Scope Plugin Extension

Overview

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

// structs

struct snd_pcm_scope_ops_t;

// global functions

snd_pcm_uframes_t
snd_pcm_meter_get_bufsize(snd_pcm_t* pcm);

unsigned int
snd_pcm_meter_get_channels(snd_pcm_t* pcm);

unsigned int
snd_pcm_meter_get_rate(snd_pcm_t* pcm);

snd_pcm_uframes_t
snd_pcm_meter_get_now(snd_pcm_t* pcm);

snd_pcm_uframes_t
snd_pcm_meter_get_boundary(snd_pcm_t* pcm);

int
snd_pcm_meter_add_scope(
    snd_pcm_t* pcm,
    snd_pcm_scope_t* scope
);

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

int
snd_pcm_scope_malloc(snd_pcm_scope_t** ptr);

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

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

const char*
snd_pcm_scope_get_name(snd_pcm_scope_t* scope);

void*
snd_pcm_scope_get_callback_private(snd_pcm_scope_t* scope);

void
snd_pcm_scope_set_callback_private(
    snd_pcm_scope_t* scope,
    void* val
);

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

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

Detailed Documentation

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

Global 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.

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

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_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_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

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_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

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

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

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

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

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

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

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.

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)

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

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