Unified interface contracts, lifecycle callbacks, and streaming endpoints for built-in audio components and dynamic LLEXT processing modules (Volume, Mixer, EQ, DRC, SRC, etc.). More...

Files
file	audio_stream.h
	Circular audio buffer calculation and wrap utilities for processing modules.

file	format.h
	Audio sample format conversion and size calculation helpers for modules.

file	sink_api.h
	Sink audio endpoint API for module output buffers.

file	source_api.h
	Source audio endpoint API for module input buffers.

file	base.h
	Base definitions and structures for loadable audio modules.

file	interface.h
	Dynamic module interface, lifecycle callbacks, and buffer contracts.

file	llext.h
	LLEXT manifest macros and declarations for loadable ELF extensions.

file	system_service.h
	System services provided by the base firmware to loadable modules.

file	sink_api.h
	Audio sink API helpers and stream configuration.

file	source_api.h
	Audio source API helpers and stream configuration.

Data Structures
struct	sof_audio_stream_params
	set of parameters describing audio stream this structure is shared between audio_stream.h and sink/source interface TODO: compressed formats More...

struct	cir_buf_source
	Read-only view of source data in a circular buffer. More...

struct	cir_buf_sink
	Writable view of sink data in a circular buffer. More...

struct	sof_uuid
	UUID (Universally Unique IDentifier) structure. More...

struct	sof_uuid_entry
	Connects UUID with component description. More...

Macros
#define	UUID_SIZE 16
	UUID is 16 bytes long.

#define	UUID_NAME_MAX_LEN 32
	UUID name string max length in bytes, including null termination.

#define	_UUID_INIT(va, vb, vc, d0, d1, d2, d3, d4, d5, d6, d7) { va, vb, vc, { d0, d1, d2, d3, d4, d5, d6, d7 } }

#define	_UUID(uuid_name) (&_##uuid_name)

#define	_RT_UUID(uuid_name) (&uuid_name)

#define	_DEF_UUID(entity_name, uuid_name, initializer)

#define	SOF_DEFINE_UUID(entity_name, uuid_name, va, vb, vc, vd0, vd1, vd2, vd3, vd4, vd5, vd6, vd7)
	Declares runtime UUID (aaaaaaaa-bbbb-cccc-d0d1-d2d3d4d5d6d7) and name.

#define	SOF_REG_UUID(name) _UUIDREG_##name
	Get UUID value sourced from the fixed SOF registry.

#define	SOF_DEFINE_REG_UUID(name) _DEF_UUID(#name, name##_uuid, SOF_REG_UUID(name))
	Defines UUID sourced from the fixed SOF registry.

#define	SOF_UUID(uuid_name) _UUID(uuid_name)
	Creates local unique 32-bit representation of UUID structure.

#define	SOF_RT_UUID(uuid_name) _RT_UUID(uuid_name)
	Dereference unique 32-bit representation of UUID structure in runtime.

Enumerations
enum	sof_audio_buffer_state { AUDIOBUF_STATE_INITIAL , AUDIOBUF_STATE_READY , AUDIOBUF_STATE_END_OF_STREAM , AUDIOBUF_STATE_END_OF_STREAM_FLUSH }
	Define states of an audio stream buffer connecting two components. More...

Functions
static size_t	circ_buf_frames_without_wrap (const void began, const void end, size_t sample_bytes, size_t channels)
	Number of whole frames available before a circular buffer wraps.

static size_t	cir_buf_samples_to_wrap_s16 (const int16_t ptr, const int16_t buf_start, size_t buf_samples)
	Calculates numbers of s16 samples to buffer wrap.

static size_t	cir_buf_samples_to_wrap_s32 (const int32_t ptr, const int32_t buf_start, size_t buf_samples)
	Calculates numbers of s32 samples to buffer wrap.

static size_t	cir_buf_samples_without_wrap_s16 (const void ptr, const void buf_end)
	Calculates numbers of s16 samples to buffer wrap when reading a circular buffer forward from current pointer towards the buffer end.

static size_t	cir_buf_samples_without_wrap_s32 (const void ptr, const void buf_end)
	Calculates numbers of s32 samples to buffer wrap when reading a circular buffer forward from current pointer towards the buffer end.

static size_t	cir_buf_bytes_without_wrap (const void ptr, const void buf_end)
	Calculates number of bytes to buffer wrap when reading a circular buffer forward from current pointer towards the buffer end.

static void *	cir_buf_wrap (const void ptr, const void buf_addr, const void *buf_end)
	Verifies the pointer and performs rollover when reaching the end of the circular buffer.

static const void *	source_cir_buf_wrap (const void ptr, const void buf_addr, const void *buf_end)
	Verifies a read pointer and performs rollover when reaching the end of the circular buffer.

static size_t	cir_buf_bytes_without_wrap_rewind (const void ptr, const void buf_start)
	Calculates number of bytes to buffer wrap when reading a circular buffer backwards from current pointer towards the buffer start.

static const void *	source_cir_buf_rewind_wrap (const void ptr, const void buf_start, const void *buf_end)
	Verifies the pointer and performs rollover when reading a read-only circular buffer backwards past its start address.

void	sink_init (struct sof_sink sink, const struct sink_ops ops, struct sof_audio_stream_params *audio_stream_params)
	Initialize sink API structure before any operation.

size_t	sink_get_num_of_processed_bytes (struct sof_sink *sink)
	Get total number of bytes processed by the sink (committed by sink_commit_buffer()).

void	sink_reset_num_of_processed_bytes (struct sof_sink *sink)
	Reset counter of total processed bytes to zero.

bool	sink_get_overrun (struct sof_sink *sink)
	Check if buffer overrun is permitted on sink stream.

void	sink_set_min_free_space (struct sof_sink *sink, size_t min_free_space)
	Set minimum free space required in sink buffer.

void	source_init (struct sof_source source, const struct source_ops ops, struct sof_audio_stream_params *audio_stream_params)
	Initialize source API structure before any operation.

size_t	source_get_num_of_processed_bytes (struct sof_source *source)
	Get total number of bytes processed by the source (freed by source_release_data()).

void	source_reset_num_of_processed_bytes (struct sof_source *source)
	Reset counter of total processed bytes to zero.

bool	source_get_underrun (struct sof_source *source)
	Check if buffer underrun is permitted on source stream.

uint32_t	source_get_id (struct sof_source *source)
	Get unique stream identifier for source.

int	source_set_frm_fmt (struct sof_source *source, enum sof_ipc_frame frm_fmt)
	Set audio frame format for source.

int	source_set_valid_fmt (struct sof_source *source, enum sof_ipc_frame valid_sample_fmt)
	Set valid sample format for source.

int	source_set_rate (struct sof_source *source, unsigned int rate)
	Set sample rate for source.

int	source_set_channels (struct sof_source *source, unsigned int channels)
	Set channel count for source.

int	source_set_underrun (struct sof_source *source, bool underrun_permitted)
	Configure whether underrun is permitted on source.

int	source_set_buffer_fmt (struct sof_source *source, uint32_t buffer_fmt)
	Set buffer format for source.

void	source_set_min_available (struct sof_source *source, size_t min_available)
	Set minimum available data requirement in bytes.

int	source_set_params (struct sof_source source, struct sof_ipc_stream_params params, bool force_update)
	Configure initial set of audio parameters.

int	source_set_alignment_constants (struct sof_source *source, const uint32_t byte_align, const uint32_t frame_align_req)
	Set byte and frame alignment constants for source stream.

Detailed Description

Unified interface contracts, lifecycle callbacks, and streaming endpoints for built-in audio components and dynamic LLEXT processing modules (Volume, Mixer, EQ, DRC, SRC, etc.).

UUID API specification.

Macro Definition Documentation

◆ _DEF_UUID

#define _DEF_UUID	(	entity_name,
		uuid_name,
		initializer
	)

Value:

    const STRUCT_SECTION_ITERABLE(sof_uuid_entry, _##uuid_name) =   \
        { .id = initializer, .name = entity_name };     \
    extern const struct sof_uuid                    \
        __attribute__((alias("_" #uuid_name))) uuid_name

◆ _RT_UUID

#define _RT_UUID ( uuid_name ) (&uuid_name)

◆ _UUID

#define _UUID ( uuid_name ) (&_##uuid_name)

◆ _UUID_INIT

#define _UUID_INIT	(	va,
		vb,
		vc,
		d0,
		d1,
		d2,
		d3,
		d4,
		d5,
		d6,
		d7
	)	{ va, vb, vc, { d0, d1, d2, d3, d4, d5, d6, d7 } }

◆ SOF_DEFINE_REG_UUID

#define SOF_DEFINE_REG_UUID ( name ) _DEF_UUID(#name, name##_uuid, SOF_REG_UUID(name))

Defines UUID sourced from the fixed SOF registry.

As for SOF_DEFINE_UUID(), but the ID value is sourced by name from the uuid-registry.txt file distributed with the source tree. The string name field will be identical with the name passed (which is passed as a symbol!), runtime symbol (e.g. the "uuid_name" argument to SOF_DEFINE_UUID()) will be the same, postfixed with a "_uuid".

Parameters

name	Name of the UUID, must match an entry in uuid-registry.txt

◆ SOF_DEFINE_UUID

#define SOF_DEFINE_UUID	(	entity_name,
		uuid_name,
		va,
		vb,
		vc,
		vd0,
		vd1,
		vd2,
		vd3,
		vd4,
		vd5,
		vd6,
		vd7
	)

Value:

_DEF_UUID(entity_name, uuid_name, \

_UUID_INIT(va, vb, vc, vd0, vd1, vd2, vd3, vd4, vd5, vd6, vd7))

_UUID_INIT

#define _UUID_INIT(va, vb, vc, d0, d1, d2, d3, d4, d5, d6, d7)

Definition uuid.h:67

_DEF_UUID

#define _DEF_UUID(entity_name, uuid_name, initializer)

Definition uuid.h:90

Declares runtime UUID (aaaaaaaa-bbbb-cccc-d0d1-d2d3d4d5d6d7) and name.

UUID value from variables declared with this macro are accessible in runtime code - to dereference use SOF_RT_UUID()

Parameters

entity_name	Name of the object pinted by the software tools.
uuid_name	Uuid symbol name used with SOF_UUID() and SOF_RT_UUID().
va	aaaaaaaa value.
vb	bbbb value.
vc	cccc value.
vd0	d0 value (note how d0 and d1 are grouped in formatted uuid)
vd1	d1 value.
vd2	d2 value.
vd3	d3 value.
vd4	d4 value.
vd5	d5 value.
vd6	d6 value.
vd7	d7 value.

◆ SOF_REG_UUID

#define SOF_REG_UUID ( name ) _UUIDREG_##name

Get UUID value sourced from the fixed SOF registry.

The ID value is sourced by name from the uuid-registry.txt file distributed with the source tree.

Parameters

name	Name of the UUID, must match an entry in uuid-registry.txt

◆ SOF_RT_UUID

#define SOF_RT_UUID ( uuid_name ) _RT_UUID(uuid_name)

Dereference unique 32-bit representation of UUID structure in runtime.

Parameters

uuid_name UUID symbol name declared with DECLARE_SOF_RT_UUID().

◆ SOF_UUID

#define SOF_UUID ( uuid_name ) _UUID(uuid_name)

Creates local unique 32-bit representation of UUID structure.

In Zephyr builds, this has the same address as the result of SOF_RT_UUID, but has type of "struct sof_uuid *" and not "struct sof_uid_record *"

Parameters

uuid_name UUID symbol name declared with DECLARE_SOF_UUID() or DECLARE_SOF_RT_UUID().

◆ UUID_NAME_MAX_LEN

#define UUID_NAME_MAX_LEN 32

UUID name string max length in bytes, including null termination.

◆ UUID_SIZE

#define UUID_SIZE 16

UUID is 16 bytes long.

Enumeration Type Documentation

◆ sof_audio_buffer_state

enum sof_audio_buffer_state

Define states of an audio stream buffer connecting two components.

This enum represents the lifecycle of an audio stream, including its initialization, readiness, and end-of-stream handling. It is used to track and manage the state transitions of the stream during audio processing.

Enumerator
AUDIOBUF_STATE_INITIAL
AUDIOBUF_STATE_READY
AUDIOBUF_STATE_END_OF_STREAM
AUDIOBUF_STATE_END_OF_STREAM_FLUSH

Function Documentation

◆ cir_buf_bytes_without_wrap()

static size_t cir_buf_bytes_without_wrap	(	const void *	ptr,
		const void *	buf_end
	)

inlinestatic

Calculates number of bytes to buffer wrap when reading a circular buffer forward from current pointer towards the buffer end.

Parameters

ptr	Read or write pointer of circular buffer.
buf_end	End address of circular buffer.

Returns: Number of bytes between the pointer and the buffer end.

◆ cir_buf_bytes_without_wrap_rewind()

static size_t cir_buf_bytes_without_wrap_rewind	(	const void *	ptr,
		const void *	buf_start
	)

inlinestatic

Calculates number of bytes to buffer wrap when reading a circular buffer backwards from current pointer towards the buffer start.

Parameters

ptr	Read or write pointer of circular buffer.
buf_start	Start address of circular buffer.

Returns: Number of bytes between the buffer start and the pointer.

◆ cir_buf_samples_to_wrap_s16()

static size_t cir_buf_samples_to_wrap_s16	(	const int16_t *	ptr,
		const int16_t *	buf_start,
		size_t	buf_samples
	)

inlinestatic

Calculates numbers of s16 samples to buffer wrap.

Parameters

ptr	Read or write pointer of circular buffer.
buf_start	Start address of circular buffer.
buf_samples	Total size of circular buffer in samples.

Returns: Number of samples to buffer wrap.

◆ cir_buf_samples_to_wrap_s32()

static size_t cir_buf_samples_to_wrap_s32	(	const int32_t *	ptr,
		const int32_t *	buf_start,
		size_t	buf_samples
	)

inlinestatic

Calculates numbers of s32 samples to buffer wrap.

Parameters

ptr	Read or write pointer of circular buffer.
buf_start	Start address of circular buffer.
buf_samples	Total size of circular buffer in samples.

Returns: Number of samples to buffer wrap.

◆ cir_buf_samples_without_wrap_s16()

static size_t cir_buf_samples_without_wrap_s16	(	const void *	ptr,
		const void *	buf_end
	)

inlinestatic

Calculates numbers of s16 samples to buffer wrap when reading a circular buffer forward from current pointer towards the buffer end.

Parameters

ptr	Read or write pointer of circular buffer.
buf_end	End address of circular buffer.

Returns: Number of s16 samples between the pointer and the buffer end.

◆ cir_buf_samples_without_wrap_s32()

static size_t cir_buf_samples_without_wrap_s32	(	const void *	ptr,
		const void *	buf_end
	)

inlinestatic

Calculates numbers of s32 samples to buffer wrap when reading a circular buffer forward from current pointer towards the buffer end.

Parameters

ptr	Read or write pointer of circular buffer.
buf_end	End address of circular buffer.

Returns: Number of s32 samples between the pointer and the buffer end.

◆ cir_buf_wrap()

static void * cir_buf_wrap	(	const void *	ptr,
		const void *	buf_addr,
		const void *	buf_end
	)

inlinestatic

Verifies the pointer and performs rollover when reaching the end of the circular buffer.

Parameters

ptr	Read pointer that may have moved past the buffer end.
buf_addr	Start address of the circular buffer.
buf_end	End address of the circular buffer.

Returns: Pointer, adjusted if necessary.

◆ circ_buf_frames_without_wrap()

static size_t circ_buf_frames_without_wrap	(	const void *	began,
		const void *	end,
		size_t	sample_bytes,
		size_t	channels
	)

inlinestatic

Number of whole frames available before a circular buffer wraps.

Computes (end - began) / channels expressed in frames. The pointer distance is evaluated in bytes so the helper works for any sample width.

Parameters

began	current position in the circular buffer
end	one past the last sample of the circular buffer
sample_bytes	size of a single sample in bytes (2 for s16, 4 for s32)
channels	number of channels, i.e. samples per frame

Returns: number of frames that can be processed without wrapping

◆ sink_get_num_of_processed_bytes()

size_t sink_get_num_of_processed_bytes ( struct sof_sink * sink )

Get total number of bytes processed by the sink (committed by sink_commit_buffer()).

Parameters

[in] sink Pointer to sink structure.

Returns: Total number of processed bytes.

◆ sink_get_overrun()

bool sink_get_overrun ( struct sof_sink * sink )

Check if buffer overrun is permitted on sink stream.

Parameters

[in] sink Pointer to sink structure.

Returns: True if overrun is permitted by audio stream params, false otherwise.

◆ sink_init()

void sink_init	(	struct sof_sink *	sink,
		const struct sink_ops *	ops,
		struct sof_audio_stream_params *	audio_stream_params
	)

Initialize sink API structure before any operation.

NOTE: audio_stream_params must be accessible by the caller core, and the implementation must ensure coherent access to the parameters (e.g. for a cross-core shared queue, it must be located in non-cached memory).

Parameters

[in,out]	sink	Pointer to sink structure.
[in]	ops	Pointer to API operations vtable.
[in]	audio_stream_params	Pointer to structure with audio parameters.

◆ sink_reset_num_of_processed_bytes()

void sink_reset_num_of_processed_bytes ( struct sof_sink * sink )

Reset counter of total processed bytes to zero.

Parameters

[in,out] sink Pointer to sink structure.

◆ sink_set_min_free_space()

void sink_set_min_free_space	(	struct sof_sink *	sink,
		size_t	min_free_space
	)

Set minimum free space required in sink buffer.

Parameters

[in,out]	sink	Pointer to sink structure.
[in]	min_free_space	Minimum free space in bytes.

◆ source_cir_buf_rewind_wrap()

static const void * source_cir_buf_rewind_wrap	(	const void *	ptr,
		const void *	buf_start,
		const void *	buf_end
	)

inlinestatic

Verifies the pointer and performs rollover when reading a read-only circular buffer backwards past its start address.

Parameters

ptr	Pointer that may have moved below the buffer start.
buf_start	Start address of the circular buffer.
buf_end	End address of the circular buffer.

Returns: Pointer, wrapped to the end of the buffer if necessary.

◆ source_cir_buf_wrap()

static const void * source_cir_buf_wrap	(	const void *	ptr,
		const void *	buf_addr,
		const void *	buf_end
	)

inlinestatic

Verifies a read pointer and performs rollover when reaching the end of the circular buffer.

Parameters

ptr	Read pointer that may have moved past the buffer end.
buf_addr	Start address of the circular buffer.
buf_end	End address of the circular buffer.

Returns: Pointer, adjusted if necessary.

◆ source_get_id()

uint32_t source_get_id ( struct sof_source * source )

Get unique stream identifier for source.

Parameters

[in] source Pointer to source structure.

Returns: Stream identifier.

◆ source_get_num_of_processed_bytes()

size_t source_get_num_of_processed_bytes ( struct sof_source * source )

Get total number of bytes processed by the source (freed by source_release_data()).

Parameters

[in] source Pointer to source structure.

Returns: Total number of processed bytes.

◆ source_get_underrun()

bool source_get_underrun ( struct sof_source * source )

Check if buffer underrun is permitted on source stream.

Parameters

[in] source Pointer to source structure.

Returns: True if underrun is permitted by audio stream params, false otherwise.

◆ source_init()

void source_init	(	struct sof_source *	source,
		const struct source_ops *	ops,
		struct sof_audio_stream_params *	audio_stream_params
	)

Initialize source API structure before any operation.

NOTE: audio_stream_params must be accessible by the caller core, and the implementation must ensure coherent access to the parameters (e.g. for a cross-core shared queue, it must be located in non-cached memory).

Parameters

[in,out]	source	Pointer to source structure.
[in]	ops	Pointer to API operations vtable.
[in]	audio_stream_params	Pointer to structure with audio parameters.

◆ source_reset_num_of_processed_bytes()

void source_reset_num_of_processed_bytes ( struct sof_source * source )

Reset counter of total processed bytes to zero.

Parameters

[in,out] source Pointer to source structure.

◆ source_set_alignment_constants()

int source_set_alignment_constants	(	struct sof_source *	source,
		const uint32_t	byte_align,
		const uint32_t	frame_align_req
	)

Set byte and frame alignment constants for source stream.

Sets frame_align_shift and frame_align of stream according to byte_align and frame_align_req requirements. Once the channel number and frame size are determined, the frame_align and frame_align_shift are determined too. These features are used by audio_stream_get_avail_frames_aligned() to calculate available frames.

Note: This must be called in component prepare or param functions only once after channel count and frame size are known and before stream copying begins. If omitted or called late, aligned availability can evaluate to zero and no data will be copied.

Parameters

[in,out]	source	Pointer to source structure.
[in]	byte_align	Processing byte alignment requirement.
[in]	frame_align_req	Processing frames alignment requirement.

Returns: 0 on success, negative error code on failure.

◆ source_set_buffer_fmt()

int source_set_buffer_fmt	(	struct sof_source *	source,
		uint32_t	buffer_fmt
	)

Set buffer format for source.

Parameters

[in,out]	source	Pointer to source structure.
[in]	buffer_fmt	Buffer format identifier.

Returns: 0 on success, negative error code on failure.

◆ source_set_channels()

int source_set_channels	(	struct sof_source *	source,
		unsigned int	channels
	)

Set channel count for source.

Parameters

[in,out]	source	Pointer to source structure.
[in]	channels	Number of audio channels.

Returns: 0 on success, negative error code on failure.

◆ source_set_frm_fmt()

int source_set_frm_fmt	(	struct sof_source *	source,
		enum sof_ipc_frame	frm_fmt
	)

Set audio frame format for source.

Parameters

[in,out]	source	Pointer to source structure.
[in]	frm_fmt	Audio frame format.

Returns: 0 on success, negative error code on failure.

◆ source_set_min_available()

void source_set_min_available	(	struct sof_source *	source,
		size_t	min_available
	)

Set minimum available data requirement in bytes.

Parameters

[in,out]	source	Pointer to source structure.
[in]	min_available	Minimum available bytes.

◆ source_set_params()

int source_set_params	(	struct sof_source *	source,
		struct sof_ipc_stream_params *	params,
		bool	force_update
	)

Configure initial set of audio parameters.

Parameters

[in,out]	source	Pointer to source structure.
[in]	params	Audio stream parameters.
[in]	force_update	True to force parameters override.

Returns: 0 on success, negative error code on failure.

◆ source_set_rate()

int source_set_rate	(	struct sof_source *	source,
		unsigned int	rate
	)

Set sample rate for source.

Parameters

[in,out]	source	Pointer to source structure.
[in]	rate	Sample rate in Hz.

Returns: 0 on success, negative error code on failure.

◆ source_set_underrun()

int source_set_underrun	(	struct sof_source *	source,
		bool	underrun_permitted
	)

Configure whether underrun is permitted on source.

Parameters

[in,out]	source	Pointer to source structure.
[in]	underrun_permitted	True if underrun is permitted, false otherwise.

Returns: 0 on success, negative error code on failure.

◆ source_set_valid_fmt()

int source_set_valid_fmt	(	struct sof_source *	source,
		enum sof_ipc_frame	valid_sample_fmt
	)

Set valid sample format for source.

Parameters

[in,out]	source	Pointer to source structure.
[in]	valid_sample_fmt	Valid sample format.

Returns: 0 on success, negative error code on failure.

Files

Data Structures

Macros

Enumerations

Functions

Detailed Description

Macro Definition Documentation

◆ _DEF_UUID

◆ _RT_UUID

◆ _UUID

◆ _UUID_INIT

◆ SOF_DEFINE_REG_UUID

◆ SOF_DEFINE_UUID

◆ SOF_REG_UUID

◆ SOF_RT_UUID

◆ SOF_UUID

◆ UUID_NAME_MAX_LEN

◆ UUID_SIZE

Enumeration Type Documentation

◆ sof_audio_buffer_state

Function Documentation

◆ cir_buf_bytes_without_wrap()

◆ cir_buf_bytes_without_wrap_rewind()

◆ cir_buf_samples_to_wrap_s16()

◆ cir_buf_samples_to_wrap_s32()

◆ cir_buf_samples_without_wrap_s16()

◆ cir_buf_samples_without_wrap_s32()

◆ cir_buf_wrap()

◆ circ_buf_frames_without_wrap()

◆ sink_get_num_of_processed_bytes()

◆ sink_get_overrun()

◆ sink_init()

◆ sink_reset_num_of_processed_bytes()

◆ sink_set_min_free_space()

◆ source_cir_buf_rewind_wrap()

◆ source_cir_buf_wrap()

◆ source_get_id()

◆ source_get_num_of_processed_bytes()

◆ source_get_underrun()

◆ source_init()

◆ source_reset_num_of_processed_bytes()

◆ source_set_alignment_constants()

◆ source_set_buffer_fmt()

◆ source_set_channels()

◆ source_set_frm_fmt()

◆ source_set_min_available()

◆ source_set_params()

◆ source_set_rate()

◆ source_set_underrun()

◆ source_set_valid_fmt()