2 * Copyright (C) 2005-2009 Andre Noll <maan@systemlinux.org>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file alsa_write.c paraslash's alsa output plugin */
10 * Based in parts on aplay.c from the alsa-utils-1.0.8 package,
11 * Copyright (c) by Jaroslav Kysela <perex@suse.cz>, which is
12 * based on the vplay program by Michael Beck.
16 #include <sys/types.h>
18 #include <alsa/asoundlib.h>
27 #include "alsa_write.cmdline.h"
30 /** always use 16 bit little endian */
31 #define FORMAT SND_PCM_FORMAT_S16_LE
33 /** Data specific to the alsa writer. */
34 struct private_alsa_write_data
{
35 /** The alsa handle */
37 /** Determined and set by alsa_open(). */
39 /** Don't write anything until this time. */
40 struct timeval next_chunk
;
41 /** The approximate maximum buffer duration in us. */
44 * The samplerate given by command line option or the decoder
45 * of the writer node group.
49 * The number of channels, given by command line option or the
50 * decoder of the writer node group.
55 /* Install PCM software and hardware configuration. */
56 static int alsa_init(struct private_alsa_write_data
*pad
,
57 struct alsa_write_args_info
*conf
)
59 snd_pcm_hw_params_t
*hwparams
;
60 snd_pcm_sw_params_t
*swparams
;
61 snd_pcm_uframes_t buffer_size
, start_threshold
, stop_threshold
;
62 snd_pcm_uframes_t period_size
;
65 err
= snd_pcm_open(&pad
->handle
, conf
->device_arg
,
66 SND_PCM_STREAM_PLAYBACK
, SND_PCM_NONBLOCK
);
70 snd_pcm_hw_params_alloca(&hwparams
);
71 snd_pcm_sw_params_alloca(&swparams
);
72 if (snd_pcm_hw_params_any(pad
->handle
, hwparams
) < 0)
73 return -E_BROKEN_CONF
;
74 if (snd_pcm_hw_params_set_access(pad
->handle
, hwparams
,
75 SND_PCM_ACCESS_RW_INTERLEAVED
) < 0)
76 return -E_ACCESS_TYPE
;
77 if (snd_pcm_hw_params_set_format(pad
->handle
, hwparams
, FORMAT
) < 0)
78 return -E_SAMPLE_FORMAT
;
79 if (snd_pcm_hw_params_set_channels(pad
->handle
, hwparams
,
81 return -E_CHANNEL_COUNT
;
82 if (snd_pcm_hw_params_set_rate_near(pad
->handle
, hwparams
,
83 &pad
->samplerate
, 0) < 0)
85 err
= snd_pcm_hw_params_get_buffer_time_max(hwparams
, &pad
->buffer_time
, 0);
86 if (err
< 0 || !pad
->buffer_time
)
87 return -E_GET_BUFFER_TIME
;
88 PARA_INFO_LOG("buffer time: %d\n", pad
->buffer_time
);
89 if (snd_pcm_hw_params_set_buffer_time_near(pad
->handle
, hwparams
,
90 &pad
->buffer_time
, 0) < 0)
91 return -E_SET_BUFFER_TIME
;
92 if (snd_pcm_hw_params(pad
->handle
, hwparams
) < 0)
94 snd_pcm_hw_params_get_period_size(hwparams
, &period_size
, 0);
95 snd_pcm_hw_params_get_buffer_size(hwparams
, &buffer_size
);
96 PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", buffer_size
,
98 if (period_size
== buffer_size
)
100 snd_pcm_sw_params_current(pad
->handle
, swparams
);
101 snd_pcm_sw_params_set_avail_min(pad
->handle
, swparams
, period_size
);
105 start_threshold
= PARA_MIN(buffer_size
,
106 (snd_pcm_uframes_t
)pad
->samplerate
);
107 if (snd_pcm_sw_params_set_start_threshold(pad
->handle
, swparams
,
108 start_threshold
) < 0)
109 return -E_START_THRESHOLD
;
110 stop_threshold
= buffer_size
;
111 if (snd_pcm_sw_params_set_stop_threshold(pad
->handle
, swparams
,
113 return -E_STOP_THRESHOLD
;
114 if (snd_pcm_sw_params(pad
->handle
, swparams
) < 0)
115 PARA_WARNING_LOG("unable to install sw params\n");
116 pad
->bytes_per_frame
= snd_pcm_format_physical_width(FORMAT
)
118 if (pad
->bytes_per_frame
<= 0)
119 return -E_PHYSICAL_WIDTH
;
120 PARA_INFO_LOG("bytes per frame: %d\n", pad
->bytes_per_frame
);
121 if (snd_pcm_nonblock(pad
->handle
, 1))
122 PARA_ERROR_LOG("failed to set nonblock mode\n");
126 /* Open an instance of the alsa writer. */
127 static int alsa_open(struct writer_node
*wn
)
129 struct alsa_write_args_info
*conf
= wn
->conf
;
130 struct writer_node_group
*wng
= wn
->wng
;
131 struct private_alsa_write_data
*pad
= para_calloc(sizeof(*pad
));
133 wn
->private_data
= pad
;
134 if (!conf
->samplerate_given
&& wng
->samplerate
)
135 pad
->samplerate
= *wng
->samplerate
;
137 pad
->samplerate
= conf
->samplerate_arg
;
138 if (!conf
->channels_given
&& wng
->channels
)
139 pad
->channels
= *wng
->channels
;
141 pad
->channels
= conf
->channels_arg
;
142 PARA_INFO_LOG("%d channel(s), %dHz\n", pad
->channels
, pad
->samplerate
);
143 tv_add(now
, &(struct timeval
){0, 100 * 1000}, &pad
->next_chunk
);
147 static int alsa_write_pre_select(struct sched
*s
, struct writer_node
*wn
)
149 struct private_alsa_write_data
*pad
= wn
->private_data
;
150 struct writer_node_group
*wng
= wn
->wng
;
155 if (tv_diff(now
, &pad
->next_chunk
, &diff
) < 0) {
156 if (tv_diff(&s
->timeout
, &diff
, NULL
) > 0)
159 s
->timeout
.tv_sec
= 0;
160 s
->timeout
.tv_usec
= 1;
165 static int alsa_write_post_select(__a_unused
struct sched
*s
,
166 struct writer_node
*wn
)
168 struct private_alsa_write_data
*pad
= wn
->private_data
;
169 struct writer_node_group
*wng
= wn
->wng
;
170 size_t bytes
= *wng
->loaded
- wn
->written
;
171 unsigned char *data
= (unsigned char*)*wng
->bufp
+ wn
->written
;
173 snd_pcm_sframes_t ret
, frames
, avail
;
175 if (*wng
->input_error
< 0 && (!pad
->handle
|| bytes
< pad
->bytes_per_frame
)) {
176 wn
->written
= *wng
->loaded
;
177 return *wng
->input_error
;
179 if (!bytes
) /* no data available */
181 if (tv_diff(now
, &pad
->next_chunk
, NULL
) < 0)
184 int err
= alsa_init(pad
, wn
->conf
);
188 frames
= bytes
/ pad
->bytes_per_frame
;
189 if (!frames
) /* less than a single frame available */
191 avail
= snd_pcm_avail_update(pad
->handle
);
194 frames
= PARA_MIN(frames
, avail
);
195 ret
= snd_pcm_writei(pad
->handle
, data
, frames
);
197 PARA_WARNING_LOG("%s\n", snd_strerror(-ret
));
199 snd_pcm_prepare(pad
->handle
);
204 return -E_ALSA_WRITE
;
206 wn
->written
+= ret
* pad
->bytes_per_frame
;
209 /* wait until 50% buffer space is available */
210 ms2tv(pad
->buffer_time
/ 2000, &tv
);
211 tv_add(now
, &tv
, &pad
->next_chunk
);
215 static void alsa_close(struct writer_node
*wn
)
217 struct private_alsa_write_data
*pad
= wn
->private_data
;
218 PARA_INFO_LOG("closing writer node %p\n", wn
);
221 snd_pcm_drain(pad
->handle
);
222 snd_pcm_close(pad
->handle
);
223 snd_config_update_free_global();
228 __malloc
static void *alsa_parse_config(const char *options
)
231 struct alsa_write_args_info
*conf
232 = para_calloc(sizeof(struct alsa_write_args_info
));
234 PARA_INFO_LOG("options: %s, %zd\n", options
, strcspn(options
, " \t"));
235 ret
= alsa_cmdline_parser_string(options
, conf
, "alsa_write");
238 PARA_INFO_LOG("help given: %d\n", conf
->help_given
);
246 * the init function of the alsa writer
248 * \param w pointer to the writer to initialize
252 void alsa_write_init(struct writer
*w
)
254 struct alsa_write_args_info dummy
;
256 alsa_cmdline_parser_init(&dummy
);
258 w
->close
= alsa_close
;
259 w
->pre_select
= alsa_write_pre_select
;
260 w
->post_select
= alsa_write_post_select
;
261 w
->parse_config
= alsa_parse_config
;
262 w
->shutdown
= NULL
; /* nothing to do */
263 w
->help
= (struct ggo_help
) {
264 .short_help
= alsa_write_args_info_help
,
265 .detailed_help
= alsa_write_args_info_detailed_help