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.
15 #include <sys/types.h>
17 #include <alsa/asoundlib.h>
26 #include "alsa_write.cmdline.h"
29 /** always use 16 bit little endian */
30 #define FORMAT SND_PCM_FORMAT_S16_LE
32 /** data specific to the alsa writer */
33 struct private_alsa_write_data
{
34 /** the alsa handle */
36 /** determined and set by alsa_open() */
37 size_t bytes_per_frame
;
38 /** don't write anything until this time */
39 struct timeval next_chunk
;
40 /** the return value of snd_pcm_hw_params_get_buffer_time_max() */
43 * the samplerate given by command line option or the decoder
44 * of the writer node group
48 * the number of channels, also given by command line option or the
49 * decoder of the writer node group
54 /* Install PCM software and hardware configuration. */
55 static int alsa_init(struct private_alsa_write_data
*pad
,
56 struct alsa_write_args_info
*conf
)
58 snd_pcm_hw_params_t
*hwparams
;
59 snd_pcm_sw_params_t
*swparams
;
60 snd_pcm_uframes_t buffer_size
, start_threshold
, stop_threshold
;
61 snd_pcm_uframes_t period_size
;
64 err
= snd_pcm_open(&pad
->handle
, conf
->device_arg
,
65 SND_PCM_STREAM_PLAYBACK
, SND_PCM_NONBLOCK
);
69 snd_pcm_hw_params_alloca(&hwparams
);
70 snd_pcm_sw_params_alloca(&swparams
);
71 if (snd_pcm_hw_params_any(pad
->handle
, hwparams
) < 0)
72 return -E_BROKEN_CONF
;
73 if (snd_pcm_hw_params_set_access(pad
->handle
, hwparams
,
74 SND_PCM_ACCESS_RW_INTERLEAVED
) < 0)
75 return -E_ACCESS_TYPE
;
76 if (snd_pcm_hw_params_set_format(pad
->handle
, hwparams
, FORMAT
) < 0)
77 return -E_SAMPLE_FORMAT
;
78 if (snd_pcm_hw_params_set_channels(pad
->handle
, hwparams
,
80 return -E_CHANNEL_COUNT
;
81 if (snd_pcm_hw_params_set_rate_near(pad
->handle
, hwparams
,
82 &pad
->samplerate
, 0) < 0)
84 err
= snd_pcm_hw_params_get_buffer_time_max(hwparams
, &pad
->buffer_time
, 0);
85 if (err
< 0 || !pad
->buffer_time
)
86 return -E_GET_BUFFER_TIME
;
87 PARA_INFO_LOG("buffer time: %d\n", pad
->buffer_time
);
88 if (snd_pcm_hw_params_set_buffer_time_near(pad
->handle
, hwparams
,
89 &pad
->buffer_time
, 0) < 0)
90 return -E_SET_BUFFER_TIME
;
91 if (snd_pcm_hw_params(pad
->handle
, hwparams
) < 0)
93 snd_pcm_hw_params_get_period_size(hwparams
, &period_size
, 0);
94 snd_pcm_hw_params_get_buffer_size(hwparams
, &buffer_size
);
95 PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", buffer_size
,
97 if (period_size
== buffer_size
)
99 snd_pcm_sw_params_current(pad
->handle
, swparams
);
100 snd_pcm_sw_params_set_avail_min(pad
->handle
, swparams
, period_size
);
104 start_threshold
= buffer_size
;
105 if (snd_pcm_sw_params_set_start_threshold(pad
->handle
, swparams
,
106 start_threshold
) < 0)
107 return -E_START_THRESHOLD
;
108 stop_threshold
= buffer_size
;
109 if (snd_pcm_sw_params_set_stop_threshold(pad
->handle
, swparams
,
111 return -E_STOP_THRESHOLD
;
112 if (snd_pcm_sw_params(pad
->handle
, swparams
) < 0)
113 PARA_WARNING_LOG("unable to install sw params\n");
114 pad
->bytes_per_frame
= snd_pcm_format_physical_width(FORMAT
)
116 PARA_INFO_LOG("bytes per frame: %zu\n", pad
->bytes_per_frame
);
117 if (snd_pcm_nonblock(pad
->handle
, 1))
118 PARA_ERROR_LOG("failed to set nonblock mode\n");
122 /* Open an instance of the alsa writer. */
123 static int alsa_open(struct writer_node
*wn
)
125 struct alsa_write_args_info
*conf
= wn
->conf
;
126 struct writer_node_group
*wng
= wn
->wng
;
127 struct private_alsa_write_data
*pad
= para_calloc(sizeof(*pad
));
129 wn
->private_data
= pad
;
130 if (!conf
->samplerate_given
&& wng
->samplerate
)
131 pad
->samplerate
= *wng
->samplerate
;
133 pad
->samplerate
= conf
->samplerate_arg
;
134 if (!conf
->channels_given
&& wng
->channels
)
135 pad
->channels
= *wng
->channels
;
137 pad
->channels
= conf
->channels_arg
;
138 PARA_INFO_LOG("%d channel(s), %dHz\n", pad
->channels
, pad
->samplerate
);
139 tv_add(now
, &(struct timeval
){0, 100 * 1000}, &pad
->next_chunk
);
143 static int alsa_write_pre_select(struct sched
*s
, struct writer_node
*wn
)
145 struct private_alsa_write_data
*pad
= wn
->private_data
;
146 struct writer_node_group
*wng
= wn
->wng
;
151 if (tv_diff(now
, &pad
->next_chunk
, &diff
) < 0) {
152 if (tv_diff(&s
->timeout
, &diff
, NULL
) > 0)
155 s
->timeout
.tv_sec
= 0;
156 s
->timeout
.tv_usec
= 1;
161 static int alsa_write_post_select(__a_unused
struct sched
*s
,
162 struct writer_node
*wn
)
164 struct private_alsa_write_data
*pad
= wn
->private_data
;
165 struct writer_node_group
*wng
= wn
->wng
;
166 size_t frames
, bytes
= *wng
->loaded
- wn
->written
;
167 unsigned char *data
= (unsigned char*)wng
->buf
+ wn
->written
;
169 snd_pcm_sframes_t ret
;
171 if (!bytes
) /* no data available */
173 if (tv_diff(now
, &pad
->next_chunk
, NULL
) < 0)
176 int err
= alsa_init(pad
, wn
->conf
);
180 frames
= bytes
/ pad
->bytes_per_frame
;
181 ret
= snd_pcm_writei(pad
->handle
, data
, frames
);
183 PARA_WARNING_LOG("EPIPE\n");
184 snd_pcm_prepare(pad
->handle
);
187 if (ret
< 0 && ret
!= -EAGAIN
) {
188 PARA_WARNING_LOG("alsa error (%zu frames, ret = %d\n",
190 return -E_ALSA_WRITE
;
193 PARA_DEBUG_LOG("EAGAIN\n");
195 wn
->written
+= ret
* pad
->bytes_per_frame
;
196 if (ret
== frames
) /* we wrote everything, try again immediately */
197 pad
->next_chunk
= *now
;
199 ms2tv(pad
->buffer_time
/ pad
->bytes_per_frame
/ 1000, &tv
);
200 tv_add(now
, &tv
, &pad
->next_chunk
);
203 if (*wng
->input_error
< 0) {
204 wn
->written
= *wng
->loaded
;
205 return *wng
->input_error
;
210 static void alsa_close(struct writer_node
*wn
)
212 struct private_alsa_write_data
*pad
= wn
->private_data
;
213 PARA_INFO_LOG("closing writer node %p\n", wn
);
214 snd_pcm_drain(pad
->handle
);
215 snd_pcm_close(pad
->handle
);
216 snd_config_update_free_global();
220 __malloc
static void *alsa_parse_config(const char *options
)
223 struct alsa_write_args_info
*conf
224 = para_calloc(sizeof(struct alsa_write_args_info
));
226 PARA_INFO_LOG("options: %s, %zd\n", options
, strcspn(options
, " \t"));
227 ret
= alsa_cmdline_parser_string(options
, conf
, "alsa_write");
230 PARA_INFO_LOG("help given: %d\n", conf
->help_given
);
238 * the init function of the alsa writer
240 * \param w pointer to the writer to initialize
244 void alsa_write_init(struct writer
*w
)
246 struct alsa_write_args_info dummy
;
248 alsa_cmdline_parser_init(&dummy
);
250 w
->close
= alsa_close
;
251 w
->pre_select
= alsa_write_pre_select
;
252 w
->post_select
= alsa_write_post_select
;
253 w
->parse_config
= alsa_parse_config
;
254 w
->shutdown
= NULL
; /* nothing to do */
255 w
->help
= (struct ggo_help
) {
256 .short_help
= alsa_write_args_info_help
,
257 .detailed_help
= alsa_write_args_info_detailed_help