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/*
* ALSA audio driver, since OSS is pretty much dead at this stage.
*/
#include "audio/linux_alsa.h"
#if DEMOLIB_USE_ALSA
#include "exception.h"
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <errno.h>
#include <sys/time.h>
#include <alsa/pcm.h>
#include <alsa/asoundlib.h>
#include <algorithm>
#define SAMPLE_RATE 44100
#define NUM_CHANNELS 2
#define BYTES_PER_FRAME (sizeof(short) * NUM_CHANNELS)
ALSAAudioDriver::ALSAAudioDriver(const char *device, AudioProvider *prv, float jump, MainLoop *lp)
{
this->prov = prv;
snd_pcm_hw_params_t *hw_params;
snd_pcm_hw_params_alloca(&hw_params);
die_on_error("snd_pcm_open()", snd_pcm_open(&this->pcm_handle, device, SND_PCM_STREAM_PLAYBACK, 0));
/* Set format. */
die_on_error("snd_pcm_hw_params_any()", snd_pcm_hw_params_any(this->pcm_handle, hw_params));
die_on_error("snd_pcm_hw_params_set_access()", snd_pcm_hw_params_set_access(this->pcm_handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED));
die_on_error("snd_pcm_hw_params_set_format()", snd_pcm_hw_params_set_format(this->pcm_handle, hw_params, SND_PCM_FORMAT_S16));
die_on_error("snd_pcm_hw_params_set_rate()", snd_pcm_hw_params_set_rate(this->pcm_handle, hw_params, SAMPLE_RATE, 0));
die_on_error("snd_pcm_hw_params_set_channels", snd_pcm_hw_params_set_channels(this->pcm_handle, hw_params, NUM_CHANNELS));
/* Match the OSS driver: Fragment size of 4 kB = 1024 samples.
* Ask for 64 periods (a bit over a second).
*/
unsigned int num_periods = 64;
int dir = 0;
die_on_error("snd_pcm_hw_params_set_periods_near", snd_pcm_hw_params_set_periods_near(this->pcm_handle, hw_params, &num_periods, &dir));
this->period_size = 65536 / num_periods;
dir = 0;
die_on_error("snd_pcm_hw_params_set_period_size_near", snd_pcm_hw_params_set_period_size_near(this->pcm_handle, hw_params, &this->period_size, &dir));
die_on_error("snd_pcm_hw_params", snd_pcm_hw_params(this->pcm_handle, hw_params));
//snd_pcm_hw_params_free(hw_params);
this->bytes_written = (int)(jump * SAMPLE_RATE) * BYTES_PER_FRAME;
this->eof = false;
this->in_outbuf = 0;
}
ALSAAudioDriver::~ALSAAudioDriver()
{
snd_pcm_close(this->pcm_handle);
}
bool ALSAAudioDriver::run()
{
if (this->eof) {
struct timeval now;
gettimeofday(&now, NULL);
float secs =
(float)(now.tv_sec - eof_time.tv_sec) +
(float)(now.tv_usec - eof_time.tv_usec) * 0.000001f;
this->bytes_played += (int)(secs * SAMPLE_RATE * BYTES_PER_FRAME);
memcpy(&this->eof_time, &now, sizeof(struct timeval));
return true;
}
snd_pcm_sframes_t avail = 0, delay = 0;
int err = snd_pcm_avail_delay(this->pcm_handle, &avail, &delay);
if (err < 0) {
/* Don't die on this, as it is nearly always just an underrun. */
fprintf(stderr, "warning: snd_pcm_avail_delay() returned '%s'\n", snd_strerror(err));
} else {
this->bytes_played = this->bytes_written - delay * BYTES_PER_FRAME;
}
while (avail >= int(this->period_size)) {
/* whopee, we can output :-) */
if (in_outbuf < 65536) {
int ret = this->prov->fill_buf(this->outbuf + in_outbuf, 65536 - in_outbuf);
if (ret == 0) {
/* switch to software timer */
this->eof = true;
gettimeofday(&this->eof_time, NULL);
return true;
}
in_outbuf += ret;
}
/* write only whole periods */
int periods_to_write = std::min<int>(avail, in_outbuf / BYTES_PER_FRAME) / this->period_size;
if (periods_to_write > 0) {
int ret = snd_pcm_writei(this->pcm_handle, this->outbuf, periods_to_write * this->period_size);
if (ret < 0) {
/* Don't die on this, as it is nearly always just an underrun. */
fprintf(stderr, "warning: snd_pcm_writei() returned '%s'\n",
snd_strerror(ret));
} else {
in_outbuf -= ret * BYTES_PER_FRAME;
this->bytes_written += ret * BYTES_PER_FRAME;
memmove(outbuf, outbuf + ret * BYTES_PER_FRAME, in_outbuf);
}
}
avail = snd_pcm_avail_update(this->pcm_handle);
}
return false;
}
float ALSAAudioDriver::get_time()
{
return (float)(this->bytes_played) / SAMPLE_RATE / BYTES_PER_FRAME;
}
void ALSAAudioDriver::die_on_error(const char *func_name, int err)
{
if (err < 0) {
throw new FatalException("snd_pcm_open()", snd_strerror(err));
}
}
std::vector<ALSAAudioDriver::ALSASoundCard> ALSAAudioDriver::enumerate_sound_cards()
{
std::vector<ALSASoundCard> ret;
char **hints;
int err = snd_device_name_hint(-1, "pcm", (void ***)&hints);
if (err != 0) {
return ret;
}
for (char **n = hints; *n != NULL; ++n) {
ALSASoundCard sc;
char *name = snd_device_name_get_hint(*n, "NAME");
char *desc = snd_device_name_get_hint(*n, "DESC");
if (name != NULL && strcmp(name, "null") != 0 && strncmp(name, "dsnoop:", 7) != 0) {
char buf[256];
if (desc == NULL) {
snprintf(buf, sizeof(buf), "ALSA: %s", name);
} else {
/*
* Remove everything after the first newline;
* the descriptions tend to be a bit verbose.
*/
char *nl = strchr(desc, '\n');
if (nl != NULL) {
*nl = '\0';
}
snprintf(buf, sizeof(buf), "ALSA: %s (%s)", desc, name);
}
sc.device = name;
sc.description = buf;
ret.push_back(sc);
}
free(name);
free(desc);
}
snd_device_name_free_hint((void **)hints);
return ret;
}
#endif /* DEMOLIB_USE_ALSA */
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