2 * Copyright (C) 2009-2014 Andre Noll <maan@tuebingen.mpg.de>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file oss_write.c Paraslash's oss output plugin. */
10 #include <sys/ioctl.h>
12 #include <sys/soundcard.h>
20 #include "buffer_tree.h"
22 #include "write_common.h"
23 #include "oss_write.cmdline.h"
26 /** Data specific to the oss writer. */
27 struct private_oss_write_data {
28 /** The file handle of the device. */
30 /** Four bytes for stereo streams, two bytes for mono streams. */
35 * We keep one bit of static storage to make sure only one instance of the oss
36 * writer is running at any given time.
38 static bool sound_device_busy;
40 static bool sound_device_is_busy(void)
42 return sound_device_busy;
45 static void set_sound_device_busy(void)
47 assert(!sound_device_busy);
48 sound_device_busy = true;
51 static void set_sound_device_idle(void)
53 assert(sound_device_busy);
54 sound_device_busy = false;
57 static int get_oss_format(enum sample_format sf)
60 case SF_S8: return AFMT_S8;
61 case SF_U8: return AFMT_U8;
62 case SF_S16_LE: return AFMT_S16_LE;
63 case SF_S16_BE: return AFMT_S16_BE;
64 case SF_U16_LE: return AFMT_U16_LE;
65 case SF_U16_BE: return AFMT_U16_BE;
66 default: return AFMT_S16_LE;
70 static void oss_pre_select(struct sched *s, void *context)
72 struct writer_node *wn = context;
73 struct private_oss_write_data *powd = wn->private_data;
74 int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
76 if (ret == 0 || (sound_device_is_busy() && !powd))
79 return sched_min_delay(s);
80 para_fd_set(powd->fd, &s->wfds, &s->max_fileno);
83 static void oss_close(struct writer_node *wn)
85 struct private_oss_write_data *powd = wn->private_data;
91 set_sound_device_idle();
95 * The Open Sound System Programmer's Guide sayeth:
97 * Set sampling parameters always so that number of channels (mono/stereo) is
98 * set before selecting sampling rate (speed). Failing to do this will make
99 * your program incompatible with cards such as the SoundBlaster Pro which
100 * supports 44.1 kHz in mono but just 22.05 kHz in stereo. A program which
101 * selects 44.1 kHz speed and then sets the device to stereo mode will
102 * incorrectly believe that the device is still in 44.1 kHz mode when actually
103 * the speed is decreased to 22.05 kHz.
105 static int oss_init(struct writer_node *wn, unsigned sample_rate,
106 unsigned channels, int sample_format)
110 struct oss_write_args_info *conf = wn->conf;
111 struct private_oss_write_data *powd = para_calloc(sizeof(*powd));
113 PARA_INFO_LOG("opening %s\n", conf->device_arg);
114 ret = para_open(conf->device_arg, O_WRONLY, 0);
118 ret = mark_fd_nonblocking(powd->fd);
122 sample_format = format = get_oss_format(sample_format);
123 ret = ioctl(powd->fd, SNDCTL_DSP_SETFMT, &format);
125 ret = -ERRNO_TO_PARA_ERROR(errno);
128 ret = -E_BAD_SAMPLE_FORMAT;
129 if (format != sample_format)
131 /* set number of channels */
133 ret = ioctl(powd->fd, SNDCTL_DSP_CHANNELS, &ch);
135 ret = -ERRNO_TO_PARA_ERROR(errno);
138 ret = -E_BAD_CHANNEL_COUNT;
141 if (format == SF_U8 || format == SF_S8)
142 powd->bytes_per_frame = ch;
144 powd->bytes_per_frame = ch * 2;
149 * If we request a higher sampling rate than is supported by the
150 * device, the the highest possible speed is automatically used. The
151 * value actually used is returned as the new value of the argument.
154 ret = ioctl(powd->fd, SNDCTL_DSP_SPEED, &rate);
156 ret = -ERRNO_TO_PARA_ERROR(errno);
159 if (rate != sample_rate) {
160 unsigned min = PARA_MIN(rate, sample_rate),
161 max = PARA_MAX(rate, sample_rate);
163 * Check whether the returned sample rate differs significantly
164 * from the requested one.
166 ret = -E_BAD_SAMPLERATE;
167 if (100 * max > 110 * min) /* more than 10% deviation */
169 PARA_NOTICE_LOG("using %dHz rather than %dHz\n", rate,
172 wn->min_iqs = powd->bytes_per_frame;
173 wn->private_data = powd;
179 PARA_ERROR_LOG("failed to init %s: %s\n", conf->device_arg,
180 para_strerror(-ret));
184 static int oss_post_select(__a_unused struct sched *s, void *context)
186 struct writer_node *wn = context;
187 struct private_oss_write_data *powd = wn->private_data;
188 struct btr_node *btrn = wn->btrn;
189 size_t frames, bytes;
194 ret = task_get_notification(wn->task);
197 ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
201 int32_t rate, ch, format;
203 if (sound_device_is_busy())
205 get_btr_sample_rate(btrn, &rate);
206 get_btr_channels(btrn, &ch);
207 get_btr_sample_format(btrn, &format);
208 ret = oss_init(wn, rate, ch, format);
211 set_sound_device_busy();
214 btr_merge(btrn, wn->min_iqs);
215 bytes = btr_next_buffer(btrn, &data);
216 frames = bytes / powd->bytes_per_frame;
217 if (!frames) { /* eof and less than a single frame available */
218 ret = -E_WRITE_COMMON_EOF;
222 if (!FD_ISSET(powd->fd, &s->wfds))
224 /* get maximal number of bytes that can be written */
225 ret = ioctl(powd->fd, SNDCTL_DSP_GETOSPACE, &abi);
227 size_t max_frames = abi.bytes / powd->bytes_per_frame;
230 /* cap number of frames to avoid sound artefacts */
231 frames = PARA_MIN(frames, max_frames);
233 ret = xwrite(powd->fd, data, frames * powd->bytes_per_frame);
236 btr_consume(btrn, ret);
240 btr_remove_node(&wn->btrn);
244 __malloc static void *oss_parse_config_or_die(int argc, char **argv)
246 struct oss_write_args_info *conf = para_calloc(sizeof(*conf));
248 /* exits on errors */
249 oss_write_cmdline_parser(argc, argv, conf);
253 static void oss_free_config(void *conf)
255 oss_write_cmdline_parser_free(conf);
259 * The init function of the oss writer.
261 * \param w Pointer to the writer to initialize.
265 void oss_write_init(struct writer *w)
267 struct oss_write_args_info dummy;
269 oss_write_cmdline_parser_init(&dummy);
270 w->close = oss_close;
271 w->pre_select = oss_pre_select;
272 w->post_select = oss_post_select;
273 w->parse_config_or_die = oss_parse_config_or_die;
274 w->free_config = oss_free_config;
275 w->help = (struct ggo_help)DEFINE_GGO_HELP(oss_write);
276 oss_write_cmdline_parser_free(&dummy);