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/***************************************************************************
alsa.c - description
-------------------
begin : Sat Mar 01 2003
copyright : (C) 2002 by Pete Bernert
email : BlackDove@addcom.de
***************************************************************************/
/***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. See also the license.txt file for *
* additional informations. *
* *
***************************************************************************/
#include <stdio.h>
#include <string.h>
#define ALSA_PCM_NEW_HW_PARAMS_API
#define ALSA_PCM_NEW_SW_PARAMS_API
#include <alsa/asoundlib.h>
#include "out.h"
static snd_pcm_t *handle = NULL;
static snd_pcm_uframes_t buffer_size;
static void alsa_finish(void);
// SETUP SOUND
static int alsa_init(void)
{
snd_pcm_hw_params_t *hwparams;
snd_pcm_status_t *status;
snd_ctl_t *ctl_handle = NULL;
snd_ctl_card_info_t *info;
unsigned int pspeed;
int pchannels;
int format;
unsigned int buffer_time = 100000;
unsigned int period_time = buffer_time / 4;
const char *alsa_name = "default";
const char *name;
int retval = -1;
int err;
name = getenv("ALSA_NAME");
if (name != NULL)
alsa_name = name;
snd_ctl_card_info_alloca(&info);
if ((err = snd_ctl_open(&ctl_handle, alsa_name, 0)) < 0) {
printf("control open: %s\n", snd_strerror(err));
}
else if ((err = snd_ctl_card_info(ctl_handle, info)) < 0) {
printf("control info: %s\n", snd_strerror(err));
snd_ctl_card_info_clear(info);
}
if (ctl_handle != NULL)
snd_ctl_close(ctl_handle);
name = snd_ctl_card_info_get_name(info);
if (name != NULL) {
if (strcasecmp(name, "PulseAudio") == 0) {
// PulseAudio's ALSA emulation is known to be broken..
printf("alsa: refusing to run under PulseAudio's emulation\n");
return -1;
}
else {
printf("alsa: using '%s', set ALSA_NAME to change\n", name);
}
}
pchannels=2;
pspeed = 44100;
format = SND_PCM_FORMAT_S16;
if ((err = snd_pcm_open(&handle, alsa_name,
SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK)) < 0)
{
printf("Audio open error: %s\n", snd_strerror(err));
return -1;
}
if((err = snd_pcm_nonblock(handle, 0))<0)
{
printf("Can't set blocking moded: %s\n", snd_strerror(err));
goto out;
}
snd_pcm_hw_params_alloca(&hwparams);
if((err=snd_pcm_hw_params_any(handle, hwparams))<0)
{
printf("Broken configuration for this PCM: %s\n", snd_strerror(err));
goto out;
}
if((err=snd_pcm_hw_params_set_access(handle, hwparams, SND_PCM_ACCESS_RW_INTERLEAVED))<0)
{
printf("Access type not available: %s\n", snd_strerror(err));
goto out;
}
if((err=snd_pcm_hw_params_set_format(handle, hwparams, format))<0)
{
printf("Sample format not available: %s\n", snd_strerror(err));
goto out;
}
if((err=snd_pcm_hw_params_set_channels(handle, hwparams, pchannels))<0)
{
printf("Channels count not available: %s\n", snd_strerror(err));
goto out;
}
if((err=snd_pcm_hw_params_set_rate_near(handle, hwparams, &pspeed, 0))<0)
{
printf("Rate not available: %s\n", snd_strerror(err));
goto out;
}
if((err=snd_pcm_hw_params_set_buffer_time_near(handle, hwparams, &buffer_time, 0))<0)
{
printf("Buffer time error: %s\n", snd_strerror(err));
goto out;
}
if((err=snd_pcm_hw_params_set_period_time_near(handle, hwparams, &period_time, 0))<0)
{
printf("Period time error: %s\n", snd_strerror(err));
goto out;
}
if((err=snd_pcm_hw_params(handle, hwparams))<0)
{
printf("Unable to install hw params: %s\n", snd_strerror(err));
goto out;
}
snd_pcm_status_alloca(&status);
if((err=snd_pcm_status(handle, status))<0)
{
printf("Unable to get status: %s\n", snd_strerror(err));
goto out;
}
buffer_size = snd_pcm_status_get_avail(status);
retval = 0;
out:
if (retval != 0)
alsa_finish();
return retval;
}
// REMOVE SOUND
static void alsa_finish(void)
{
if(handle != NULL)
{
snd_pcm_drop(handle);
snd_pcm_close(handle);
handle = NULL;
}
}
// GET BYTES BUFFERED
static int alsa_busy(void)
{
int l;
if (handle == NULL) // failed to open?
return 1;
l = snd_pcm_avail(handle);
if (l < 0) return 0;
if (l < buffer_size / 2) // can we write in at least the half of fragments?
l = 1; // -> no? wait
else l = 0; // -> else go on
return l;
}
// FEED SOUND DATA
static void alsa_feed(void *pSound, int lBytes)
{
char sbuf[4096];
if (handle == NULL) return;
if (snd_pcm_state(handle) == SND_PCM_STATE_XRUN)
{
memset(sbuf, 0, sizeof(sbuf));
snd_pcm_prepare(handle);
snd_pcm_writei(handle, sbuf, sizeof(sbuf) / 4);
snd_pcm_writei(handle, sbuf, sizeof(sbuf) / 4);
snd_pcm_writei(handle, sbuf, sizeof(sbuf) / 4);
}
else
{
int l = snd_pcm_avail(handle);
if (l < lBytes / 4)
{
if (l == 0)
return;
lBytes = l * 4;
}
}
snd_pcm_writei(handle, pSound, lBytes / 4);
}
void out_register_alsa(struct out_driver *drv)
{
drv->name = "alsa";
drv->init = alsa_init;
drv->finish = alsa_finish;
drv->busy = alsa_busy;
drv->feed = alsa_feed;
}
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