alsa_common.h File Reference

#include <alsa/asoundlib.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "debug.h"
#include "utils/color_out.h"
#include "types.h"

Include dependency graph for alsa_common.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Functions
static const char *	alsa_get_pcm_state_name (snd_pcm_state_t state) __attribute__((unused))
static void	audio_alsa_list_devices (void)
static void	audio_alsa_probe (struct device_info **available_devices, int *count, const char **whitelist, size_t whitelist_size)
static int	get_rate_near (snd_pcm_t *handle, snd_pcm_hw_params_t *params, unsigned int approx_val)
static void	print_alsa_device_info (snd_pcm_t *handle, const char *module_name)

Variables
static const snd_pcm_format_t	bps_to_snd_fmts []

Detailed Description

Author

Martin Pulec pulec.nosp@m.@ces.nosp@m.net.c.nosp@m.z

Definition in file alsa_common.h.

Function Documentation

alsa_get_pcm_state_name()

static const char * alsa_get_pcm_state_name ( snd_pcm_state_t state )

static

Definition at line 208 of file alsa_common.h.

                                                                  {
        switch (state) {
                case SND_PCM_STATE_OPEN:
                        return "Open";
                case SND_PCM_STATE_SETUP:
                        return "Setup installed";
                case SND_PCM_STATE_PREPARED:
                        return "Ready to start";
                case SND_PCM_STATE_RUNNING:
                        return "Running";
                case SND_PCM_STATE_XRUN:
                        return "Stopped: underrun (playback) or overrun (capture) detected";
                case SND_PCM_STATE_DRAINING:
                        return "Draining: running (playback) or stopped (capture)";
                case SND_PCM_STATE_PAUSED:
                        return "Paused";
                case SND_PCM_STATE_SUSPENDED:
                        return "Hardware is suspended";
                case SND_PCM_STATE_DISCONNECTED:
                        return "Hardware is disconnected";
                default:
                        return "(unknown)";
        }
}

References state.

Referenced by audio_play_alsa_put_frame(), and audio_play_alsa_reconfigure().

audio_alsa_list_devices()

static void audio_alsa_list_devices ( void )

inlinestatic

Definition at line 114 of file alsa_common.h.

{
        struct device_info *available_devices;
        int count;
        audio_alsa_probe(&available_devices, &count, NULL, 0);
        strcpy(available_devices[0].dev, "");
        strcpy(available_devices[0].name, "default ALSA device (same as \"alsa:default\")");
        for(int i = 0; i < count; i++){
                const char * const id = available_devices[i].dev;
                color_printf(TERM_FG_RED "\talsa%s" TERM_FG_RESET, id);
                for (int j = 0; j < 30 - (int) strlen(id); ++j) putchar(' ');
                printf(": %s\n", available_devices[i].name);
        }
        free(available_devices);
}

References audio_alsa_probe(), color_printf(), count, device_info::dev, name, TERM_FG_RED, and TERM_FG_RESET.

Referenced by audio_cap_alsa_help(), and audio_play_alsa_help().

Here is the call graph for this function:

audio_alsa_probe()

static void audio_alsa_probe ( struct device_info ** available_devices, int * count, const char ** whitelist, size_t whitelist_size )

inlinestatic

Definition at line 50 of file alsa_common.h.

{
        void **hints;
        snd_device_name_hint(-1, "pcm", &hints);
 
        size_t device_count = 0;
        for (void **it = hints; *it != NULL; it++) device_count++;
 
        *available_devices = calloc(device_count + 1 , sizeof(struct device_info));
        strcpy((*available_devices)[0].dev, "");
        strcpy((*available_devices)[0].name, "Default Linux audio");
        *count = 1;
 
        for(void **it = hints; *it != NULL; it++){
                char *id = snd_device_name_get_hint(*it, "NAME");
 
                bool whitelisted = false;
                for(size_t i = 0; i < whitelist_size; i++){
                        if(strstr(id, whitelist[i])){
                                whitelisted = true;
                                break;
                        }
                }
                if(!whitelisted && whitelist_size > 0) {
                        free(id);
                        continue;
                }
 
                strcpy((*available_devices)[*count].dev, ":");
                strncat((*available_devices)[*count].dev, id,
                                sizeof (*available_devices)[*count].dev -
                                strlen((*available_devices)[*count].dev) - 1);
                free(id);
 
                char *name = snd_device_name_get_hint(*it, "DESC");
                char *tok = name;
                while(tok){
                        char *newline = strchr(tok, '\n');
                        if(newline){
                                *newline = '\0';
                                strncat((*available_devices)[*count].name, tok,
                                                sizeof (*available_devices)[*count].name -
                                                strlen((*available_devices)[*count].name) - 1);
                                strncat((*available_devices)[*count].name, " - ",
                                                sizeof (*available_devices)[*count].name -
                                                strlen((*available_devices)[*count].name) - 1);
                                tok = newline + 1;
                        } else {
                                strncat((*available_devices)[*count].name, tok,
                                                sizeof (*available_devices)[*count].name -
                                                strlen((*available_devices)[*count].name) - 1);
                                tok = NULL;
                        }
                }
                free(name);
                (*count)++;
        }
 
        snd_device_name_free_hint(hints);
}

References count, and name.

Referenced by audio_alsa_list_devices(), audio_cap_alsa_probe(), and audio_play_alsa_probe().

get_rate_near()

static int get_rate_near ( snd_pcm_t * handle, snd_pcm_hw_params_t * params, unsigned int approx_val )

static

Finds equal or nearest higher sample rate that device supports. If none exist, pick highest lower value.

Returns

sample rate, 0 if none was found

Definition at line 144 of file alsa_common.h.

                                                                                                  {
        int ret = 0;
        int dir = 0;
        int rc;
        unsigned int rate = approx_val;
        // try exact sample rate
        rc = snd_pcm_hw_params_set_rate_min(handle, params, &rate, &dir);
        if (rc != 0) {
                dir = 1;
                // or higher
                rc = snd_pcm_hw_params_set_rate_min(handle, params, &rate, &dir);
        }
 
        if (rc == 0) {
                // read the rate
                rc = snd_pcm_hw_params_get_rate_min(params, &rate, NULL);
                if (rc == 0) {
                        ret = rate;
                }
                // restore configuration space
                rate = 0;
                dir = 1;
                rc = snd_pcm_hw_params_set_rate_min(handle, params, &rate, &dir);
                assert(rc == 0);
        }
 
        // we did not succeed, try lower sample rate
        if (ret == 0) {
                unsigned int rate = approx_val;
                dir = 0;
                unsigned int orig_max;
                rc = snd_pcm_hw_params_get_rate_max(params, &orig_max, NULL);
                assert(rc == 0);
 
                rc = snd_pcm_hw_params_set_rate_max(handle, params, &rate, &dir);
                if (rc != 0) {
                        dir = -1;
                        rc = snd_pcm_hw_params_set_rate_max(handle, params, &rate, &dir);
                }
 
                if (rc == 0) {
                        rc = snd_pcm_hw_params_get_rate_max(params, &rate, NULL);
                        if (rc == 0) {
                                ret = rate;
                        }
                        // restore configuration space
                        dir = 0;
                        rc = snd_pcm_hw_params_set_rate_max(handle, params, &orig_max, &dir);
                        assert(rc == 0);
                }
        }
        return ret;
}

Referenced by audio_cap_alsa_init(), and audio_play_alsa_query_format().

print_alsa_device_info()

static void print_alsa_device_info ( snd_pcm_t * handle, const char * module_name )

static

Definition at line 198 of file alsa_common.h.

                                                                               {
        snd_pcm_info_t *info;
        snd_pcm_info_alloca(&info);
        if (snd_pcm_info(handle, info) == 0) {
                log_msg(LOG_LEVEL_NOTICE, "%sUsing device: %s\n",
                                module_name, snd_pcm_info_get_name(info));
        }
}

References LOG_LEVEL_NOTICE, and log_msg().

Referenced by audio_cap_alsa_init(), and audio_play_alsa_init().

Here is the call graph for this function:

Variable Documentation

bps_to_snd_fmts

const snd_pcm_format_t bps_to_snd_fmts[]

static

Initial value:

= {
        [0] = SND_PCM_FORMAT_UNKNOWN,
        [1] = SND_PCM_FORMAT_U8,
        [2] = SND_PCM_FORMAT_S16_LE,
        [3] = SND_PCM_FORMAT_S24_3LE,
        [4] = SND_PCM_FORMAT_S32_LE,
}

Definition at line 130 of file alsa_common.h.

                                                  {
        [0] = SND_PCM_FORMAT_UNKNOWN,
        [1] = SND_PCM_FORMAT_U8,
        [2] = SND_PCM_FORMAT_S16_LE,
        [3] = SND_PCM_FORMAT_S24_3LE,
        [4] = SND_PCM_FORMAT_S32_LE,
};

Referenced by audio_cap_alsa_init(), audio_play_alsa_query_format(), and audio_play_alsa_reconfigure().