summaryrefslogtreecommitdiffstats
path: root/src/module-alsa-sink.c
blob: 7afd24fd5189b284792045243e41f571e0775230 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
#include <assert.h>
#include <stdio.h>
#include <sys/poll.h>

#include <asoundlib.h>

#include "module.h"
#include "core.h"
#include "memchunk.h"
#include "sink.h"
#include "modargs.h"
#include "util.h"
#include "sample-util.h"

struct userdata {
    snd_pcm_t *pcm_handle;
    struct pa_sink *sink;
    void **io_sources;
    unsigned n_io_sources;

    size_t frame_size, fragment_size;
    struct pa_memchunk memchunk, silence;
};

static const char* const valid_modargs[] = {
    "device",
    "sink_name",
    NULL
};

#define DEFAULT_SINK_NAME "alsa_output"
#define DEFAULT_DEVICE "plughw:0,0"

static void xrun_recovery(struct userdata *u) {
    assert(u);

    fprintf(stderr, "*** XRUN ***\n");
    
    if (snd_pcm_prepare(u->pcm_handle) < 0)
        fprintf(stderr, "snd_pcm_prepare() failed\n");
}

static void do_write(struct userdata *u) {
    assert(u);

    for (;;) {
        struct pa_memchunk *memchunk = NULL;
        snd_pcm_sframes_t frames;
        
        if (u->memchunk.memblock)
            memchunk = &u->memchunk;
        else {
            if (pa_sink_render(u->sink, u->fragment_size, &u->memchunk) < 0)
                memchunk = &u->silence;
            else
                memchunk = &u->memchunk;
        }
            
        assert(memchunk->memblock && memchunk->memblock->data && memchunk->length && memchunk->memblock->length && (memchunk->length % u->frame_size) == 0);

        assert(u->pcm_handle);
        assert(memchunk->memblock);
        assert(memchunk->memblock->data);
        assert(memchunk->length);
        assert(u->frame_size);
        
        if ((frames = snd_pcm_writei(u->pcm_handle, memchunk->memblock->data + memchunk->index, memchunk->length / u->frame_size)) < 0) {
            if (frames == -EPIPE) {
                xrun_recovery(u);
                continue;
            }

            fprintf(stderr, "snd_pcm_writei() failed\n");
            return;
        }

        if (memchunk == &u->memchunk) {
            memchunk->index += frames * u->frame_size;
            memchunk->length -= frames * u->frame_size;

            if (memchunk->length == 0) {
                pa_memblock_unref(memchunk->memblock);
                memchunk->memblock = NULL;
                memchunk->index = memchunk->length = 0;
            }
        }
        
        break;
    }
}

static void io_callback(struct pa_mainloop_api*a, void *id, int fd, enum pa_mainloop_api_io_events events, void *userdata) {
    struct userdata *u = userdata;
    assert(u && a && id);

    if (snd_pcm_state(u->pcm_handle) == SND_PCM_STATE_XRUN)
        xrun_recovery(u);

    do_write(u);
}

static uint32_t sink_get_latency_cb(struct pa_sink *s) {
    struct userdata *u = s->userdata;
    snd_pcm_sframes_t frames;
    assert(s && u && u->sink);

    if (snd_pcm_delay(u->pcm_handle, &frames) < 0) {
        fprintf(stderr, __FILE__": failed to get delay\n");
        s->get_latency = NULL;
        return 0;
    }

    if (frames < 0)
        frames = 0;
    
    return pa_samples_usec(frames * u->frame_size, &s->sample_spec);
}

int pa_module_init(struct pa_core *c, struct pa_module*m) {
    struct pa_modargs *ma = NULL;
    int ret = -1;
    struct userdata *u = NULL;
    snd_pcm_hw_params_t *hwparams;
    const char *dev;
    struct pollfd *pfds, *ppfd;
    struct pa_sample_spec ss;
    unsigned i, periods;
    snd_pcm_uframes_t buffer_size;
    void ** ios;
    
    if (!(ma = pa_modargs_new(m->argument, valid_modargs))) {
        fprintf(stderr, __FILE__": failed to parse module arguments\n");
        goto fail;
    }
    
    u = malloc(sizeof(struct userdata));
    assert(u);
    memset(u, 0, sizeof(struct userdata));
    m->userdata = u;
    
    if (snd_pcm_open(&u->pcm_handle, dev = pa_modargs_get_value(ma, "device", DEFAULT_DEVICE), SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK) < 0) {
        fprintf(stderr, "Error opening PCM device %s\n", dev);
        goto fail;
    }
    
    ss.format = PA_SAMPLE_S16LE;
    ss.rate = 44100;
    ss.channels = 2;

    periods = 12;
    buffer_size = periods*256;

    snd_pcm_hw_params_alloca(&hwparams);
    if (snd_pcm_hw_params_any(u->pcm_handle, hwparams) < 0 ||
        snd_pcm_hw_params_set_access(u->pcm_handle, hwparams, SND_PCM_ACCESS_RW_INTERLEAVED) < 0 ||
        snd_pcm_hw_params_set_format(u->pcm_handle, hwparams, SND_PCM_FORMAT_S16_LE) < 0 ||
        snd_pcm_hw_params_set_rate_near(u->pcm_handle, hwparams, &ss.rate, NULL) < 0 ||
        snd_pcm_hw_params_set_channels(u->pcm_handle, hwparams, ss.channels) < 0 ||
        snd_pcm_hw_params_set_periods_near(u->pcm_handle, hwparams, &periods, NULL) < 0 || 
        snd_pcm_hw_params_set_buffer_size_near(u->pcm_handle, hwparams, &buffer_size) < 0 || 
        snd_pcm_hw_params(u->pcm_handle, hwparams) < 0) {
        fprintf(stderr, "Error setting HW params.\n");
        goto fail;
    }

    u->sink = pa_sink_new(c, pa_modargs_get_value(ma, "sink_name", DEFAULT_SINK_NAME), 0, &ss);
    assert(u->sink);

    u->sink->get_latency = sink_get_latency_cb;
    u->sink->userdata = u;
    pa_sink_set_owner(u->sink, m);
    u->sink->description = pa_sprintf_malloc("Advanced Linux Sound Architecture PCM on '%s'", dev);

    u->n_io_sources = snd_pcm_poll_descriptors_count(u->pcm_handle);

    pfds = malloc(sizeof(struct pollfd) * u->n_io_sources);
    assert(pfds);
    if (snd_pcm_poll_descriptors(u->pcm_handle, pfds, u->n_io_sources) < 0) {
        printf("Unable to obtain poll descriptors for playback.\n");
        free(pfds);
        goto fail;
    }
    
    u->io_sources = malloc(sizeof(void*) * u->n_io_sources);
    assert(u->io_sources);

    for (i = 0, ios = u->io_sources, ppfd = pfds; i < u->n_io_sources; i++, ios++, ppfd++) {
        *ios = c->mainloop->source_io(c->mainloop, ppfd->fd,
                                      ((ppfd->events & POLLIN) ? PA_MAINLOOP_API_IO_EVENT_INPUT : 0) |
                                      ((ppfd->events & POLLOUT) ? PA_MAINLOOP_API_IO_EVENT_OUTPUT : 0), io_callback, u);
        assert(*ios);
    }

    free(pfds);

    u->frame_size = pa_sample_size(&ss);
    u->fragment_size = buffer_size*u->frame_size/periods;

    fprintf(stderr, __FILE__": using %u fragments of size %u bytes.\n", periods, u->fragment_size);

    u->silence.memblock = pa_memblock_new(u->silence.length = u->fragment_size);
    assert(u->silence.memblock);
    pa_silence_memblock(u->silence.memblock, &ss);
    u->silence.index = 0;

    u->memchunk.memblock = NULL;
    u->memchunk.index = u->memchunk.length = 0;
    
    ret = 0;
     
finish:
     if (ma)
         pa_modargs_free(ma);
    
    return ret;

fail:
    
    if (u)
        pa_module_done(c, m);

    goto finish;
}

void pa_module_done(struct pa_core *c, struct pa_module*m) {
    struct userdata *u;
    assert(c && m);

    if ((u = m->userdata)) {
        unsigned i;
        void **ios;
        
        pa_sink_free(u->sink);

        for (ios = u->io_sources, i = 0; i < u->n_io_sources; i++, ios++)
            c->mainloop->cancel_io(c->mainloop, *ios);
        free(u->io_sources);
        
        if (u->pcm_handle) {
            snd_pcm_drop(u->pcm_handle);
            snd_pcm_close(u->pcm_handle);
        }

        if (u->memchunk.memblock)
            pa_memblock_unref(u->memchunk.memblock);
        if (u->silence.memblock)
            pa_memblock_unref(u->silence.memblock);
        
        free(u);
    }
}