Group PJMEDIA_SDP

group PJMEDIA_SDP

SDP data structure representation and parsing.

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.

Defines

PJMEDIA_MAX_SDP_FMT: The PJMEDIA_MAX_SDP_FMT macro defines maximum format in a media line.

PJMEDIA_MAX_SDP_BANDW: The PJMEDIA_MAX_SDP_BANDW macro defines maximum bandwidth information lines in a media line.

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

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

Functions

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.

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.

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.

See also

pjmedia_sdp_media_add_attr

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.

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.

See also

pjmedia_sdp_media_remove_all_attr

Parameters:

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

Returns:

Number of attributes removed.

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.

See also

pjmedia_sdp_media_remove_attr

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.

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().

See also

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.

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.

See also

pjmedia_sdp_attr_to_rtpmap

Parameters:

attr – Generic attribute to be converted to rtpmap, which name must be “rtpmap”. Attribute value must be terminated with a NULL, CR, or LF character.
rtpmap – SDP rtpmap attribute to be initialized.

Returns:

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

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.

pj_status_t pjmedia_sdp_attr_get_ssrc(const pjmedia_sdp_attr *attr, pjmedia_sdp_ssrc_attr *rtcp)

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

Parameters:

attr – Generic attribute to be converted to ssrc, which name must be “ssrc”.
rtcp – SDP ssrc attribute to be initialized.

Returns:

PJ_SUCCESS on success.

pjmedia_sdp_attr *pjmedia_sdp_attr_create_ssrc(pj_pool_t *pool, pj_uint32_t ssrc, const pj_str_t *cname)

Create a=ssrc attribute.

Parameters:

pool – Pool to create the attribute.
ssrc – SSRC identifier.
cname – CNAME.

Returns:

SDP SSRC 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.

pj_status_t pjmedia_sdp_conn_cmp(const pjmedia_sdp_conn *conn1, const pjmedia_sdp_conn *conn2, unsigned option)

Compare connection info.

Parameters:

conn1 – The first connection info to compare.
conn2 – The second connection info to compare.
option – Comparison option, which should be zero for now.

Returns:

PJ_SUCCESS when both connection info are equal, otherwise returns PJMEDIA_SDP_ECONNNOTEQUAL.

pjmedia_sdp_bandw *pjmedia_sdp_bandw_clone(pj_pool_t *pool, const pjmedia_sdp_bandw *rhs)

Clone bandwidth info.

Parameters:

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

Returns:

The new bandwidth info.

int pjmedia_sdp_media_print(const pjmedia_sdp_media *media, char *buf, pj_size_t size)

Print media description to a buffer.

Parameters:

media – The media description.
buf – The buffer.
size – The buffer length.

Returns:

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

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.

int pjmedia_sdp_attr_print(const pjmedia_sdp_attr *attr, char *buf, pj_size_t size)

Print attribute to a buffer.

Parameters:

attr – The attribute.
buf – The buffer.
size – The buffer length.

Returns:

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

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_uint32_t pjmedia_sdp_transport_get_proto(const pj_str_t *tp)

Get media transport protocol info, i.e: base transport and profiles, from the provided SDP media transport name string.

Parameters:: tp – The SDP media transport name.
Returns:: Media transport info, combination of transport protocol and profile bit flag defined in pjmedia_tp_proto.

pj_status_t pjmedia_sdp_media_deactivate(pj_pool_t *pool, pjmedia_sdp_media *m)

Deactivate SDP media.

Parameters:

pool – Memory pool to allocate memory from.
m – The SDP media to deactivate.

Returns:

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

pjmedia_sdp_media *pjmedia_sdp_media_clone_deactivate(pj_pool_t *pool, const pjmedia_sdp_media *rhs)

Clone SDP media description and deactivate the new SDP media.

Parameters:

pool – Memory pool to allocate memory for the clone.
rhs – The SDP media to clone.

Returns:

New media descrption with deactivated indication.

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

Parse SDP message.

Note that the input message buffer MUST be NULL terminated and have length at least len+1 (len MUST NOT include the NULL terminator).

Parameters:

pool – The pool to allocate SDP session description.
buf – The message buffer, MUST be NULL terminated.
len – The length of the message, excluding NULL terminator.
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.

pj_status_t pjmedia_sdp_validate2(const pjmedia_sdp_session *sdp, pj_bool_t strict)

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.
strict – Flag whether the check should be strict, i.e: allow media without connection line when port is zero.

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.

pj_status_t pjmedia_sdp_session_add_attr(pjmedia_sdp_session *s, pjmedia_sdp_attr *attr)

Add new attribute to the session descriptor.

Parameters:

s – The SDP session description.
attr – Attribute to add.

Returns:

PJ_SUCCESS or the appropriate error code.

struct pjmedia_sdp_attr

#include <sdp.h>

Generic representation of attribute.

See also

pjmedia_sdp_attr

Public Members

pj_str_t name: Attribute name.

pj_str_t value: Attribute value.

struct pjmedia_sdp_rtpmap

#include <sdp.h>

This structure declares SDP rtpmap attribute.

See also

pjmedia_sdp_rtpmap

Public Members

pj_str_t pt: Payload type.

pj_str_t enc_name: Encoding name.

unsigned clock_rate: Clock rate.

pj_str_t param: Parameter.

struct pjmedia_sdp_fmtp

#include <sdp.h>

This structure describes SDP fmtp attribute.

Public Members

pj_str_t fmt: Format type.

pj_str_t fmt_param: Format specific parameter.

struct pjmedia_sdp_rtcp_attr

#include <sdp.h>

This structure describes SDP rtcp attribute.

Public Members

unsigned port: RTCP port number.

pj_str_t net_type: Optional network type.

pj_str_t addr_type: Optional address type.

pj_str_t addr: Optional address.

struct pjmedia_sdp_ssrc_attr

#include <sdp.h>

This structure describes SDP ssrc attribute.

Public Members

pj_uint32_t ssrc: RTP SSRC.

pj_str_t cname: RTCP CNAME.

struct pjmedia_sdp_conn

#include <sdp.h>

This structure describes SDP connection info (“c=” line).

See also

pjmedia_sdp_conn

Public Members

pj_str_t net_type: Network type (“IN”).

pj_str_t addr_type: Address type (“IP4”, “IP6”).

pj_str_t addr: The address.

pj_uint8_t ttl: Multicast address TTL

pj_uint8_t no_addr: Multicast number of addresses

struct pjmedia_sdp_bandw

#include <sdp.h>

This structure describes SDP bandwidth info (“b=” line).

Public Members

pj_str_t modifier: Bandwidth modifier.

pj_uint32_t value: Bandwidth value.

struct pjmedia_sdp_media

#include <sdp.h>

This structure describes SDP media descriptor. A SDP media descriptor starts with “m=” line and contains the media attributes and optional connection line.

See also

pjmedia_sdp_media

Public Members

pj_str_t media: Media type (“audio”, “video”)

pj_uint16_t port: Port number.

unsigned port_count: Port count, used only when >2

pj_str_t transport: Transport (“RTP/AVP”)

unsigned fmt_count: Number of formats.

pj_str_t fmt[32]: Media formats.

struct pjmedia_sdp_media::[anonymous] desc: Media descriptor line (“m=” line)

pjmedia_sdp_conn *conn: Optional connection info.

unsigned bandw_count: Number of bandwidth info.

pjmedia_sdp_bandw *bandw[4]: Bandwidth info.

unsigned attr_count: Number of attributes.

pjmedia_sdp_attr *attr[(32 * 2 + 4)]: Attributes.

struct pjmedia_sdp_session

#include <sdp.h>

This structure describes SDP session description. A SDP session descriptor contains complete information about a session, and normally is exchanged with remote media peer using signaling protocol such as SIP.

See also

pjmedia_sdp_session

Public Members

pj_str_t user: User

pj_uint_t id: Session ID

pj_uint_t version: Session version

pj_str_t net_type: Network type (“IN”)

pj_str_t addr_type: Address type (“IP4”, “IP6”)

pj_str_t addr: The address.

struct pjmedia_sdp_session::[anonymous] origin: Session origin (o= line)

pj_str_t name: Subject line (s=)

pjmedia_sdp_conn *conn: Connection line (c=)

unsigned bandw_count: Number of bandwidth info (b=)

pjmedia_sdp_bandw *bandw[4]: Bandwidth info array (b=)

pj_uint_t start: Start time.

pj_uint_t stop: Stop time.

struct pjmedia_sdp_session::[anonymous] time: Session time (t= line)

unsigned attr_count: Number of attributes.

pjmedia_sdp_attr *attr[(32 * 2 + 4)]: Attributes array.

unsigned media_count: Number of media.

pjmedia_sdp_media *media[16]: Media array.