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Data Structures

struct  pjmedia_stream_info
 

Typedefs

typedef struct pjmedia_channel pjmedia_channel
 

Functions

pj_status_t pjmedia_stream_info_from_sdp (pjmedia_stream_info *si, pj_pool_t *pool, pjmedia_endpt *endpt, const pjmedia_sdp_session *local, const pjmedia_sdp_session *remote, unsigned stream_idx)
 
pj_status_t pjmedia_stream_create (pjmedia_endpt *endpt, pj_pool_t *pool, const pjmedia_stream_info *info, pjmedia_transport *tp, void *user_data, pjmedia_stream **p_stream)
 
pj_status_t pjmedia_stream_destroy (pjmedia_stream *stream)
 
char pjmedia_stream_get_last_jb_frame_type (pjmedia_stream *stream)
 
pj_status_t pjmedia_stream_get_port (pjmedia_stream *stream, pjmedia_port **p_port)
 
pjmedia_transportpjmedia_stream_get_transport (pjmedia_stream *st)
 
pj_status_t pjmedia_stream_start (pjmedia_stream *stream)
 
pj_status_t pjmedia_stream_get_info (const pjmedia_stream *stream, pjmedia_stream_info *info)
 
pj_status_t pjmedia_stream_get_stat (const pjmedia_stream *stream, pjmedia_rtcp_stat *stat)
 
pj_status_t pjmedia_stream_reset_stat (pjmedia_stream *stream)
 
pj_status_t pjmedia_stream_get_stat_jbuf (const pjmedia_stream *stream, pjmedia_jb_state *state)
 
pj_status_t pjmedia_stream_pause (pjmedia_stream *stream, pjmedia_dir dir)
 
pj_status_t pjmedia_stream_resume (pjmedia_stream *stream, pjmedia_dir dir)
 
pj_status_t pjmedia_stream_dial_dtmf (pjmedia_stream *stream, const pj_str_t *ascii_digit)
 
pj_bool_t pjmedia_stream_check_dtmf (pjmedia_stream *stream)
 
pj_status_t pjmedia_stream_get_dtmf (pjmedia_stream *stream, char *ascii_digits, unsigned *size)
 
pj_status_t pjmedia_stream_set_dtmf_callback (pjmedia_stream *stream, void(*cb)(pjmedia_stream *, void *user_data, int digit), void *user_data)
 
pj_status_t pjmedia_stream_send_rtcp_sdes (pjmedia_stream *stream)
 
pj_status_t pjmedia_stream_send_rtcp_bye (pjmedia_stream *stream)
 
pj_status_t pjmedia_stream_get_rtp_session_info (pjmedia_stream *stream, pjmedia_stream_rtp_sess_info *session_info)
 

Detailed Description

A media stream is a bidirectional multimedia communication between two endpoints. It corresponds to a media description (m= line) in SDP session descriptor.

A media stream consists of two unidirectional channels:

A media stream exports media port interface (see Media Ports Framework) and application normally uses this interface to interconnect the stream to other PJMEDIA components.

A media stream internally manages the following objects:

Streams are created by calling pjmedia_stream_create(), specifying pjmedia_stream_info structure in the parameter. Application can construct the pjmedia_stream_info structure manually, or use pjmedia_stream_info_from_sdp() or pjmedia_session_info_from_sdp() functions to construct the pjmedia_stream_info from local and remote SDP session descriptors.

Application can also use Media Sessions to indirectly create the streams.

Typedef Documentation

Opaque declaration for media channel. Media channel is unidirectional flow of media from sender to receiver.

Function Documentation

pj_status_t pjmedia_stream_info_from_sdp ( pjmedia_stream_info si,
pj_pool_t pool,
pjmedia_endpt endpt,
const pjmedia_sdp_session local,
const pjmedia_sdp_session remote,
unsigned  stream_idx 
)

This function will initialize the stream info based on information in both SDP session descriptors for the specified stream index. The remaining information will be taken from default codec parameters. If socket info array is specified, the socket will be copied to the session info as well.

Parameters
siStream info structure to be initialized.
poolPool to allocate memory.
endptPJMEDIA endpoint instance.
localLocal SDP session descriptor.
remoteRemote SDP session descriptor.
stream_idxMedia stream index in the session descriptor.
Returns
PJ_SUCCESS if stream info is successfully initialized.
pj_status_t pjmedia_stream_create ( pjmedia_endpt endpt,
pj_pool_t pool,
const pjmedia_stream_info info,
pjmedia_transport tp,
void *  user_data,
pjmedia_stream **  p_stream 
)

Create a media stream based on the specified parameter. After the stream has been created, application normally would want to get the media port interface of the streams, by calling pjmedia_stream_get_port(). The media port interface exports put_frame() and get_frame() function, used to transmit and receive media frames from the stream.

Without application calling put_frame() and get_frame(), there will be no media frames transmitted or received by the stream.

Parameters
endptMedia endpoint.
poolPool to allocate memory for the stream. A large number of memory may be needed because jitter buffer needs to preallocate some storage.
infoStream information.
tpStream transport instance used to transmit and receive RTP/RTCP packets to/from the underlying transport.
user_dataArbitrary user data (for future callback feature).
p_streamPointer to receive the media stream.
Returns
PJ_SUCCESS on success.
pj_status_t pjmedia_stream_destroy ( pjmedia_stream *  stream)

Destroy the media stream.

Parameters
streamThe media stream.
Returns
PJ_SUCCESS on success.
char pjmedia_stream_get_last_jb_frame_type ( pjmedia_stream *  stream)

Get the last frame type retreived from the jitter buffer.

Parameters
streamThe media stream.
Returns
Jitter buffer frame type.
pj_status_t pjmedia_stream_get_port ( pjmedia_stream *  stream,
pjmedia_port **  p_port 
)

Get the media port interface of the stream. The media port interface declares put_frame() and get_frame() function, which is the only way for application to transmit and receive media frames from the stream.

Parameters
streamThe media stream.
p_portPointer to receive the port interface.
Returns
PJ_SUCCESS on success.
pjmedia_transport* pjmedia_stream_get_transport ( pjmedia_stream *  st)

Get the media transport object associated with this stream.

Parameters
stThe media stream.
Returns
The transport object being used by the stream.
pj_status_t pjmedia_stream_start ( pjmedia_stream *  stream)

Start the media stream. This will start the appropriate channels in the media stream, depending on the media direction that was set when the stream was created.

Parameters
streamThe media stream.
Returns
PJ_SUCCESS on success.
pj_status_t pjmedia_stream_get_info ( const pjmedia_stream *  stream,
pjmedia_stream_info info 
)

Get the stream info.

Parameters
streamThe media stream.
infoStream info.
Returns
PJ_SUCCESS on success.
pj_status_t pjmedia_stream_get_stat ( const pjmedia_stream *  stream,
pjmedia_rtcp_stat stat 
)

Get the stream statistics. See also pjmedia_stream_get_stat_jbuf()

Parameters
streamThe media stream.
statMedia stream statistics.
Returns
PJ_SUCCESS on success.
pj_status_t pjmedia_stream_reset_stat ( pjmedia_stream *  stream)

Reset the stream statistics.

Parameters
streamThe media stream.
Returns
PJ_SUCCESS on success.
pj_status_t pjmedia_stream_get_stat_jbuf ( const pjmedia_stream *  stream,
pjmedia_jb_state state 
)

Get current jitter buffer state. See also pjmedia_stream_get_stat()

Parameters
streamThe media stream.
stateJitter buffer state.
Returns
PJ_SUCCESS on success.
pj_status_t pjmedia_stream_pause ( pjmedia_stream *  stream,
pjmedia_dir  dir 
)

Pause the individual channel in the stream.

Parameters
streamThe media channel.
dirWhich direction to pause.
Returns
PJ_SUCCESS on success.
pj_status_t pjmedia_stream_resume ( pjmedia_stream *  stream,
pjmedia_dir  dir 
)

Resume the individual channel in the stream.

Parameters
streamThe media channel.
dirWhich direction to resume.
Returns
PJ_SUCCESS on success;
pj_status_t pjmedia_stream_dial_dtmf ( pjmedia_stream *  stream,
const pj_str_t ascii_digit 
)

Transmit DTMF to this stream. The DTMF will be transmitted uisng RTP telephone-events as described in RFC 2833. This operation is only valid for audio stream.

Parameters
streamThe media stream.
ascii_digitString containing digits to be sent to remote as described on RFC 2833 section 3.10. If PJMEDIA_HAS_DTMF_FLASH is enabled, character 'R' is used to represent the event type 16 (flash) as stated in RFC 4730. Currently the maximum number of digits are 32.
Returns
PJ_SUCCESS on success.
pj_bool_t pjmedia_stream_check_dtmf ( pjmedia_stream *  stream)

Check if the stream has incoming DTMF digits in the incoming DTMF queue. Incoming DTMF digits received via RFC 2833 mechanism are saved in the incoming digits queue.

Parameters
streamThe media stream.
Returns
Non-zero (PJ_TRUE) if the stream has received DTMF digits in the .
pj_status_t pjmedia_stream_get_dtmf ( pjmedia_stream *  stream,
char *  ascii_digits,
unsigned *  size 
)

Retrieve the incoming DTMF digits from the stream, and remove the digits from stream's DTMF buffer. Note that the digits buffer will not be NULL terminated.

Parameters
streamThe media stream.
ascii_digitsBuffer to receive the digits. The length of this buffer is indicated in the "size" argument.
sizeOn input, contains the maximum digits to be copied to the buffer. On output, it contains the actual digits that has been copied to the buffer.
Returns
Non-zero (PJ_TRUE) if the stream has received DTMF digits in the .
pj_status_t pjmedia_stream_set_dtmf_callback ( pjmedia_stream *  stream,
void(*)(pjmedia_stream *, void *user_data, int digit)  cb,
void *  user_data 
)

Set callback to be called upon receiving DTMF digits. If callback is registered, the stream will not buffer incoming DTMF but rather call the callback as soon as DTMF digit is received completely.

Parameters
streamThe media stream.
cbCallback to be called upon receiving DTMF digits. The DTMF digits will be given to the callback as ASCII digits.
user_dataUser data to be returned back when the callback is called.
Returns
PJ_SUCCESS on success.
pj_status_t pjmedia_stream_send_rtcp_sdes ( pjmedia_stream *  stream)

Send RTCP SDES for the media stream.

Parameters
streamThe media stream.
Returns
PJ_SUCCESS on success.
pj_status_t pjmedia_stream_send_rtcp_bye ( pjmedia_stream *  stream)

Send RTCP BYE for the media stream.

Parameters
streamThe media stream.
Returns
PJ_SUCCESS on success.
pj_status_t pjmedia_stream_get_rtp_session_info ( pjmedia_stream *  stream,
pjmedia_stream_rtp_sess_info session_info 
)

Get the RTP session information of the media stream. This function can be useful for app with custom media transport to inject/filter some outgoing/incoming proprietary packets into normal audio RTP traffics. This will return the original pointer to the internal states of the stream, and generally it is not advisable for app to modify them.

Parameters
streamThe media stream.
session_infoThe stream session info.
Returns
PJ_SUCCESS on success.

 


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