git.sesse.net Git - vlc/blob - src/misc/decoder_fifo.c

   1 /*****************************************************************************
   2  * decoder_fifo.c: auxiliaries functions used in decoder_fifo.h
   3  *****************************************************************************
   4  * Copyright (C) 1998, 1999, 2000 VideoLAN
   5  *
   6  * Authors:
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public
  19  * License along with this program; if not, write to the
  20  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  21  * Boston, MA 02111-1307, USA.
  22  *****************************************************************************/
  23
  24 #include <sys/types.h>                        /* on BSD, uio.h needs types.h */
  25 #include <sys/uio.h>                                          /* for input.h */
  26
  27 #include "config.h"
  28 #include "common.h"
  29 #include "mtime.h"
  30 #include "threads.h"
  31
  32 #include "debug.h"                 /* XXX?? temporaire, requis par netlist.h */
  33
  34 #include "input.h"
  35 #include "input_netlist.h"
  36 #include "decoder_fifo.h"
  37
  38 void decoder_fifo_next( bit_stream_t * p_bit_stream )
  39 {
  40     /* We are looking for the next TS packet that contains real data,
  41      * and not just a PES header */
  42     do
  43     {
  44         /* We were reading the last TS packet of this PES packet... It's
  45          * time to jump to the next PES packet */
  46         if ( p_bit_stream->p_ts->p_next_ts == NULL )
  47         {
  48             /* We are going to read/write the start and end indexes of the
  49              * decoder fifo and to use the fifo's conditional variable,
  50              * that's why we need to take the lock before */
  51             vlc_mutex_lock( &p_bit_stream->p_decoder_fifo->data_lock );
  52
  53             /* Is the input thread dying ? */
  54             if ( p_bit_stream->p_input->b_die )
  55             {
  56                 vlc_mutex_unlock( &(p_bit_stream->p_decoder_fifo->data_lock) );
  57                 return;
  58             }
  59
  60             /* We should increase the start index of the decoder fifo, but
  61              * if we do this now, the input thread could overwrite the
  62              * pointer to the current PES packet, and we weren't able to
  63              * give it back to the netlist. That's why we free the PES
  64              * packet first. */
  65             input_NetlistFreePES( p_bit_stream->p_input, DECODER_FIFO_START(*p_bit_stream->p_decoder_fifo) );
  66             DECODER_FIFO_INCSTART( *p_bit_stream->p_decoder_fifo );
  67
  68             while ( DECODER_FIFO_ISEMPTY(*p_bit_stream->p_decoder_fifo) )
  69             {
  70                 vlc_cond_wait( &p_bit_stream->p_decoder_fifo->data_wait, &p_bit_stream->p_decoder_fifo->data_lock );
  71                 if ( p_bit_stream->p_input->b_die )
  72                 {
  73                     vlc_mutex_unlock( &(p_bit_stream->p_decoder_fifo->data_lock) );
  74                     return;
  75                 }
  76             }
  77
  78             /* The next byte could be found in the next PES packet */
  79             p_bit_stream->p_ts = DECODER_FIFO_START( *p_bit_stream->p_decoder_fifo )->p_first_ts;
  80
  81             /* We can release the fifo's data lock */
  82             vlc_mutex_unlock( &p_bit_stream->p_decoder_fifo->data_lock );
  83         }
  84         /* Perhaps the next TS packet of the current PES packet contains
  85          * real data (ie its payload's size is greater than 0) */
  86         else
  87         {
  88             p_bit_stream->p_ts = p_bit_stream->p_ts->p_next_ts;
  89         }
  90     } while ( p_bit_stream->p_ts->i_payload_start == p_bit_stream->p_ts->i_payload_end );
  91
  92     /* We've found a TS packet which contains interesting data... */
  93     p_bit_stream->p_byte = p_bit_stream->p_ts->buffer + p_bit_stream->p_ts->i_payload_start;
  94     p_bit_stream->p_end = p_bit_stream->p_ts->buffer + p_bit_stream->p_ts->i_payload_end;
  95 }