PipeWire: Stream

PipeWire 0.3.66

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Files | Data Structures | Macros | Enumerations | Functions
Stream

PipeWire stream objects. More...

## Files
file | stream.h
| `pipewire/stream.h`

## Data Structures
struct | pw_buffer
| a buffer structure obtained from pw_stream_dequeue_buffer(). More...
struct | pw_stream_control
struct | pw_time
| A time structure. More...
struct | pw_stream_events
| Events for a stream. More...
struct | pw_stream

## Macros
#define | PW_VERSION_STREAM_EVENTS 2

## Enumerations
enum | pw_stream_state { PW_STREAM_STATE_ERROR = -1 , PW_STREAM_STATE_UNCONNECTED = 0 , PW_STREAM_STATE_CONNECTING = 1 , PW_STREAM_STATE_PAUSED = 2 , PW_STREAM_STATE_STREAMING = 3 }
| The state of a stream. More...
enum | pw_stream_flags { PW_STREAM_FLAG_NONE = 0 , PW_STREAM_FLAG_AUTOCONNECT = (1 << 0) , PW_STREAM_FLAG_INACTIVE = (1 << 1) , PW_STREAM_FLAG_MAP_BUFFERS = (1 << 2) , PW_STREAM_FLAG_DRIVER = (1 << 3) , PW_STREAM_FLAG_RT_PROCESS = (1 << 4) , PW_STREAM_FLAG_NO_CONVERT = (1 << 5) , PW_STREAM_FLAG_EXCLUSIVE = (1 << 6) , PW_STREAM_FLAG_DONT_RECONNECT = (1 << 7) , PW_STREAM_FLAG_ALLOC_BUFFERS = (1 << 8) , PW_STREAM_FLAG_TRIGGER = (1 << 9) }
| Extra flags that can be used in pw_stream_connect() More...

## Functions
const char * | pw_stream_state_as_string (enum pw_stream_state state)
| Convert a stream state to a readable string.
struct pw_stream * | pw_stream_new (struct pw_core *core, const char *name, struct pw_properties *props)
| Create a new unconneced Stream.
struct pw_stream * | pw_stream_new_simple (struct pw_loop *loop, const char *name, struct pw_properties *props, const struct pw_stream_events *events, void *data)
void | pw_stream_destroy (struct pw_stream *stream)
| Destroy a stream.
void | pw_stream_add_listener (struct pw_stream *stream, struct spa_hook *listener, const struct pw_stream_events *events, void *data)
enum pw_stream_state | pw_stream_get_state (struct pw_stream *stream, const char **error)
const char * | pw_stream_get_name (struct pw_stream *stream)
struct pw_core * | pw_stream_get_core (struct pw_stream *stream)
const struct pw_properties * | pw_stream_get_properties (struct pw_stream *stream)
int | pw_stream_update_properties (struct pw_stream *stream, const struct spa_dict *dict)
int | pw_stream_connect (struct pw_stream *stream, enum pw_direction direction, uint32_t target_id, enum pw_stream_flags flags, const struct spa_pod **params, uint32_t n_params)
| Connect a stream for input or output on port_path.
uint32_t | pw_stream_get_node_id (struct pw_stream *stream)
| Get the node ID of the stream.
int | pw_stream_disconnect (struct pw_stream *stream)
| Disconnect stream
int | pw_stream_set_error (struct pw_stream *stream, int res, const char *error,...) 1(3
| Set the stream in error state.
int int | pw_stream_update_params (struct pw_stream *stream, const struct spa_pod **params, uint32_t n_params)
| Complete the negotiation process with result code res.
const struct pw_stream_control * | pw_stream_get_control (struct pw_stream *stream, uint32_t id)
| Get control values.
int | pw_stream_set_control (struct pw_stream *stream, uint32_t id, uint32_t n_values, float *values,...)
| Set control values.
int | pw_stream_get_time_n (struct pw_stream *stream, struct pw_time *time, size_t size)
| Query the time on the stream.
int | pw_stream_get_time (struct pw_stream *stream, struct pw_time *time)
| Query the time on the stream, deprecated since 0.3.50, use pw_stream_get_time_n() to get the fields added since 0.3.50.
struct pw_buffer * | pw_stream_dequeue_buffer (struct pw_stream *stream)
| Get a buffer that can be filled for playback streams or consumed for capture streams.
int | pw_stream_queue_buffer (struct pw_stream *stream, struct pw_buffer *buffer)
| Submit a buffer for playback or recycle a buffer for capture.
int | pw_stream_set_active (struct pw_stream *stream, bool active)
| Activate or deactivate the stream.
int | pw_stream_flush (struct pw_stream *stream, bool drain)
| Flush a stream.
bool | pw_stream_is_driving (struct pw_stream *stream)
| Check if the stream is driving.
int | pw_stream_trigger_process (struct pw_stream *stream)
| Trigger a push/pull on the stream.

## Detailed Description

PipeWire stream objects.

The stream object provides a convenient way to send and receive data streams from/to PipeWire.

See also Streams and Core API

## Macro Definition Documentation

## ◆ PW_VERSION_STREAM_EVENTS

#define PW_VERSION_STREAM_EVENTS 2

Examples
  audio-capture.c, audio-src.c, tutorial4.c, tutorial5.c, video-play-fixate.c, video-play-pull.c, video-play-reneg.c, video-play.c, video-src-alloc.c, video-src-fixate.c, video-src-reneg.c, and video-src.c.

## Enumeration Type Documentation

## ◆ pw_stream_state

enum pw_stream_state

The state of a stream.

Enumerator
PW_STREAM_STATE_ERROR | the stream is in error
PW_STREAM_STATE_UNCONNECTED | unconnected
PW_STREAM_STATE_CONNECTING | connection is in progress
PW_STREAM_STATE_PAUSED | paused
PW_STREAM_STATE_STREAMING | streaming

## ◆ pw_stream_flags

enum pw_stream_flags

Extra flags that can be used in pw_stream_connect()

Enumerator
PW_STREAM_FLAG_NONE | no flags
PW_STREAM_FLAG_AUTOCONNECT | try to automatically connect this stream
PW_STREAM_FLAG_INACTIVE | start the stream inactive, pw_stream_set_active() needs to be called explicitly
PW_STREAM_FLAG_MAP_BUFFERS | mmap the buffers except DmaBuf
PW_STREAM_FLAG_DRIVER | be a driver
PW_STREAM_FLAG_RT_PROCESS | call process from the realtime thread. You MUST use RT safe functions in the process callback.
PW_STREAM_FLAG_NO_CONVERT | don't convert format
PW_STREAM_FLAG_EXCLUSIVE | require exclusive access to the device
PW_STREAM_FLAG_DONT_RECONNECT | don't try to reconnect this stream when the sink/source is removed
PW_STREAM_FLAG_ALLOC_BUFFERS | the application will allocate buffer memory. In the add_buffer event, the data of the buffer should be set
PW_STREAM_FLAG_TRIGGER | the output stream will not be scheduled automatically but _trigger_process() needs to be called. This can be used when the output of the stream depends on input from other streams.

## Function Documentation

## ◆ pw_stream_state_as_string()

const char * pw_stream_state_as_string | ( | enum pw_stream_state | state | ) |

Convert a stream state to a readable string.

Examples
  video-play-fixate.c, video-play-pull.c, video-play-reneg.c, video-play.c, video-src-alloc.c, video-src-fixate.c, video-src-reneg.c, and video-src.c.

## ◆ pw_stream_new()

struct pw_stream * pw_stream_new | ( | struct pw_core * | core,
|  | const char * | name,
|  | struct pw_properties * | props
| ) |  |

Create a new unconneced Stream.

Returns
  a newly allocated Stream

Parameters

  core | a pw_core name a stream media name
  props | stream properties, ownership is taken

Examples
  video-src.c.

## ◆ pw_stream_new_simple()

struct pw_stream * pw_stream_new_simple | ( | struct pw_loop * | loop,
|  | const char * | name,
|  | struct pw_properties * | props,
|  | const struct pw_stream_events * | events,
|  | void * | data
| ) |  |

Parameters

  loop | a Loop to use
  name | a stream media name
  props | stream properties, ownership is taken
  events | stream events
  data | data passed to events

Examples
  audio-capture.c, audio-src.c, tutorial4.c, tutorial5.c, video-play-fixate.c, video-play-pull.c, video-play-reneg.c, video-play.c, video-src-alloc.c, video-src-fixate.c, and video-src-reneg.c.

## ◆ pw_stream_destroy()

void pw_stream_destroy | ( | struct pw_stream * | stream | ) |

Destroy a stream.

Examples
  audio-capture.c, audio-src.c, tutorial4.c, tutorial5.c, video-play-fixate.c, video-play-pull.c, video-play-reneg.c, video-play.c, video-src-alloc.c, video-src-fixate.c, and video-src-reneg.c.

## ◆ pw_stream_add_listener()

void pw_stream_add_listener | ( | struct pw_stream * | stream,
|  | struct spa_hook * | listener,
|  | const struct pw_stream_events * | events,
|  | void * | data
| ) |  |

Examples
  video-src.c.

## ◆ pw_stream_get_state()

enum pw_stream_state pw_stream_get_state | ( | struct pw_stream * | stream,
|  | const char ** | error
| ) |  |

## ◆ pw_stream_get_name()

const char * pw_stream_get_name | ( | struct pw_stream * | stream | ) |

## ◆ pw_stream_get_core()

struct pw_core * pw_stream_get_core | ( | struct pw_stream * | stream | ) |

## ◆ pw_stream_get_properties()

const struct pw_properties * pw_stream_get_properties | ( | struct pw_stream * | stream | ) |

## ◆ pw_stream_update_properties()

int pw_stream_update_properties | ( | struct pw_stream * | stream,
|  | const struct spa_dict * | dict
| ) |  |

## ◆ pw_stream_connect()

int pw_stream_connect | ( | struct pw_stream * | stream,
|  | enum pw_direction | direction,
|  | uint32_t | target_id,
|  | enum pw_stream_flags | flags,
|  | const struct spa_pod ** | params,
|  | uint32_t | n_params
| ) |  |

Connect a stream for input or output on port_path.

Returns
  0 on success < 0 on error.

You should connect to the process event and use pw_stream_dequeue_buffer() to get the latest metadata and data.

Parameters

  stream | a pw_stream direction the stream direction
  target_id | should have the value PW_ID_ANY. To select a specific target node, specify the PW_KEY_OBJECT_SERIAL or the PW_KEY_NODE_NAME value of the target node in the PW_KEY_TARGET_OBJECT property of the stream. Specifying target nodes by their id is deprecated.
  flags | stream flags
  params | an array with params. The params should ideally contain supported formats.
  n_params | number of items in params

Examples
  audio-capture.c, audio-src.c, tutorial4.c, tutorial5.c, video-play-fixate.c, video-play-pull.c, video-play-reneg.c, video-play.c, video-src-alloc.c, video-src-fixate.c, video-src-reneg.c, and video-src.c.

## ◆ pw_stream_get_node_id()

uint32_t pw_stream_get_node_id | ( | struct pw_stream * | stream | ) |

Get the node ID of the stream.

Returns
  node ID.

Examples
  video-src-alloc.c, video-src-fixate.c, video-src-reneg.c, and video-src.c.

## ◆ pw_stream_disconnect()

int pw_stream_disconnect | ( | struct pw_stream * | stream | ) |

Disconnect stream

## ◆ pw_stream_set_error()

int pw_stream_set_error | ( | struct pw_stream * | stream,
|  | int | res,
|  | const char * | error,
|  |  | ...
| ) |  |

Set the stream in error state.

Parameters

  stream | a pw_stream res a result code
  error | an error message

Examples
  video-play-fixate.c, video-play-pull.c, video-play-reneg.c, and video-play.c.

## ◆ pw_stream_update_params()

int int pw_stream_update_params | ( | struct pw_stream * | stream,
|  | const struct spa_pod ** | params,
|  | uint32_t | n_params
| ) |  |

Complete the negotiation process with result code res.

This function should be called after notification of the format.

When res indicates success, params contain the parameters for the allocation state.

Parameters

  stream | a pw_stream params an array of params. The params should ideally contain parameters for doing buffer allocation.
  n_params | number of elements in params

Examples
  video-play-fixate.c, video-play-pull.c, video-play-reneg.c, video-play.c, video-src-alloc.c, video-src-fixate.c, video-src-reneg.c, and video-src.c.

## ◆ pw_stream_get_control()

const struct pw_stream_control * pw_stream_get_control | ( | struct pw_stream * | stream,
|  | uint32_t | id
| ) |  |

Get control values.

## ◆ pw_stream_set_control()

int pw_stream_set_control | ( | struct pw_stream * | stream,
|  | uint32_t | id,
|  | uint32_t | n_values,
|  | float * | values,
|  |  | ...
| ) |  |

Set control values.

## ◆ pw_stream_get_time_n()

int pw_stream_get_time_n | ( | struct pw_stream * | stream,
|  | struct pw_time * | time,
|  | size_t | size
| ) |  |

Query the time on the stream.

## ◆ pw_stream_get_time()

int pw_stream_get_time | ( | struct pw_stream * | stream,
|  | struct pw_time * | time
| ) |  |

Query the time on the stream, deprecated since 0.3.50, use pw_stream_get_time_n() to get the fields added since 0.3.50.

## ◆ pw_stream_dequeue_buffer()

struct pw_buffer * pw_stream_dequeue_buffer | ( | struct pw_stream * | stream | ) |

Get a buffer that can be filled for playback streams or consumed for capture streams.

Examples
  audio-capture.c, audio-src.c, tutorial4.c, tutorial5.c, video-play-fixate.c, video-play-pull.c, video-play-reneg.c, video-play.c, video-src-alloc.c, video-src-fixate.c, video-src-reneg.c, and video-src.c.

## ◆ pw_stream_queue_buffer()

int pw_stream_queue_buffer | ( | struct pw_stream * | stream,
|  | struct pw_buffer * | buffer
| ) |  |

Submit a buffer for playback or recycle a buffer for capture.

Examples
  audio-capture.c, audio-src.c, tutorial4.c, tutorial5.c, video-play-fixate.c, video-play-pull.c, video-play-reneg.c, video-play.c, video-src-alloc.c, video-src-fixate.c, video-src-reneg.c, and video-src.c.

## ◆ pw_stream_set_active()

int pw_stream_set_active | ( | struct pw_stream * | stream,
|  | bool | active
| ) |  |

Activate or deactivate the stream.

Examples
  video-play.c.

## ◆ pw_stream_flush()

int pw_stream_flush | ( | struct pw_stream * | stream,
|  | bool | drain
| ) |  |

Flush a stream.

When drain is true, the drained callback will be called when all data is played or recorded

## ◆ pw_stream_is_driving()

bool pw_stream_is_driving | ( | struct pw_stream * | stream | ) |

Check if the stream is driving.

The stream needs to have the PW_STREAM_FLAG_DRIVER set. When the stream is driving, pw_stream_trigger_process() needs to be called when data is available (output) or needed (input). Since 0.3.34

Examples
  video-src-alloc.c, video-src-fixate.c, and video-src-reneg.c.

## ◆ pw_stream_trigger_process()

int pw_stream_trigger_process | ( | struct pw_stream * | stream | ) |

Trigger a push/pull on the stream.

One iteration of the graph will scheduled and process() will be called. Since 0.3.34

Examples
  video-play-pull.c, video-src-alloc.c, video-src-fixate.c, video-src-reneg.c, and video-src.c.