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

   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.h
  21  * @brief RTP player
  22  */
  23
  24 #ifndef PLAYRTP_H
  25 #define PLAYRTP_H
  26
  27 /** @brief Maximum samples per packet we'll support
  28  *
  29  * NB that two channels = two samples in this program.
  30  */
  31 #define MAXSAMPLES 2048
  32
  33 /** @brief Number of samples to infill by in one go
  34  *
  35  * This is an upper bound - in practice we expect the underlying audio API to
  36  * only ask for a much smaller number of samples in any one go.
  37  */
  38 #define INFILL_SAMPLES (44100 * 2)      /* 1s */
  39
  40 /** @brief Received packet
  41  *
  42  * Received packets are kept in a binary heap (see @ref pheap) ordered by
  43  * timestamp.
  44  */
  45 struct packet {
  46   /** @brief Next packet in @ref next_free_packet or @ref received_packets */
  47   struct packet *next;
  48
  49   /** @brief Number of samples in this packet */
  50   uint32_t nsamples;
  51
  52   /** @brief Timestamp from RTP packet
  53    *
  54    * NB that "timestamps" are really sample counters.  Use lt() or lt_packet()
  55    * to compare timestamps.
  56    */
  57   uint32_t timestamp;
  58
  59   /** @brief Flags
  60    *
  61    * Valid values are:
  62    * - @ref IDLE - the idle bit was set in the RTP packet
  63    */
  64   unsigned flags;
  65 /** @brief idle bit set in RTP packet*/
  66 #define IDLE 0x0001
  67
  68   /** @brief Raw sample data
  69    *
  70    * Only the first @p nsamples samples are defined; the rest is uninitialized
  71    * data.
  72    */
  73   uint16_t samples_raw[MAXSAMPLES];
  74 };
  75
  76 /** @brief Structure of free packet list */
  77 union free_packet {
  78   struct packet p;
  79   union free_packet *next;
  80 };
  81
  82 /** @brief Return true iff \f$a < b\f$ in sequence-space arithmetic
  83  *
  84  * Specifically it returns true if \f$(a-b) mod 2^{32} < 2^{31}\f$.
  85  *
  86  * See also lt_packet().
  87  */
  88 static inline int lt(uint32_t a, uint32_t b) {
  89   return (uint32_t)(a - b) & 0x80000000;
  90 }
  91
  92 /** @brief Return true iff a >= b in sequence-space arithmetic */
  93 static inline int ge(uint32_t a, uint32_t b) {
  94   return !lt(a, b);
  95 }
  96
  97 /** @brief Return true iff a > b in sequence-space arithmetic */
  98 static inline int gt(uint32_t a, uint32_t b) {
  99   return lt(b, a);
 100 }
 101
 102 /** @brief Return true iff a <= b in sequence-space arithmetic */
 103 static inline int le(uint32_t a, uint32_t b) {
 104   return !lt(b, a);
 105 }
 106
 107 /** @brief Ordering for packets, used by @ref pheap */
 108 static inline int lt_packet(const struct packet *a, const struct packet *b) {
 109   return lt(a->timestamp, b->timestamp);
 110 }
 111
 112 /** @brief Return true if @p p contains @p timestamp
 113  *
 114  * Containment implies that a sample @p timestamp exists within the packet.
 115  */
 116 static inline int contains(const struct packet *p, uint32_t timestamp) {
 117   const uint32_t packet_start = p->timestamp;
 118   const uint32_t packet_end = p->timestamp + p->nsamples;
 119
 120   return (ge(timestamp, packet_start)
 121           && lt(timestamp, packet_end));
 122 }
 123
 124 /** @struct pheap
 125  * @brief Binary heap of packets ordered by timestamp */
 126 HEAP_TYPE(pheap, struct packet *, lt_packet);
 127
 128 struct packet *playrtp_new_packet(void);
 129 void playrtp_free_packet(struct packet *p);
 130 void playrtp_fill_buffer(void);
 131 struct packet *playrtp_next_packet(void);
 132
 133 extern const char *device;
 134 extern struct packet *received_packets;
 135 extern struct packet **received_tail;
 136 extern pthread_mutex_t receive_lock;
 137 extern pthread_cond_t receive_cond;
 138 extern uint32_t nreceived;
 139 extern struct pheap packets;
 140 extern volatile uint32_t nsamples;
 141 extern uint32_t next_timestamp;
 142 extern int active;
 143 extern pthread_mutex_t lock;
 144 extern pthread_cond_t cond;
 145 extern unsigned minbuffer;
 146
 147 extern int16_t *dump_buffer;
 148 extern size_t dump_index;
 149 extern size_t dump_size;
 150
 151 void playrtp_oss(void), playrtp_alsa(void), playrtp_coreaudio(void);
 152
 153 #endif /* PLAYRTP_H */
 154
 155 /*
 156 Local Variables:
 157 c-basic-offset:2
 158 comment-column:40
 159 fill-column:79
 160 indent-tabs-mode:nil
 161 End:
 162 */