mpd/src/output/ao_plugin.c

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/* the Music Player Daemon (MPD)
* Copyright (C) 2003-2007 by Warren Dukes (warren.dukes@gmail.com)
* This project's homepage is: http://www.musicpd.org
*
* 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.
*
* 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, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "../output_api.h"
#include <ao/ao.h>
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#include <glib.h>
#undef G_LOG_DOMAIN
#define G_LOG_DOMAIN "ao"
static int driverInitCount;
typedef struct _AoData {
size_t writeSize;
int driverId;
ao_option *options;
ao_device *device;
} AoData;
static AoData *newAoData(void)
{
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AoData *ret = g_malloc(sizeof(AoData));
ret->device = NULL;
ret->options = NULL;
return ret;
}
static void audioOutputAo_error(const char *msg)
{
const char *error;
switch (errno) {
case AO_ENODRIVER:
error = "No such libao driver";
break;
case AO_ENOTLIVE:
error = "This driver is not a libao live device";
break;
case AO_EBADOPTION:
error = "Invalid libao option";
break;
case AO_EOPENDEVICE:
error = "Cannot open the libao device";
break;
case AO_EFAIL:
error = "Generic libao failure";
break;
default:
error = strerror(errno);
}
g_warning("%s: %s\n", msg, error);
}
static void *
audioOutputAo_initDriver(struct audio_output *ao,
G_GNUC_UNUSED const struct audio_format *audio_format,
const struct config_param *param)
{
ao_info *ai;
AoData *ad = newAoData();
const char *value;
ad->writeSize = config_get_block_unsigned(param, "write_size", 1024);
if (driverInitCount == 0) {
ao_initialize();
}
driverInitCount++;
value = config_get_block_string(param, "driver", "default");
if (0 == strcmp(value, "default")) {
ad->driverId = ao_default_driver_id();
} else if ((ad->driverId = ao_driver_id(value)) < 0)
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g_error("\"%s\" is not a valid ao driver at line %i\n",
value, param->line);
if ((ai = ao_driver_info(ad->driverId)) == NULL) {
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g_error("problems getting driver info for device defined at line %i\n"
"you may not have permission to the audio device\n", param->line);
}
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g_debug("using ao driver \"%s\" for \"%s\"\n", ai->short_name,
audio_output_get_name(ao));
value = config_get_block_string(param, "options", NULL);
if (value != NULL) {
gchar **options = g_strsplit(value, ";", 0);
for (unsigned i = 0; options[i] != NULL; ++i) {
gchar **key_value = g_strsplit(options[i], "=", 2);
if (key_value[0] == NULL || key_value[1] == NULL)
g_error("problems parsing options \"%s\"\n",
options[i]);
ao_append_option(&ad->options, key_value[0],
key_value[1]);
g_strfreev(key_value);
}
g_strfreev(options);
}
return ad;
}
static void freeAoData(AoData * ad)
{
ao_free_options(ad->options);
g_free(ad);
}
static void audioOutputAo_finishDriver(void *data)
{
AoData *ad = (AoData *)data;
freeAoData(ad);
driverInitCount--;
if (driverInitCount == 0)
ao_shutdown();
}
static void audioOutputAo_dropBufferedAudio(G_GNUC_UNUSED void *data)
{
/* not supported by libao */
}
static void audioOutputAo_closeDevice(void *data)
{
AoData *ad = (AoData *)data;
if (ad->device) {
ao_close(ad->device);
ad->device = NULL;
}
}
static bool
audioOutputAo_openDevice(void *data, struct audio_format *audio_format)
{
ao_sample_format format;
AoData *ad = (AoData *)data;
if (ad->device) {
audioOutputAo_closeDevice(ad);
}
/* support for 24 bit samples in libao is currently dubious,
and until we have sorted that out, resample everything to
16 bit */
if (audio_format->bits > 16)
audio_format->bits = 16;
format.bits = audio_format->bits;
format.rate = audio_format->sample_rate;
format.byte_format = AO_FMT_NATIVE;
format.channels = audio_format->channels;
ad->device = ao_open_live(ad->driverId, &format, ad->options);
if (ad->device == NULL) {
audioOutputAo_error("Failed to open libao");
return false;
}
return true;
}
/**
* For whatever reason, libao wants a non-const pointer. Let's hope
* it does not write to the buffer, and use the union deconst hack to
* work around this API misdesign.
*/
static int ao_play_deconst(ao_device *device, const void *output_samples,
uint_32 num_bytes)
{
union {
const void *in;
void *out;
} u;
u.in = output_samples;
return ao_play(device, u.out, num_bytes);
}
static size_t
audioOutputAo_play(void *data, const void *chunk, size_t size)
{
AoData *ad = (AoData *)data;
if (ad->device == NULL)
return false;
if (size > ad->writeSize)
size = ad->writeSize;
if (ao_play_deconst(ad->device, chunk, size) == 0) {
audioOutputAo_error("Closing libao device due to play error");
return 0;
}
return size;
}
const struct audio_output_plugin aoPlugin = {
.name = "ao",
.init = audioOutputAo_initDriver,
.finish = audioOutputAo_finishDriver,
.open = audioOutputAo_openDevice,
.play = audioOutputAo_play,
.cancel = audioOutputAo_dropBufferedAudio,
.close = audioOutputAo_closeDevice,
};