Stream

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

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) , PW_STREAM_FLAG_ASYNC = (1 << 10) ,   PW_STREAM_FLAG_EARLY_PROCESS = (1 << 11) }
	Extra flags that can be used in pw_stream_connect() More...

Macros
#define	PW_VERSION_STREAM_EVENTS   2

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,...)
	Set the stream in error state.
int	pw_stream_update_params (struct pw_stream *stream, const struct spa_pod **params, uint32_t n_params)
	Update the param exposed on the stream.
int	pw_stream_set_param (struct pw_stream *stream, uint32_t id, const struct spa_pod *param)
	Set a parameter on the stream.
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.
uint64_t	pw_stream_get_nsec (struct pw_stream *stream)
	Get the current time in nanoseconds.
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, Core API

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 that is not explicitly marked as mappable.
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.
PW_STREAM_FLAG_ASYNC	Buffers will not be dequeued/queued from the realtime process() function. This is assumed when RT_PROCESS is unset but can also be the case when the process() function does a trigger_process() that will then dequeue/queue a buffer from another process() function. since 0.3.73
PW_STREAM_FLAG_EARLY_PROCESS	Call process as soon as there is a buffer to dequeue. This is only relevant for playback and when not using RT_PROCESS. It can be used to keep the maximum number of buffers queued. Since 0.3.81

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.

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

Update the param exposed on the stream.

Parameters

stream	a Stream
params	an array of params.
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_set_param()

int pw_stream_set_param	(	struct pw_stream *	stream,
		uint32_t	id,
		const struct spa_pod *	param )

Set a parameter on the stream.

This is like pw_stream_set_control() but with a complete spa_pod param. It can also be called from the param_changed event handler to intercept and modify the param for the adapter. Since 0.3.70

Parameters

stream	a Stream
id	the id of the param
param	the params to set

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_nsec()

uint64_t pw_stream_get_nsec

(

struct pw_stream *

stream

)

Get the current time in nanoseconds.

This value can be compared with the pw_time_now value. Since 1.0.4

Examples

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

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.