| 1 | /* |
| 2 | * This file is part of DisOrder. |
| 3 | * Copyright (C) 2007 Richard Kettlewell |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License as published by |
| 7 | * the Free Software Foundation; either version 2 of the License, or |
| 8 | * (at your option) any later version. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, but |
| 11 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | * General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License |
| 16 | * along with this program; if not, write to the Free Software |
| 17 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 |
| 18 | * USA |
| 19 | */ |
| 20 | /** @file clients/playrtp-alsa.c |
| 21 | * @brief RTP player - ALSA support |
| 22 | */ |
| 23 | |
| 24 | #include <config.h> |
| 25 | |
| 26 | #if HAVE_ALSA_ASOUNDLIB_H |
| 27 | #include "types.h" |
| 28 | |
| 29 | #include <poll.h> |
| 30 | #include <alsa/asoundlib.h> |
| 31 | #include <assert.h> |
| 32 | #include <pthread.h> |
| 33 | |
| 34 | #include "mem.h" |
| 35 | #include "log.h" |
| 36 | #include "vector.h" |
| 37 | #include "heap.h" |
| 38 | #include "playrtp.h" |
| 39 | |
| 40 | /** @brief PCM handle */ |
| 41 | static snd_pcm_t *pcm; |
| 42 | |
| 43 | /** @brief True when @ref pcm is up and running */ |
| 44 | static int playrtp_alsa_prepared = 1; |
| 45 | |
| 46 | static void playrtp_alsa_init(void) { |
| 47 | snd_pcm_hw_params_t *hwparams; |
| 48 | snd_pcm_sw_params_t *swparams; |
| 49 | /* Only support one format for now */ |
| 50 | const int sample_format = SND_PCM_FORMAT_S16_BE; |
| 51 | unsigned rate = 44100; |
| 52 | const int channels = 2; |
| 53 | const int samplesize = channels * sizeof(uint16_t); |
| 54 | snd_pcm_uframes_t pcm_bufsize = MAXSAMPLES * samplesize * 3; |
| 55 | /* If we can write more than this many samples we'll get a wakeup */ |
| 56 | const int avail_min = 256; |
| 57 | int err; |
| 58 | |
| 59 | /* Open ALSA */ |
| 60 | if((err = snd_pcm_open(&pcm, |
| 61 | device ? device : "default", |
| 62 | SND_PCM_STREAM_PLAYBACK, |
| 63 | SND_PCM_NONBLOCK))) |
| 64 | fatal(0, "error from snd_pcm_open: %d", err); |
| 65 | /* Set up 'hardware' parameters */ |
| 66 | snd_pcm_hw_params_alloca(&hwparams); |
| 67 | if((err = snd_pcm_hw_params_any(pcm, hwparams)) < 0) |
| 68 | fatal(0, "error from snd_pcm_hw_params_any: %d", err); |
| 69 | if((err = snd_pcm_hw_params_set_access(pcm, hwparams, |
| 70 | SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) |
| 71 | fatal(0, "error from snd_pcm_hw_params_set_access: %d", err); |
| 72 | if((err = snd_pcm_hw_params_set_format(pcm, hwparams, |
| 73 | sample_format)) < 0) |
| 74 | |
| 75 | fatal(0, "error from snd_pcm_hw_params_set_format (%d): %d", |
| 76 | sample_format, err); |
| 77 | if((err = snd_pcm_hw_params_set_rate_near(pcm, hwparams, &rate, 0)) < 0) |
| 78 | fatal(0, "error from snd_pcm_hw_params_set_rate (%d): %d", |
| 79 | rate, err); |
| 80 | if((err = snd_pcm_hw_params_set_channels(pcm, hwparams, |
| 81 | channels)) < 0) |
| 82 | fatal(0, "error from snd_pcm_hw_params_set_channels (%d): %d", |
| 83 | channels, err); |
| 84 | if((err = snd_pcm_hw_params_set_buffer_size_near(pcm, hwparams, |
| 85 | &pcm_bufsize)) < 0) |
| 86 | fatal(0, "error from snd_pcm_hw_params_set_buffer_size (%d): %d", |
| 87 | MAXSAMPLES * samplesize * 3, err); |
| 88 | if((err = snd_pcm_hw_params(pcm, hwparams)) < 0) |
| 89 | fatal(0, "error calling snd_pcm_hw_params: %d", err); |
| 90 | /* Set up 'software' parameters */ |
| 91 | snd_pcm_sw_params_alloca(&swparams); |
| 92 | if((err = snd_pcm_sw_params_current(pcm, swparams)) < 0) |
| 93 | fatal(0, "error calling snd_pcm_sw_params_current: %d", err); |
| 94 | if((err = snd_pcm_sw_params_set_avail_min(pcm, swparams, avail_min)) < 0) |
| 95 | fatal(0, "error calling snd_pcm_sw_params_set_avail_min %d: %d", |
| 96 | avail_min, err); |
| 97 | if((err = snd_pcm_sw_params(pcm, swparams)) < 0) |
| 98 | fatal(0, "error calling snd_pcm_sw_params: %d", err); |
| 99 | } |
| 100 | |
| 101 | /** @brief Wait until ALSA wants some audio */ |
| 102 | static void wait_alsa(void) { |
| 103 | struct pollfd fds[64]; |
| 104 | int nfds, err; |
| 105 | unsigned short events; |
| 106 | |
| 107 | for(;;) { |
| 108 | do { |
| 109 | if((nfds = snd_pcm_poll_descriptors(pcm, |
| 110 | fds, sizeof fds / sizeof *fds)) < 0) |
| 111 | fatal(0, "error calling snd_pcm_poll_descriptors: %d", nfds); |
| 112 | } while(poll(fds, nfds, -1) < 0 && errno == EINTR); |
| 113 | if((err = snd_pcm_poll_descriptors_revents(pcm, fds, nfds, &events))) |
| 114 | fatal(0, "error calling snd_pcm_poll_descriptors_revents: %d", err); |
| 115 | if(events & POLLOUT) |
| 116 | return; |
| 117 | } |
| 118 | } |
| 119 | |
| 120 | /** @brief Play some sound via ALSA |
| 121 | * @param s Pointer to sample data |
| 122 | * @param n Number of samples |
| 123 | * @return 0 on success, -1 on non-fatal error |
| 124 | */ |
| 125 | static int playrtp_alsa_writei(const void *s, size_t n) { |
| 126 | /* Do the write */ |
| 127 | const snd_pcm_sframes_t frames_written = snd_pcm_writei(pcm, s, n / 2); |
| 128 | if(frames_written < 0) { |
| 129 | /* Something went wrong */ |
| 130 | switch(frames_written) { |
| 131 | case -EAGAIN: |
| 132 | return 0; |
| 133 | case -EPIPE: |
| 134 | error(0, "error calling snd_pcm_writei: %ld", |
| 135 | (long)frames_written); |
| 136 | return -1; |
| 137 | default: |
| 138 | fatal(0, "error calling snd_pcm_writei: %ld", |
| 139 | (long)frames_written); |
| 140 | } |
| 141 | } else { |
| 142 | /* Success */ |
| 143 | next_timestamp += frames_written * 2; |
| 144 | return 0; |
| 145 | } |
| 146 | } |
| 147 | |
| 148 | /** @brief Play the relevant part of a packet |
| 149 | * @param p Packet to play |
| 150 | * @return 0 on success, -1 on non-fatal error |
| 151 | */ |
| 152 | static int playrtp_alsa_play(const struct packet *p) { |
| 153 | return playrtp_alsa_writei(p->samples_raw + next_timestamp - p->timestamp, |
| 154 | (p->timestamp + p->nsamples) - next_timestamp); |
| 155 | } |
| 156 | |
| 157 | /** @brief Play some silence |
| 158 | * @param p Next packet or NULL |
| 159 | * @return 0 on success, -1 on non-fatal error |
| 160 | */ |
| 161 | static int playrtp_alsa_infill(const struct packet *p) { |
| 162 | static const uint16_t zeros[INFILL_SAMPLES]; |
| 163 | size_t samples_available = INFILL_SAMPLES; |
| 164 | |
| 165 | if(p && samples_available > p->timestamp - next_timestamp) |
| 166 | samples_available = p->timestamp - next_timestamp; |
| 167 | return playrtp_alsa_writei(zeros, samples_available); |
| 168 | } |
| 169 | |
| 170 | static void playrtp_alsa_enable(void){ |
| 171 | int err; |
| 172 | |
| 173 | if(!playrtp_alsa_prepared) { |
| 174 | if((err = snd_pcm_prepare(pcm))) |
| 175 | fatal(0, "error calling snd_pcm_prepare: %d", err); |
| 176 | playrtp_alsa_prepared = 1; |
| 177 | } |
| 178 | } |
| 179 | |
| 180 | /** @brief Reset ALSA state after we lost synchronization */ |
| 181 | static void playrtp_alsa_disable(int hard_reset) { |
| 182 | int err; |
| 183 | |
| 184 | if((err = snd_pcm_nonblock(pcm, 0))) |
| 185 | fatal(0, "error calling snd_pcm_nonblock: %d", err); |
| 186 | if(hard_reset) { |
| 187 | if((err = snd_pcm_drop(pcm))) |
| 188 | fatal(0, "error calling snd_pcm_drop: %d", err); |
| 189 | } else |
| 190 | if((err = snd_pcm_drain(pcm))) |
| 191 | fatal(0, "error calling snd_pcm_drain: %d", err); |
| 192 | if((err = snd_pcm_nonblock(pcm, 1))) |
| 193 | fatal(0, "error calling snd_pcm_nonblock: %d", err); |
| 194 | playrtp_alsa_prepared = 0; |
| 195 | } |
| 196 | |
| 197 | void playrtp_alsa(void) { |
| 198 | int escape; |
| 199 | const struct packet *p; |
| 200 | |
| 201 | playrtp_alsa_init(); |
| 202 | pthread_mutex_lock(&lock); |
| 203 | for(;;) { |
| 204 | /* Wait for the buffer to fill up a bit */ |
| 205 | playrtp_fill_buffer(); |
| 206 | playrtp_alsa_enable(); |
| 207 | escape = 0; |
| 208 | info("Playing..."); |
| 209 | /* Keep playing until the buffer empties out, or ALSA tells us to get |
| 210 | * lost */ |
| 211 | while((nsamples >= minbuffer |
| 212 | || (nsamples > 0 |
| 213 | && contains(pheap_first(&packets), next_timestamp))) |
| 214 | && !escape) { |
| 215 | /* Wait for ALSA to ask us for more data */ |
| 216 | pthread_mutex_unlock(&lock); |
| 217 | wait_alsa(); |
| 218 | pthread_mutex_lock(&lock); |
| 219 | /* ALSA is ready for more data, find something to play */ |
| 220 | p = playrtp_next_packet(); |
| 221 | /* Play it or play some silence */ |
| 222 | if(contains(p, next_timestamp)) |
| 223 | escape = playrtp_alsa_play(p); |
| 224 | else |
| 225 | escape = playrtp_alsa_infill(p); |
| 226 | } |
| 227 | active = 0; |
| 228 | /* We stop playing for a bit until the buffer re-fills */ |
| 229 | pthread_mutex_unlock(&lock); |
| 230 | playrtp_alsa_disable(escape); |
| 231 | pthread_mutex_lock(&lock); |
| 232 | } |
| 233 | } |
| 234 | |
| 235 | #endif |
| 236 | |
| 237 | /* |
| 238 | Local Variables: |
| 239 | c-basic-offset:2 |
| 240 | comment-column:40 |
| 241 | fill-column:79 |
| 242 | indent-tabs-mode:nil |
| 243 | End: |
| 244 | */ |