Introduction; Legal Notices; What Is Time Code - AEC PCIe-TC User Manual

INTRODUCTION

Adrienne Electronics Corporation (AEC) developed the PCIe-TC family of
PCI Express bus (x1) plug-in boards to provide effective, fast, and low cost
ways of reading and/or generating time codes via personal computers.
This booklet has been prepared to assist the average user with installing
and successfully using a PCIe-TC board in their computer. We have a
separate "PCIe-TC Board Reference Manual" for more advanced users
who need to write software at the register level for our PCIe-TC boards.
You probably ordered something other than a "PCIe-TC" board, and are at
this point wondering why we sent you a "PCIe-TC" user guide to accom-
pany your PCIe-LTC/RDR board, for example. The simple answer is that
we use the term "PCIe-TC" to refer to all of our PCIe-LTC, PCIe-VITC,
and PCIe-VLTC boards. There are potentially many different board mod-
els here, and it is much easier for us to write one generic "PCIe-TC" manual
than it is to write many different manuals. All PCIe-TC boards use the
same basic hardware and software interface inside your PC, so a single
manual works well here, and application software written for one board
model will usually work with all PCIe-TC board models.
Most of you will only need to read the INSTALLATION section starting
on page 5, plug the board into your PC, attach external cables and signal
sources, then fire up the test/demo program to make sure that everything
is working OK. You may also need to install Windows software drivers
before you can begin using the desired application program.

LEGAL NOTICES

PCIe-TC, PCIe-LTC, PCIe-VITC, PCIe-VLTC, and AEC are trademarks
of Adrienne Electronics Corporation. The PCIe-TC board layout and the
PCIe-TC board firmware and software are all protected by copyright. This
manual is Copyright (C) 2012 Adrienne Electronics Corporation. You may
print one or two copies for use with each PCIe-TC board you own. All
other rights reserved. Windows is a trademark of Microsoft Corporation.
SMPTE is a trademark of the Society of Motion Picture and Television
Engineers.
PCIe-TC User Guide Page 2 April 2012

WHAT IS TIME CODE?

Time Code assigns to each video frame (picture) a unique number, having
the format Hours:Minutes:Seconds:Frames. This number may then be
used for editing and/or control purposes. Time code standards have been
around for many years, and are sponsored by both SMPTE (for NTSC)
and the EBU (for PAL and SECAM). Time code is also used in the 24fps
FILM environment, and in some audio only applications.
There are actually two different kinds of time code commonly used in the
television business. Vertical Interval Time Code (VITC) is encoded in the
vertical interval (non visible portion) of a video signal. Longitudinal Time
Code (LTC) is a specialized audio signal which is usually recorded on an
audio track of a video tape, next to its associated video signal.
Use of VITC frees up one audio track for other purposes, such as stereo
audio. It also allows time code to be read at very low (including still) tape
speeds, where fine positioning is important. However VITC cannot usu-
ally be read at tape speeds much above play speed.
LTC is commonly used because it is usually lower cost than VITC, can be
added to a video tape after the initial video recording, and it can be read
during high shuttle speeds (fast forward and rewind). However, due to
record/playback limitations of tape machines, LTC cannot be read reli-
ably at very low tape speeds.
In many cases LTC and VITC will be used at the same time, because of
the advantages each has to offer.
PCIe-TC User Guide Page 3 April 2012