Stream Object

PipeWire stream objects. More...

Data Structures
struct	pw_buffer
struct	pw_stream_control
struct	pw_time
	A time structure. More...
struct	pw_stream_events
	Events for a stream. More...

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) }
	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. More...
struct pw_stream *	pw_stream_new (struct pw_core *core, const char *name, struct pw_properties *props)
	Create a new unconneced Stream Object. More...
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. More...
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. More...
uint32_t	pw_stream_get_node_id (struct pw_stream *stream)
	Get the node ID of the stream. More...
int	pw_stream_disconnect (struct pw_stream *stream)
	Disconnect stream More...
int	pw_stream_set_error (struct pw_stream *stream, int res, const char *error,...) 1(3
	Set the stream in error state. More...
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. More...
int	pw_stream_set_control (struct pw_stream *stream, uint32_t id, uint32_t n_values, float *values,...)
	Set control values. More...
int	pw_stream_get_time (struct pw_stream *stream, struct pw_time *time)
	Query the time on the stream More...
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. More...
int	pw_stream_queue_buffer (struct pw_stream *stream, struct pw_buffer *buffer)
	Submit a buffer for playback or recycle a buffer for capture. More...
int	pw_stream_set_active (struct pw_stream *stream, bool active)
	Activate or deactivate the stream. More...
int	pw_stream_flush (struct pw_stream *stream, bool drain)
	Flush a stream. More...
bool	pw_stream_is_driving (struct pw_stream *stream)
	Check if the stream is driving. More...
int	pw_stream_trigger_process (struct pw_stream *stream)
	Trigger a push/pull on the stream. More...

Detailed Description

PipeWire stream objects.

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

See also Media Streams and Core API

Enumeration Type Documentation

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_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

Function Documentation

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
	)

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 Object
direction	the stream direction
target_id	the target object id to connect to or PW_ID_ANY to let the manager select a target.
flags	stream flags
params	an array with params. The params should ideally contain supported formats.
n_params	number of items in params

References NAME, props, PW_DIRECTION_INPUT, pw_log_debug, SPA_CONTAINER_OF, SPA_DIRECTION_INPUT, and SPA_DIRECTION_OUTPUT.

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.

References SPA_CONTAINER_OF.

pw_stream_destroy()

void pw_stream_destroy

(

struct pw_stream *

stream

)

Destroy a stream.

References stream::link, NAME, pw_log_debug, pw_stream_disconnect(), SPA_CONTAINER_OF, spa_hook_remove(), and spa_list_remove().

pw_stream_disconnect()

int pw_stream_disconnect

(

struct pw_stream *

stream

)

Disconnect stream

References stream::link, NAME, pw_core_disconnect(), pw_impl_node_destroy(), pw_impl_node_set_active(), pw_log_debug, pw_proxy_destroy(), SPA_CONTAINER_OF, spa_hook_remove(), and spa_list_remove().

Referenced by pw_stream_destroy().

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

References impl::context, pw_loop_invoke, and SPA_CONTAINER_OF.

pw_stream_get_core()

struct pw_core* pw_stream_get_core

(

struct pw_stream *

stream

)

pw_stream_get_name()

const char* pw_stream_get_name

(

struct pw_stream *

stream

)

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.

pw_stream_get_properties()

const struct pw_properties* pw_stream_get_properties

(

struct pw_stream *

stream

)

pw_stream_get_state()

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

References stream::listener, pw_stream_events::process, spa_hook::removed, SPA_CALLBACKS_INIT, SPA_CONTAINER_OF, and spa_hook_list_append().

pw_stream_get_time()

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

Query the time on the stream

References pw_time::delay, spa_fraction::denom, NAME, pw_time::now, spa_fraction::num, pw_log_trace, pw_time::queued, pw_time::rate, impl::seq, SPA_CONTAINER_OF, SPA_DIRECTION_INPUT, SPA_NSEC_PER_SEC, pw_time::ticks, and stream::time.

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

References SPA_CONTAINER_OF.

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 Object.

Returns

a newly allocated Stream Object

Parameters

core	a The PipeWire Core Global Object
name	a stream media name
props	stream properties, ownership is taken

References impl::context, and stream::impl.

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

References stream::impl, props, pw_context_new(), and pw_properties_new().

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.

References buffer::busy, spa_meta_busy::count, buffer::id, NAME, pw_log_trace, and SPA_CONTAINER_OF.

pw_stream_set_active()

int pw_stream_set_active	(	struct pw_stream *	stream,
		bool	active
	)

Activate or deactivate the stream.

References stream::active, NAME, pw_impl_node_set_active(), pw_log_debug, and SPA_CONTAINER_OF.

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.

References NAME, pw_log_debug, SPA_CONTAINER_OF, SPA_PARAM_Props, SPA_POD_BUILDER_INIT, spa_pod_builder_push_object(), SPA_TYPE_OBJECT_Props, and control::values.

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 Object
res	a result code
error	an error message

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.

References PW_STREAM_STATE_CONNECTING, PW_STREAM_STATE_ERROR, PW_STREAM_STATE_PAUSED, PW_STREAM_STATE_STREAMING, and PW_STREAM_STATE_UNCONNECTED.

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

References impl::context, NAME, pw_log_trace, pw_loop_invoke, SPA_CONTAINER_OF, and SPA_DIRECTION_OUTPUT.

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 Stream Object
params	an array of params. The params should ideally contain parameters for doing buffer allocation.
n_params	number of elements in params

References NAME, pw_log_debug, and SPA_CONTAINER_OF.

pw_stream_update_properties()

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

References pw_impl_node_update_properties(), pw_properties_update(), and SPA_CONTAINER_OF.