# Setting timestamp frequencies for full-duplex RTP endpoints

Set the timestamp frequency for an RTP endpoint by changing the rtpTsFreq parameter in the MSP_CMD_RTPFDX_CONFIG command.

The default timestamp frequency is 90,000 Hz. To set a frequency value other than the default, use a value other than zero or all ones (0xFFFFFFFF).

Note: This feature is for all video full-duplex and simplex send RTP endpoints. The procedure and example are shown for full-duplex endpoints.

The following table describes how to set timestamp frequencies:

Step | Action
1 | Disable the RTP endpoint by invoking mspDisableEndpoint.
2 | Create the MSP_CMD_RTPFDX_CONFIG command, and send it to the CG board. The MSP_CMD_RTPFDX_CONFIG command uses the standard MSPP msp_ENDPOINT_RTPFDX_CONFIG structure to set the timestamp frequency. For more information, see Creating and sending MSPP commands and the MSPP Service Developer's Reference Manual.
3 | Enable the RTP endpoint by invoking mspEnable.

The following event can be returned:

Event | Description
MSPEVN_SENDCOMMAND_DONE | MSP_CMD_RTPFDX_CONFIG command was successfully sent to the specified RTP endpoint on the CG board.

#### Example

The following example shows how to set the timestamp frequency for an RTP endpoint with the MSP handle ephd:

msp_ENDPOINT_RTPFDX_CONFIG mConfig;
CTA_EVENT event;
DWORD ret, expectedEvent
memset(&mConfig, 0xFF, sizeof(mConfig));
mConfig.rtpTsFreq = H2NMS_DWORD(97000) ;
ret = mspDisableEndpoint(ephd);
ret = mspSendCommand(ephd, mspBuildCommand(MSP_ENDPOINT_RTPFDX_VIDEO_H263,
MSP_CMD_RTPFDX_CONFIG), &mConfig, sizeof(mConfig));
if (ret != SUCCESS)
printf("\n\t ERROR: mspSendCommand returned failure.\n");
expectedEvent = (MSPEVN_SENDCOMMAND_DONE | MSP_CMD_RTPFDX_CONFIG);
if (WaitForSpecificEvent(gw, ctaQueueHd, expectedEvent, &event) != 0)
printf("\n\tERROR: mspSendCommand failed to send valid completion event\n");
ret = mspEnableEndpoint(ephd);