2 * Copyright (C) 2005-2008 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
55 * open and prepare the PCM handle for writing
57 * Install PCM software and hardware configuration. Exit on errors.
59 static int alsa_open(struct writer_node
*w
)
61 snd_pcm_hw_params_t
*hwparams
;
62 snd_pcm_sw_params_t
*swparams
;
63 snd_pcm_uframes_t buffer_size
, start_threshold
, stop_threshold
;
65 snd_pcm_uframes_t period_size
;
66 struct private_alsa_write_data
*pad
= para_calloc(sizeof(struct
67 private_alsa_write_data
));
68 struct alsa_write_args_info
*conf
= w
->conf
;
69 struct writer_node_group
*wng
= w
->wng
;
71 if (!conf
->samplerate_given
&& wng
->samplerate
)
72 pad
->samplerate
= *wng
->samplerate
;
74 pad
->samplerate
= conf
->samplerate_arg
;
75 if (!conf
->channels_given
&& wng
->channels
)
76 pad
->channels
= *wng
->channels
;
78 pad
->channels
= conf
->channels_arg
;
79 PARA_INFO_LOG("%d channel(s), %dHz\n", pad
->channels
, pad
->samplerate
);
80 w
->private_data
= pad
;
81 err
= snd_pcm_open(&pad
->handle
, conf
->device_arg
,
82 SND_PCM_STREAM_PLAYBACK
, SND_PCM_NONBLOCK
);
86 snd_pcm_hw_params_alloca(&hwparams
);
87 snd_pcm_sw_params_alloca(&swparams
);
88 if (snd_pcm_hw_params_any(pad
->handle
, hwparams
) < 0)
89 return -E_BROKEN_CONF
;
90 if (snd_pcm_hw_params_set_access(pad
->handle
, hwparams
,
91 SND_PCM_ACCESS_RW_INTERLEAVED
) < 0)
92 return -E_ACCESS_TYPE
;
93 if (snd_pcm_hw_params_set_format(pad
->handle
, hwparams
, FORMAT
) < 0)
94 return -E_SAMPLE_FORMAT
;
95 if (snd_pcm_hw_params_set_channels(pad
->handle
, hwparams
,
97 return -E_CHANNEL_COUNT
;
98 if (snd_pcm_hw_params_set_rate_near(pad
->handle
, hwparams
,
99 &pad
->samplerate
, 0) < 0)
101 err
= snd_pcm_hw_params_get_buffer_time_max(hwparams
, &pad
->buffer_time
, 0);
102 if (err
< 0 || !pad
->buffer_time
)
103 return -E_GET_BUFFER_TIME
;
104 PARA_INFO_LOG("buffer time: %d\n", pad
->buffer_time
);
105 if (snd_pcm_hw_params_set_buffer_time_near(pad
->handle
, hwparams
,
106 &pad
->buffer_time
, 0) < 0)
107 return -E_SET_BUFFER_TIME
;
108 if (snd_pcm_hw_params(pad
->handle
, hwparams
) < 0)
110 snd_pcm_hw_params_get_period_size(hwparams
, &period_size
, 0);
111 snd_pcm_hw_params_get_buffer_size(hwparams
, &buffer_size
);
112 PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", buffer_size
,
114 if (period_size
== buffer_size
)
115 return -E_BAD_PERIOD
;
116 snd_pcm_sw_params_current(pad
->handle
, swparams
);
117 snd_pcm_sw_params_set_avail_min(pad
->handle
, swparams
, period_size
);
121 start_threshold
= buffer_size
;
122 if (snd_pcm_sw_params_set_start_threshold(pad
->handle
, swparams
,
123 start_threshold
) < 0)
124 return -E_START_THRESHOLD
;
125 stop_threshold
= buffer_size
;
126 if (snd_pcm_sw_params_set_stop_threshold(pad
->handle
, swparams
,
128 return -E_STOP_THRESHOLD
;
129 if (snd_pcm_sw_params(pad
->handle
, swparams
) < 0)
130 PARA_WARNING_LOG("unable to install sw params\n");
131 pad
->bytes_per_frame
= snd_pcm_format_physical_width(FORMAT
)
133 PARA_INFO_LOG("bytes per frame: %zu\n", pad
->bytes_per_frame
);
134 if (snd_pcm_nonblock(pad
->handle
, 1))
135 PARA_ERROR_LOG("failed to set nonblock mode\n");
136 tv_add(now
, &(struct timeval
){0, 100 * 1000}, &pad
->next_chunk
);
137 return period_size
* pad
->bytes_per_frame
;
140 static int alsa_write_pre_select(struct sched
*s
, struct writer_node
*wn
)
142 struct private_alsa_write_data
*pad
= wn
->private_data
;
143 struct writer_node_group
*wng
= wn
->wng
;
146 if (*wng
->loaded
< pad
->bytes_per_frame
)
148 if (tv_diff(now
, &pad
->next_chunk
, &diff
) < 0) {
149 if (tv_diff(&s
->timeout
, &diff
, NULL
) > 0)
152 s
->timeout
.tv_sec
= 0;
153 s
->timeout
.tv_usec
= 1;
156 // PARA_INFO_LOG("timeout: %lu\n", tv2ms(&s->timeout));
159 static int alsa_write_post_select(__a_unused
struct sched
*s
,
160 struct writer_node
*wn
)
162 struct private_alsa_write_data
*pad
= wn
->private_data
;
163 struct writer_node_group
*wng
= wn
->wng
;
164 size_t frames
= (*wng
->loaded
- wn
->written
) / pad
->bytes_per_frame
;
165 snd_pcm_sframes_t ret
;
166 unsigned char *data
= (unsigned char*)wng
->buf
+ wn
->written
;
169 // PARA_INFO_LOG("%zd frames\n", frames);
171 if (*wng
->input_error
)
172 wn
->written
= *wng
->loaded
;
175 if (tv_diff(now
, &pad
->next_chunk
, NULL
) < 0)
177 ret
= snd_pcm_writei(pad
->handle
, data
, frames
);
179 PARA_WARNING_LOG("EPIPE\n");
180 snd_pcm_prepare(pad
->handle
);
183 if (ret
< 0 && ret
!= -EAGAIN
) {
184 PARA_WARNING_LOG("alsa error (%zu frames, ret = %d\n",
186 return -E_ALSA_WRITE
;
189 PARA_DEBUG_LOG("EAGAIN\n");
191 wn
->written
+= ret
* pad
->bytes_per_frame
;
192 if (ret
== frames
) /* we wrote everything, try again immediately */
193 pad
->next_chunk
= *now
;
195 ms2tv(pad
->buffer_time
/ pad
->bytes_per_frame
/ 1000, &tv
);
196 tv_add(now
, &tv
, &pad
->next_chunk
);
201 static void alsa_close(struct writer_node
*wn
)
203 struct private_alsa_write_data
*pad
= wn
->private_data
;
204 PARA_INFO_LOG("closing writer node %p\n", wn
);
205 snd_pcm_drain(pad
->handle
);
206 snd_pcm_close(pad
->handle
);
207 snd_config_update_free_global();
211 __malloc
static void *alsa_parse_config(const char *options
)
214 struct alsa_write_args_info
*conf
215 = para_calloc(sizeof(struct alsa_write_args_info
));
217 PARA_INFO_LOG("options: %s, %zd\n", options
, strcspn(options
, " \t"));
218 ret
= alsa_cmdline_parser_string(options
, conf
, "alsa_write");
221 PARA_INFO_LOG("help given: %d\n", conf
->help_given
);
229 * the init function of the alsa writer
231 * \param w pointer to the writer to initialize
235 void alsa_write_init(struct writer
*w
)
237 struct alsa_write_args_info dummy
;
239 alsa_cmdline_parser_init(&dummy
);
241 w
->close
= alsa_close
;
242 w
->pre_select
= alsa_write_pre_select
;
243 w
->post_select
= alsa_write_post_select
;
244 w
->parse_config
= alsa_parse_config
;
245 w
->shutdown
= NULL
; /* nothing to do */
246 w
->help
= (struct ggo_help
) {
247 .short_help
= alsa_write_args_info_help
,
248 .detailed_help
= alsa_write_args_info_detailed_help