mdw@git.distorted.org.uk Git - disorder/blob - clients/playrtp-alsa.c

   1 /*
   2  * This file is part of DisOrder.
   3  * Copyright (C) 2008 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 3 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,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU 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, see <http://www.gnu.org/licenses/>.
  17  */
  18 /** @file clients/playrtp-alsa.c
  19  * @brief RTP player - ALSA support
  20  *
  21  * This has been rewritten to use the @ref alsabg.h interface and is therefore
  22  * now closely modelled on @ref playrtp-coreaudio.c.  Given a similar interface
  23  * wrapping OSS the whole of playrtp could probably be greatly simplified.
  24  */
  25
  26 #include "common.h"
  27
  28 #if HAVE_ALSA_ASOUNDLIB_H
  29
  30 #include <poll.h>
  31 #include <alsa/asoundlib.h>
  32 #include <pthread.h>
  33 #include <arpa/inet.h>
  34
  35 #include "mem.h"
  36 #include "log.h"
  37 #include "vector.h"
  38 #include "heap.h"
  39 #include "playrtp.h"
  40 #include "alsabg.h"
  41
  42 /** @brief Callback from alsa_bg_collect() */
  43 static int playrtp_alsa_supply(void *dst,
  44                                unsigned supply_nsamples) {
  45   unsigned samples_available;
  46   const struct packet *p;
  47
  48   pthread_mutex_lock(&lock);
  49   p = playrtp_next_packet();
  50   if(p && contains(p, next_timestamp)) {
  51     /* This packet is ready to play */
  52     const uint32_t packet_end = p->timestamp + p->nsamples;
  53     const uint32_t offset = next_timestamp - p->timestamp;
  54     const uint16_t *src = (void *)(p->samples_raw + offset);
  55     samples_available = packet_end - next_timestamp;
  56     if(samples_available > supply_nsamples)
  57       samples_available = supply_nsamples;
  58     next_timestamp += samples_available;
  59     memcpy(dst, src, samples_available * sizeof (int16_t));
  60     /* We don't bother junking the packet - that'll be dealt with next time
  61      * round */
  62   } else {
  63     /* No packet is ready to play (and there might be no packet at all) */
  64     samples_available = p ? p->timestamp - next_timestamp : supply_nsamples;
  65     if(samples_available > supply_nsamples)
  66       samples_available = supply_nsamples;
  67     /*info("infill %d", samples_available);*/
  68     next_timestamp += samples_available;
  69     /* Unlike Core Audio the buffer is not guaranteed to be 0-filled */
  70     memset(dst, 0, samples_available * sizeof (int16_t));
  71   }
  72   pthread_mutex_unlock(&lock);
  73   return samples_available;
  74 }
  75
  76 void playrtp_alsa(void) {
  77   alsa_bg_init(device ? device : "default",
  78                playrtp_alsa_supply);
  79   pthread_mutex_lock(&lock);
  80   for(;;) {
  81     /* Wait for the buffer to fill up a bit */
  82     playrtp_fill_buffer();
  83     /* Start playing now */
  84     info("Playing...");
  85     next_timestamp = pheap_first(&packets)->timestamp;
  86     active = 1;
  87     alsa_bg_enable();
  88     /* Wait until the buffer empties out */
  89     while(nsamples >= minbuffer
  90           || (nsamples > 0
  91               && contains(pheap_first(&packets), next_timestamp))) {
  92       pthread_cond_wait(&cond, &lock);
  93     }
  94     /* Stop playing for a bit until the buffer re-fills */
  95     alsa_bg_disable();
  96     active = 0;
  97     /* Go back round */
  98   }
  99 }
 100
 101 #endif
 102
 103 /*
 104 Local Variables:
 105 c-basic-offset:2
 106 comment-column:40
 107 fill-column:79
 108 indent-tabs-mode:nil
 109 End:
 110 */