| 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 | */ |