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 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.h
  19  * @brief RTP player
  20  */
  21
  22 #ifndef PLAYRTP_H
  23 #define PLAYRTP_H
  24
  25 /** @brief Maximum samples per packet we'll support
  26  *
  27  * NB that two channels = two samples in this program.
  28  */
  29 #define MAXSAMPLES 2048
  30
  31 /** @brief Number of samples to infill by in one go
  32  *
  33  * This is an upper bound - in practice we expect the underlying audio API to
  34  * only ask for a much smaller number of samples in any one go.
  35  */
  36 #define INFILL_SAMPLES (44100 * 2)      /* 1s */
  37
  38 /** @brief Received packet
  39  *
  40  * Received packets are kept in a binary heap (see @ref pheap) ordered by
  41  * timestamp.
  42  */
  43 struct packet {
  44   /** @brief Next packet in @ref next_free_packet or @ref received_packets */
  45   struct packet *next;
  46
  47   /** @brief Number of samples in this packet */
  48   uint32_t nsamples;
  49
  50   /** @brief Timestamp from RTP packet
  51    *
  52    * NB that "timestamps" are really sample counters.  Use lt() or lt_packet()
  53    * to compare timestamps.
  54    */
  55   uint32_t timestamp;
  56
  57   /** @brief Flags
  58    *
  59    * Valid values are:
  60    * - @ref IDLE - the idle bit was set in the RTP packet
  61    * - @ref SILENT - packet is entirely silent
  62    */
  63   unsigned flags;
  64 /** @brief idle bit set in RTP packet*/
  65 #define IDLE 0x0001
  66
  67 /** @brief RTP packet is entirely silent */
  68 #define SILENT 0x0002
  69
  70   /** @brief Raw sample data
  71    *
  72    * Only the first @p nsamples samples are defined; the rest is uninitialized
  73    * data.
  74    */
  75   uint16_t samples_raw[MAXSAMPLES];
  76 };
  77
  78 /** @brief Structure of free packet list */
  79 union free_packet {
  80   struct packet p;
  81   union free_packet *next;
  82 };
  83
  84 /** @brief Return true iff \f$a < b\f$ in sequence-space arithmetic
  85  *
  86  * Specifically it returns true if \f$(a-b) mod 2^{32} < 2^{31}\f$.
  87  *
  88  * See also lt_packet().
  89  */
  90 static inline int lt(uint32_t a, uint32_t b) {
  91   return (uint32_t)(a - b) & 0x80000000;
  92 }
  93
  94 /** @brief Return true iff a >= b in sequence-space arithmetic */
  95 static inline int ge(uint32_t a, uint32_t b) {
  96   return !lt(a, b);
  97 }
  98
  99 /** @brief Return true iff a > b in sequence-space arithmetic */
 100 static inline int gt(uint32_t a, uint32_t b) {
 101   return lt(b, a);
 102 }
 103
 104 /** @brief Return true iff a <= b in sequence-space arithmetic */
 105 static inline int le(uint32_t a, uint32_t b) {
 106   return !lt(b, a);
 107 }
 108
 109 /** @brief Ordering for packets, used by @ref pheap */
 110 static inline int lt_packet(const struct packet *a, const struct packet *b) {
 111   return lt(a->timestamp, b->timestamp);
 112 }
 113
 114 /** @brief Return true if @p p contains @p timestamp
 115  *
 116  * Containment implies that a sample @p timestamp exists within the packet.
 117  */
 118 static inline int contains(const struct packet *p, uint32_t timestamp) {
 119   const uint32_t packet_start = p->timestamp;
 120   const uint32_t packet_end = p->timestamp + p->nsamples;
 121
 122   return (ge(timestamp, packet_start)
 123           && lt(timestamp, packet_end));
 124 }
 125
 126 /** @struct pheap
 127  * @brief Binary heap of packets ordered by timestamp */
 128 HEAP_TYPE(pheap, struct packet *, lt_packet);
 129
 130 struct packet *playrtp_new_packet(void);
 131 void playrtp_free_packet(struct packet *p);
 132 void playrtp_fill_buffer(void);
 133 struct packet *playrtp_next_packet(void);
 134
 135 extern struct packet *received_packets;
 136 extern struct packet **received_tail;
 137 extern pthread_mutex_t receive_lock;
 138 extern pthread_cond_t receive_cond;
 139 extern uint32_t nreceived;
 140 extern struct pheap packets;
 141 extern volatile uint32_t nsamples;
 142 extern uint32_t next_timestamp;
 143 extern int active;
 144 extern pthread_mutex_t lock;
 145 extern pthread_cond_t cond;
 146 extern unsigned minbuffer;
 147
 148 extern int16_t *dump_buffer;
 149 extern size_t dump_index;
 150 extern size_t dump_size;
 151
 152 void playrtp_oss(void), playrtp_alsa(void), playrtp_coreaudio(void);
 153
 154 #endif /* PLAYRTP_H */
 155
 156 /*
 157 Local Variables:
 158 c-basic-offset:2
 159 comment-column:40
 160 fill-column:79
 161 indent-tabs-mode:nil
 162 End:
 163 */