M-AUDIO MIDISPORT 8x8/s - Manual (Page 24)

The SMPTE Reader is capable of automatically detecting the incoming SMPTE
format. When it does, it displays the format to the "Format" LEDs on the
MIDISPORT front panel. Automatic format detection will take between 3 and 31
frames, depending on the incoming format and the value of the first SMPTE
frame received. When using the MIDISPORT with a sequencer program synced
to MIDI Time Code, at least 3 to 5 seconds of pre-roll are recommended for
proper synchronization.
IMPORTANT: When 29.97 format code is received at the SMPTE In
port, the MIDISPORT will indicate 30 fps. This is because MTC
does not support 29.97 – instead it uses 30fps format messages
that run at the slightly slower 29.97 fps rate.
The SMPTE Reader has the ability to "flywheel" during periods of invalid
incoming time code. Flywheeling is the ability to continue to generate
sequential time code even during drop outs of the incoming SMPTE to which the
MIDISPORT is synchronized. The SMPTE reader will continue to flywheel
through a set number of SMPTE frames before deciding the SMPTE input stream
is "dead." If the incoming SMPTE becomes valid again in less frames than the
flywheel setting, everything continues normally. However, if the number of
invalid frames exceeds the flywheel setting, the SMPTE Reader will declare that
it is no longer locked and then quit regenerating and sending MTC. The
Flywheel setting is configured via the Remote Control software and may be set
to anything between 0 and 127. "Jam sync" is equivalent to a flywheel setting of
0 frames (see the section "SMPTE/MIDI Time Code Tutorial" later in this
manual) and allows the SMPTE reader to continue generating time code long
after the incoming SMPTE data is invalid or no longer present. In fact, the
generator will continue to put out correct sequential SMPTE and MTC time code
indefinitely, or until you press the WRITE button to abort it.
Once locked to a valid incoming SMPTE stream, the SMPTE Reader lights the
"Locked" LED on the MIDISPORT front panel. Whenever invalid incoming
SMPTE is detected, the "Locked" LED will blink for approximately 0.25 seconds
for each bad frame, or until flywheeling has completed.
The SMPTE Reader is capable of decoding User Bits from the incoming SMPTE
stream. The most current User Bits are stored to the MIDISPORT internally and
may be used later during SMPTE writing.
SMPTE "Write" Button
The SMPTE "Write" button has two purposes: 1) to manually control the SMPTE
writer, and 2) to stop the SMPTE Reader when it is performing a "jam sync."
When the "Write" button is pressed and immediately released, SMPTE time code
starts writing at the preset start offset. The SMPTE Writer will continue to run
until the "Write" button is pressed again. The "Write" button may also be used to
change the start offset. To manually increment the start offset, press and hold
the "Write" button — this will increment the stored start offset by 1 hour every
time the "Write" LED blinks. The blinking occurs approximately once a second.
Release the "Write" button to begin writing at the new offset. The default start
time for SMPTE writing is 01:00:00:00, or one hour.
24