espeakup/alsa.c
2010-05-04 22:55:13 -05:00

122 lines
2.9 KiB
C

/*
* espeakup - interface which allows speakup to use espeak
*
* Copyright (C) 2008 William Hubbs
*
* 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 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* File: alsa.c
* Description: Produce audio by calling the ALSA library directly.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <alsa/asoundlib.h>
#include "espeakup.h"
static pthread_mutex_t audio_mutex = PTHREAD_MUTEX_INITIALIZER;
static snd_pcm_t *handle;
static const unsigned int channels = 1;
static const int soft_resample = 1;
static const unsigned int latency = 25000;
static void lock_audio_mutex(void)
{
pthread_mutex_lock(&audio_mutex);
}
static void unlock_audio_mutex(void)
{
pthread_mutex_unlock(&audio_mutex);
}
static int alsa_callback(short *audio, int numsamples, espeak_EVENT * events)
{
int frames = 0;
int rc = 0;
lock_audio_mutex();
if (stop_requested || !should_run) {
unlock_audio_mutex();
return 1;
}
while (numsamples > 0 && (!stop_requested && should_run)) {
frames = snd_pcm_writei(handle, audio, numsamples);
if (frames < 0)
frames = snd_pcm_recover(handle, frames, !debug);
if (frames < 0) {
fprintf(stderr, "snd_pcm_writei failed: %s\n", snd_strerror(frames));
break;
}
if (frames > 0 && frames < numsamples && debug)
fprintf(stderr, "Short write (expected %i, wrote %i)\n", numsamples, frames);
numsamples -= frames;
audio += frames;
}
rc = (stop_requested || !should_run);
unlock_audio_mutex();
return rc;
}
void select_audio_mode(void)
{
audio_mode = AUDIO_OUTPUT_RETRIEVAL;
}
int init_audio(unsigned int rate)
{
int err;
/* Open PCM device for playback. */
err = snd_pcm_open(&handle, "default", SND_PCM_STREAM_PLAYBACK, 0);
if (err < 0) {
fprintf(stderr, "Playback open error: %s\n", snd_strerror(err));
return err;
}
/* Set parameters. */
err = snd_pcm_set_params(handle,
SND_PCM_FORMAT_S16_LE,
SND_PCM_ACCESS_RW_INTERLEAVED,
channels,
rate,
soft_resample,
latency);
if (err < 0) {
fprintf(stderr, "Playback open error: %s\n", snd_strerror(err));
return err;
}
espeak_SetSynthCallback(alsa_callback);
return 0;
}
void stop_audio(void)
{
lock_audio_mutex();
if (snd_pcm_drop(handle) < 0)
fprintf(stderr, "Negative return from snd_pcm_drop!\n");
snd_pcm_prepare(handle);
unlock_audio_mutex();
}