SDPOPS Module

Daniel-Constantin Mierla

Edited by

Daniel-Constantin Mierla


Table of Contents

1. Admin Guide
1. Overview
2. Dependencies
2.1. Kamailio Modules
2.2. External Libraries or Applications
3. Parameters
4. Functions
4.1. sdp_remove_codecs_by_id(list)
4.2. sdp_remove_codecs_by_name(list)
4.3. sdp_keep_codecs_by_id(list)
4.4. sdp_keep_codecs_by_name(list)
4.5. sdp_with_media(type)
4.6. sdp_print(level)

List of Examples

1.1. sdp_remove_codecs_by_id usage
1.2. sdp_remove_codecs_by_name usage
1.3. sdp_keep_codecs_by_id usage
1.4. sdp_keep_codecs_by_name usage
1.5. sdp_with_media usage
1.6. sdp_print usage

Chapter 1. Admin Guide

1. Overview

This module provides function for checking and managing the SDP payloads of SIP messages.

Examples of what this module offers: remove codecs from SDP, check the media stream types, return attributes of SDP document. For the full least of the features provided by this module and the implementation state, read further to the list of exported functions.

2. Dependencies

2.1. Kamailio Modules

The following modules must be loaded before this module:

  • none.

2.2. External Libraries or Applications

The following libraries or applications must be installed before running Kamailio with this module loaded:

  • None

3. Parameters

The module does not export any config parameter yet.

4. Functions

4.1.  sdp_remove_codecs_by_id(list)

Remove the codecs provided in the parameter 'list' from all media streams found in SDP payload. The parameter 'list' must be one or a comma separated list of numeric codec IDs. The parameter can be a static string or a variable holding the list of numeric codec IDs.

This function can be used from ANY_ROUTE.

Example 1.1. sdp_remove_codecs_by_id usage

...
# remove PCMU
sdp_remove_codecs_by_id("0");
# remove PCMU, PCMA and GSM
sdp_remove_codecs_by_id("0,8,3");
...

4.2.  sdp_remove_codecs_by_name(list)

Remove the codecs provided in the parameter 'list' from all media streams found in SDP payload. The parameter 'list' must be one or a comma separated list of codec names. The parameter can be a static string or a variable holding the list of codec names.

This function can be used from ANY_ROUTE.

Example 1.2. sdp_remove_codecs_by_name usage

...
# remove PCMU
sdp_remove_codecs_by_name("PCMU");
# remove PCMU, PCMA and GSM
sdp_remove_codecs_by_name("PCMU,PCMA,GSM");
...

4.3.  sdp_keep_codecs_by_id(list)

Keep only the codecs provided in the parameter 'list' from all media streams found in SDP payload. The parameter 'list' must be one or a comma separated list of numeric codec IDs. The parameter can be a static string or a variable holding the list of numeric codec IDs.

This function can be used from ANY_ROUTE.

Example 1.3. sdp_keep_codecs_by_id usage

...
# keep only PCMU
sdp_keep_codecs_by_id("0");
# keep PCMU, PCMA and GSM
sdp_keep_codecs_by_id("0,8,3");
...

4.4.  sdp_keep_codecs_by_name(list)

Keep only the codecs provided in the parameter 'list' from all media streams found in SDP payload. The parameter 'list' must be one or a comma separated list of codec names. The parameter can be a static string or a variable holding the list of codec names.

This function can be used from ANY_ROUTE.

Example 1.4. sdp_keep_codecs_by_name usage

...
# keep only PCMU
sdp_keep_codecs_by_name("PCMU");
# keep PCMU, PCMA and GSM
sdp_keep_codecs_by_name("PCMU,PCMA,GSM");
...

4.5.  sdp_with_media(type)

Return true of the SDP has 'media=type ...' line. Useful to check the content of the RTP sessions, such as 'audio' or 'video'. The parameter can be static string or variable holding the media type.

This function can be used from ANY_ROUTE.

Example 1.5. sdp_with_media usage

...
# check for video stream
if(sdp_with_media("video"))
{
    # the session has a video stream
}
...

4.6.  sdp_print(level)

Print the SDP internal structure to log 'level'. The parameter can be static integer or variable holding the integer value of the log level.

This function can be used from ANY_ROUTE.

Example 1.6. sdp_print usage

...
# print the SDP
sdp_print("1");
...