Group PJSUA_LIB_MEDIA¶

group PJSUA_LIB_MEDIA

Media manipulation.

PJSUA has rather powerful media features, which are built around the PJMEDIA conference bridge. Basically, all media “ports” (such as calls, WAV players, WAV playlist, file recorders, sound device, tone generators, etc) are terminated in the conference bridge, and application can manipulate the interconnection between these terminations freely.

The conference bridge provides powerful switching and mixing functionality for application. With the conference bridge, each conference slot (e.g. a call) can transmit to multiple destinations, and one destination can receive from multiple sources. If more than one media terminations are terminated in the same slot, the conference bridge will mix the signal automatically.

Application connects one media termination/slot to another by calling pjsua_conf_connect() function. This will establish unidirectional media flow from the source termination to the sink termination. To establish bidirectional media flow, application wound need to make another call to pjsua_conf_connect(), this time inverting the source and destination slots in the parameter.

For example, to stream a WAV file to remote call, application may use the following steps:

pj_status_t stream_to_call( pjsua_call_id call_id )
{
   pjsua_player_id player_id;
   
   status = pjsua_player_create("mysong.wav", 0, &player_id);
   if (status != PJ_SUCCESS)
      return status;

   status = pjsua_conf_connect( pjsua_player_get_conf_port(),
                         pjsua_call_get_conf_port() );
}

Other features of PJSUA media:

efficient N to M interconnections between media terminations.
media termination can be connected to itself to create loopback media.
the media termination may have different clock rates, and resampling will be done automatically by conference bridge.
media terminations may also have different frame time; the conference bridge will perform the necessary bufferring to adjust the difference between terminations.
interconnections are removed automatically when media termination is removed from the bridge.
sound device may be changed even when there are active media interconnections.
correctly report call’s media quality (in pjsua_call_dump()) from RTCP packet exchange.

Defines

PJSUA_MAX_CONF_PORTS¶: Max ports in the conference bridge. This setting is the default value for pjsua_media_config.max_media_ports.

PJSUA_DEFAULT_CLOCK_RATE¶: The default clock rate to be used by the conference bridge. This setting is the default value for pjsua_media_config.clock_rate.

PJSUA_DEFAULT_AUDIO_FRAME_PTIME¶: Default frame length in the conference bridge. This setting is the default value for pjsua_media_config.audio_frame_ptime.

PJSUA_DEFAULT_CODEC_QUALITY¶: Default codec quality settings. This setting is the default value for pjsua_media_config.quality.

PJSUA_DEFAULT_ILBC_MODE¶: Default iLBC mode. This setting is the default value for pjsua_media_config.ilbc_mode.

PJSUA_DEFAULT_EC_TAIL_LEN¶: The default echo canceller tail length. This setting is the default value for pjsua_media_config.ec_tail_len.

PJSUA_MAX_PLAYERS¶: The maximum file player.

PJSUA_MAX_RECORDERS¶: The maximum file player.

Functions

void pjsua_media_config_default(pjsua_media_config *cfg)¶

Use this function to initialize media config.

Parameters: cfg – The media config to be initialized.

unsigned pjsua_conf_get_max_ports(void)¶

Get maxinum number of conference ports.

Returns: Maximum number of ports in the conference bridge.

unsigned pjsua_conf_get_active_ports(void)¶

Get current number of active ports in the bridge.

Returns: The number.

pj_status_t pjsua_enum_conf_ports(pjsua_conf_port_id id[], unsigned *count)¶

Enumerate all conference ports.

Parameters

id – Array of conference port ID to be initialized.
count – On input, specifies max elements in the array. On return, it contains actual number of elements that have been initialized.

Returns

PJ_SUCCESS on success, or the appropriate error code.

pj_status_t pjsua_conf_get_port_info(pjsua_conf_port_id port_id, pjsua_conf_port_info *info)¶

Get information about the specified conference port

Parameters

port_id – Port identification.
info – Pointer to store the port info.

Returns

PJ_SUCCESS on success, or the appropriate error code.

pj_status_t pjsua_conf_add_port(pj_pool_t *pool, pjmedia_port *port, pjsua_conf_port_id *p_id)¶

Add arbitrary media port to PJSUA’s conference bridge. Application can use this function to add the media port that it creates. For media ports that are created by PJSUA-LIB (such as calls, file player, or file recorder), PJSUA-LIB will automatically add the port to the bridge.

Parameters

pool – Pool to use.
port – Media port to be added to the bridge.
p_id – Optional pointer to receive the conference slot id.

Returns

PJ_SUCCESS on success, or the appropriate error code.

pj_status_t pjsua_conf_remove_port(pjsua_conf_port_id port_id)¶

Remove arbitrary slot from the conference bridge. Application should only call this function if it registered the port manually with previous call to pjsua_conf_add_port().

Parameters: port_id – The slot id of the port to be removed.
Returns: PJ_SUCCESS on success, or the appropriate error code.

pj_status_t pjsua_conf_connect(pjsua_conf_port_id source, pjsua_conf_port_id sink)¶

Establish unidirectional media flow from souce to sink. One source may transmit to multiple destinations/sink. And if multiple sources are transmitting to the same sink, the media will be mixed together. Source and sink may refer to the same ID, effectively looping the media.

If bidirectional media flow is desired, application needs to call this function twice, with the second one having the arguments reversed.

Parameters

source – Port ID of the source media/transmitter.
sink – Port ID of the destination media/received.

Returns

PJ_SUCCESS on success, or the appropriate error code.

pj_status_t pjsua_conf_disconnect(pjsua_conf_port_id source, pjsua_conf_port_id sink)¶

Disconnect media flow from the source to destination port.

Parameters

source – Port ID of the source media/transmitter.
sink – Port ID of the destination media/received.

Returns

PJ_SUCCESS on success, or the appropriate error code.

pj_status_t pjsua_conf_adjust_tx_level(pjsua_conf_port_id slot, float level)¶

Adjust the signal level to be transmitted from the bridge to the specified port by making it louder or quieter.

Parameters

slot – The conference bridge slot number.
level – Signal level adjustment. Value 1.0 means no level adjustment, while value 0 means to mute the port.

Returns

PJ_SUCCESS on success, or the appropriate error code.

pj_status_t pjsua_conf_adjust_rx_level(pjsua_conf_port_id slot, float level)¶

Adjust the signal level to be received from the specified port (to the bridge) by making it louder or quieter.

Parameters

slot – The conference bridge slot number.
level – Signal level adjustment. Value 1.0 means no level adjustment, while value 0 means to mute the port.

Returns

PJ_SUCCESS on success, or the appropriate error code.

pj_status_t pjsua_conf_get_signal_level(pjsua_conf_port_id slot, unsigned *tx_level, unsigned *rx_level)¶

Get last signal level transmitted to or received from the specified port. The signal level is an integer value in zero to 255, with zero indicates no signal, and 255 indicates the loudest signal level.

Parameters

slot – The conference bridge slot number.
tx_level – Optional argument to receive the level of signal transmitted to the specified port (i.e. the direction is from the bridge to the port).
rx_level – Optional argument to receive the level of signal received from the port (i.e. the direction is from the port to the bridge).

Returns

PJ_SUCCESS on success.

pj_status_t pjsua_player_create(const pj_str_t *filename, unsigned options, pjsua_player_id *p_id)¶

Create a file player, and automatically add this player to the conference bridge.

Parameters

filename – The filename to be played. Currently only WAV files are supported, and the WAV file MUST be formatted as 16bit PCM mono/single channel (any clock rate is supported).
options – Optional option flag. Application may specify PJMEDIA_FILE_NO_LOOP to prevent playback loop.
p_id – Pointer to receive player ID.

Returns

PJ_SUCCESS on success, or the appropriate error code.

pj_status_t pjsua_playlist_create(const pj_str_t file_names[], unsigned file_count, const pj_str_t *label, unsigned options, pjsua_player_id *p_id)¶

Create a file playlist media port, and automatically add the port to the conference bridge.

Parameters

file_names – Array of file names to be added to the play list. Note that the files must have the same clock rate, number of channels, and number of bits per sample.
file_count – Number of files in the array.
label – Optional label to be set for the media port.
options – Optional option flag. Application may specify PJMEDIA_FILE_NO_LOOP to prevent looping.
p_id – Optional pointer to receive player ID.

Returns

PJ_SUCCESS on success, or the appropriate error code.

pjsua_conf_port_id pjsua_player_get_conf_port(pjsua_player_id id)¶

Get conference port ID associated with player or playlist.

Parameters: id – The file player ID.
Returns: Conference port ID associated with this player.

pj_status_t pjsua_player_get_port(pjsua_player_id id, pjmedia_port **p_port)¶

Get the media port for the player or playlist.

Parameters

id – The player ID.
p_port – The media port associated with the player.

Returns

PJ_SUCCESS on success.

pj_status_t pjsua_player_set_pos(pjsua_player_id id, pj_uint32_t samples)¶

Set playback position. This operation is not valid for playlist.

Parameters

id – The file player ID.
samples – The playback position, in samples. Application can specify zero to re-start the playback.

Returns

PJ_SUCCESS on success, or the appropriate error code.

pj_status_t pjsua_player_destroy(pjsua_player_id id)¶

Close the file of playlist, remove the player from the bridge, and free resources associated with the file player or playlist.

Parameters: id – The file player ID.
Returns: PJ_SUCCESS on success, or the appropriate error code.

pj_status_t pjsua_recorder_create(const pj_str_t *filename, unsigned enc_type, void *enc_param, pj_ssize_t max_size, unsigned options, pjsua_recorder_id *p_id)¶

Create a file recorder, and automatically connect this recorder to the conference bridge. The recorder currently supports recording WAV file. The type of the recorder to use is determined by the extension of the file (e.g. “.wav”).

Parameters

filename – Output file name. The function will determine the default format to be used based on the file extension. Currently “.wav” is supported on all platforms.
enc_type – Optionally specify the type of encoder to be used to compress the media, if the file can support different encodings. This value must be zero for now.
enc_param – Optionally specify codec specific parameter to be passed to the file writer. For .WAV recorder, this value must be NULL.
max_size – Maximum file size. Specify zero or -1 to remove size limitation. This value must be zero or -1 for now.
options – Optional options.
p_id – Pointer to receive the recorder instance.

Returns

PJ_SUCCESS on success, or the appropriate error code.

pjsua_conf_port_id pjsua_recorder_get_conf_port(pjsua_recorder_id id)¶

Get conference port associated with recorder.

Parameters: id – The recorder ID.
Returns: Conference port ID associated with this recorder.

pj_status_t pjsua_recorder_get_port(pjsua_recorder_id id, pjmedia_port **p_port)¶

Get the media port for the recorder.

Parameters

id – The recorder ID.
p_port – The media port associated with the recorder.

Returns

PJ_SUCCESS on success.

pj_status_t pjsua_recorder_destroy(pjsua_recorder_id id)¶

Destroy recorder (this will complete recording).

Parameters: id – The recorder ID.
Returns: PJ_SUCCESS on success, or the appropriate error code.

pj_status_t pjsua_enum_aud_devs(pjmedia_aud_dev_info info[], unsigned *count)¶

Enum all audio devices installed in the system.

Parameters

info – Array of info to be initialized.
count – On input, specifies max elements in the array. On return, it contains actual number of elements that have been initialized.

Returns

PJ_SUCCESS on success, or the appropriate error code.

pj_status_t pjsua_enum_snd_devs(pjmedia_snd_dev_info info[], unsigned *count)¶

Enum all sound devices installed in the system (old API).

Parameters

info – Array of info to be initialized.
count – On input, specifies max elements in the array. On return, it contains actual number of elements that have been initialized.

Returns

PJ_SUCCESS on success, or the appropriate error code.

pj_status_t pjsua_get_snd_dev(int *capture_dev, int *playback_dev)¶

Get currently active sound devices. If sound devices has not been created (for example when pjsua_start() is not called), it is possible that the function returns PJ_SUCCESS with -1 as device IDs.

Parameters

capture_dev – On return it will be filled with device ID of the capture device.
playback_dev – On return it will be filled with device ID of the device ID of the playback device.

Returns

PJ_SUCCESS on success, or the appropriate error code.

pj_status_t pjsua_set_snd_dev(int capture_dev, int playback_dev)¶

Select or change sound device. Application may call this function at any time to replace current sound device.

Parameters

capture_dev – Device ID of the capture device.
playback_dev – Device ID of the playback device.

Returns

PJ_SUCCESS on success, or the appropriate error code.

pj_status_t pjsua_set_null_snd_dev(void)¶

Set pjsua to use null sound device. The null sound device only provides the timing needed by the conference bridge, and will not interract with any hardware.

Returns: PJ_SUCCESS on success, or the appropriate error code.

pjmedia_port *pjsua_set_no_snd_dev(void)¶

Disconnect the main conference bridge from any sound devices, and let application connect the bridge to it’s own sound device/master port.

Returns: The port interface of the conference bridge, so that application can connect this to it’s own sound device or master port.

pj_status_t pjsua_set_ec(unsigned tail_ms, unsigned options)¶

Change the echo cancellation settings.

The behavior of this function depends on whether the sound device is currently active, and if it is, whether device or software AEC is being used.

If the sound device is currently active, and if the device supports AEC, this function will forward the change request to the device and it will be up to the device on whether support the request. If software AEC is being used (the software EC will be used if the device does not support AEC), this function will change the software EC settings. In all cases, the setting will be saved for future opening of the sound device.

If the sound device is not currently active, this will only change the default AEC settings and the setting will be applied next time the sound device is opened.

Parameters

tail_ms – The tail length, in miliseconds. Set to zero to disable AEC.
options – Options to be passed to pjmedia_echo_create(). Normally the value should be zero.

Returns

PJ_SUCCESS on success.

pj_status_t pjsua_get_ec_tail(unsigned *p_tail_ms)¶

Get current echo canceller tail length.

Parameters: p_tail_ms – Pointer to receive the tail length, in miliseconds. If AEC is disabled, the value will be zero.
Returns: PJ_SUCCESS on success.

pj_bool_t pjsua_snd_is_active(void)¶: Check whether the sound device is currently active. The sound device may be inactive if the application has set the auto close feature to non-zero (the snd_auto_close_time setting in pjsua_media_config), or if null sound device or no sound device has been configured via the pjsua_set_no_snd_dev() function.

pj_status_t pjsua_snd_set_setting(pjmedia_aud_dev_cap cap, const void *pval, pj_bool_t keep)¶

Configure sound device setting to the sound device being used. If sound device is currently active, the function will forward the setting to the sound device instance to be applied immediately, if it supports it.

The setting will be saved for future opening of the sound device, if the “keep” argument is set to non-zero. If the sound device is currently inactive, and the “keep” argument is false, this function will return error.

Note that in case the setting is kept for future use, it will be applied to any devices, even when application has changed the sound device to be used.

Note also that the echo cancellation setting should be set with pjsua_set_ec() API instead.

See also pjmedia_aud_stream_set_cap() for more information about setting an audio device capability.

Parameters

cap – The sound device setting to change.
pval – Pointer to value. Please see pjmedia_aud_dev_cap documentation about the type of value to be supplied for each setting.
keep – Specify whether the setting is to be kept for future use.

Returns

PJ_SUCCESS on success or the appropriate error code.

pj_status_t pjsua_snd_get_setting(pjmedia_aud_dev_cap cap, void *pval)¶

Retrieve a sound device setting. If sound device is currently active, the function will forward the request to the sound device. If sound device is currently inactive, and if application had previously set the setting and mark the setting as kept, then that setting will be returned. Otherwise, this function will return error.

Note that echo cancellation settings should be retrieved with pjsua_get_ec_tail() API instead.

Parameters

cap – The sound device setting to retrieve.
pval – Pointer to receive the value. Please see pjmedia_aud_dev_cap documentation about the type of value to be supplied for each setting.

Returns

PJ_SUCCESS on success or the appropriate error code.

pj_status_t pjsua_enum_codecs(pjsua_codec_info id[], unsigned *count)¶

Enum all supported codecs in the system.

Parameters

id – Array of ID to be initialized.
count – On input, specifies max elements in the array. On return, it contains actual number of elements that have been initialized.

Returns

PJ_SUCCESS on success, or the appropriate error code.

pj_status_t pjsua_codec_set_priority(const pj_str_t *codec_id, pj_uint8_t priority)¶

Change codec priority.

Parameters

codec_id – Codec ID, which is a string that uniquely identify the codec (such as “speex/8000”). Please see pjsua manual or pjmedia codec reference for details.
priority – Codec priority, 0-255, where zero means to disable the codec.

Returns

PJ_SUCCESS on success, or the appropriate error code.

pj_status_t pjsua_codec_get_param(const pj_str_t *codec_id, pjmedia_codec_param *param)¶

Get codec parameters.

Parameters

codec_id – Codec ID.
param – Structure to receive codec parameters.

Returns

PJ_SUCCESS on success, or the appropriate error code.

pj_status_t pjsua_codec_set_param(const pj_str_t *codec_id, const pjmedia_codec_param *param)¶

Set codec parameters.

Parameters

codec_id – Codec ID.
param – Codec parameter to set. Set to NULL to reset codec parameter to library default settings.

Returns

PJ_SUCCESS on success, or the appropriate error code.

pj_status_t pjsua_media_transports_create(const pjsua_transport_config *cfg)¶

Create UDP media transports for all the calls. This function creates one UDP media transport for each call.

Parameters: cfg – Media transport configuration. The “port” field in the configuration is used as the start port to bind the sockets.
Returns: PJ_SUCCESS on success, or the appropriate error code.

pj_status_t pjsua_media_transports_attach(pjsua_media_transport tp[], unsigned count, pj_bool_t auto_delete)¶

Register custom media transports to be used by calls. There must enough media transports for all calls.

Parameters

tp – The media transport array.
count – Number of elements in the array. This number MUST match the number of maximum calls configured when pjsua is created.
auto_delete – Flag to indicate whether the transports should be destroyed when pjsua is shutdown.

Returns

PJ_SUCCESS on success, or the appropriate error code.

struct pjsua_media_config¶

#include <pjsua.h>

This structure describes media configuration, which will be specified when calling pjsua_init(). Application MUST initialize this structure by calling pjsua_media_config_default().

Forward declaration

struct pjsua_codec_info¶: #include <pjsua.h>
This structure describes codec information, which can be retrieved by calling pjsua_enum_codecs().

struct pjsua_conf_port_info¶: #include <pjsua.h>
This structure descibes information about a particular media port that has been registered into the conference bridge. Application can query this info by calling pjsua_conf_get_port_info().

struct pjsua_media_transport¶: #include <pjsua.h>
This structure holds information about custom media transport to be registered to pjsua.