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1 | /* |
2 | * This file is part of DisOrder |
3 | * Copyright (C) 2005, 2006, 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 server/speaker.h |
21 | * @brief Speaker process |
22 | */ |
23 | #ifndef SPEAKER_H |
24 | #define SPEAKER_H |
25 | |
26 | #ifdef WORDS_BIGENDIAN |
27 | # define MACHINE_AO_FMT AO_FMT_BIG |
28 | #else |
29 | # define MACHINE_AO_FMT AO_FMT_LITTLE |
30 | #endif |
31 | |
32 | /** @brief How many seconds of input to buffer |
33 | * |
34 | * While any given connection has this much audio buffered, no more reads will |
35 | * be issued for that connection. The decoder will have to wait. |
36 | */ |
37 | #define BUFFER_SECONDS 5 |
38 | |
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39 | /** @brief Minimum number of frames to try to play at once |
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40 | * |
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41 | * The main loop will only attempt to play any audio when this many |
42 | * frames are available (or the current track has reached the end). |
43 | * The actual number of frames it attempts to play will often be |
44 | * larger than this (up to three times). |
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45 | * |
46 | * For ALSA we request a buffer of three times this size and set the low |
47 | * watermark to this amount. The goal is then to keep between 1 and 3 times |
48 | * this many frames in play. |
49 | * |
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50 | * For other we attempt to play up to three times this many frames per |
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51 | * shot. In practice we will often only send much less than this. |
52 | */ |
53 | #define FRAMES 4096 |
54 | |
55 | /** @brief Bytes to send per network packet |
56 | * |
57 | * Don't make this too big or arithmetic will start to overflow. |
58 | */ |
59 | #define NETWORK_BYTES (1024+sizeof(struct rtp_header)) |
60 | |
61 | /** @brief Maximum RTP playahead (ms) */ |
62 | #define RTP_AHEAD_MS 1000 |
63 | |
64 | /** @brief Maximum number of FDs to poll for */ |
65 | #define NFDS 256 |
66 | |
67 | /** @brief Track structure |
68 | * |
69 | * Known tracks are kept in a linked list. Usually there will be at most two |
70 | * of these but rearranging the queue can cause there to be more. |
71 | */ |
72 | struct track { |
73 | struct track *next; /* next track */ |
74 | int fd; /* input FD */ |
75 | char id[24]; /* ID */ |
76 | size_t start, used; /* start + bytes used */ |
77 | int eof; /* input is at EOF */ |
78 | int got_format; /* got format yet? */ |
79 | ao_sample_format format; /* sample format */ |
80 | unsigned long long played; /* number of frames played */ |
81 | char *buffer; /* sample buffer */ |
82 | size_t size; /* sample buffer size */ |
83 | int slot; /* poll array slot */ |
84 | }; |
85 | |
86 | /** @brief Structure of a backend */ |
87 | struct speaker_backend { |
88 | /** @brief Which backend this is |
89 | * |
90 | * @c -1 terminates the list. |
91 | */ |
92 | int backend; |
93 | |
94 | /** @brief Flags |
95 | * |
96 | * Possible values |
97 | * - @ref FIXED_FORMAT |
98 | */ |
99 | unsigned flags; |
100 | /** @brief Lock to configured sample format */ |
101 | #define FIXED_FORMAT 0x0001 |
102 | |
103 | /** @brief Initialization |
104 | * |
105 | * Called once at startup. This is responsible for one-time setup |
106 | * operations, for instance opening a network socket to transmit to. |
107 | * |
108 | * When writing to a native sound API this might @b not imply opening the |
109 | * native sound device - that might be done by @c activate below. |
110 | */ |
111 | void (*init)(void); |
112 | |
113 | /** @brief Activation |
114 | * @return 0 on success, non-0 on error |
115 | * |
116 | * Called to activate the output device. |
117 | * |
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118 | * On input @ref device_state may be anything. If it is @ref |
119 | * device_open then the device is already open but might be using |
120 | * the wrong sample format. The device should be reconfigured to |
121 | * use the right sample format. |
122 | * |
123 | * If it is @ref device_error then a retry is underway and an |
124 | * attempt to recover or re-open the device (with the right sample |
125 | * format) should be made. |
126 | * |
127 | * If it is @ref device_closed then the device should be opened with |
128 | * the right sample format. |
129 | * |
130 | * If the @ref FIXED_FORMAT flag is not set then @ref device_format |
131 | * must be set on success. |
132 | * |
133 | * Some devices are effectively always open and have no error state, |
134 | * in which case this callback can be NULL. In this case @ref |
135 | * FIXED_FORMAT must be set. Note that @ref device_state still |
136 | * switches between @ref device_open and @ref device_closd in this |
137 | * case. |
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138 | */ |
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139 | void (*activate)(void); |
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140 | |
141 | /** @brief Play sound |
142 | * @param frames Number of frames to play |
143 | * @return Number of frames actually played |
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144 | * |
145 | * If an error occurs (and it is not immediately recovered) this |
146 | * should set @ref device_state to @ref device_error. |
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147 | */ |
148 | size_t (*play)(size_t frames); |
149 | |
150 | /** @brief Deactivation |
151 | * |
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152 | * Called to deactivate the sound device. This is the inverse of @c |
153 | * activate above. |
154 | * |
155 | * For sound devices that are open all the time and have no error |
156 | * state, this callback can be NULL. Note that @ref device_state |
157 | * still switches between @ref device_open and @ref device_closd in |
158 | * this case. |
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159 | */ |
160 | void (*deactivate)(void); |
161 | |
162 | /** @brief Called before poll() |
163 | * |
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164 | * Called before the call to poll(). Should call addfd() to update |
165 | * the FD array and stash the slot number somewhere safe. This will |
166 | * only be called if @ref device_state = @ref device_open. |
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167 | */ |
168 | void (*beforepoll)(void); |
169 | |
170 | /** @brief Called after poll() |
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171 | * @return 1 if output device ready for play, 0 otherwise |
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172 | * |
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173 | * Called after the call to poll(). This will only be called if |
174 | * @ref device_state = @ref device_open. |
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175 | * |
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176 | * The return value should be 1 if the device was ready to play, or |
177 | * 0 if it was not. |
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178 | */ |
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179 | int (*ready)(void); |
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180 | }; |
181 | |
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182 | /** @brief Possible device states */ |
183 | enum device_states { |
184 | /** @brief The device is closed */ |
185 | device_closed, |
186 | |
187 | /** @brief The device is open and ready to receive sound |
188 | * |
189 | * The current device sample format is potentially part of this state. |
190 | */ |
191 | device_open, |
192 | |
193 | /** @brief An error has occurred on the device |
194 | * |
195 | * This state is used to ensure that a small interval is left |
196 | * between retrying the device. If errors just set @ref |
197 | * device_closed then the main loop would busy-wait on broken output |
198 | * devices. |
199 | * |
200 | * The current device sample format is potentially part of this state. |
201 | */ |
202 | device_error |
203 | }; |
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204 | |
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205 | extern enum device_states device_state; |
206 | extern ao_sample_format device_format; |
207 | extern struct track *tracks; |
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208 | extern struct track *playing; |
209 | |
210 | #endif /* SPEAKER_H */ |
211 | |
212 | /* |
213 | Local Variables: |
214 | c-basic-offset:2 |
215 | comment-column:40 |
216 | fill-column:79 |
217 | indent-tabs-mode:nil |
218 | End: |
219 | */ |