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SDP Parsing and Data Structure

SDP data structure representation and parsing. More...

Data Structures

struct  pjmedia_sdp_attr
 
struct  pjmedia_sdp_rtpmap
 
struct  pjmedia_sdp_fmtp
 
struct  pjmedia_sdp_rtcp_attr
 
struct  pjmedia_sdp_conn
 
struct  pjmedia_sdp_bandw
 
struct  pjmedia_sdp_media
 
struct  pjmedia_sdp_session
 

Macros

#define PJMEDIA_MAX_SDP_FMT   32
 
#define PJMEDIA_MAX_SDP_BANDW   4
 
#define PJMEDIA_MAX_SDP_ATTR   (PJMEDIA_MAX_SDP_FMT*2 + 4)
 
#define PJMEDIA_MAX_SDP_MEDIA   16
 

Functions

pjmedia_sdp_attrpjmedia_sdp_attr_create (pj_pool_t *pool, const char *name, const pj_str_t *value)
 
pjmedia_sdp_attrpjmedia_sdp_attr_clone (pj_pool_t *pool, const pjmedia_sdp_attr *attr)
 
pjmedia_sdp_attrpjmedia_sdp_attr_find (unsigned count, pjmedia_sdp_attr *const attr_array[], const pj_str_t *name, const pj_str_t *fmt)
 
pjmedia_sdp_attrpjmedia_sdp_attr_find2 (unsigned count, pjmedia_sdp_attr *const attr_array[], const char *name, const pj_str_t *fmt)
 
pj_status_t pjmedia_sdp_attr_add (unsigned *count, pjmedia_sdp_attr *attr_array[], pjmedia_sdp_attr *attr)
 
unsigned pjmedia_sdp_attr_remove_all (unsigned *count, pjmedia_sdp_attr *attr_array[], const char *name)
 
pj_status_t pjmedia_sdp_attr_remove (unsigned *count, pjmedia_sdp_attr *attr_array[], pjmedia_sdp_attr *attr)
 
pj_status_t pjmedia_sdp_attr_to_rtpmap (pj_pool_t *pool, const pjmedia_sdp_attr *attr, pjmedia_sdp_rtpmap **p_rtpmap)
 
pj_status_t pjmedia_sdp_attr_get_rtpmap (const pjmedia_sdp_attr *attr, pjmedia_sdp_rtpmap *rtpmap)
 
pj_status_t pjmedia_sdp_rtpmap_to_attr (pj_pool_t *pool, const pjmedia_sdp_rtpmap *rtpmap, pjmedia_sdp_attr **p_attr)
 
pj_status_t pjmedia_sdp_attr_get_fmtp (const pjmedia_sdp_attr *attr, pjmedia_sdp_fmtp *fmtp)
 
pj_status_t pjmedia_sdp_attr_get_rtcp (const pjmedia_sdp_attr *attr, pjmedia_sdp_rtcp_attr *rtcp)
 
pjmedia_sdp_attrpjmedia_sdp_attr_create_rtcp (pj_pool_t *pool, const pj_sockaddr *a)
 
pjmedia_sdp_connpjmedia_sdp_conn_clone (pj_pool_t *pool, const pjmedia_sdp_conn *rhs)
 
pj_status_t pjmedia_sdp_conn_cmp (const pjmedia_sdp_conn *conn1, const pjmedia_sdp_conn *conn2, unsigned option)
 
pjmedia_sdp_bandwpjmedia_sdp_bandw_clone (pj_pool_t *pool, const pjmedia_sdp_bandw *rhs)
 
pjmedia_sdp_mediapjmedia_sdp_media_clone (pj_pool_t *pool, const pjmedia_sdp_media *rhs)
 
pjmedia_sdp_attrpjmedia_sdp_media_find_attr (const pjmedia_sdp_media *m, const pj_str_t *name, const pj_str_t *fmt)
 
pjmedia_sdp_attrpjmedia_sdp_media_find_attr2 (const pjmedia_sdp_media *m, const char *name, const pj_str_t *fmt)
 
pj_status_t pjmedia_sdp_media_add_attr (pjmedia_sdp_media *m, pjmedia_sdp_attr *attr)
 
unsigned pjmedia_sdp_media_remove_all_attr (pjmedia_sdp_media *m, const char *name)
 
pj_status_t pjmedia_sdp_media_remove_attr (pjmedia_sdp_media *m, pjmedia_sdp_attr *attr)
 
pj_status_t pjmedia_sdp_media_cmp (const pjmedia_sdp_media *sd1, const pjmedia_sdp_media *sd2, unsigned option)
 
pj_status_t pjmedia_sdp_transport_cmp (const pj_str_t *t1, const pj_str_t *t2)
 
pj_status_t pjmedia_sdp_media_deactivate (pj_pool_t *pool, pjmedia_sdp_media *m)
 
pjmedia_sdp_mediapjmedia_sdp_media_clone_deactivate (pj_pool_t *pool, const pjmedia_sdp_media *rhs)
 
pj_status_t pjmedia_sdp_parse (pj_pool_t *pool, char *buf, pj_size_t len, pjmedia_sdp_session **p_sdp)
 
int pjmedia_sdp_print (const pjmedia_sdp_session *sdp, char *buf, pj_size_t size)
 
pj_status_t pjmedia_sdp_validate (const pjmedia_sdp_session *sdp)
 
pj_status_t pjmedia_sdp_validate2 (const pjmedia_sdp_session *sdp, pj_bool_t strict)
 
pjmedia_sdp_sessionpjmedia_sdp_session_clone (pj_pool_t *pool, const pjmedia_sdp_session *sdp)
 
pj_status_t pjmedia_sdp_session_cmp (const pjmedia_sdp_session *sd1, const pjmedia_sdp_session *sd2, unsigned option)
 
pj_status_t pjmedia_sdp_session_add_attr (pjmedia_sdp_session *s, pjmedia_sdp_attr *attr)
 

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.

Macro Definition Documentation

#define PJMEDIA_MAX_SDP_FMT   32

The PJMEDIA_MAX_SDP_FMT macro defines maximum format in a media line.

#define PJMEDIA_MAX_SDP_BANDW   4

The PJMEDIA_MAX_SDP_BANDW macro defines maximum bandwidth information lines 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.

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
poolPool to create the attribute.
nameAttribute name.
valueOptional 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
poolPool to be used.
attrThe 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
countNumber of attributes in the array.
attr_arrayArray of attributes.
nameAttribute name to find.
fmtOptional 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
countNumber of attributes in the array.
attr_arrayArray of attributes.
nameAttribute name to find.
fmtOptional 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
countNumber of attributes in the array.
attr_arrayArray of attributes.
attrThe 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
countNumber of attributes in the array.
attr_arrayArray of attributes.
nameAttribute 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
countNumber of attributes in the array.
attr_arrayArray of attributes.
attrThe 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
poolPool used to create the rtpmap attribute.
attrGeneric attribute to be converted to rtpmap, which name must be "rtpmap".
p_rtpmapPointer 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
attrGeneric attribute to be converted to rtpmap, which name must be "rtpmap".
rtpmapSDP 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
poolPool to be used.
rtpmapThe rtpmap attribute.
p_attrPointer 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
attrGeneric attribute to be converted to fmtp, which name must be "fmtp".
fmtpSDP 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
attrGeneric attribute to be converted to rtcp, which name must be "rtcp".
rtcpSDP 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
poolPool to create the attribute.
aSocket 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
poolPool to allocate memory for the new connection info.
rhsThe 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
conn1The first connection info to compare.
conn1The second connection info to compare.
optionComparison 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
poolPool to allocate memory for the new bandwidth info.
rhsThe bandwidth into to clone.
Returns
The new bandwidth info.
pjmedia_sdp_media* pjmedia_sdp_media_clone ( pj_pool_t pool,
const pjmedia_sdp_media rhs 
)

Clone SDP media description.

Parameters
poolPool to allocate memory for the new media description.
rhsThe 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
mThe SDP media description.
nameAttribute name to find.
fmtOptional 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
mThe SDP media description.
nameAttribute name to find.
fmtOptional 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
mThe SDP media description.
attrAttribute 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
mThe SDP media description.
nameAttribute 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
mThe SDP media descriptor.
attrThe 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
sd1The first SDP media to compare.
sd2The second SDP media to compare.
optionComparison 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
t1The first media transport to compare.
t2The 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
poolMemory pool to allocate memory from.
mThe 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
poolMemory pool to allocate memory for the clone.
rhsThe 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.

Parameters
poolThe pool to allocate SDP session description.
bufThe message buffer.
lenThe length of the message.
p_sdpPointer 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
sdpThe SDP session description.
bufThe buffer.
sizeThe 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
sdpThe 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
sdpThe SDP session descriptor to validate.
strictFlag 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
poolThe pool used to clone the session.
sdpThe 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
sd1The first SDP session to compare.
sd2The second SDP session to compare.
optionMust 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
sThe SDP session description.
attrAttribute to add.
Returns
PJ_SUCCESS or the appropriate error code.

 


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