Gpio (General Purpose In/Out); Synchronizing With The Syncstation; Synchronization Basics; Timecode (Positional References) - Steinberg Nuendo SyncStation Operation Manual

GPIO (General Purpose In/Out)

With the GPIO interface, the SyncStation can receive and
send various external signals, such as "red light" and "on-
line" indicators including support for a record punch foot-
switch. The GPIO pin assignment is listed in the section
"GPIO pin assignment"

Synchronizing with the SyncStation

Before exploring all of the options in the SyncStation, a
basic understanding of the concepts and terms involved in
audio and video synchronization is needed. For many, this
knowledge may be old news and it is provided here only as
a convenient way of defining the terms used in this manual.

Synchronization basics

There are three basic components of audio/visual synchro-
nization: position, speed, and phase. If these parameters
are known for a particular device, a second device can
have its speed and position "resolved" to the first in order
to have the two devices play in perfect sync with one an-
other. The process of "resolving" the one device to the
other is performed by the synchronizer, in this case, the
Nuendo SyncStation.
The synchronizer analyzes the position of the primary (ma-
ster) device and moves the secondary device to the same
position in time. When playback begins, the synchronizer
analyzes the speed of the master device and adjusts the
playback speed of the secondary (slave) device to per-
fectly match the first and then maintain that speed in a
highly accurate manner, sample-accurate if possible.
The phase component is the alignment of each frame of
timecode to the corresponding sample of audio. Simpler,
low-resolution synchronization scenarios often ignore the
phase relationship between timecode and word clock.
Since the SyncStation handles video sync, timecode and
word clock in one device, it can use the extended System
Link connection to correct the phase between Nuendo and
the video frame reference. This is essential for truly sample-
accurate synchronization between audio and video.
on page 42.

Timecode (positional references)

The position of any device in the system is most often de-
scribed using timecode. Timecode represents time using
hours, minutes, seconds, and frames to provide a location
for each device. Each frame represents a visual film or
video frame.
Film uses another positional standard called feet+
frames, which uses lengths of film in feet plus additional
frames to denote its position on the timeline. While
Nuendo is capable of displaying feet+frames counters
and rulers for both 16mm and 35mm film, it is for internal
reference only. The SyncStation does not have the ability
to resolve direct film synchronization signals (e.g. tach
pulses).
Timecode can be communicated in several ways:
• LTC (Longitudinal Timecode) is an analog signal that can be
recorded on tape. It should be used for positional information
primarily. It can also be used for speed and phase information
as a last resort if no other clock source is available.
• VITC (Vertical Interval Timecode) is contained within a com-
posite video signal. It is recorded onto video tape and is phys-
ically tied to each video frame.
• MTC (MIDI Timecode) is identical to LTC except that it is
transmitted via MIDI connections and is a digital signal. MTC
is accurate to 1/4 of a frame.
• Sony P2 (9-Pin, RS422) Machine Control also has a time-
code protocol that is mainly used for locating and is not nearly
accurate enough for speed and phase. It can be used in cer-
tain situations where there is no other alternative.
As a timecode synchronizer, the SyncStation can use either
LTC, MTC, 9-Pin timecode or its internal generator as a po-
sitional reference and generate outgoing timecode based
on that reference. This is called the timecode source. For
more information on how to set the timecode source, see
"Unit 01 - Master & Timecode Source"
Timecode has several standards that are used commonly.
The subject of the various timecode formats can be very
confusing due to the use and misuse of various shorthand
names for specific timecode standards and frame rates.
The confusing part of this is that regardless of how many
frames of video there are per second of timecode, those
frames can be moving at different rates depending on the
speed of the video reference.
8
Introduction
on page 23.