Timecode and Control

In the early days of video editing, timecode signals and deck control were carried on separate connections. Timecode was conveyed on a BNC cable as an LTC signal, or was embedded in the video as VITC. Deck control was performed using manufacturer-specific interfaces, and there was a thriving market for translator boxes to make decks from Ampex, JVC, Panasonic, and Sony speak a common language.

Fortunately, those days are (mostly) gone. Modern decks interface using serial control protocols that carry commands, status, and timecode together. Final Cut Pro expects to talk to decks using either RS-422 or FireWire; if you can't find a deck to play back a tape that speaks one of those languages, or for which there is not a protocol converter, you'll probably be best off dubbing the tape to a more modern format on a VTR that allows modern control, or just use Capture Now to grab the video.

Control Interfaces at a Glance
Names	Connectors	Comments
RS-422, Sony serial, 9-pin	9-pin D-shell	Most common professional control interface
FireWire, A/VC	4- or 6-pin FireWire	DV, DVCAM, DVCPRO, and HDV equipment
LANC, Control-L	2.5mm miniplug, 5-pin miniDIN	Video8, Hi8, Betamax, ED-Beta, consumer DV gear
Ampex RS-422, Ampex serial	9-pin D-shell	Ampex VTRs only; not compatible with Sony protocol
RS-232	9- or 25-pin D-shell	Industrial gear; manufacturer- and model-specific command protocols; usually not frame-accurate
VISCA	8-pin miniDIN	Sony industrial gear, Hi8 animation recorders
Control-M, Panasonic 5-pin	5-pin round connector	Panasonic VHS, SVHS
Control-S	Small miniplug	Some Sony gear; control only; no feedback
Parallel	Various, depending on manufacturer	Ancient VHS, ¾", and similar VTRs

RS-422

Most professional VTRs use a serial protocol commonly called RS-422 for timecode and control. (RS-422, strictly speaking, defines the electrical and signaling parameters of the serial link, not the protocol that runs on it, but that's an academic distinction for our purposes.) It's based on the serial protocol Sony developed for its broadcast ¾-inch decks, although it's evolved over time and become the lingua franca of deck control. You'll also see it referred to as Sony protocol, 9-pin control, BVU-800 protocol, and BWV protocol, and many decks simply label it as Remote.

RS-422 ports on VTRs use a 9-pin D-shell connector. Macs no longer have serial ports built in, but many video capture cards incorporate them, and USB-to-serial adapters are available for Macs without such cards. The pinout used on VTR ports is unlike the pinout on 9-pin serial ports in the rest of the world, so you'll need to use a cable built specifically for the purpose of deck control. Most capture cards with RS-422 ports should have the appropriate cable bundled with them. For controlling VTRs with USB-to-serial adapters (most of which use the same round serial connector as older Macs), use cables from Addenda Electronics (www.addenda.com).

Tip

Addenda Electronics carries cables and adapters for almost any serial-to-serial connection task. When in doubt, check their Web site for any oddball adapter you might require.

The RS-422 protocol includes frame-accurate deck control (on decks that support frame accuracy; not all do!) as well as full timecode capability. Depending on the deck, the timecode reported may be LTC, VITC, or digital timecode; it makes little difference as far as deck control goes. Over RS-422, a Betacam SP deck with SMPTE timecode, a Hi8 deck playing back Hi8 timecode, and a DVCAM deck playing back DV timecode all appear the same and afford the same frame-level addressability.

On appropriately equipped editing decks, RS-422 lets you insert video and audio separately and frame-accurately, so you can use such decks to insert-edit new scenes into existing programs using FCP's Edit To Tape capability.

Note

You'll need to provide a common reference signal to the deck and the Mac for frame-accurate RS-422 control, as described in the "Sync and Blackburst Generators" section later in this lesson.

FireWire

FireWire carries control and timecode information along with video and audio. FCP comes equipped right out of the box to talk to decks using the FireWire port built into all current Macs.

Most DV, DVCAM, and HDV decks offer FireWire control, as do some DVCPRO, DVCPRO50, and DVPROHD decks. Basically, if a deck has FireWire for video and audio I/O, it offers FireWire control as well.

FireWire offers frame-accurate capturing, but FireWire-controlled decks aren't equipped to provide frame-accurate insert editing. You can use the assemble-edit capability of FCP's Edit to Tape and Print to Video functions, but not the insert-edit function of Edit to Tape.

Some decks offer both FireWire and RS-422 control. The RS-422 control usually has more capabilities than the FireWire control does; if your deck offers both, you may have better results with RS-422 than with FireWire, even if you're still capturing your video and audio over FireWire.

LANC

Some Sony VTRs, mostly in the consumer lineup, offer LANC control, also called Control-L. It's a serial protocol on a very small 2.5mm miniplug. (Older VTRs used a 5-pin plug.) With the RS-4/L adapter from Addenda Electronics or the LPort422 from Sweet Pea Communications (www.spcomms.com/lport), it's possible to control them using RS-422, letting you integrate such decks into a 422-controlled environment.

However, LANC is not frame-accurate, and the performance of decks controlled by LANC is somewhat hit or miss. You're better off finding a deck in the format in question (VHS, S-VHS, Video8, Hi8, and DV decks use LANC) that has RS-422 or FireWire (in the case of DV) than using the Addenda adapter. Of course, if you're using ED-Beta (Betamax's answer to S-VHS), you'll probably have to use the adapter, as ED-Beta and Betamax decks with RS-422 are mighty hard to find.

Other Interfaces

Aside from the three main control interfaces described earlier, you'll find a variety of other control schemes in use, usually on non-broadcast, non-DV decks, or on older equipment.

Ampex Serial

Older Ampex VTRs used an incompatible RS-422 protocol. Solution: capture your tapes using a newer Ampex or Sony VTR.

RS-232

Some decks offer RS-232 serial control instead of RS-422. RS-232 decks typically use different (and more limited) command protocols than RS-422 has, so the simple answeran RS-232 to RS-422 adapterwon't work with FCP.

FCP supports a limited number of RS-323-controlled decks directly with presets for the Sony S-VHS SVO-2100, Sony Betacam SP UVW-1400, and generic Panasonic and JVC 232 protocols; otherwise your best bet is to move the affected tape into a deck with RS-422 control.

VISCA

A few Sony decks, mostly Hi8, use a serial protocol called VISCA (Video Systems Control Architecture), which FCP supports. VISCA, like LANC, isn't frame-accurate. FCP can use a VISCA deck (or a Sony VBox LANC-to-VISCA adapter), but you're more likely to get repeatable results using an RS-422-controllable deck in the appropriate format.

Control-M

Also called Panasonic 5-pin, Control-M is used on some Panasonic decks. Sweet Pea's PanPort422 lets you talk RS-422 to these decks, with the same caveats as with LANC-controlled decks.

Control-S

A control-only protocol used in some Sony equipment. You can send commands, but you can't get status or timecode back. Think of it like an infrared remote control using a wire.

Parallel

Multi-pin parallel control ports were the state of the art prior to serial controllers. Don't even think about controlling such decks with FCP.

Caveats

No control system is perfect. The grapevine is full of reports of timecode slippage and inaccuracies with FireWire control, but RS-422 control isn't immune from such problems, either. Breaks in timecode, a gap between takes on tape, and improperly configured capture and deck-control settings inside FCP can play havoc with smooth machine control regardless of tape format or control type. Always test whatever setup you have for proper operation before committing yourself to frame-accurate operations, and capture with handles on your clips just to be on the safe side.