1 /*****************************************************************************
2 * audio_output.h : audio output thread interface
4 *****************************************************************************
6 * - <sys/soundcard.h> ( audio_buf_info )
7 * - "common.h" ( boolean_t )
8 * - "mtime.h" ( mtime_t )
9 * - "vlc_thread.h" ( vlc_thread_t )
10 *****************************************************************************/
14 * - Créer un flag destroy dans les fifos audio pour indiquer au thread audio
15 * qu'il peut libérer la mémoire occupée par le buffer de la fifo lorsqu'il
16 * le désire (fin du son ou fin du thread)
17 * - Redéplacer les #define dans config.h
22 * Defines => "config.h"
25 /* Default output device. You probably should not change this. */
26 #define AOUT_DEFAULT_DEVICE "/dev/dsp"
28 /* Default audio output format (AFMT_S16_NE = Native Endianess) */
29 #define AOUT_DEFAULT_FORMAT AFMT_S16_NE
31 /* Default stereo mode (0 stands for mono, 1 for stereo) */
32 #define AOUT_DEFAULT_STEREO 1
34 /* Audio output rate, in Hz */
35 #define AOUT_MIN_RATE 22050 /* ?? */
36 #define AOUT_DEFAULT_RATE 44100
37 #define AOUT_MAX_RATE 48000
39 /* Number of audio output frames contained in an audio output fifo.
40 * (AOUT_FIFO_SIZE + 1) must be a power of 2, in order to optimise the
41 * %(AOUT_FIFO_SIZE + 1) operation with an &AOUT_FIFO_SIZE.
42 * With 511 we have at least 511*384/2/48000=2 seconds of sound */
43 #define AOUT_FIFO_SIZE 511
45 /* Maximum number of audio fifos. The value of AOUT_MAX_FIFOS should be a power
46 * of two, in order to optimize the '/AOUT_MAX_FIFOS' and '*AOUT_MAX_FIFOS'
47 * operations with '>>' and '<<' (gcc changes this at compilation-time) */
48 #define AOUT_MAX_FIFOS 2
50 /* Duration (in microseconds) of an audio output buffer should be :
51 * - short, in order to be able to play a new song very quickly (especially a
52 * song from the interface)
53 * - long, in order to perform the buffer calculations as few as possible */
54 #define AOUT_BUFFER_DURATION 100000
59 #define AOUT_FIFO_ISEMPTY( fifo ) ( (fifo).l_end_frame == (fifo).i_start_frame )
60 #define AOUT_FIFO_ISFULL( fifo ) ( ((((fifo).l_end_frame + 1) - (fifo).l_start_frame) & AOUT_FIFO_SIZE) == 0 )
62 /*****************************************************************************
64 *****************************************************************************/
67 /* Path to the audio output device (default is set to "/dev/dsp") */
71 /* Format of the audio output samples (see <sys/soundcard.h>) */
73 /* Following boolean is set to 0 if output sound is mono, 1 if stereo */
75 /* Rate of the audio output sound (in Hz) */
78 /* Buffer information structure, used by aout_dspGetBufInfo() to store the
79 * current state of the internal sound card buffer */
80 audio_buf_info buf_info;
84 /*****************************************************************************
86 *****************************************************************************
87 * This structure is used to keep the progression of an index up-to-date, in
88 * order to avoid rounding problems and heavy computations, as the function
89 * that handles this structure only uses additions.
90 *****************************************************************************/
93 /* The remainder is used to keep track of the fractional part of the
98 * The increment structure is initialized with the result of an euclidean
101 * l_euclidean_numerator l_euclidean_remainder
102 * ----------------------- = l_euclidean_integer + -----------------------
103 * l_euclidean_denominator l_euclidean_denominator
106 long l_euclidean_integer;
107 long l_euclidean_remainder;
108 long l_euclidean_denominator;
112 /*****************************************************************************
114 *****************************************************************************/
117 /* See the fifo types below */
124 vlc_mutex_t data_lock;
125 vlc_cond_t data_wait;
130 /* The start frame is the first frame in the buffer that contains decoded
131 * audio data. It it also the first frame in the current timestamped frame
132 * area, ie the first dated frame in the decoded part of the buffer. :-p */
134 boolean_t b_start_frame;
135 /* The next frame is the end frame of the current timestamped frame area,
136 * ie the first dated frame after the start frame. */
138 boolean_t b_next_frame;
139 /* The end frame is the first frame, after the start frame, that doesn't
140 * contain decoded audio data. That's why the end frame is the first frame
141 * where the audio decoder can store its decoded audio frames. */
145 aout_increment_t unit_increment;
146 /* The following variable is used to store the number of remaining audio
147 * units in the current timestamped frame area. */
152 #define AOUT_EMPTY_FIFO 0
153 #define AOUT_INTF_MONO_FIFO 1
154 #define AOUT_INTF_STEREO_FIFO 2
155 #define AOUT_ADEC_MONO_FIFO 3
156 #define AOUT_ADEC_STEREO_FIFO 4
158 /*****************************************************************************
160 *****************************************************************************/
161 typedef struct aout_thread_s
163 vlc_thread_t thread_id;
168 vlc_mutex_t fifos_lock;
169 aout_fifo_t fifo[ AOUT_MAX_FIFOS ];
172 /* The s32 buffer is used to mix all the audio fifos together before
173 * converting them and storing them in the audio output buffer */
176 /* The size of the audio output buffer is kept in audio units, as this is
177 * the only unit that is common with every audio decoder and audio fifo */
181 /* date is the moment where the first audio unit of the output buffer
187 /*****************************************************************************
189 *****************************************************************************/
190 aout_thread_t * aout_CreateThread ( int *pi_status );
191 void aout_DestroyThread ( aout_thread_t *p_aout, int *pi_status );
194 aout_fifo_t * aout_CreateFifo ( aout_thread_t *p_aout, aout_fifo_t *p_fifo );
195 void aout_DestroyFifo ( aout_fifo_t *p_fifo );