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>
25 #include "alsa_write.cmdline.h"
28 /** always use 16 bit little endian */
29 #define FORMAT SND_PCM_FORMAT_S16_LE
31 /** data specific to the alsa writer */
32 struct private_alsa_write_data
{
33 /** the alsa handle */
35 /** determined and set by alsa_open() */
36 size_t bytes_per_frame
;
37 /** don't write anything until this time */
38 struct timeval next_chunk
;
39 /** the return value of snd_pcm_hw_params_get_buffer_time_max() */
42 * the samplerate given by command line option or the decoder
43 * of the writer node group
47 * the number of channels, also given by command line option or the
48 * decoder of the writer node group
54 * open and prepare the PCM handle for writing
56 * Install PCM software and hardware configuration. Exit on errors.
58 static int alsa_open(struct writer_node
*w
)
60 snd_pcm_hw_params_t
*hwparams
;
61 snd_pcm_sw_params_t
*swparams
;
62 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 snd_pcm_info_alloca(&info
);
82 err
= snd_pcm_open(&pad
->handle
, conf
->device_arg
,
83 SND_PCM_STREAM_PLAYBACK
, SND_PCM_NONBLOCK
);
86 if ((err
= snd_pcm_info(pad
->handle
, info
)) < 0)
87 return -E_SND_PCM_INFO
;
89 snd_pcm_hw_params_alloca(&hwparams
);
90 snd_pcm_sw_params_alloca(&swparams
);
91 if (snd_pcm_hw_params_any(pad
->handle
, hwparams
) < 0)
92 return -E_BROKEN_CONF
;
93 if (snd_pcm_hw_params_set_access(pad
->handle
, hwparams
,
94 SND_PCM_ACCESS_RW_INTERLEAVED
) < 0)
95 return -E_ACCESS_TYPE
;
96 if (snd_pcm_hw_params_set_format(pad
->handle
, hwparams
, FORMAT
) < 0)
97 return -E_SAMPLE_FORMAT
;
98 if (snd_pcm_hw_params_set_channels(pad
->handle
, hwparams
,
100 return -E_CHANNEL_COUNT
;
101 if (snd_pcm_hw_params_set_rate_near(pad
->handle
, hwparams
,
102 &pad
->samplerate
, 0) < 0)
104 err
= snd_pcm_hw_params_get_buffer_time_max(hwparams
, &pad
->buffer_time
, 0);
105 if (err
< 0 || !pad
->buffer_time
)
106 return -E_GET_BUFFER_TIME
;
107 PARA_INFO_LOG("buffer time: %d\n", pad
->buffer_time
);
108 if (snd_pcm_hw_params_set_buffer_time_near(pad
->handle
, hwparams
,
109 &pad
->buffer_time
, 0) < 0)
110 return -E_SET_BUFFER_TIME
;
111 if (snd_pcm_hw_params(pad
->handle
, hwparams
) < 0)
113 snd_pcm_hw_params_get_period_size(hwparams
, &period_size
, 0);
114 snd_pcm_hw_params_get_buffer_size(hwparams
, &buffer_size
);
115 PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", buffer_size
,
117 if (period_size
== buffer_size
)
118 return -E_BAD_PERIOD
;
119 snd_pcm_sw_params_current(pad
->handle
, swparams
);
120 snd_pcm_sw_params_set_avail_min(pad
->handle
, swparams
, period_size
);
124 start_threshold
= buffer_size
;
125 if (snd_pcm_sw_params_set_start_threshold(pad
->handle
, swparams
,
126 start_threshold
) < 0)
127 return -E_START_THRESHOLD
;
128 stop_threshold
= buffer_size
;
129 if (snd_pcm_sw_params_set_stop_threshold(pad
->handle
, swparams
,
131 return -E_STOP_THRESHOLD
;
132 if (snd_pcm_sw_params(pad
->handle
, swparams
) < 0)
134 pad
->bytes_per_frame
= snd_pcm_format_physical_width(FORMAT
)
136 if (snd_pcm_nonblock(pad
->handle
, 1))
137 PARA_ERROR_LOG("%s\n", "failed to set nonblock mode");
138 return period_size
* pad
->bytes_per_frame
;
141 static int alsa_write_pre_select(struct sched
*s
, struct writer_node
*wn
)
143 struct private_alsa_write_data
*pad
= wn
->private_data
;
144 struct writer_node_group
*wng
= wn
->wng
;
147 if (*wng
->loaded
< pad
->bytes_per_frame
)
149 if (tv_diff(now
, &pad
->next_chunk
, &diff
) < 0) {
150 if (tv_diff(&s
->timeout
, &diff
, NULL
) > 0)
153 s
->timeout
.tv_sec
= 0;
154 s
->timeout
.tv_usec
= 1;
157 // PARA_INFO_LOG("timeout: %lu\n", tv2ms(&s->timeout));
160 static int alsa_write_post_select(__a_unused
struct sched
*s
,
161 struct writer_node
*wn
)
163 struct private_alsa_write_data
*pad
= wn
->private_data
;
164 struct writer_node_group
*wng
= wn
->wng
;
165 size_t frames
= (*wng
->loaded
- wn
->written
) / pad
->bytes_per_frame
;
166 snd_pcm_sframes_t ret
;
167 unsigned char *data
= (unsigned char*)wng
->buf
+ wn
->written
;
170 // PARA_INFO_LOG("%zd frames\n", frames);
172 if (*wng
->input_error
)
173 wn
->written
= *wng
->loaded
;
176 if (tv_diff(now
, &pad
->next_chunk
, NULL
) < 0)
178 ret
= snd_pcm_writei(pad
->handle
, data
, frames
);
180 PARA_WARNING_LOG("EPIPE\n");
181 snd_pcm_prepare(pad
->handle
);
184 if (ret
< 0 && ret
!= -EAGAIN
) {
185 PARA_WARNING_LOG("alsa error (%zu frames, ret = %d\n",
187 return -E_ALSA_WRITE
;
189 if (ret
== -EAGAIN
) { /* try again in 5ms */
190 PARA_WARNING_LOG("EAGAIN\n");
193 wn
->written
+= ret
* pad
->bytes_per_frame
;
194 ms2tv(pad
->buffer_time
/ 4000, &tv
);
196 tv_add(now
, &tv
, &pad
->next_chunk
);
200 static void alsa_close(struct writer_node
*wn
)
202 struct private_alsa_write_data
*pad
= wn
->private_data
;
203 PARA_INFO_LOG("closing writer node %p\n", wn
);
204 snd_pcm_drain(pad
->handle
);
205 snd_pcm_close(pad
->handle
);
206 snd_config_update_free_global();
210 __malloc
static void *alsa_parse_config(const char *options
)
212 struct alsa_write_args_info
*conf
213 = para_calloc(sizeof(struct alsa_write_args_info
));
214 PARA_INFO_LOG("options: %s, %zd\n", options
, strcspn(options
, " \t"));
215 int ret
= alsa_cmdline_parser_string(options
, conf
, "alsa_write");
218 PARA_INFO_LOG("help given: %d\n", conf
->help_given
);
226 * the init function of the alsa writer
228 * \param w pointer to the writer to initialize
232 void alsa_write_init(struct writer
*w
)
235 w
->close
= alsa_close
;
236 w
->pre_select
= alsa_write_pre_select
;
237 w
->post_select
= alsa_write_post_select
;
238 w
->parse_config
= alsa_parse_config
;
239 w
->shutdown
= NULL
; /* nothing to do */