User`s guide

Dialogic
®
System Release 6.0 PCI for Windows
®
Release Update, Rev 62 — January 30, 2008 254
Dialogic Corporation
1.72 dx_reciottdata( ) Enhancements
The Service Update provides the following enhancements to the dx_reciottdata( )
function:
• Initial silence compression
• Voice activity detector (VAD) with event notification
These enhancements are applicable to the following boards:
• Dialogic
®
DM/V, DM/V-A, DM/V-B, DM/VF, and DMV160LP Media Boards
• Dialogic
®
DM/IP Boards
1.72.1 Feature Description
The dx_reciottdata( ) function, used to record voice data, has two new modes:
RM_VADNOTIFY
generates an event on detection of VAD during the recording operation. The new
event is TDX_VAD.
Note: TDX_VAD is not an indication of function termination; it is an unsolicited
event.
RM_ISCR
adds initial silence compression to the VAD detection capability.
Note: The RM_ISCR mode can only be used in conjunction with RM_VADNOTIFY.
To enable these modes, OR them to the dx_reciottdata( ) function mode parameter. For
example:
t_Return=dx_reciottdata(DevHandle, Iott, Tpt, &t_Xpb, EV_ASYNC|RM_VADNOTIFY);
t_Return=dx_reciottdata(DevHandle, Iott, Tpt, &t_Xpb, EV_ASYNC|RM_VADNOTIFY|RM_ISCR);
When these two modes are used together, no data is recorded as output until voice
activity is detected on the line. The TDX_VAD event indicates the initiation of voice. The
output file will be empty before the VAD is detected, although some initial silence may be
included as specified in the FCD file.
Initial silence is the amount of silence on the line before VAD is detected. When using
RM_ISCR, the default value for the amount of allowable silence is 3 seconds. Any initial
silence longer than that will be truncated. This default value can be changed by modifying
a parameter in the CONFIG file for the board and then generating a new FCD file. See
Section 1.72.2, “Configuring the Software”, on page 255.