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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 | |
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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 | |
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124 | /** @struct pheap |
125 | * @brief Binary heap of packets ordered by timestamp */ |
126 | HEAP_TYPE(pheap, struct packet *, lt_packet); |
127 | |
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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); |
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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; |
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145 | extern unsigned minbuffer; |
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146 | |
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147 | void playrtp_oss(void), playrtp_alsa(void), playrtp_coreaudio(void); |
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148 | |
149 | #endif /* PLAYRTP_H */ |
150 | |
151 | /* |
152 | Local Variables: |
153 | c-basic-offset:2 |
154 | comment-column:40 |
155 | fill-column:79 |
156 | indent-tabs-mode:nil |
157 | End: |
158 | */ |