of data that no computer can).

These VCR's (or VTR - the C just came in after reel tapes disappeared) all talk to each other over something that looks serial like. Modern ones may have RS-422 or 232.

Let's now visit consumer land:

Control-S (sony) is simply a wire send of their IR protocol.
This is actually really useful. Same signals as IR means that if you can demodulate the IR. A device called the (slink-e does this, albeit the software is on Windows only last I checked. (cool toy)).

LAN-C/Control-L. Described HERE, and I quote:

Control-L, otherwise known as LANC, stands for Local Application Control. This protocol is used as a pro-sumer edit control protocol on a variety of Sony equipment. Other manufacturers such as Nikon and Canon also use LANC in some of their equipment.

This 2-way communication happens at 9600 baud, and is organised as 8 byte data packets sent every field.

For a good reference on LANC see, with details on the data packet format and various commands - see:
http://home.t-online.de/home/mb.koenig/lanc.htm

There are serial adapters. Or you can do your own and save the money and spend the time.

STFG

[Stavr0]

Search the Fscking Google ;-)

Something I found at www.dunfield.com
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splitter and listener?

[StandardDeviant]

I'm not familiar with this thing at all, but if the information is carried over a serial cable, could you make or buy some sort of Y-splitter, with one end feeding into a listening serial port so you can match up actions with output? Same theory as figuring out what a proprietary networking protocol is doing by putting a packet sniffer between the output-generating machine and it's server or client.

Anyhow, just my 0.02 USD. (Oh, and there are perl modules to do serial programming IIRC. So pushing the bits shouldn't be a problem, just see CPAN.) An even easier approach would be finding some docs ;-) but that has less hack appeal.

--
"Overrated" is "overfuckingused".