snd_pcm_channel_setup_t

Current configuration of a PCM channel

Synopsis:

typedef struct snd_pcm_channel_setup
{
    int32_t             channel;
    int32_t             mode;
    snd_pcm_format_t    format;
    snd_pcm_digital_t   digital;
    union
    {
        struct
        {
            int32_t     queue_size;
            uint8_t     reserved[124]; /* must be filled with zeroes */
        }       stream;
        struct
        {
            int32_t     frag_size;
            int32_t     frags;
            int32_t     frags_min;
            int32_t     frags_max;
            uint32_t    max_frag_size;
            uint8_t     reserved[124]; /* must be filled with zeroes */
        }       block;
        uint8_t     reserved[128];     /* must be filled with zeroes */
    }       buf;
    int16_t         msbits_per_sample;
    int16_t         pad1;
    int32_t         mixer_device;
    snd_mixer_eid_t *mixer_eid;
    snd_mixer_gid_t *mixer_gid;
    uint8_t         mmap_valid:1;
    uint8_t         mmap_active:1;
    int32_t         mixer_card;
    uint8_t         reserved[104];     /* must be filled with zeroes */
}       snd_pcm_channel_setup_t;

Description:

The snd_pcm_channel_setup_t structure describes the current configuration of a PCM channel. The members include:

channel

The channel direction; One of SND_PCM_CHANNEL_PLAYBACK or SND_PCM_CHANNEL_CAPTURE.

mode

The channel mode: SND_PCM_MODE_BLOCK. (SND_PCM_MODE_STREAM is deprecated.)

format

The data format; see snd_pcm_format_t. Note that the rate member may differ from the requested one.

digital

Not currently implemented.

queue_size

The real queue size (which may differ from requested one).

frag_size

The real fragment size (which may differ from requested one).

frags

The number of fragments.

frags_min

Capture: the minimum filled fragments to allow wakeup. Playback: the minimum free fragments to allow wakeup.

frags_max

Playback: the maximum filled fragments to allow wakeup. The value also specifies the maximum number of used fragments plus one.

max_frag_size

The maximum fragment size.

msbits_per_sample

How many most-significant bits are physically used.

mixer_device

Mixer device for this subchannel.

mixer_eid

A pointer to the mixer element identification for this subchannel.

mixer_gid

A pointer to the mixer group identification for this subchannel; see snd_mixer_gid_t.

mmap_valid

The channel can use mmapped access.

mmap_active

The channel is using mmapped transfers.

mixer_card

The mixer card.

Classification:

QNX Neutrino

See also:

snd_mixer_gid_t, snd_pcm_channel_setup(), snd_pcm_format_t, snd_pcm_plugin_setup()