SDP Parsing and Data Structure
[Media Sessions]

Detailed Description

The basic SDP session descriptor and elements are described in header file <pjmedia/sdp.h>. This file contains declaration for SDP session descriptor and SDP media descriptor, along with their attributes. This file also declares functions to parse SDP message.

Define Documentation

#define PJMEDIA_MAX_SDP_FMT 32

The PJMEDIA_MAX_SDP_FMT macro defines maximum format in a media line.

#define PJMEDIA_MAX_SDP_ATTR (PJMEDIA_MAX_SDP_FMT*2 + 4)

The PJMEDIA_MAX_SDP_ATTR macro defines maximum SDP attributes in media and session descriptor.

#define PJMEDIA_MAX_SDP_MEDIA 16

The PJMEDIA_MAX_SDP_MEDIA macro defines maximum SDP media lines in a SDP session descriptor.

Typedef Documentation

typedef struct pjmedia_sdp_attr pjmedia_sdp_attr

See also:: pjmedia_sdp_attr

typedef struct pjmedia_sdp_rtpmap pjmedia_sdp_rtpmap

See also:: pjmedia_sdp_rtpmap

typedef struct pjmedia_sdp_fmtp pjmedia_sdp_fmtp

See also:: pjmedia_sdp_fmtp

typedef struct pjmedia_sdp_conn pjmedia_sdp_conn

See also:: pjmedia_sdp_conn

typedef struct pjmedia_sdp_media pjmedia_sdp_media

See also:: pjmedia_sdp_media

typedef struct pjmedia_sdp_session pjmedia_sdp_session

See also:: pjmedia_sdp_session

Function Documentation

pjmedia_sdp_attr* pjmedia_sdp_attr_create	(	pj_pool_t *	pool,
		const char *	name,
		const pj_str_t *	value
	)

Create SDP attribute.

Parameters:

	pool	Pool to create the attribute.
	name	Attribute name.
	value	Optional attribute value.

Returns:: The new SDP attribute.

pjmedia_sdp_attr* pjmedia_sdp_attr_clone	(	pj_pool_t *	pool,
		const pjmedia_sdp_attr *	attr
	)

Clone attribute

Parameters:

	pool	Pool to be used.
	attr	The attribute to clone.

Returns:: New attribute as cloned from the attribute.

pjmedia_sdp_attr* pjmedia_sdp_attr_find	(	unsigned	count,
		pjmedia_sdp_attr *const	attr_array[],
		const pj_str_t *	name,
		const pj_str_t *	fmt
	)

Find the first attribute with the specified type.

Parameters:

	count	Number of attributes in the array.
	attr_array	Array of attributes.
	name	Attribute name to find.
	fmt	Optional string to indicate which payload format to find for rtpmap and fmt attributes. For other types of attributes, the value should be NULL.

Returns:: The specified attribute, or NULL if it can't be found.

See also:: pjmedia_sdp_attr_find2, pjmedia_sdp_media_find_attr, pjmedia_sdp_media_find_attr2

pjmedia_sdp_attr* pjmedia_sdp_attr_find2	(	unsigned	count,
		pjmedia_sdp_attr *const	attr_array[],
		const char *	name,
		const pj_str_t *	fmt
	)

Find the first attribute with the specified type.

Parameters:

	count	Number of attributes in the array.
	attr_array	Array of attributes.
	name	Attribute name to find.
	fmt	Optional string to indicate which payload format to find for rtpmap and fmt attributes. For other types of attributes, the value should be NULL.

Returns:: The specified attribute, or NULL if it can't be found.

See also:: pjmedia_sdp_attr_find, pjmedia_sdp_media_find_attr, pjmedia_sdp_media_find_attr2

pj_status_t pjmedia_sdp_attr_add	(	unsigned *	count,
		pjmedia_sdp_attr *	attr_array[],
		pjmedia_sdp_attr *	attr
	)

Add a new attribute to array of attributes.

Parameters:

	count	Number of attributes in the array.
	attr_array	Array of attributes.
	attr	The attribute to add.

Returns:: PJ_SUCCESS or the error code.

See also:: pjmedia_sdp_media_add_attr

unsigned pjmedia_sdp_attr_remove_all	(	unsigned *	count,
		pjmedia_sdp_attr *	attr_array[],
		const char *	name
	)

Remove all attributes with the specified name in array of attributes.

Parameters:

	count	Number of attributes in the array.
	attr_array	Array of attributes.
	name	Attribute name to find.

Returns:: Number of attributes removed.

See also:: pjmedia_sdp_media_remove_all_attr

pj_status_t pjmedia_sdp_attr_remove	(	unsigned *	count,
		pjmedia_sdp_attr *	attr_array[],
		pjmedia_sdp_attr *	attr
	)

Remove the specified attribute from the attribute array.

Parameters:

	count	Number of attributes in the array.
	attr_array	Array of attributes.
	attr	The attribute instance to remove.

Returns:: PJ_SUCCESS when attribute has been removed, or PJ_ENOTFOUND when the attribute can not be found.

See also:: pjmedia_sdp_media_remove_attr

pj_status_t pjmedia_sdp_attr_to_rtpmap	(	pj_pool_t *	pool,
		const pjmedia_sdp_attr *	attr,
		pjmedia_sdp_rtpmap **	p_rtpmap
	)

Convert generic attribute to SDP rtpmap. This function allocates a new attribute and call pjmedia_sdp_attr_get_rtpmap().

Parameters:

	pool	Pool used to create the rtpmap attribute.
	attr	Generic attribute to be converted to rtpmap, which name must be "rtpmap".
	p_rtpmap	Pointer to receive SDP rtpmap attribute.

Returns:: PJ_SUCCESS if the attribute can be successfully converted to rtpmap type.

See also:: pjmedia_sdp_attr_get_rtpmap

pj_status_t pjmedia_sdp_attr_get_rtpmap	(	const pjmedia_sdp_attr *	attr,
		pjmedia_sdp_rtpmap *	rtpmap
	)

Get the rtpmap representation of the same SDP attribute.

Parameters:

	attr	Generic attribute to be converted to rtpmap, which name must be "rtpmap".
	rtpmap	SDP rtpmap attribute to be initialized.

Returns:: PJ_SUCCESS if the attribute can be successfully converted to rtpmap attribute.

See also:: pjmedia_sdp_attr_to_rtpmap

pj_status_t pjmedia_sdp_rtpmap_to_attr	(	pj_pool_t *	pool,
		const pjmedia_sdp_rtpmap *	rtpmap,
		pjmedia_sdp_attr **	p_attr
	)

Convert rtpmap attribute to generic attribute.

Parameters:

	pool	Pool to be used.
	rtpmap	The rtpmap attribute.
	p_attr	Pointer to receive the generic SDP attribute.

Returns:: PJ_SUCCESS on success.

pj_status_t pjmedia_sdp_attr_get_fmtp	(	const pjmedia_sdp_attr *	attr,
		pjmedia_sdp_fmtp *	fmtp
	)

Get the fmtp representation of the same SDP attribute.

Parameters:

	attr	Generic attribute to be converted to fmtp, which name must be "fmtp".
	fmtp	SDP fmtp attribute to be initialized.

Returns:: PJ_SUCCESS on success.

pj_status_t pjmedia_sdp_attr_get_rtcp	(	const pjmedia_sdp_attr *	attr,
		pjmedia_sdp_rtcp_attr *	rtcp
	)

Parse a generic SDP attribute to get SDP rtcp attribute values.

Parameters:

	attr	Generic attribute to be converted to rtcp, which name must be "rtcp".
	rtcp	SDP rtcp attribute to be initialized.

Returns:: PJ_SUCCESS on success.

pjmedia_sdp_attr* pjmedia_sdp_attr_create_rtcp	(	pj_pool_t *	pool,
		const pj_sockaddr *	a
	)

Create a=rtcp attribute.

Parameters:

	pool	Pool to create the attribute.
	a	Socket address.

Returns:: SDP RTCP attribute.

pjmedia_sdp_conn* pjmedia_sdp_conn_clone	(	pj_pool_t *	pool,
		const pjmedia_sdp_conn *	rhs
	)

Clone connection info.

Parameters:

	pool	Pool to allocate memory for the new connection info.
	rhs	The connection into to clone.

Returns:: The new connection info.

pjmedia_sdp_media* pjmedia_sdp_media_clone	(	pj_pool_t *	pool,
		const pjmedia_sdp_media *	rhs
	)

Clone SDP media description.

Parameters:

	pool	Pool to allocate memory for the new media description.
	rhs	The media descriptin to clone.

Returns:: New media description.

pjmedia_sdp_attr* pjmedia_sdp_media_find_attr	(	const pjmedia_sdp_media *	m,
		const pj_str_t *	name,
		const pj_str_t *	fmt
	)

Find the first occurence of the specified attribute name in the media descriptor. Optionally the format may be specified.

Parameters:

	m	The SDP media description.
	name	Attribute name to find.
	fmt	Optional payload type to match in the attribute list, when the attribute is rtpmap or fmtp. For other types of SDP attributes, this value should be NULL.

Returns:: The first instance of the specified attribute or NULL.

pjmedia_sdp_attr* pjmedia_sdp_media_find_attr2	(	const pjmedia_sdp_media *	m,
		const char *	name,
		const pj_str_t *	fmt
	)

Find the first occurence of the specified attribute name in the SDP media descriptor. Optionally the format may be specified.

Parameters:

	m	The SDP media description.
	name	Attribute name to find.
	fmt	Optional payload type to match in the attribute list, when the attribute is rtpmap or fmtp. For other types of SDP attributes, this value should be NULL.

Returns:: The first instance of the specified attribute or NULL.

pj_status_t pjmedia_sdp_media_add_attr	(	pjmedia_sdp_media *	m,
		pjmedia_sdp_attr *	attr
	)

Add new attribute to the media descriptor.

Parameters:

	m	The SDP media description.
	attr	Attribute to add.

Returns:: PJ_SUCCESS or the appropriate error code.

unsigned pjmedia_sdp_media_remove_all_attr	(	pjmedia_sdp_media *	m,
		const char *	name
	)

Remove all attributes with the specified name from the SDP media descriptor.

Parameters:

	m	The SDP media description.
	name	Attribute name to remove.

Returns:: The number of attributes removed.

pj_status_t pjmedia_sdp_media_remove_attr	(	pjmedia_sdp_media *	m,
		pjmedia_sdp_attr *	attr
	)

Remove the occurence of the specified attribute from the SDP media descriptor.

Parameters:

	m	The SDP media descriptor.
	attr	The attribute to find and remove.

Returns:: PJ_SUCCESS if the attribute can be found and has been removed from the array.

pj_status_t pjmedia_sdp_media_cmp	(	const pjmedia_sdp_media *	sd1,
		const pjmedia_sdp_media *	sd2,
		unsigned	option
	)

Compare two SDP media for equality.

Parameters:

	sd1	The first SDP media to compare.
	sd2	The second SDP media to compare.
	option	Comparison option, which should be zero for now.

Returns:: PJ_SUCCESS when both SDP medias are equal, or the appropriate status code describing which part of the descriptors that are not equal.

pj_status_t pjmedia_sdp_transport_cmp	(	const pj_str_t *	t1,
		const pj_str_t *	t2
	)

Compare two media transports for compatibility.

Parameters:

	t1	The first media transport to compare.
	t2	The second media transport to compare.

Returns:: PJ_SUCCESS when both media transports are compatible, otherwise returns PJMEDIA_SDP_ETPORTNOTEQUAL.

pj_status_t pjmedia_sdp_media_deactivate	(	pj_pool_t *	pool,
		pjmedia_sdp_media *	m
	)

Deactivate SDP media.

Parameters:

The SDP media to deactivate.

Returns:: PJ_SUCCESS when SDP media successfully deactivated, otherwise appropriate status code returned.

pj_status_t pjmedia_sdp_parse	(	pj_pool_t *	pool,
		char *	buf,
		pj_size_t	len,
		pjmedia_sdp_session **	p_sdp
	)

Parse SDP message.

Parameters:

	pool	The pool to allocate SDP session description.
	buf	The message buffer.
	len	The length of the message.
	p_sdp	Pointer to receive the SDP session descriptor.

Returns:: PJ_SUCCESS if message was successfully parsed into SDP session descriptor.

int pjmedia_sdp_print	(	const pjmedia_sdp_session *	sdp,
		char *	buf,
		pj_size_t	size
	)

Print SDP description to a buffer.

Parameters:

	sdp	The SDP session description.
	buf	The buffer.
	size	The buffer length.

Returns:: the length printed, or -1 if the buffer is too short.

pj_status_t pjmedia_sdp_validate ( const pjmedia_sdp_session * sdp )

Perform semantic validation for the specified SDP session descriptor. This function perform validation beyond just syntactic verification, such as to verify the value of network type and address type, check the connection line, and verify that rtpmap attribute is present when dynamic payload type is used.

Parameters:

sdp

The SDP session descriptor to validate.

Returns:: PJ_SUCCESS on success.

pjmedia_sdp_session* pjmedia_sdp_session_clone	(	pj_pool_t *	pool,
		const pjmedia_sdp_session *	sdp
	)

Clone SDP session descriptor.

Parameters:

	pool	The pool used to clone the session.
	sdp	The SDP session to clone.

Returns:: New SDP session.

pj_status_t pjmedia_sdp_session_cmp	(	const pjmedia_sdp_session *	sd1,
		const pjmedia_sdp_session *	sd2,
		unsigned	option
	)

Compare two SDP session for equality.

Parameters:

	sd1	The first SDP session to compare.
	sd2	The second SDP session to compare.
	option	Must be zero for now.

Returns:: PJ_SUCCESS when both SDPs are equal, or otherwise the status code indicates which part of the session descriptors are not equal.

SDP Parsing and Data Structure [Media Sessions]

Detailed Description

Data Structures

Defines

Typedefs

Functions

Define Documentation

Typedef Documentation

Function Documentation

SDP Parsing and Data Structure
[Media Sessions]