2 * Copyright (C) 2009-2010 Andre Noll <maan@systemlinux.org>
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>
13 #include <sys/soundcard.h>
22 #include "buffer_tree.h"
24 #include "write_common.h"
25 #include "oss_write.cmdline.h"
28 /** Always use 16 bit little endian. */
29 #define FORMAT AFMT_S16_LE
31 /** Data specific to the oss writer. */
32 struct private_oss_write_data {
33 /** The file handle of the device. */
35 /** Four bytes for stereo streams, two bytes for mono streams. */
39 static void oss_pre_select(struct sched *s, struct task *t)
41 struct writer_node *wn = container_of(t, struct writer_node, task);
42 struct private_oss_write_data *powd = wn->private_data;
43 int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
49 para_fd_set(powd->fd, &s->wfds, &s->max_fileno);
52 static void oss_close(struct writer_node *wn)
54 struct private_oss_write_data *powd = wn->private_data;
61 * The Open Sound System Programmer's Guide sayeth:
63 * Set sampling parameters always so that number of channels (mono/stereo) is
64 * set before selecting sampling rate (speed). Failing to do this will make
65 * your program incompatible with cards such as the SoundBlaster Pro which
66 * supports 44.1 kHz in mono but just 22.05 kHz in stereo. A program which
67 * selects 44.1 kHz speed and then sets the device to stereo mode will
68 * incorrectly believe that the device is still in 44.1 kHz mode when actually
69 * the speed is decreased to 22.05 kHz.
71 static int oss_init(struct writer_node *wn, unsigned samplerate, unsigned channels)
73 int ret, format = FORMAT;
75 struct oss_write_args_info *conf = wn->conf;
76 struct private_oss_write_data *powd = wn->private_data;
78 PARA_INFO_LOG("opening %s\n", conf->device_arg);
79 ret = para_open(conf->device_arg, O_WRONLY, 0);
83 ret = mark_fd_nonblocking(powd->fd);
87 ret = ioctl(powd->fd, SNDCTL_DSP_SETFMT, &format);
89 ret = -ERRNO_TO_PARA_ERROR(errno);
92 ret = -E_BAD_SAMPLE_FORMAT;
95 /* set number of channels */
96 ret = -E_BAD_CHANNEL_COUNT;
100 ret = ioctl(powd->fd, SNDCTL_DSP_CHANNELS, &ch);
102 ret = -ERRNO_TO_PARA_ERROR(errno);
105 ret = -E_BAD_CHANNEL_COUNT;
108 powd->bytes_per_frame = ch * 2;
113 * If we request a higher sampling rate than is supported by the
114 * device, the the highest possible speed is automatically used. The
115 * value actually used is returned as the new value of the argument.
118 ret = ioctl(powd->fd, SNDCTL_DSP_SPEED, &rate);
120 ret = -ERRNO_TO_PARA_ERROR(errno);
123 if (rate != samplerate) {
124 unsigned min = PARA_MIN(rate, samplerate),
125 max = PARA_MAX(rate, samplerate);
127 * Check whether the returned sample rate differs significantly
128 * from the requested one.
130 ret = -E_BAD_SAMPLERATE;
131 if (100 * max > 110 * min) /* more than 10% deviation */
133 PARA_NOTICE_LOG("using %dHz rather than %dHz\n", rate,
136 wn->min_iqs = powd->bytes_per_frame;
144 static void oss_post_select(__a_unused struct sched *s,
147 struct writer_node *wn = container_of(t, struct writer_node, task);
148 struct oss_write_args_info *conf = wn->conf;
149 struct private_oss_write_data *powd = wn->private_data;
150 struct btr_node *btrn = wn->btrn;
151 size_t frames, bytes;
152 int ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
162 if (!conf->samplerate_given) /* config option trumps btr_exec */
163 ret = get_btr_samplerate(wn->btrn, &rate);
165 rate = conf->samplerate_arg;
167 if (!conf->channels_given)
168 ret = get_btr_channels(wn->btrn, &ch);
170 ch = conf->channels_arg;
171 ret = oss_init(wn, rate, ch);
176 bytes = btr_next_buffer(btrn, &data);
177 frames = bytes / powd->bytes_per_frame;
178 if (!frames) { /* eof and less than a single frame available */
183 if (!FD_ISSET(powd->fd, &s->wfds))
185 ret = write_nonblock(powd->fd, data, frames * powd->bytes_per_frame, 0);
188 btr_consume(btrn, ret);
193 btr_remove_node(btrn);
196 static int oss_open(struct writer_node *wn)
198 struct private_oss_write_data *powd;
200 powd = para_calloc(sizeof(*powd));
201 wn->private_data = powd;
206 __malloc static void *oss_parse_config(const char *options)
209 struct oss_write_args_info *conf = para_calloc(sizeof(*conf));
211 ret = oss_cmdline_parser_string(options, conf, "oss_write");
220 static void oss_free_config(void *conf)
222 oss_cmdline_parser_free(conf);
226 * The init function of the oss writer.
228 * \param w Pointer to the writer to initialize.
232 void oss_write_init(struct writer *w)
234 struct oss_write_args_info dummy;
236 oss_cmdline_parser_init(&dummy);
238 w->close = oss_close;
239 w->pre_select = oss_pre_select;
240 w->post_select = oss_post_select;
241 w->parse_config = oss_parse_config;
242 w->free_config = oss_free_config;
244 w->help = (struct ggo_help) {
245 .short_help = oss_write_args_info_help,
246 .detailed_help = oss_write_args_info_detailed_help
248 oss_cmdline_parser_free(&dummy);