Sound Card Filter API

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Sound Card Filter API
Sound Card API - manage audio capture/play filters.
Functions

struct _MSFilter * ms_snd_card_create_reader (MSSndCard *obj)
struct _MSFilter * ms_snd_card_create_writer (MSSndCard *obj)
MSSndCard * ms_snd_card_new (MSSndCardDesc *desc)
MSSndCard * ms_snd_card_new_with_name (MSSndCardDesc *desc, const char *name)
void ms_snd_card_destroy (MSSndCard *obj)
MSSndCard * ms_snd_card_dup (MSSndCard *card)
const char * ms_snd_card_get_driver_type (const MSSndCard *obj)
const char * ms_snd_card_get_name (const MSSndCard *obj)
const char * ms_snd_card_get_string_id (MSSndCard *obj)
unsigned int ms_snd_card_get_capabilities (const MSSndCard *obj)
void ms_snd_card_set_level (MSSndCard *obj, MSSndCardMixerElem e, int percent)
int ms_snd_card_get_level (MSSndCard *obj, MSSndCardMixerElem e)
void ms_snd_card_set_capture (MSSndCard *obj, MSSndCardCapture c)
int ms_snd_card_set_control (MSSndCard *obj, MSSndCardControlElem e, int val)
int ms_snd_card_get_control (MSSndCard *obj, MSSndCardControlElem e)
MSSndCard * ms_alsa_card_new_custom (const char *pcmdev, const char *mixdev)
void ms_alsa_card_set_forced_sample_rate (int samplerate)
Function Documentation

struct _MSFilter* ms_snd_card_create_reader ( MSSndCard * obj ) [read]
Create an INPUT filter based on the selected sound card.

Parameters:
obj A sound card object.
Returns: A MSFilter if successfull, NULL otherwise.

struct _MSFilter* ms_snd_card_create_writer ( MSSndCard * obj ) [read]
Create an OUPUT filter based on the selected sound card.

Parameters:
obj A sound card object.
Returns: A MSFilter if successfull, NULL otherwise.

MSSndCard* ms_snd_card_new ( MSSndCardDesc * desc )
Create a new sound card object.

Parameters:
desc A sound card description object.
Returns: MSSndCard if successfull, NULL otherwise.

MSSndCard* ms_snd_card_new_with_name ( MSSndCardDesc * desc,
const char * name
)
Create a new sound card object.

Parameters:
desc A sound card description object.
card mame
Returns: MSSndCard if successfull, NULL otherwise.

void ms_snd_card_destroy ( MSSndCard * obj )
Destroy sound card object.

Parameters:
obj A MSSndCard object.
MSSndCard* ms_snd_card_dup ( MSSndCard * card )
Duplicate a sound card object.

This helps to open several time a sound card.

Parameters:
card A sound card object.
Returns: MSSndCard if successfull, NULL otherwise.

const char* ms_snd_card_get_driver_type ( const MSSndCard * obj )
Retreive a sound card‘s driver type string.

Internal driver types are either: "OSS, ALSA, WINSND, PASND, CA"

Parameters:
obj A sound card object.
Returns: a string if successfull, NULL otherwise.

const char* ms_snd_card_get_name ( const MSSndCard * obj )
Retreive a sound card‘s name.

Parameters:
obj A sound card object.
Returns: a string if successfull, NULL otherwise.

const char* ms_snd_card_get_string_id ( MSSndCard * obj )
Retreive sound card‘s name (

driver_type:
name).

Parameters:
obj A sound card object.
Returns: A string if successfull, NULL otherwise.

unsigned int ms_snd_card_get_capabilities ( const MSSndCard * obj )
Retreive sound card‘s capabilities.

MS_SND_CARD_CAP_CAPTURE
MS_SND_CARD_CAP_PLAYBACK
MS_SND_CARD_CAP_CAPTURE|MS_SND_CARD_CAP_PLAYBACK

Parameters:
obj A sound card object.
Returns: A unsigned int if successfull, 0 otherwise.

void ms_snd_card_set_level ( MSSndCard * obj,
MSSndCardMixerElem e,
int percent
)
Set some mixer level value.

MS_SND_CARD_MASTER,
MS_SND_CARD_PLAYBACK,
MS_SND_CARD_CAPTURE

Note: not implemented on all sound card filters.

Parameters:
obj A sound card object.
e A sound card mixer object.
percent A volume level.
int ms_snd_card_get_level ( MSSndCard * obj,
MSSndCardMixerElem e
)
Get some mixer level value.

MS_SND_CARD_MASTER,
MS_SND_CARD_PLAYBACK,
MS_SND_CARD_CAPTURE

Note: not implemented on all sound card filters.

Parameters:
obj A sound card object.
e A sound card mixer object.
Returns: A int if successfull, <0 otherwise.

void ms_snd_card_set_capture ( MSSndCard * obj,
MSSndCardCapture c
)
Set some source for capture.

MS_SND_CARD_MIC,
MS_SND_CARD_LINE

Note: not implemented on all sound card filters.

Parameters:
obj A sound card object.
c A sound card capture value.
Returns: A int if successfull, 0 otherwise.

int ms_snd_card_set_control ( MSSndCard * obj,
MSSndCardControlElem e,
int val
)
Set some mixer control.

MS_SND_CARD_MASTER_MUTE, -> 0: unmute, 1: mute
MS_SND_CARD_PLAYBACK_MUTE, -> 0: unmute, 1: mute
MS_SND_CARD_CAPTURE_MUTE -> 0: unmute, 1: mute

Note: not implemented on all sound card filters.

Parameters:
obj A sound card object.
e A sound card control object.
percent A value for control.
Returns: 0 if successfull, <0 otherwise.

int ms_snd_card_get_control ( MSSndCard * obj,
MSSndCardControlElem e
)
Get some mixer control.

MS_SND_CARD_MASTER_MUTE, -> return 0: unmute, 1: mute
MS_SND_CARD_PLAYBACK_MUTE, -> return 0: unmute, 1: mute
MS_SND_CARD_CAPTURE_MUTE -> return 0: unmute, 1: mute

Note: not implemented on all sound card filters.

Parameters:
obj A sound card object.
e A sound card mixer object.
Returns: A int if successfull, <0 otherwise.

MSSndCard* ms_alsa_card_new_custom ( const char * pcmdev,
const char * mixdev
)
Create a alsa card with user supplied pcm name and mixer name.

Parameters:
pcmdev The pcm device name following alsa conventions (ex: plughw:0)
mixdev The mixer device name following alsa conventions.
Returns: a MSSndCard object, NULL if alsa support is not available.

void ms_alsa_card_set_forced_sample_rate ( int samplerate )
Use supplied sample rate to open alsa devices (forced rate). Has no interest except workarouding driver bugs. Use -1 to revert to normal behavior.

Sound Card Filter API

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原文地址：http://www.cnblogs.com/samaritan/p/4236119.html