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>
28 #include "buffer_tree.h"
30 #include "alsa_write.cmdline.h"
33 /** always use 16 bit little endian */
34 #define FORMAT SND_PCM_FORMAT_S16_LE
36 /** Data specific to the alsa writer. */
37 struct private_alsa_write_data
{
38 /** The alsa handle */
40 /** Determined and set by alsa_open(). */
42 /** The approximate maximum buffer duration in us. */
44 /* Number of frames that fit into the buffer. */
45 unsigned buffer_frames
;
47 * The samplerate given by command line option or the decoder
48 * of the writer node group.
52 * The number of channels, given by command line option or the
53 * decoder of the writer node group.
58 /* Install PCM software and hardware configuration. */
59 static int alsa_init(struct private_alsa_write_data
*pad
,
60 struct alsa_write_args_info
*conf
)
62 snd_pcm_hw_params_t
*hwparams
;
63 snd_pcm_sw_params_t
*swparams
;
64 snd_pcm_uframes_t buffer_size
, start_threshold
, stop_threshold
;
65 snd_pcm_uframes_t period_size
;
68 err
= snd_pcm_open(&pad
->handle
, conf
->device_arg
,
69 SND_PCM_STREAM_PLAYBACK
, SND_PCM_NONBLOCK
);
73 snd_pcm_hw_params_alloca(&hwparams
);
74 snd_pcm_sw_params_alloca(&swparams
);
75 if (snd_pcm_hw_params_any(pad
->handle
, hwparams
) < 0)
76 return -E_BROKEN_CONF
;
77 if (snd_pcm_hw_params_set_access(pad
->handle
, hwparams
,
78 SND_PCM_ACCESS_RW_INTERLEAVED
) < 0)
79 return -E_ACCESS_TYPE
;
80 if (snd_pcm_hw_params_set_format(pad
->handle
, hwparams
, FORMAT
) < 0)
81 return -E_SAMPLE_FORMAT
;
82 if (snd_pcm_hw_params_set_channels(pad
->handle
, hwparams
,
84 return -E_CHANNEL_COUNT
;
85 if (snd_pcm_hw_params_set_rate_near(pad
->handle
, hwparams
,
86 &pad
->samplerate
, NULL
) < 0)
88 err
= snd_pcm_hw_params_get_buffer_time_max(hwparams
,
89 &pad
->buffer_time
, NULL
);
90 if (err
< 0 || !pad
->buffer_time
)
91 return -E_GET_BUFFER_TIME
;
92 PARA_INFO_LOG("buffer time: %d\n", pad
->buffer_time
);
93 if (snd_pcm_hw_params_set_buffer_time_near(pad
->handle
, hwparams
,
94 &pad
->buffer_time
, NULL
) < 0)
95 return -E_SET_BUFFER_TIME
;
96 if (snd_pcm_hw_params(pad
->handle
, hwparams
) < 0)
98 snd_pcm_hw_params_get_period_size(hwparams
, &period_size
, NULL
);
99 snd_pcm_hw_params_get_buffer_size(hwparams
, &buffer_size
);
100 PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", buffer_size
,
102 if (period_size
== buffer_size
)
103 return -E_BAD_PERIOD
;
104 snd_pcm_sw_params_current(pad
->handle
, swparams
);
105 snd_pcm_sw_params_set_avail_min(pad
->handle
, swparams
, period_size
);
109 start_threshold
= PARA_MIN(buffer_size
,
110 (snd_pcm_uframes_t
)pad
->samplerate
);
111 if (snd_pcm_sw_params_set_start_threshold(pad
->handle
, swparams
,
112 start_threshold
) < 0)
113 return -E_START_THRESHOLD
;
114 stop_threshold
= buffer_size
;
115 if (snd_pcm_sw_params_set_stop_threshold(pad
->handle
, swparams
,
117 return -E_STOP_THRESHOLD
;
118 if (snd_pcm_sw_params(pad
->handle
, swparams
) < 0)
119 PARA_WARNING_LOG("unable to install sw params\n");
120 pad
->bytes_per_frame
= snd_pcm_format_physical_width(FORMAT
)
122 if (pad
->bytes_per_frame
<= 0)
123 return -E_PHYSICAL_WIDTH
;
124 PARA_INFO_LOG("bytes per frame: %d\n", pad
->bytes_per_frame
);
125 if (snd_pcm_nonblock(pad
->handle
, 1))
126 PARA_ERROR_LOG("failed to set nonblock mode\n");
127 pad
->buffer_frames
= 1000 * pad
->buffer_time
/ pad
->samplerate
;
128 PARA_INFO_LOG("max buffered frames: %d\n", pad
->buffer_frames
);
132 /* Open an instance of the alsa writer. */
133 static int alsa_open_nobtr(struct writer_node
*wn
)
135 struct alsa_write_args_info
*conf
= wn
->conf
;
136 struct writer_node_group
*wng
= wn
->wng
;
137 struct private_alsa_write_data
*pad
= para_calloc(sizeof(*pad
));
139 wn
->private_data
= pad
;
140 if (!conf
->samplerate_given
&& wng
->samplerate
)
141 pad
->samplerate
= *wng
->samplerate
;
143 pad
->samplerate
= conf
->samplerate_arg
;
144 if (!conf
->channels_given
&& wng
->channels
)
145 pad
->channels
= *wng
->channels
;
147 pad
->channels
= conf
->channels_arg
;
148 PARA_INFO_LOG("%d channel(s), %dHz\n", pad
->channels
, pad
->samplerate
);
152 static int alsa_open_btr(struct writer_node
*wn
)
154 struct alsa_write_args_info
*conf
= wn
->conf
;
155 struct private_alsa_write_data
*pad
= para_calloc(sizeof(*pad
));
159 sprintf(wn
->task
.status
, "alsa writer");
160 wn
->private_data
= pad
;
163 pad
->samplerate
= conf
->samplerate_arg
;
164 pad
->channels
= conf
->channels_arg
;
166 if (!conf
->samplerate_given
) { /* config option trumps btr_exec */
167 /* ask parent btr nodes */
168 ret
= btr_exec_up(wn
->btrn
, "samplerate", &buf
);
171 ret
= para_atoi32(buf
, &rate
);
172 if (ret
< 0) /* should not happen */
174 pad
->samplerate
= rate
;
179 if (!conf
->channels_given
) {
180 ret
= btr_exec_up(wn
->btrn
, "channels", &buf
);
183 ret
= para_atoi32(buf
, &ch
);
190 PARA_INFO_LOG("%d channel(s), %dHz\n", pad
->channels
, pad
->samplerate
);
198 static int alsa_open(struct writer_node
*wn
)
200 struct alsa_write_args_info
*conf
= wn
->conf
;
202 if (conf
->buffer_tree_given
)
203 return alsa_open_btr(wn
);
205 return alsa_open_nobtr(wn
);
209 static int alsa_write_pre_select(struct sched
*s
, struct writer_node
*wn
)
211 struct alsa_write_args_info
*conf
= wn
->conf
;
212 struct private_alsa_write_data
*pad
= wn
->private_data
;
213 struct writer_node_group
*wng
= wn
->wng
;
215 snd_pcm_sframes_t avail
, underrun
;
219 if (conf
->buffer_tree_given
) {
220 size_t sz
= btr_get_input_queue_size(wn
->btrn
);
221 if (sz
< pad
->bytes_per_frame
)
224 if (*wng
->loaded
- wn
->written
< pad
->bytes_per_frame
)
228 * Data is available to be written to the alsa handle. Compute number
229 * of milliseconds until next buffer underrun would occur.
231 * snd_pcm_avail_update() updates the current available count of
232 * samples for writing. It is a light method to obtain current stream
233 * position, because it does not require the user <-> kernel context
234 * switch, but the value is less accurate, because ring buffer pointers
235 * are updated in kernel drivers only when an interrupt occurs.
237 avail
= snd_pcm_avail_update(pad
->handle
);
240 underrun
= (pad
->buffer_frames
- avail
) * pad
->buffer_time
241 / pad
->buffer_frames
/ 1000;
245 ms2tv(underrun
, &tv
);
246 if (tv_diff(&s
->timeout
, &tv
, NULL
) > 0)
248 //PARA_CRIT_LOG("timout: %lu\n", tv2ms(&s->timeout));
252 static void alsa_write_pre_select_btr(struct sched
*s
, struct task
*t
)
254 struct writer_node
*wn
= container_of(t
, struct writer_node
, task
);
255 t
->error
= alsa_write_pre_select(s
, wn
);
258 static void xrun(snd_pcm_t
*handle
)
260 snd_pcm_status_t
*status
;
262 struct timeval tv
, diff
;
264 snd_pcm_status_alloca(&status
);
265 ret
= snd_pcm_status(handle
, status
);
268 if (snd_pcm_status_get_state(status
) != SND_PCM_STATE_XRUN
)
270 snd_pcm_status_get_trigger_tstamp(status
, &tv
);
271 tv_diff(now
, &tv
, &diff
);
272 PARA_WARNING_LOG("underrun: %lums\n", tv2ms(&diff
));
275 static int alsa_write_post_select(__a_unused
struct sched
*s
,
276 struct writer_node
*wn
)
278 struct private_alsa_write_data
*pad
= wn
->private_data
;
279 struct writer_node_group
*wng
= wn
->wng
;
280 size_t bytes
= *wng
->loaded
- wn
->written
;
281 unsigned char *data
= (unsigned char*)*wng
->bufp
+ wn
->written
;
282 snd_pcm_sframes_t ret
, frames
, avail
;
284 if (*wng
->input_error
< 0 && (!pad
->handle
|| bytes
< pad
->bytes_per_frame
)) {
285 wn
->written
= *wng
->loaded
;
286 return *wng
->input_error
;
288 if (!bytes
) /* no data available */
291 int err
= alsa_init(pad
, wn
->conf
);
295 frames
= bytes
/ pad
->bytes_per_frame
;
296 if (!frames
) /* less than a single frame available */
298 avail
= snd_pcm_avail_update(pad
->handle
);
301 frames
= PARA_MIN(frames
, avail
);
302 ret
= snd_pcm_writei(pad
->handle
, data
, frames
);
304 wn
->written
+= ret
* pad
->bytes_per_frame
;
309 snd_pcm_prepare(pad
->handle
);
312 PARA_WARNING_LOG("%s\n", snd_strerror(-ret
));
315 return -E_ALSA_WRITE
;
318 static void alsa_close(struct writer_node
*wn
)
320 struct private_alsa_write_data
*pad
= wn
->private_data
;
321 PARA_INFO_LOG("closing writer node %p\n", wn
);
324 snd_pcm_drain(pad
->handle
);
325 snd_pcm_close(pad
->handle
);
326 snd_config_update_free_global();
331 static void alsa_write_post_select_btr(__a_unused
struct sched
*s
,
334 struct writer_node
*wn
= container_of(t
, struct writer_node
, task
);
335 struct private_alsa_write_data
*pad
= wn
->private_data
;
338 snd_pcm_sframes_t frames
, avail
;
342 bytes
= btr_next_buffer(wn
->btrn
, &data
);
343 //PARA_CRIT_LOG("have: %zu\n", bytes);
345 ret
= -E_ALSA_ORPHAN
;
346 if (btr_no_parent(wn
->btrn
) && (!pad
->handle
|| bytes
< pad
->bytes_per_frame
))
349 if (bytes
== 0) /* no data available */
351 PARA_CRIT_LOG("alsa init\n");
352 ret
= alsa_init(pad
, wn
->conf
);
359 if (bytes
>= pad
->bytes_per_frame
)
361 /* should not be possible to reach this */
362 PARA_CRIT_LOG("dropping %zu byte buffer\n", bytes
);
363 btr_consume(wn
->btrn
, bytes
);
364 bytes
= btr_next_buffer(wn
->btrn
, &data
);
366 frames
= bytes
/ pad
->bytes_per_frame
;
367 avail
= snd_pcm_avail_update(pad
->handle
);
370 frames
= PARA_MIN(frames
, avail
);
371 //PARA_CRIT_LOG("writing %ld frames\n", frames);
372 frames
= snd_pcm_writei(pad
->handle
, data
, frames
);
374 btr_consume(wn
->btrn
, frames
* pad
->bytes_per_frame
);
377 if (frames
== -EPIPE
) {
379 snd_pcm_prepare(pad
->handle
);
382 PARA_WARNING_LOG("%s\n", snd_strerror(-frames
));
383 if (frames
== -EAGAIN
)
389 btr_del_node(wn
->btrn
);
394 __malloc
static void *alsa_parse_config(const char *options
)
397 struct alsa_write_args_info
*conf
398 = para_calloc(sizeof(struct alsa_write_args_info
));
400 PARA_INFO_LOG("options: %s, %zd\n", options
, strcspn(options
, " \t"));
401 ret
= alsa_cmdline_parser_string(options
, conf
, "alsa_write");
404 PARA_INFO_LOG("help given: %d\n", conf
->help_given
);
412 * the init function of the alsa writer
414 * \param w pointer to the writer to initialize
418 void alsa_write_init(struct writer
*w
)
420 struct alsa_write_args_info dummy
;
422 alsa_cmdline_parser_init(&dummy
);
424 w
->close
= alsa_close
;
425 w
->pre_select
= alsa_write_pre_select
;
426 w
->pre_select_btr
= alsa_write_pre_select_btr
;
427 w
->post_select
= alsa_write_post_select
;
428 w
->post_select_btr
= alsa_write_post_select_btr
;
429 w
->parse_config
= alsa_parse_config
;
430 w
->shutdown
= NULL
; /* nothing to do */
431 w
->help
= (struct ggo_help
) {
432 .short_help
= alsa_write_args_info_help
,
433 .detailed_help
= alsa_write_args_info_detailed_help
435 alsa_cmdline_parser_free(&dummy
);