Chapter 3 — Using the VTR API
33
Properties Exposed Through IVTRCenter
Properties Exposed Through IVTRCenter
The following properties are exposed through the IVTRCenter interface:
ComPort –
This property, a long, identifies which of the communication ports
on the encoder is connected to the tape deck. On most Vela encoders, the
number of each of the communication ports is marked on the chassis. Typically
the ComPort property will be set to either 1 or 2.
The ComPort property can be retrieved by calling val = GetComPort(). It can
be set by calling PutComPort(val). In both cases, the variable “val” is defined
as a long.
DropFrame –
This property, a BOOL, reports whether or not the current time
code read from the tape deck is a drop frame time code. To retrieve the value of
this property, call val = GetDropFrame(), where val is defined as a BOOL. If
the GetDropFrame method returns 1, the time code is drop-frame time code. If
the method returns 0, the time code is a non-drop-frame time code. There is no
Put()
method available for this property.
HardError –
This property, a BOOL, determines whether or not the VTR inter-
face encountered an error during the previous operation or method call. Use
the call val = GetHardError() to retrieve the value of the property. If the value
returned is 1, an error was encountered during the last operation. If the return
value is 0, the last operation was successful.
MarkIn –
This value, a BSTR, represents the current value of the inpoint or
mark-in set on the tape deck. The format of the property is “hh:mm:ss:ff,”
where “01:02:03:04” represents a mark-in of 1 hour, 2 minutes, 3 seconds, and
4 frames.
There are two access methods,
Get()
and
Put()
, available for this property. The
Get()
method queries the tape deck to determine the current setting of its mark-
in. It returns the retrieved value to the calling application. The
Put()
method
accepts a mark-in value as an argument, sending a command to the tape deck
to set its inpoint or mark-in to that value. Where val is defined as a
_bstr_t
, the
Get()
and
Put()
methods for MarkIn are called as follows:
val = m_IVtr->GetMarkIn();
m_IVtr->PutMarkIn(val);
MarkOut –
This value, a BSTR, represents the current value of the outpoint or
mark-out set on the tape deck. The format of the property is “hh:mm:ss:ff,”
where “01:02:03:04” represents a time code of 1 hour, 2 minutes, 3 seconds,
and 4 frames.
