git.sesse.net Git - vlc/blob - src/ac3_decoder/ac3_decoder.c

   1 /*****************************************************************************
   2  * ac3_decoder.c: ac3 decoder thread
   3  * (c)1999 VideoLAN
   4  *****************************************************************************/
   5
   6 /*****************************************************************************
   7  * Preamble
   8  *****************************************************************************/
   9 #include <unistd.h>                                              /* getpid() */
  10
  11 #include <stdio.h>                                           /* "intf_msg.h" */
  12 #include <stdlib.h>                                      /* malloc(), free() */
  13 #include <sys/soundcard.h>                               /* "audio_output.h" */
  14 #include <sys/uio.h>                                            /* "input.h" */
  15
  16 #include "common.h"
  17 #include "config.h"
  18 #include "mtime.h"
  19 #include "vlc_thread.h"
  20 #include "debug.h"                                      /* "input_netlist.h" */
  21
  22 #include "intf_msg.h"                        /* intf_DbgMsg(), intf_ErrMsg() */
  23
  24 #include "input.h"                                           /* pes_packet_t */
  25 #include "input_netlist.h"                         /* input_NetlistFreePES() */
  26 #include "decoder_fifo.h"         /* DECODER_FIFO_(ISEMPTY|START|INCSTART)() */
  27
  28 #include "audio_output.h"
  29
  30 #include "ac3_decoder.h"
  31
  32 /*****************************************************************************
  33  * Local prototypes
  34  *****************************************************************************/
  35 static int      InitThread              ( ac3dec_thread_t * p_adec );
  36 static void     RunThread               ( ac3dec_thread_t * p_adec );
  37 static void     ErrorThread             ( ac3dec_thread_t * p_adec );
  38 static void     EndThread               ( ac3dec_thread_t * p_adec );
  39
  40 //static byte_t   GetByte                 ( bit_stream_t * p_bit_stream );
  41 //static void     NeedBits                ( bit_stream_t * p_bit_stream, int i_bits );
  42 //static void     DumpBits                ( bit_stream_t * p_bit_stream, int i_bits );
  43 //static int      FindHeader              ( adec_thread_t * p_adec );
  44
  45 /*****************************************************************************
  46  * ac3dec_CreateThread: creates an ac3 decoder thread
  47  *****************************************************************************/
  48 ac3dec_thread_t * ac3dec_CreateThread( input_thread_t * p_input )
  49 {
  50     ac3dec_thread_t *   p_ac3dec;
  51
  52     intf_DbgMsg("ac3dec debug: creating ac3 decoder thread\n");
  53
  54     /* Allocate the memory needed to store the thread's structure */
  55     if ( (p_ac3dec = (ac3dec_thread_t *)malloc( sizeof(ac3dec_thread_t) )) == NULL )
  56     {
  57         intf_ErrMsg("ac3dec error: not enough memory for ac3dec_CreateThread() to create the new thread\n");
  58         return( NULL );
  59     }
  60
  61     /*
  62      * Initialize the thread properties
  63      */
  64     p_ac3dec->b_die = 0;
  65     p_ac3dec->b_error = 0;
  66
  67     /*
  68      * Initialize the input properties
  69      */
  70     /* Initialize the decoder fifo's data lock and conditional variable and set
  71      * its buffer as empty */
  72     vlc_mutex_init( &p_ac3dec->fifo.data_lock );
  73     vlc_cond_init( &p_ac3dec->fifo.data_wait );
  74     p_ac3dec->fifo.i_start = 0;
  75     p_ac3dec->fifo.i_end = 0;
  76     /* Initialize the bit stream structure */
  77     p_ac3dec->bit_stream.p_input = p_input;
  78     p_ac3dec->bit_stream.p_decoder_fifo = &p_ac3dec->fifo;
  79     p_ac3dec->bit_stream.fifo.buffer = 0;
  80     p_ac3dec->bit_stream.fifo.i_available = 0;
  81
  82     /*
  83      * Initialize the output properties
  84      */
  85     p_ac3dec->p_aout = p_input->p_aout;
  86     p_ac3dec->p_aout_fifo = NULL;
  87
  88     /* Spawn the ac3 decoder thread */
  89     if ( vlc_thread_create(&p_ac3dec->thread_id, "ac3 decoder", (vlc_thread_func_t)RunThread, (void *)p_ac3dec) )
  90     {
  91         intf_ErrMsg( "ac3dec error: can't spawn ac3 decoder thread\n" );
  92         free( p_ac3dec );
  93         return( NULL );
  94     }
  95
  96     intf_DbgMsg( "ac3dec debug: ac3 decoder thread (%p) created\n", p_ac3dec );
  97     return( p_ac3dec );
  98 }
  99
 100 /*****************************************************************************
 101  * ac3dec_DestroyThread: destroys an ac3 decoder thread
 102  *****************************************************************************/
 103 void ac3dec_DestroyThread( ac3dec_thread_t * p_ac3dec )
 104 {
 105     intf_DbgMsg( "ac3dec debug: requesting termination of ac3 decoder thread %p\n", p_ac3dec );
 106
 107     /* Ask thread to kill itself */
 108     p_ac3dec->b_die = 1;
 109     /* Make sure the decoder thread leaves the GetByte() function */
 110     vlc_mutex_lock( &(p_ac3dec->fifo.data_lock) );
 111     vlc_cond_signal( &(p_ac3dec->fifo.data_wait) );
 112     vlc_mutex_unlock( &(p_ac3dec->fifo.data_lock) );
 113
 114     /* Waiting for the decoder thread to exit */
 115     /* Remove this as soon as the "status" flag is implemented */
 116     vlc_thread_join( p_ac3dec->thread_id );
 117 }
 118
 119 /* Following functions are local */
 120
 121 /*****************************************************************************
 122  * decode_find_sync()
 123  *****************************************************************************/
 124 static __inline__ int decode_find_sync( ac3dec_thread_t * p_ac3dec )
 125 {
 126     while ( (!p_ac3dec->b_die) && (!p_ac3dec->b_error) )
 127     {
 128         NeedBits( &(p_ac3dec->bit_stream), 16 );
 129         if ( (p_ac3dec->bit_stream.fifo.buffer >> (32 - 16)) == 0x0b77 )
 130         {
 131             DumpBits( &(p_ac3dec->bit_stream), 16 );
 132             p_ac3dec->total_bits_read = 16;
 133             return( 0 );
 134         }
 135         DumpBits( &(p_ac3dec->bit_stream), 1 );
 136     }
 137     return( -1 );
 138 }
 139
 140 /*****************************************************************************
 141  * InitThread : initialize an ac3 decoder thread
 142  *****************************************************************************/
 143 static int InitThread( ac3dec_thread_t * p_ac3dec )
 144 {
 145     aout_fifo_t         aout_fifo;
 146
 147     intf_DbgMsg( "ac3dec debug: initializing ac3 decoder thread %p\n", p_ac3dec );
 148
 149     /* Our first job is to initialize the bit stream structure with the
 150      * beginning of the input stream */
 151     vlc_mutex_lock( &p_ac3dec->fifo.data_lock );
 152     while ( DECODER_FIFO_ISEMPTY(p_ac3dec->fifo) )
 153     {
 154         vlc_cond_wait( &p_ac3dec->fifo.data_wait, &p_ac3dec->fifo.data_lock );
 155     }
 156     p_ac3dec->bit_stream.p_ts = DECODER_FIFO_START( p_ac3dec->fifo )->p_first_ts;
 157     p_ac3dec->bit_stream.i_byte = p_ac3dec->bit_stream.p_ts->i_payload_start;
 158     vlc_mutex_unlock( &p_ac3dec->fifo.data_lock );
 159
 160     aout_fifo.i_type = AOUT_ADEC_STEREO_FIFO;
 161     aout_fifo.b_stereo = 1;
 162
 163     aout_fifo.l_frame_size = AC3DEC_FRAME_SIZE;
 164
 165     /* Creating the audio output fifo */
 166     if ( (p_ac3dec->p_aout_fifo = aout_CreateFifo(p_ac3dec->p_aout, &aout_fifo)) == NULL )
 167     {
 168         return( -1 );
 169     }
 170
 171     intf_DbgMsg( "ac3dec debug: ac3 decoder thread %p initialized\n", p_ac3dec );
 172     return( 0 );
 173 }
 174
 175 /*****************************************************************************
 176  * RunThread : ac3 decoder thread
 177  *****************************************************************************/
 178 static void RunThread( ac3dec_thread_t * p_ac3dec )
 179 {
 180     intf_DbgMsg( "ac3dec debug: running ac3 decoder thread (%p) (pid == %i)\n", p_ac3dec, getpid() );
 181
 182     /* Initializing the ac3 decoder thread */
 183     if ( InitThread(p_ac3dec) )
 184     {
 185         p_ac3dec->b_error = 1;
 186     }
 187
 188     /* ac3 decoder thread's main loop */
 189     while ( (!p_ac3dec->b_die) && (!p_ac3dec->b_error) )
 190     {
 191         if ( decode_find_sync(p_ac3dec) == 0 )
 192         {
 193             fprintf( stderr, "ac3dec debug: decode_find_sync() == 0\n" );
 194         }
 195     }
 196
 197     /* If b_error is set, the ac3 decoder thread enters the error loop */
 198     if ( p_ac3dec->b_error )
 199     {
 200         ErrorThread( p_ac3dec );
 201     }
 202
 203     /* End of the ac3 decoder thread */
 204     EndThread( p_ac3dec );
 205 }
 206
 207 /*****************************************************************************
 208  * ErrorThread : ac3 decoder's RunThread() error loop
 209  *****************************************************************************/
 210 static void ErrorThread( ac3dec_thread_t * p_ac3dec )
 211 {
 212     /* We take the lock, because we are going to read/write the start/end
 213      * indexes of the decoder fifo */
 214     vlc_mutex_lock( &p_ac3dec->fifo.data_lock );
 215
 216     /* Wait until a `die' order is sent */
 217     while( !p_ac3dec->b_die )
 218     {
 219         /* Trash all received PES packets */
 220         while( !DECODER_FIFO_ISEMPTY(p_ac3dec->fifo) )
 221         {
 222             input_NetlistFreePES( p_ac3dec->bit_stream.p_input, DECODER_FIFO_START(p_ac3dec->fifo) );
 223             DECODER_FIFO_INCSTART( p_ac3dec->fifo );
 224         }
 225
 226         /* Waiting for the input thread to put new PES packets in the fifo */
 227         vlc_cond_wait( &p_ac3dec->fifo.data_wait, &p_ac3dec->fifo.data_lock );
 228     }
 229
 230     /* We can release the lock before leaving */
 231     vlc_mutex_unlock( &p_ac3dec->fifo.data_lock );
 232 }
 233
 234 /*****************************************************************************
 235  * EndThread : ac3 decoder thread destruction
 236  *****************************************************************************/
 237 static void EndThread( ac3dec_thread_t * p_ac3dec )
 238 {
 239     intf_DbgMsg( "ac3dec debug: destroying ac3 decoder thread %p\n", p_ac3dec );
 240
 241     /* If the audio output fifo was created, we destroy it */
 242     if ( p_ac3dec->p_aout_fifo != NULL )
 243     {
 244         aout_DestroyFifo( p_ac3dec->p_aout_fifo );
 245     }
 246
 247     /* Destroy descriptor */
 248     free( p_ac3dec );
 249
 250     intf_DbgMsg( "ac3dec debug: ac3 decoder thread %p destroyed\n", p_ac3dec );
 251 }