1 /* Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
3 /** \file alsa_write.c paraslash's alsa output plugin */
6 * Based in parts on aplay.c from the alsa-utils-1.0.8 package,
7 * Copyright (c) by Jaroslav Kysela <perex@suse.cz>, which is
8 * based on the vplay program by Michael Beck.
12 #include <sys/types.h>
13 #include <alsa/asoundlib.h>
16 #include "write_cmd.lsg.h"
22 #include "buffer_tree.h"
26 /** Data specific to the alsa writer. */
27 struct private_alsa_write_data
{
28 /** The alsa handle */
30 /** Determined and set by alsa_init(). */
33 * If the sample rate is not given at the command line and no wav
34 * header was detected, the btr exec mechanism is employed to query the
35 * ancestor buffer tree nodes for this information. In a typical setup
36 * the decoder passes the sample rate back to the alsa writer.
38 * \sa \ref btr_exec_up().
42 * The sample format (8/16 bit, signed/unsigned, little/big endian) is
43 * determined in the same way as the \a sample_rate.
45 snd_pcm_format_t sample_format
;
46 /* The number of channels, again determined like \a sample_rate. */
48 /* time until buffer underrun occurs, in milliseconds */
50 struct timeval drain_barrier
;
51 /* File descriptor for select(). */
55 static snd_pcm_format_t
get_alsa_pcm_format(enum sample_format sf
)
58 case SF_S8
: return SND_PCM_FORMAT_S8
;
59 case SF_U8
: return SND_PCM_FORMAT_U8
;
60 case SF_S16_LE
: return SND_PCM_FORMAT_S16_LE
;
61 case SF_S16_BE
: return SND_PCM_FORMAT_S16_BE
;
62 case SF_U16_LE
: return SND_PCM_FORMAT_U16_LE
;
63 case SF_U16_BE
: return SND_PCM_FORMAT_U16_BE
;
64 default: return SND_PCM_FORMAT_S16_LE
;
68 /* Install PCM software and hardware configuration. */
69 static int alsa_init(struct writer_node
*wn
)
71 struct private_alsa_write_data
*pad
= wn
->private_data
;
72 snd_pcm_hw_params_t
*hwparams
= NULL
;
73 snd_pcm_sw_params_t
*swparams
= NULL
;
74 snd_pcm_uframes_t start_threshold
, stop_threshold
;
75 snd_pcm_uframes_t buffer_size
, period_size
;
76 snd_output_t
*output_log
;
78 const char *msg
, *dev
= WRITE_CMD_OPT_STRING_VAL(ALSA
, DEVICE
, wn
->lpr
);
81 PARA_INFO_LOG("opening %s\n", dev
);
82 msg
= "unable to open pcm";
83 ret
= snd_pcm_open(&pad
->handle
, dev
, SND_PCM_STREAM_PLAYBACK
,
87 ret
= snd_pcm_hw_params_malloc(&hwparams
);
89 msg
= "Broken alsa configuration";
90 ret
= snd_pcm_hw_params_any(pad
->handle
, hwparams
);
93 msg
= "access type not available";
94 ret
= snd_pcm_hw_params_set_access(pad
->handle
, hwparams
,
95 SND_PCM_ACCESS_RW_INTERLEAVED
);
98 msg
= "sample format not available";
99 ret
= snd_pcm_hw_params_set_format(pad
->handle
, hwparams
,
103 msg
= "channels count not available";
104 ret
= snd_pcm_hw_params_set_channels(pad
->handle
, hwparams
,
108 msg
= "could not set sample rate";
109 ret
= snd_pcm_hw_params_set_rate_near(pad
->handle
, hwparams
,
110 &pad
->sample_rate
, NULL
);
113 /* alsa wants microseconds */
114 pad
->buffer_time
= 1000U * WRITE_CMD_OPT_UINT32_VAL(ALSA
, BUFFER_TIME
,
116 msg
= "could not set buffer time";
117 ret
= snd_pcm_hw_params_set_buffer_time_near(pad
->handle
, hwparams
,
118 &pad
->buffer_time
, NULL
);
121 pad
->buffer_time
/= 1000; /* we prefer milliseconds */
122 period_time
= pad
->buffer_time
* 250; /* buffer time / 4 */
123 msg
= "could not set period time";
124 ret
= snd_pcm_hw_params_set_period_time_near(pad
->handle
, hwparams
,
129 msg
= "unable to install hw params";
130 ret
= snd_pcm_hw_params(pad
->handle
, hwparams
);
133 snd_pcm_hw_params_get_period_size(hwparams
, &period_size
, NULL
);
134 snd_pcm_hw_params_get_buffer_size(hwparams
, &buffer_size
);
135 msg
= "period size equals buffer size";
136 if (period_size
== buffer_size
)
139 /* software parameter setup */
140 ret
= snd_pcm_sw_params_malloc(&swparams
);
142 snd_pcm_sw_params_current(pad
->handle
, swparams
);
143 snd_pcm_sw_params_set_avail_min(pad
->handle
, swparams
, period_size
);
147 start_threshold
= PARA_MIN(buffer_size
,
148 (snd_pcm_uframes_t
)pad
->sample_rate
);
149 msg
= "could not set start threshold";
150 ret
= snd_pcm_sw_params_set_start_threshold(pad
->handle
, swparams
,
154 stop_threshold
= buffer_size
;
155 msg
= "could not set stop threshold";
156 ret
= snd_pcm_sw_params_set_stop_threshold(pad
->handle
, swparams
,
160 msg
= "unable to install sw params";
161 ret
= snd_pcm_sw_params(pad
->handle
, swparams
);
164 msg
= "unable to determine bytes per frame";
165 ret
= snd_pcm_format_physical_width(pad
->sample_format
);
168 pad
->bytes_per_frame
= ret
* pad
->channels
/ 8;
169 msg
= "failed to set alsa handle to nonblock mode";
170 ret
= snd_pcm_nonblock(pad
->handle
, 1);
173 ret
= snd_output_buffer_open(&output_log
);
177 PARA_DEBUG_LOG("dumping alsa configuration\n");
178 snd_pcm_dump(pad
->handle
, output_log
);
179 snd_pcm_hw_params_dump(hwparams
, output_log
);
180 sz
= snd_output_buffer_string(output_log
, &buf
);
181 for (p
= buf
; p
< buf
+ sz
;) {
182 char *q
= memchr(p
, '\n', buf
+ sz
- p
);
186 PARA_DEBUG_LOG("%s\n", p
);
189 snd_output_close(output_log
);
195 PARA_ERROR_LOG("%s: %s\n", msg
, snd_strerror(-ret
));
197 PARA_ERROR_LOG("%s\n", msg
);
200 snd_pcm_hw_params_free(hwparams
);
201 snd_pcm_sw_params_free(swparams
);
205 static void alsa_write_pre_select(struct sched
*s
, void *context
)
208 struct writer_node
*wn
= context
;
209 struct private_alsa_write_data
*pad
= wn
->private_data
;
210 int ret
= btr_node_status(wn
->btrn
, wn
->min_iqs
, BTR_NT_LEAF
);
221 sched_request_barrier_or_min_delay(&pad
->drain_barrier
, s
);
224 /* wait at most 50% of the buffer time */
225 sched_request_timeout_ms(pad
->buffer_time
/ 2, s
);
226 ret
= snd_pcm_poll_descriptors(pad
->handle
, &pfd
, 1);
228 PARA_ERROR_LOG("could not get alsa poll fd: %s\n",
232 pad
->poll_fd
= pfd
.fd
;
233 para_fd_set(pfd
.fd
, &s
->rfds
, &s
->max_fileno
);
236 static void alsa_close(struct writer_node
*wn
)
238 struct private_alsa_write_data
*pad
= wn
->private_data
;
239 PARA_INFO_LOG("closing writer node %p\n", wn
);
244 * It's OK to have a blocking operation here because we already made
245 * sure that the PCM output buffer is (nearly) empty.
247 snd_pcm_nonblock(pad
->handle
, 0);
248 snd_pcm_drain(pad
->handle
);
249 snd_pcm_close(pad
->handle
);
250 snd_config_update_free_global();
254 static int alsa_write_post_select(__a_unused
struct sched
*s
, void *context
)
256 struct writer_node
*wn
= context
;
257 struct private_alsa_write_data
*pad
= wn
->private_data
;
258 struct btr_node
*btrn
= wn
->btrn
;
261 snd_pcm_sframes_t frames
;
264 ret
= task_get_notification(wn
->task
);
268 ret
= btr_node_status(btrn
, wn
->min_iqs
, BTR_NT_LEAF
);
271 btr_merge(btrn
, wn
->min_iqs
);
272 bytes
= btr_next_buffer(btrn
, &data
);
273 if (ret
< 0 || bytes
< wn
->min_iqs
) { /* eof */
274 assert(btr_no_parent(btrn
));
275 ret
= -E_WRITE_COMMON_EOF
;
278 /* wait until pending frames are played */
279 if (pad
->drain_barrier
.tv_sec
== 0) {
280 PARA_DEBUG_LOG("waiting for device to drain\n");
281 tv_add(now
, &(struct timeval
)EMBRACE(0, 200 * 1000),
282 &pad
->drain_barrier
);
285 if (tv_diff(now
, &pad
->drain_barrier
, NULL
) > 0)
292 if (bytes
== 0) /* no data available */
294 pad
= wn
->private_data
= para_calloc(sizeof(*pad
));
295 get_btr_sample_rate(btrn
, &val
);
296 pad
->sample_rate
= val
;
297 get_btr_channels(btrn
, &val
);
299 get_btr_sample_format(btrn
, &val
);
300 pad
->sample_format
= get_alsa_pcm_format(val
);
302 PARA_INFO_LOG("%u channel(s), %uHz\n", pad
->channels
,
306 free(wn
->private_data
);
307 wn
->private_data
= NULL
;
310 wn
->min_iqs
= pad
->bytes_per_frame
;
313 frames
= bytes
/ pad
->bytes_per_frame
;
314 frames
= snd_pcm_writei(pad
->handle
, data
, frames
);
315 if (frames
== 0 || frames
== -EAGAIN
) {
317 if (pad
->poll_fd
>= 0 && FD_ISSET(pad
->poll_fd
, &s
->rfds
))
318 if (read(pad
->poll_fd
, buf
, 100))
323 btr_consume(btrn
, frames
* pad
->bytes_per_frame
);
326 if (frames
== -EPIPE
) {
327 PARA_WARNING_LOG("underrun (tried to write %zu bytes)\n", bytes
);
328 snd_pcm_prepare(pad
->handle
);
331 PARA_ERROR_LOG("alsa write error: %s\n", snd_strerror(-frames
));
335 btr_remove_node(&wn
->btrn
);
339 struct writer lsg_write_cmd_com_alsa_user_data
= {
341 .pre_select
= alsa_write_pre_select
,
342 .post_select
= alsa_write_post_select
,