1 /*****************************************************************************
2 * audio_output.h : audio output thread interface
3 *****************************************************************************
4 * Copyright (C) 1999, 2000 VideoLAN
5 * $Id: audio_output.h,v 1.46 2002/04/24 00:36:24 sam Exp $
7 * Authors: Michel Kaempf <maxx@via.ecp.fr>
8 * Cyril Deguet <asmax@via.ecp.fr>
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
23 *****************************************************************************/
25 /*****************************************************************************
26 * aout_bank_t, p_aout_bank (global variable)
27 *****************************************************************************
28 * This global variable is accessed by any function using the audio output.
29 *****************************************************************************/
30 typedef struct aout_bank_s
32 /* Array to all the audio outputs */
33 struct aout_thread_s *pp_aout[ AOUT_MAX_THREADS ];
36 vlc_mutex_t lock; /* Global lock */
41 extern aout_bank_t *p_aout_bank;
43 # define p_aout_bank (p_symbols->p_aout_bank)
46 /*****************************************************************************
48 *****************************************************************************
49 * This structure is used to keep the progression of an index up-to-date, in
50 * order to avoid rounding problems and heavy computations, as the function
51 * that handles this structure only uses additions.
52 *****************************************************************************/
53 typedef struct aout_increment_s
55 /* The remainder is used to keep track of the fractional part of the
60 * The increment structure is initialized with the result of an euclidean
72 /*****************************************************************************
74 *****************************************************************************/
75 typedef struct aout_fifo_s
77 /* See the fifo formats below */
84 int i_fifo; /* Just to keep track of the fifo index */
86 vlc_mutex_t data_lock;
92 /* The start frame is the first frame in the buffer that contains decoded
93 * audio data. It it also the first frame in the current timestamped frame
94 * area, ie the first dated frame in the decoded part of the buffer. :-p */
96 boolean_t b_start_frame;
97 /* The next frame is the end frame of the current timestamped frame area,
98 * ie the first dated frame after the start frame. */
100 boolean_t b_next_frame;
101 /* The end frame is the first frame, after the start frame, that doesn't
102 * contain decoded audio data. That's why the end frame is the first frame
103 * where the audio decoder can store its decoded audio frames. */
106 /* Current index in p_aout->buffer */
108 /* Max index in p_aout->buffer */
110 /* Structure used to calculate i_unit with a Bresenham algorithm */
111 aout_increment_t unit_increment;
113 /* The following variable is used to store the number of remaining audio
114 * units in the current timestamped frame area. */
119 #define AOUT_FIFO_ISEMPTY( fifo ) \
120 ( (fifo).i_end_frame == (fifo).i_start_frame )
122 #define AOUT_FIFO_ISFULL( fifo ) \
123 ( ((((fifo).i_end_frame + 1) - (fifo).i_start_frame) & AOUT_FIFO_SIZE) == 0 )
125 #define AOUT_FIFO_INC( i_index ) \
126 ( ((i_index) + 1) & AOUT_FIFO_SIZE )
128 /* List of known fifo formats */
129 #define AOUT_FIFO_NONE 0
130 #define AOUT_FIFO_PCM 1
131 #define AOUT_FIFO_SPDIF 2
133 /*****************************************************************************
134 * aout_thread_t : audio output thread descriptor
135 *****************************************************************************/
136 typedef struct aout_thread_s
138 vlc_thread_t thread_id;
142 vlc_mutex_t fifos_lock;
143 aout_fifo_t fifo[ AOUT_MAX_FIFOS ];
145 /* Plugin used and shortcuts to access its capabilities */
146 struct module_s * p_module;
147 int ( *pf_open ) ( p_aout_thread_t );
148 int ( *pf_setformat ) ( p_aout_thread_t );
149 int ( *pf_getbufinfo ) ( p_aout_thread_t, int );
150 void ( *pf_play ) ( p_aout_thread_t, byte_t *, int );
151 void ( *pf_close ) ( p_aout_thread_t );
154 /* The s32 buffer is used to mix all the audio fifos together before
155 * converting them and storing them in the audio output buffer */
158 /* The size of the audio output buffer is kept in audio units, as this is
159 * the only unit that is common with every audio decoder and audio fifo */
162 /* date is the moment where the first audio unit of the output buffer
166 /* The current volume */
170 /* Format of the audio output samples, number of channels, and
171 * rate and gain (in Hz) of the audio output sound */
176 /* Latency of the audio output plugin, in bytes */
179 /* there might be some useful private structure, such as audio_buf_info
180 * for the OSS output */
185 /* Those are from <linux/soundcard.h> but are needed because of formats
186 * on other platforms */
187 #define AOUT_FMT_U8 0x00000008
188 #define AOUT_FMT_S16_LE 0x00000010 /* Little endian signed 16 */
189 #define AOUT_FMT_S16_BE 0x00000020 /* Big endian signed 16 */
190 #define AOUT_FMT_S8 0x00000040
191 #define AOUT_FMT_U16_LE 0x00000080 /* Little endian U16 */
192 #define AOUT_FMT_U16_BE 0x00000100 /* Big endian U16 */
193 #define AOUT_FMT_AC3 0x00000400 /* Dolby Digital AC3 */
195 #ifdef WORDS_BIGENDIAN
196 #define AOUT_FMT_S16_NE AOUT_FMT_S16_BE
198 #define AOUT_FMT_S16_NE AOUT_FMT_S16_LE
201 /* Number of samples in an AC3 frame */
202 #define AC3_FRAME_SIZE 1536
204 /* Size of a frame for spdif output */
205 #define SPDIF_FRAME_SIZE 6144
207 /*****************************************************************************
209 *****************************************************************************/
211 void aout_InitBank ( void );
212 void aout_EndBank ( void );
214 aout_thread_t * aout_CreateThread ( int *, int, int );
215 void aout_DestroyThread ( aout_thread_t *, int * );
217 aout_fifo_t * aout_CreateFifo ( int, int, int, int, void * );
218 void aout_DestroyFifo ( aout_fifo_t *p_fifo );
219 void aout_FreeFifo ( aout_fifo_t *p_fifo );
221 # define aout_CreateFifo p_symbols->aout_CreateFifo
222 # define aout_DestroyFifo p_symbols->aout_DestroyFifo