Cisco TSP Media Driver
Cisco Media Driver introduces a new and innovative way for TAPI-based applications to provide media interaction such as play announcements, record calls, and so on.
Cisco TSP 8.0(1) includes support for both Cisco Media Driver and Cisco Wave Driver, but only one driver can be active at any given time.
Cisco Media Driver offers several advantages:
•
Simplified Installation and Management—Cisco Media Driver configuration can be completed through the Cisco TSP Installation Wizard. Channel and port settings are consistently and automatically applied to all configured TSP instances.
•
Performance and Scalability—Cisco Media Driver can scale to support up to 1000 configured ports with hundreds of simultaneously active media channels. Refer to the application vendor's Installation Guide to determine the number of channels supported by the TAPI application.
•
Codec Support—Cisco Media Driver supports 8KHz, 16-bit PCM, G.711 a-law, G.711 u-law natively. Additionally, G.729a can be supported when pass-through mode is enabled.
•
Reliability—Cisco Media Driver runs as an independent process, similar to Windows applications, providing greater application stability and reliability. Creating and debugging media applications is now much easier.
Cisco Rtp Library Components
Header files
The following header files contain declaration of all functions, data structures, etc. exposed by Cisco Rtp Library.
•
ciscortpapi.h
•
ciscortpbase.h
•
ciscortpcbcs.h
•
ciscortpcodec.h
•
ciscortperr.h
•
ciscortpep.h
•
ciscortpip.h
In order to use Cisco Rtp Library functionality a typical application would only need to explicitly include ciscortpapi.h and ciscortpep.h files.
Import Library
The following import library has to be linked with an application in order to use Cisco Rtp Library functionality:
•
cmrtplib.lib
DLLs
The following DLLs are installed as a part of CiscoTSP plug-in and used by Cisco Rtp Library:
•
ciscortplib.dll
•
ciscortpmon.dll
•
ciscortpg711a.dll
•
ciscortpg711u.dll
•
ciscortpg729.dll
•
ciscortppcm16.dll
TAPI Application Support
CiscoTSP and Cisco Rtp Library Interaction
In order to allow TAPI applications to associate TAPI line device with Rtp Library media endpoints Cisco TSP implements two new device classes: ciscowave/in and ciscowave/out. If TAPI line device is capable to terminate media by means of Cisco Rtp Library, an application can use ciscowave/in and ciscowave/out device class names in the TAPI lineGetID() function to obtain associated media device identifiers. Media device identifier can be used in Cisco Rtp Library APIs to create media endpoints and manipulate media on a corresponding TAPI line device.
Figure 7-1 shows high level view of TAPI application which uses Cisco TAPI service provider and Cisco Rtp Library functionalities.
Figure 7-1 TAPI Application with Cisco Components
Codec Advertisement
Cisco Media Driver devices advertise G.711 support natively. Cisco Unified CM automatically invokes Media Termination Points (MTPs) when needed to provide transcoding (see "Example 1"). If MTPs are not configured and transcoding is required, call setup fails (see "Example 2").
Example 1
1.
G729PassThrough set to OFF (default).
2.
TSP application registers CTI port 1.
3.
CTI port 1 advertises G.711 support (default).
4.
Unified CM is configured with MTPs, which can be used if transcoding is needed.
5.
CTI port 1 calls Device 1000.
6.
Device 1000 only supports G.729, so an MTP is inserted to provide transcoding.
Example 2
1.
G729PassThrough set to OFF (default).
2.
TSP application registers CTI port 1.
3.
CTI port 1 advertises G.711 support (default).
4.
Unified CM is not configured with MTPs for transcoding.
5.
CTI port 1 calls Device 1000.
6.
Device 1000 only supports G.729 and no MTPs are available, so call setup fails.
Applications which natively support G.729 can change the default codec advertisement by setting the G729PassThrough registry option to ON (1).
The TSP application is then responsible for playing the appropriate media file (G.711 or G.729) based on the compatible codecs supported by the Device receiving the media (see "Example 3").
The Registry key can be found at:
•
Windows XP: HKEY_Local_Machine/Software/Cisco Systems, Inc./ RtpLib/G729PassThrough
•
Windows Vista: HKEY_USERS\S-1-5-20\Software\Cisco Systems, Inc.\ RtpLib\G729PassThrough
Example 3
1.
G729PassThrough set to ON.
2.
TSP application registers CTI port 1.
3.
CTI port 1 advertises G.711 and G.729 support.
4.
Unified CM is not configured with MTPs for transcoding.
5.
CTI port 1 calls Device 1000.
6.
Device 1000 only supports G.729, so the application plays the appropriate G.729 media file.
Typical TAPI Application Message Flow
The message flow in Figure 7-2 is described in steps 1 and 2.
Figure 7-2 Typical TAPI Application Message Flow 1
1.
Initialize TAPI, get LINEINFO for available line devices, find devices which are capable of using Cisco Rtp Library functionalities
2.
Get media device identifier associated with a particular line device
The message flow in Figure 7-3 is described in steps 3 to 5.
Figure 7-3 Typical TAPI Application Message Flow 2
3.
Initialize Rtp Library
4.
Subscribe for media stream events for relevant devices using Cisco lineDevSpecific extension
5.
Start monitoring media events
The message flow in Figure 7-4 is described in steps 6 to 10.
Figure 7-4 Typical TAPI Application Message Flow 3
6.
Create media endpoint
7.
Get in/out stream handle and start data streaming
8.
Receive / transmit data
9.
Stop data streaming, close endpoint
10.
Close EpAPI before exiting the program
EpAPI Functions
EpApiInit
Initializes EpApi and Rtp Library.
Syntax
PRTPLIBTRACE pTraceCallback,
Parameters
pTraceCallback
Pointer to an application callback function to be called with the trace record data passed to it.
portRangeStart
First port number in the continuous range of UDP ports (port pool) which can be used to create endpoints.
numPorts
Number of ports in the UDP port range (port pool) which can be used to create endpoints.
IPAddressFamily
IP address family to be used by Rtp Library to create endpoints can be set to:
–
AF_UNSPEC: both AF_INET and AF_INET6 can be used.
–
AF_INET: AF_INET only can be used.
–
AF_INET6: AF_INET6 only can be used.
This settings can be overwritten by the pDefaultRtpAddr parameter.
pDefaultRtpAddr
IP address to be used use by Rtp Library to create endpoints. If not NULL, only this address will be used.
Return Value
If no errors occurs, this function returns true. If an error occurs, false is returned, and a specific error code can be retrieved by calling EpApiGetLastError.
Table 7-1 Error Codes for EpApiInit
|
|
EP_ERR_ADDR_NOTAVAIL |
Unable to create endpoint with specified IP address family |
EP_ERR_PARAM_INVALID |
The following describes a possible cause of the error: Invalid number of UDP ports |
RTP_ERR_INITALREADY |
Already initialized |
RTP_ERR_TIMER_NOTAVAIL |
Unable to create high resolution timer |
Remarks
An error code can be set even when EpApiInit returns true. In some cases a default action / value can be assumed even if a parameter or registry settings is invalid. In those cases EpApiInit returns true but also set a proper error code to indicate an issue.
EpApiInitByDefault
Initializes EpApi and Rtp Library with default settings.
Syntax
CMAPI bool EpApiInitByDefault (
PRTPLIBTRACE pTraceCallback,
Parameters
pTraceCallback
Pointer to an application callback function to be called with the trace record data passed to it.
Return Value
If no errors occurs, this function returns true. If an error occurs, false is returned, and a specific error code can be retrieved by calling EpApiGetLastError.
Table 7-2 Error Code for EPApilnitByDefault
|
|
RTP_ERR_INITALREADY |
Already initialized |
Remarks
Rtp Library will be initialized as if registry is set as follows:
•
UDPPortRangeStart = 50000
•
UDPPortRangeEnd = 50999
EpApiClose
Closes EpApi.
Syntax
CMAPI bool EpApiClose ();
Return Value
If no errors occurs, this function returns true. If an error occurs, false is returned, and a specific error code can be retrieved by calling EpApiGetLastError.
Table 7-3 Error Code for EpApiClose
|
|
EP_ERR_INIT |
EpAPI is not initialized. |
Remarks
As a result of this function execution all active sessions, connections and streams will be terminated, timers closed and all data freed.
EpLocalAddressGetAll
Returns an array of RTPADDR structures which contain local IP addresses available for use by Rtp Library.
Syntax
CMAPI int EpLocalAddressPortGetAll(
Parameters
pBuffer
Pointer to a memory buffer to fill in with array of RTPADDR structures or NULL.
pBufSize
•
IN—Length of the buffer (in bytes), pointed to by pBuffer.
•
OUT—Space in the buffer used or required.
Return Value
If no errors occurs, this function returns a number of available local IP addresses and an array of RTPADDR structures in the pBuffer.
If pBuffer parameter value is NULL, the function returns the number of available local IP addresses and the pBufSize will contain the buffer size required for the RTPADDR structure array.
If an error occurs, 0 is returned and a specific error code can be retrieved by calling EpApiGetLastError. In case of EP_ERR_PARAM_INVALID error, pBufSize will contain the size of the required buffer.
Table 7-4 Error Code for EpLocalAddressGetAll
|
|
EP_ERR_INIT |
EpAPI is not initialized. |
EP_ERR_PARAM_INVALID |
Buffer is not large enough. |
EpLocalAddressPortGet
Reserves port from the port pool and returns it together with a local IP address.
Syntax
CMAPI PRTPADDR EpLocalAddressPortGet();
Return Value
If no errors occurs, this function returns pointer to RTPADDR structure with the first (or default) local IP address used by Rtp Library and reserved UDP port number.
If an error occurs, NULL is returned and a specific error code can be retrieved by calling EpApiGetLastError.
Table 7-5 Error Codes for EpLocalAddressPortGet
|
|
EP_ERR_INIT |
EpAPI is not initialized. |
RTP_ERR_PORT_NOTAVAIL |
No UDP port available. |
EpLocalAddressPortGetByFamily
Reserves port from the port pool and returns it alone with a local IP address for the specified family.
Syntax
CMAPI PRTPADDR EpLocalAddressPortGetByFamily(
Parameters
IPAddressFamily
IP address family: AF_INET or AF_INET6
Returns: Pointer to RTPADDR structure or NULL.
Return Value
If no errors occurs, this function returns pointer to RTPADDR structure with the first local IP address for the specified family used by Rtp Library and reserved UDP port number. If an error occurs, NULL is returned and a specific error code can be retrieved by calling EpApiGetLastError.
Table 7-6 Error Codes for EpLocalAddressPortGetByFamily
|
|
EP_ERR_INIT |
EpAPI is not initialized. |
RTP_ERR_ADDR_NOTAVAIL |
No IP address available for specified family |
RTP_ERR_PORT_NOTAVAIL |
No UDP port available. |
EpLocalAddressPortGetByIdx
Reserves UDP port from the Rtp Library port pool and returns it in the RTPADDR data structure alone with the IP address of the network interface card specified by the index parameter.
Syntax
CMAPI PRTPADDR EpLocalAddrPortGetByIdx (
Parameters
index
Index in the list of available local network addresses returned by EpLocalAddressGetAll function call.
Return Value
If no errors occurs, this function returns pointer to RTPADDR structure which contains local IP address and reserved UDP port number. If an error occurs, NULL is returned, and a specific error code can be retrieved by calling EpApiGetLastError.
Table 7-7 Error Codes for EpLocalAddressPortGetByIdx
|
|
EP_ERR_INIT |
EpAPI is not initialized. |
EP_ERR_PARAM_INVALID |
Invalid index value. |
RTP_ERR_PORT_NOTAVAIL |
No UDP port available. |
Remarks
List of available local network addresses can be obtained by EpLocalAddressGetAll function call.
EpLocalAddrPortFree
Returns local UDP port previously reserved by EpLocalAddressGet, EpLocalAddressGetByIdx or EpLocalAddressGetByFamily back to the port pool.
Syntax
CMAPI bool EpLocalAddrPortFree (
Parameters
pLocalAddrPort
Pointer to RTPADDR data structure which contains port number of previously reserved local UDP port.
Return Value
If no errors occurs, this function returns true. If an error occurs, false is returned, and a specific error code can be retrieved by calling EpApiGetLastError.
Table 7-8 Error Code for EpLocalAddrPortFree
|
|
EP_ERR_INIT |
EpAPI is not initialized. |
Remarks
Local UDP could is reserved by EpLocalAddressGet, EpLocalAddressGetByIdx or EpLocalAddressGetByFamily.
EpOpenById
Creates media endpoint based on TSP data associated with the specified media device identifier.
Syntax
CMAPI HANDLE EpOpenById (
StreamDirection streamDir,
PRTPDATACALLBACK pCallback
Parameters
deviceId
Media device identifier obtained by calling TAPI lineGetID() for ciscowave/in or ciscowave/out device class.
streamDir
Stream direction. This parameter can be one of the following values:
–
ToApp
–
ToNwk
–
Both
pCallback
Pointer to an application callback function to be called when data buffer is received/sent or an error occurred.
Return Value
If no errors occurs, this function returns a handle which can be used to reference the endpoint. If an error occurs, NULL is returned, and a specific error code can be retrieved by calling EpApiGetLastError.
Table 7-9 Error Codes for EpOpenById
|
|
EP_ERR_INIT |
EpAPI is not initialized. |
EP_ERR_PARAM_INVALID |
The following describes a possible cause of the error: • Specified device identifier is invalid. • Required data associated with device identifier data is missing • Specified stream direction is invalid |
Remarks
Endpoint is created based on a data associated by TSP with the deviceId.
EpClose
Close endpoint created by EpOpen.
Syntax
Parameters
hEp
Endpoint handle returned by EpOpen.
Return Value
If no errors occurs, this function returns true. If an error occurs, false is returned, and a specific error code can be retrieved by calling EpApiGetLastError.
Table 7-10 Error Codes for EpClose
|
|
EP_ERR_INIT |
EpAPI is not initialized. |
EP_ERR_HANDLE_INVALID |
Specified endpoint handle is invalid. |
EpGetStreamHandle
Returns endpoint stream handle for a specified stream type and direction
Syntax
CMAPI HANDLE EpGetStreamHandle (
StreamDirection streamDir
Parameters
hEp
Endpoint handle returned by EpOpen.
streamType
Stream type. This parameter can be one of the following values:
–
STREAM_TYPE_AUDIO
–
STREAM_TYPE_VIDEO
streamDir
Stream direction. This parameter can be one of the following values:
–
ToApp
–
ToNwk
Return Value
If no errors occurs, this function returns stream handle which can be used to reference the stream. If an error occurs, NULL is returned, and a specific error code can be retrieved by calling EpApiGetLastErro r
Table 7-11 Error Codes for EpGetStreamHandle
|
|
EP_ERR_INIT |
EpAPI is not initialized. |
EP_ERR_HANDLE_INVALID |
Specified endpoint handle is invalid. |
EP_ERR_PARAM_INVALID |
Specified stream type or direction is invalid. |
EpStreamStart
Enables data flow on a specified stream
Syntax
CMAPI bool EpStreamStart (
PRTPDATACALLBACK pCallback
Parameters
hStream
Stream handle returned by EpGetStreamHandle.
pCallback
Pointer to an application callback function to be called when data buffer is received/sent or an error occurred.
Return Value
If no errors occurs, this function returns true. If an error occurs, false is returned, and a specific error code can be retrieved by calling EpApiGetLastError.
Table 7-12 Error Codes for EpStreamStart
|
|
EP_ERR_INIT |
EpAPI is not initialized. |
EP_ERR_HANDLE_INVALID |
Specified endpoint handle is invalid. |
EP_ERR_ADDR_INUSE |
Address (protocol-IPaddress-port) is already in use. |
Remarks
EpStreamStart() should be explicitly called by an application in order to stream data flow (open socket, port). It is not done implicitly by the Rtp Library as it was done before by the Cisco kernel mode wave driver.
EpStreamStop
Disables data flow on a specified stream.
Syntax
CMAPI bool EpStreamStop (
Parameters
hStream
Stream handle returned by EpGetStreamHandle.
Return Value
If no errors occurs, this function returns true. If an error occurs, false is returned, and a specific error code can be retrieved by calling EpApiGetLastError.
Table 7-13 Error Codes for EpStreamStop
|
|
EP_ERR_INIT |
EpAPI is not initialized. |
EP_ERR_HANDLE_INVALID |
Specified stream handle is invalid. |
Remarks
EpStreamStop() should be explicitly called by an application in order to disable stream data flow. It is not done implicitly by the Rtp Library as it was done before by the Cisco kernel mode wave driver.
EpStreamRead
Read data from a stream.
Syntax
CMAPI bool EpStreamRead (
PRTPDATACALLBACK pCallback
Parameters
hStream
Stream handle returned by EpGetStreamHandle.
pBuffer
Pointer to a buffer for incoming data.
bufLen
Buffer size.
pAppData
Pointer to an application data area. It will be associated with the buffer and will be passed back to the application callback function as the pAppData parameter.
pCallback
Pointer to an application callback function to be called when data buffer is received or an error occurred.
Return Value
If no errors occurs, this function returns true. If an error occurs, false is returned, and a specific error code can be retrieved by calling EpApiGetLastError.
Table 7-14 Error Codes for EpStreamRead
|
|
EP_ERR_INIT |
EpAPI is not initialized. |
EP_ERR_HANDLE_INVALID |
Specified stream handle is invalid. |
EpStreamWrite
Write data to a stream.
Syntax
CMAPI bool EpStreamWrite (
PRTPDATACALLBACK pCallback
Parameters
hStream
Stream handle returned by EpGetStreamHandle.
pBuffer
Pointer to a buffer which contains data.
bufLen
Data length
pAppData
Pointer to an application data area. It will be associated with the buffer and will be passed back to the application callback function as the pAppData parameter.
pCallback
Pointer to an application callback function to be called when data buffer has been written or an error occurred.
Return Value
If no errors occurs, this function returns true. If an error occurs, false is returned, and a specific error code can be retrieved by calling EpApiGetLastError.
Table 7-15 Error Codes for EpStreamWrite
|
|
EP_ERR_INIT |
EpAPI is not initialized. |
EP_ERR_HANDLE_INVALID |
Specified stream handle is invalid. |
EpStreamCodecInGet
Returns stream inbound codec format information.
Syntax
CMAPI bool EpStreamCodecInGet (
PWAVEFORMATEX pWaveFormat
Parameters
hStream
Stream handle returned by EpGetStreamHandle.
pWaveFormat
Pointer to a WAVEFORMATEX data structure. Upon successful completion of the request this structure is filled with stream inbound codec format data.
Return Value
If no errors occurs, this function returns true. If an error occurs, false is returned, and a specific error code can be retrieved by calling EpApiGetLastError.
Table 7-16 Error Codes for EpStreamCodecInGet
|
|
EP_ERR_INIT |
EpAPI is not initialized. |
EP_ERR_HANDLE_INVALID |
Specified stream handle is invalid. |
EpStreamCodecInSet
Sets stream inbound codec format.
Syntax
CMAPI bool EpStreamCodecInSet (
PWAVEFORMATEX pWaveFormat,
Parameters
hStream
Stream handle returned by EpGetStreamHandle.
pWaveFormat
Pointer to a WAVEFORMATEX data structure which contains codec information.
pktSizeMs
Packet size in milliseconds. If value 0 (zero) is specified a default value (20) is used.
Return Value
If no errors occurs, this function returns true. If an error occurs, false is returned, and a specific error code can be retrieved by calling EpApiGetLastError.
Table 7-17 Error Codes for EpStreamCodecInSet
|
|
EP_ERR_INIT |
EpAPI is not initialized. |
EP_ERR_HANDLE_INVALID |
Specified stream handle is invalid. |
EpStreamCodecOutGet
Returns stream outbound codec format information.
Syntax
CMAPI bool EpStreamCodecOutGet (
PWAVEFORMATEX pWaveFormat
Parameters
hStream
Stream handle returned by EpGetStreamHandle.
pWaveFormat
Pointer to a WAVEFORMATEX data structure. Upon successful completion of the request this structure is filled with stream outbound codec format data.
Return Value
If no errors occurs, this function returns true. If an error occurs, false is returned, and a specific error code can be retrieved by calling EpApiGetLastError.
Table 7-18 Error Codes for EpStreamCodecOutGet
|
|
EP_ERR_INIT |
EpAPI is not initialized. |
EP_ERR_HANDLE_INVALID |
Specified stream handle is invalid. |
EpStreamCodecOutSet
Sets stream outbound codec format.
Syntax
CMAPI bool EpStreamCodecInSet (
PWAVEFORMATEX pWaveFormat,
Parameters
hStream
Stream handle returned by EpGetStreamHandle.
pWaveFormat
Pointer to a WAVEFORMATEX data structure which contains codec information.
pktSizeMs
Packet size in milliseconds. If value 0 (zero) is specified a default value (20) is used.
Return Valu
If no errors occurs, this function returns true. If an error occurs, false is returned, and a specific error code can be retrieved by calling EpApiGetLastError.
Table 7-19 Error Codes for EpStreamCodecOutSet
|
|
EP_ERR_INIT |
EpAPI is not initialized. |
EP_ERR_HANDLE_INVALID |
Specified stream handle is invalid. |
EpApiTraceLevelSet
Sets EpApi (Rtp Library) trace level.
Syntax
CMAPI bool EpApiTraceLevelSet (
Parameters
traceLevel
Required Rtp Library trace level. This parameter can be one of the following values:
Table 7-20 Error Codes for EpApiTraceLevelSet
|
|
0 - Error |
Output only error messages (reported in Windows Event Log). |
1 - Alarm |
Output alarms and error messages (reported in Windows Event Log). |
2 - Warning |
Output warnings, alarms and error messages (reported in Windows Event Log). |
3 - Info |
Output informational messages, alarms, warnings, and error messages (not reported in Windows Event Log). |
4 - Debug |
Output debug information, informational messages, alarms, warnings, and error messages (not reported in Windows Event Log). |
Return Value
Current trace level.
EpApiGetLastError
Retrieves last-error code value. The last-error code is maintained on a per-thread basis.
Syntax
CMAPI int EpApiGetLastError();
Parameters
This function has no parameters.
Return Value
The return value is the calling thread's last error code.
EpApi Error Codes
Most of the EpApi functions do not return a specific cause of an error when the function returns but rather set global error code value which can be retrieved by calling EpApiGetLastError function. The following list describes possible error codes returned by EpApiGetLastError function. Errors are listed in numerical order.
Table 7-21 Error Codes for EpApi
|
|
EP_ERR_OK 0 |
No error occurred. |
EP_ERR_INIT 17002 |
EpAPI is not initialized. |
EP_ERR_PARAM_INVALID 17003 |
Invalid parameter. |
EP_ERR_ADDR_NOTAVAIL 17100 |
Unable to create endpoint with specified IP address family |
EP_ERR_ADDR_INUSE 17101 |
Address (Protocol - IP address - port) is already in use. |
EP_ERR_HANDLE_INVALID 17102 |
Invalid endpoint or stream handle. |
Callback Function
Application can set endpoint callback to receive an indication about operation completions, data transfers, errors, etc. Endpoint callback function type is declared as follows:
Syntax
typedef void (WINAPI *PRTPENDPOINTCALLBACK) (
StreamDirection streamDir
Parameters
hEp
Endpoint handle
hStream
Rtp stream handle
dwError
If not 0 (zero), indicates an error
pData
Endpoint handle
dwDataSize
Number of bytes received / transferred.
pUserData
Application data associated with an operation.
bIsSilence
If set to true, indicates that silence has been detected.
streamDir
Stream direction. Can be one of the following:
–
ToApp
–
ToNwk
Data Structures
RTPADDR
Basic endpoint data structure which contains all endpoint related data, such as IP address, UDP port number, etc.
typedef struct sRTPAddrInfo {
Where:
info
System defined ADDRINFOT structure
addr
System defined SOCKADDR_STORAGE structure
sock
System defined SOCKET data (bound socket)
multicast
If set to true, RTPADDR instance represents multicast address, otherwise unicast.
dscp
DSCP / QoS data
srtp
SRTP data
silence
Silence processing parameters
pktSizeMs
Packet size in milliseconds
RTPSIL
Contains silence processing related data for a specific endpoint. It uses the following SilenceType enumeration:
Where:
type
Silence detection type as it is defined in SilenceType.
duration
Duration in milliseconds.
threshold
Energy threshold.
currentOffset
Silence offset (G.729).
detecting true
Silence detection enabled.
RTPCODEC
WORD (WINAPI *formatTag) ();
WORD * (WINAPI *supported) (ULONG & nmb);
ULONG (WINAPI *fmtBytesToThis) (WORD fmt, ULONG len);
ULONG (WINAPI *thisBytesToFmt) (ULONG len, WORD fmt);
PRTPSIL (WINAPI *silenceInit)(PRTPSIL ps, SilenceType type, ULONG duration,
ULONG threshold);
ULONG (WINAPI *silenceSet) (PRTPSIL, PUCHAR, ULONG);
bool (WINAPI *isSilence) (PRTPSIL, ULONG pcktSizeInMs, bool &
beenChanged, PUCHAR, ULONG);
void (WINAPI *silenceFree)(PRTPSIL);
Trace Options
Rtp Library have several logging options to facilitate application debugging and trouble-shooting:
Reporting in the Windows Event Log
Sending trace data to the OutputDebugString and can be view by any "trace listener", for example Sysinternals DebugView
Providing trace data to an application in the trace callback
Trace Level
Trace level specifies what messages are to be included in trace output and is defined as follows:
Table 7-22 Trace Level
|
|
0 - Error |
Output only error messages (reported in Windows Event Log). |
1 - Alarm |
Output alarms and error messages (reported in Windows Event Log). |
2 - Warning |
Output warnings, alarms and error messages (reported in Windows Event Log). |
3 - Info |
Output informational messages, alarms, warnings, and error messages (not reported in Windows Event Log). |
4 - Debug |
Output debug information, informational messages, alarms, warnings, and error messages (not reported in Windows Event Log). |
Trace level can be set and modified with the EpApiTraceLevelSet() function.
Trace Callback Function
An application can set trace callback. The callback function will be invoked by Rtp Library whenever it is ready to record a trace and will be provided with the trace record data. Trace callback can be set and modified when EpApi is initialized. Trace callback function type is declared as follows:
Syntax
typedef void (WINAPI *PRTPLIBTRACE) (
Parameters
level
Current trace record level.
pData
Pointer to the current trace record data.
Known Problems or Limitations
Below is the list of currently known Rtp Library problems and limitations:
•
CSCsy13584 - RtpLib: The only supported PCM encoding is 8k16bit, mono
•
There is no G.729 transcoding available