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. More...
unsigned int	snd_pcm_meter_get_channels (snd_pcm_t *pcm)
	Get meter channels from a SND_PCM_TYPE_METER PCM. More...
unsigned int	snd_pcm_meter_get_rate (snd_pcm_t *pcm)
	Get meter rate from a SND_PCM_TYPE_METER PCM. More...
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. More...
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. More...
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. More...
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. More...
int	snd_pcm_scope_malloc (snd_pcm_scope_t **ptr)
	allocate an invalid snd_pcm_scope_t using standard malloc More...
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. More...
void	snd_pcm_scope_set_name (snd_pcm_scope_t *scope, const char *val)
	Set name of a SND_PCM_TYPE_METER PCM scope. More...
const char *	snd_pcm_scope_get_name (snd_pcm_scope_t *scope)
	Get name of a SND_PCM_TYPE_METER PCM scope. More...
void *	snd_pcm_scope_get_callback_private (snd_pcm_scope_t *scope)
	Get callbacks private value for a SND_PCM_TYPE_METER PCM scope. More...
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. More...
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. More...
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. More...

Detailed Description

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

Function Documentation

snd_pcm_meter_add_scope()

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_meter_get_boundary()

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_meter_get_bufsize()

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

snd_pcm_meter_get_channels()

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_meter_get_now()

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

snd_pcm_meter_get_rate()

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_meter_search_scope()

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

snd_pcm_scope_get_callback_private()

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

snd_pcm_scope_get_name()

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

snd_pcm_scope_malloc()

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

snd_pcm_scope_s16_get_channel_buffer()

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

snd_pcm_scope_s16_open()

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)

snd_pcm_scope_set_callback_private()

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

snd_pcm_scope_set_name()

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

snd_pcm_scope_set_ops()

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