Scope Plugin Extension

Data Structures
struct	snd_pcm_scope_ops_t
Functions
snd_pcm_uframes_t	snd_pcm_meter_get_bufsize (snd_pcm_t *pcm)
	Get meter buffer size from a SND_PCM_TYPE_METER PCM.
unsigned int	snd_pcm_meter_get_channels (snd_pcm_t *pcm)
	Get meter channels from a SND_PCM_TYPE_METER PCM.
unsigned int	snd_pcm_meter_get_rate (snd_pcm_t *pcm)
	Get meter rate from a SND_PCM_TYPE_METER PCM.
snd_pcm_uframes_t	snd_pcm_meter_get_now (snd_pcm_t *pcm)
	Get meter "now" frame pointer from a SND_PCM_TYPE_METER PCM.
snd_pcm_uframes_t	snd_pcm_meter_get_boundary (snd_pcm_t *pcm)
	Get boundary for frame pointers from a SND_PCM_TYPE_METER PCM.
int	snd_pcm_meter_add_scope (snd_pcm_t *pcm, snd_pcm_scope_t *scope)
	Add a scope to a SND_PCM_TYPE_METER PCM.
snd_pcm_scope_t *	snd_pcm_meter_search_scope (snd_pcm_t *pcm, const char *name)
	Search an installed scope inside a SND_PCM_TYPE_METER PCM.
int	snd_pcm_scope_malloc (snd_pcm_scope_t **ptr)
	allocate an invalid snd_pcm_scope_t using standard malloc
void	snd_pcm_scope_set_ops (snd_pcm_scope_t *scope, const snd_pcm_scope_ops_t *val)
	Set callbacks for a SND_PCM_TYPE_METER PCM scope.
void	snd_pcm_scope_set_name (snd_pcm_scope_t *scope, const char *val)
	Set name of a SND_PCM_TYPE_METER PCM scope.
const char *	snd_pcm_scope_get_name (snd_pcm_scope_t *scope)
	Get name of a SND_PCM_TYPE_METER PCM scope.
void *	snd_pcm_scope_get_callback_private (snd_pcm_scope_t *scope)
	Get callbacks private value for a SND_PCM_TYPE_METER PCM scope.
void	snd_pcm_scope_set_callback_private (snd_pcm_scope_t *scope, void *val)
	Get callbacks private value for a SND_PCM_TYPE_METER PCM scope.
int	snd_pcm_scope_s16_open (snd_pcm_t *pcm, const char *name, snd_pcm_scope_t **scopep)
	Add a s16 pseudo scope to a SND_PCM_TYPE_METER PCM.
int16_t *	snd_pcm_scope_s16_get_channel_buffer (snd_pcm_scope_t *scope, unsigned int channel)
	Get s16 pseudo scope frames buffer for a channel.

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Detailed Description

See the PCM (digital audio) interface page for more details.

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Function Documentation

int snd_pcm_meter_add_scope	(	snd_pcm_t *	pcm,
		snd_pcm_scope_t *	scope
	)

Add a scope to a SND_PCM_TYPE_METER PCM.

Parameters:

pcm	PCM handle
scope	Scope handle

Returns:

0 on success otherwise a negative error code

snd_pcm_uframes_t snd_pcm_meter_get_boundary

(

snd_pcm_t *

pcm

)

Get boundary for frame pointers from a SND_PCM_TYPE_METER PCM.

Parameters:

pcm	PCM handle

Returns:

boundary in frames

snd_pcm_uframes_t snd_pcm_meter_get_bufsize

(

snd_pcm_t *

pcm

)

Get meter buffer size from a SND_PCM_TYPE_METER PCM.

Parameters:

pcm	PCM handle

Returns:

meter buffer size in frames

unsigned int snd_pcm_meter_get_channels

(

snd_pcm_t *

pcm

)

Get meter channels from a SND_PCM_TYPE_METER PCM.

Parameters:

pcm	PCM handle

Returns:

meter channels count

snd_pcm_uframes_t snd_pcm_meter_get_now

(

snd_pcm_t *

pcm

)

Get meter "now" frame pointer from a SND_PCM_TYPE_METER PCM.

Parameters:

pcm	PCM handle

Returns:

"now" frame pointer in frames (0 ... boundary - 1) see snd_pcm_meter_get_boundary

unsigned int snd_pcm_meter_get_rate

(

snd_pcm_t *

pcm

)

Get meter rate from a SND_PCM_TYPE_METER PCM.

Parameters:

pcm	PCM handle

Returns:

approximate rate

snd_pcm_scope_t* snd_pcm_meter_search_scope	(	snd_pcm_t *	pcm,
		const char *	name
	)

Search an installed scope inside a SND_PCM_TYPE_METER PCM.

Parameters:

pcm	PCM handle
name	scope name

Returns:

pointer to found scope or NULL if none is found

void* snd_pcm_scope_get_callback_private

(

snd_pcm_scope_t *

scope

)

Get callbacks private value for a SND_PCM_TYPE_METER PCM scope.

Parameters:

scope

PCM meter scope

Returns:

Private data value

const char* snd_pcm_scope_get_name

(

snd_pcm_scope_t *

scope

)

Get name of a SND_PCM_TYPE_METER PCM scope.

Parameters:

scope

PCM meter scope

Returns:

scope name

int snd_pcm_scope_malloc

(

snd_pcm_scope_t **

ptr

)

allocate an invalid snd_pcm_scope_t using standard malloc

Parameters:

ptr	returned pointer

Returns:

0 on success otherwise negative error code

int16_t* snd_pcm_scope_s16_get_channel_buffer	(	snd_pcm_scope_t *	scope,
		unsigned int	channel
	)

Get s16 pseudo scope frames buffer for a channel.

Parameters:

scope	s16 pseudo scope handle
channel	Channel

Returns:

Pointer to channel buffer

int snd_pcm_scope_s16_open	(	snd_pcm_t *	pcm,
		const char *	name,
		snd_pcm_scope_t **	scopep
	)

Add a s16 pseudo scope to a SND_PCM_TYPE_METER PCM.

Parameters:

pcm	The pcm handle
name	Scope name
scopep	Pointer to newly created and added scope

Returns:

0 on success otherwise a negative error code

s16 pseudo scope convert SND_PCM_TYPE_METER PCM frames in CPU endian 16 bit frames for use with other scopes. Don't forget to insert it before and to not insert it more time (see snd_pcm_meter_search_scope)

void snd_pcm_scope_set_callback_private	(	snd_pcm_scope_t *	scope,
		void *	val
	)

Get callbacks private value for a SND_PCM_TYPE_METER PCM scope.

Parameters:

scope	PCM meter scope
val	Private data value

void snd_pcm_scope_set_name	(	snd_pcm_scope_t *	scope,
		const char *	val
	)

Set name of a SND_PCM_TYPE_METER PCM scope.

Parameters:

scope	PCM meter scope
val	scope name

void snd_pcm_scope_set_ops	(	snd_pcm_scope_t *	scope,
		const snd_pcm_scope_ops_t *	val
	)

Set callbacks for a SND_PCM_TYPE_METER PCM scope.

Parameters:

scope	PCM meter scope
val	callbacks