git.sesse.net Git - vlc/blob - src/input/input_ext-dec.c

   1 /*****************************************************************************
   2  * input_ext-dec.c: services to the decoders
   3  *****************************************************************************
   4  * Copyright (C) 1998, 1999, 2000 VideoLAN
   5  * $Id: input_ext-dec.c,v 1.16 2001/05/08 00:43:57 sam Exp $
   6  *
   7  * Authors: Christophe Massiot <massiot@via.ecp.fr>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  22  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27 #include "defs.h"
  28
  29 #include <string.h>                                    /* memcpy(), memset() */
  30 #include <sys/types.h>                                              /* off_t */
  31
  32 #include "config.h"
  33 #include "common.h"
  34 #include "threads.h"
  35 #include "mtime.h"
  36
  37 #include "intf_msg.h"
  38
  39 #include "stream_control.h"
  40 #include "input_ext-dec.h"
  41 #include "input_ext-intf.h"
  42
  43 #include "input.h"
  44
  45 /*****************************************************************************
  46  * InitBitstream: initialize a bit_stream_t structure
  47  *****************************************************************************/
  48 void InitBitstream( bit_stream_t * p_bit_stream, decoder_fifo_t * p_fifo,
  49                     void (* pf_bitstream_callback)( struct bit_stream_s *,
  50                                                     boolean_t ),
  51                     void * p_callback_arg )
  52 {
  53     p_bit_stream->p_decoder_fifo = p_fifo;
  54     p_bit_stream->pf_next_data_packet = NextDataPacket;
  55     p_bit_stream->pf_bitstream_callback = pf_bitstream_callback;
  56     p_bit_stream->p_callback_arg = p_callback_arg;
  57
  58     /* Get the first data packet. */
  59     vlc_mutex_lock( &p_fifo->data_lock );
  60     while ( DECODER_FIFO_ISEMPTY( *p_fifo ) )
  61     {
  62         if ( p_fifo->b_die )
  63         {
  64             vlc_mutex_unlock( &p_fifo->data_lock );
  65             return;
  66         }
  67         vlc_cond_wait( &p_fifo->data_wait, &p_fifo->data_lock );
  68     }
  69     p_bit_stream->p_data = DECODER_FIFO_START( *p_fifo )->p_first;
  70     p_bit_stream->p_byte = p_bit_stream->p_data->p_payload_start;
  71     p_bit_stream->p_end  = p_bit_stream->p_data->p_payload_end;
  72     p_bit_stream->fifo.buffer = 0;
  73     p_bit_stream->fifo.i_available = 0;
  74     vlc_mutex_unlock( &p_fifo->data_lock );
  75
  76     /* Call back the decoder. */
  77     if( p_bit_stream->pf_bitstream_callback != NULL )
  78     {
  79         p_bit_stream->pf_bitstream_callback( p_bit_stream, 1 );
  80     }
  81
  82     if( p_bit_stream->p_byte <= p_bit_stream->p_end - sizeof(WORD_TYPE) )
  83     {
  84         /* Get aligned on a word boundary.
  85          * NB : we _will_ get aligned, because we have at most
  86          * sizeof(WORD_TYPE) - 1 bytes to store, and at least
  87          * sizeof(WORD_TYPE) - 1 empty bytes in the bit buffer. */
  88         AlignWord( p_bit_stream );
  89     }
  90 }
  91
  92 /*****************************************************************************
  93  * NextDataPacket: go to the next data packet
  94  *****************************************************************************/
  95 void NextDataPacket( bit_stream_t * p_bit_stream )
  96 {
  97     decoder_fifo_t *    p_fifo = p_bit_stream->p_decoder_fifo;
  98     boolean_t           b_new_pes;
  99
 100     /* We are looking for the next data packet that contains real data,
 101      * and not just a PES header */
 102     do
 103     {
 104         /* We were reading the last data packet of this PES packet... It's
 105          * time to jump to the next PES packet */
 106         if( p_bit_stream->p_data->p_next == NULL )
 107         {
 108             /* We are going to read/write the start and end indexes of the
 109              * decoder fifo and to use the fifo's conditional variable,
 110              * that's why we need to take the lock before. */
 111             vlc_mutex_lock( &p_fifo->data_lock );
 112
 113             /* Free the previous PES packet. */
 114             p_fifo->pf_delete_pes( p_fifo->p_packets_mgt,
 115                                    DECODER_FIFO_START( *p_fifo ) );
 116             DECODER_FIFO_INCSTART( *p_fifo );
 117
 118             if( DECODER_FIFO_ISEMPTY( *p_fifo ) )
 119             {
 120                 /* Wait for the input to tell us when we receive a packet. */
 121                 vlc_cond_wait( &p_fifo->data_wait, &p_fifo->data_lock );
 122             }
 123
 124             /* The next byte could be found in the next PES packet */
 125             p_bit_stream->p_data = DECODER_FIFO_START( *p_fifo )->p_first;
 126
 127             vlc_mutex_unlock( &p_fifo->data_lock );
 128
 129             b_new_pes = 1;
 130         }
 131         else
 132         {
 133             /* Perhaps the next data packet of the current PES packet contains
 134              * real data (ie its payload's size is greater than 0). */
 135             p_bit_stream->p_data = p_bit_stream->p_data->p_next;
 136
 137             b_new_pes = 0;
 138         }
 139     } while ( p_bit_stream->p_data->p_payload_start
 140                == p_bit_stream->p_data->p_payload_end );
 141
 142     /* We've found a data packet which contains interesting data... */
 143     p_bit_stream->p_byte = p_bit_stream->p_data->p_payload_start;
 144     p_bit_stream->p_end  = p_bit_stream->p_data->p_payload_end;
 145
 146     /* Call back the decoder. */
 147     if( p_bit_stream->pf_bitstream_callback != NULL )
 148     {
 149         p_bit_stream->pf_bitstream_callback( p_bit_stream, b_new_pes );
 150     }
 151 }
 152
 153 /*****************************************************************************
 154  * UnalignedShowBits : return i_bits bits from the bit stream, even when
 155  * not aligned on a word boundary
 156  *****************************************************************************/
 157 u32 UnalignedShowBits( bit_stream_t * p_bit_stream, unsigned int i_bits )
 158 {
 159     /* We just fill in the bit buffer. */
 160     while( p_bit_stream->fifo.i_available < i_bits )
 161     {
 162         if( p_bit_stream->p_byte < p_bit_stream->p_end )
 163         {
 164             p_bit_stream->fifo.buffer |= *(p_bit_stream->p_byte++)
 165                                             << (8 * sizeof(WORD_TYPE) - 8
 166                                             - p_bit_stream->fifo.i_available);
 167             p_bit_stream->fifo.i_available += 8;
 168         }
 169         else
 170         {
 171             p_bit_stream->pf_next_data_packet( p_bit_stream );
 172
 173             if( (ptrdiff_t)p_bit_stream->p_byte & (sizeof(WORD_TYPE) - 1) )
 174             {
 175                 /* We are not aligned anymore. */
 176                 if( ((ptrdiff_t)p_bit_stream->p_byte
 177                                     & (sizeof(WORD_TYPE) - 1)) * 8
 178                         < p_bit_stream->fifo.i_available )
 179                 {
 180                     /* We are not aligned, and won't be. Copy the first word
 181                      * of the packet in a temporary buffer, and we'll see
 182                      * later. */
 183                     int     i;
 184
 185                     /* sizeof(WORD_TYPE) - number of bytes to trash
 186                      * from the last payload */
 187                     int     j;
 188
 189                     p_bit_stream->i_showbits_buffer = 0;
 190
 191                     for( j = i = 0 ; i < sizeof(WORD_TYPE) ; i++ )
 192                     {
 193                         if( p_bit_stream->p_byte >= p_bit_stream->p_end )
 194                         {
 195                             j = i;
 196                             p_bit_stream->pf_next_data_packet( p_bit_stream );
 197                         }
 198                         ((byte_t *)&p_bit_stream->i_showbits_buffer)[i] =
 199                             * p_bit_stream->p_byte;
 200                         p_bit_stream->p_byte++;
 201                     }
 202
 203                     /* This is kind of kludgy. */
 204                     p_bit_stream->p_data->p_payload_start +=
 205                                                          sizeof(WORD_TYPE) - j;
 206                     p_bit_stream->p_byte =
 207                         (byte_t *)&p_bit_stream->i_showbits_buffer;
 208                     p_bit_stream->p_end =
 209                         (byte_t *)&p_bit_stream->i_showbits_buffer
 210                             + sizeof(WORD_TYPE);
 211                     p_bit_stream->showbits_data.p_next = p_bit_stream->p_data;
 212                     p_bit_stream->p_data = &p_bit_stream->showbits_data;
 213                 }
 214                 else
 215                 {
 216                     /* We are not aligned, but we can be. */
 217                     AlignWord( p_bit_stream );
 218                 }
 219             }
 220
 221             return( ShowBits( p_bit_stream, i_bits ) );
 222         }
 223     }
 224     return( p_bit_stream->fifo.buffer >> (8 * sizeof(WORD_TYPE) - i_bits) );
 225 }
 226
 227 /*****************************************************************************
 228  * UnalignedGetBits : returns i_bits bits from the bit stream and removes
 229  * them from the buffer, even when the bit stream is not aligned on a word
 230  * boundary
 231  *****************************************************************************/
 232 u32 UnalignedGetBits( bit_stream_t * p_bit_stream, unsigned int i_bits )
 233 {
 234     u32         i_result;
 235
 236     i_result = p_bit_stream->fifo.buffer
 237                     >> (8 * sizeof(WORD_TYPE) - i_bits);
 238     i_bits = -p_bit_stream->fifo.i_available;
 239
 240     /* Gather missing bytes. */
 241     while( i_bits >= 8 )
 242     {
 243         if( p_bit_stream->p_byte < p_bit_stream->p_end )
 244         {
 245             i_result |= *(p_bit_stream->p_byte++) << (i_bits - 8);
 246             i_bits -= 8;
 247         }
 248         else
 249         {
 250             p_bit_stream->pf_next_data_packet( p_bit_stream );
 251             i_result |= *(p_bit_stream->p_byte++) << (i_bits - 8);
 252             i_bits -= 8;
 253         }
 254     }
 255
 256     /* Gather missing bits. */
 257     if( i_bits > 0 )
 258     {
 259         unsigned int    i_tmp = 8 - i_bits;
 260
 261         if( p_bit_stream->p_byte < p_bit_stream->p_end )
 262         {
 263             i_result |= *p_bit_stream->p_byte >> i_tmp;
 264             p_bit_stream->fifo.buffer = *(p_bit_stream->p_byte++)
 265                  << ( sizeof(WORD_TYPE) * 8 - i_tmp );
 266             p_bit_stream->fifo.i_available = i_tmp;
 267         }
 268         else
 269         {
 270             p_bit_stream->pf_next_data_packet( p_bit_stream );
 271             i_result |= *p_bit_stream->p_byte >> i_tmp;
 272             p_bit_stream->fifo.buffer = *(p_bit_stream->p_byte++)
 273                  << ( sizeof(WORD_TYPE) * 8 - i_tmp );
 274             p_bit_stream->fifo.i_available = i_tmp;
 275         }
 276     }
 277     else
 278     {
 279         p_bit_stream->fifo.i_available = 0;
 280         p_bit_stream->fifo.buffer = 0;
 281     }
 282
 283     if( p_bit_stream->p_byte <= p_bit_stream->p_end - sizeof(WORD_TYPE) )
 284     {
 285         /* Get aligned on a word boundary. Otherwise it is safer
 286          * to do it the next time.
 287          * NB : we _will_ get aligned, because we have at most
 288          * sizeof(WORD_TYPE) - 1 bytes to store, and at least
 289          * sizeof(WORD_TYPE) - 1 empty bytes in the bit buffer. */
 290         AlignWord( p_bit_stream );
 291     }
 292
 293     return( i_result );
 294 }
 295
 296 /*****************************************************************************
 297  * UnalignedRemoveBits : removes i_bits (== -i_available) from the bit
 298  * buffer, even when the bit stream is not aligned on a word boundary
 299  *****************************************************************************/
 300 void UnalignedRemoveBits( bit_stream_t * p_bit_stream )
 301 {
 302     /* First remove all unnecessary bytes. */
 303     while( p_bit_stream->fifo.i_available <= -8 )
 304     {
 305         if( p_bit_stream->p_byte < p_bit_stream->p_end )
 306         {
 307             p_bit_stream->p_byte++;
 308             p_bit_stream->fifo.i_available += 8;
 309         }
 310         else
 311         {
 312             p_bit_stream->pf_next_data_packet( p_bit_stream );
 313             p_bit_stream->p_byte++;
 314             p_bit_stream->fifo.i_available += 8;
 315         }
 316     }
 317
 318     /* Remove unnecessary bits. */
 319     if( p_bit_stream->fifo.i_available < 0 )
 320     {
 321         if( p_bit_stream->p_byte < p_bit_stream->p_end )
 322         {
 323             p_bit_stream->fifo.buffer = *(p_bit_stream->p_byte++)
 324                  << ( sizeof(WORD_TYPE) * 8 - 8
 325                          - p_bit_stream->fifo.i_available );
 326             p_bit_stream->fifo.i_available += 8;
 327         }
 328         else
 329         {
 330             p_bit_stream->pf_next_data_packet( p_bit_stream );
 331             p_bit_stream->fifo.buffer = *(p_bit_stream->p_byte++)
 332                  << ( sizeof(WORD_TYPE) * 8 - 8
 333                          - p_bit_stream->fifo.i_available );
 334             p_bit_stream->fifo.i_available += 8;
 335         }
 336     }
 337     else
 338     {
 339         p_bit_stream->fifo.buffer = 0;
 340     }
 341
 342     if( p_bit_stream->p_byte <= p_bit_stream->p_end - sizeof(WORD_TYPE) )
 343     {
 344         /* Get aligned on a word boundary. Otherwise it is safer
 345          * to do it the next time.
 346          * NB : we _will_ get aligned, because we have at most
 347          * sizeof(WORD_TYPE) - 1 bytes to store, and at least
 348          * sizeof(WORD_TYPE) - 1 empty bytes in the bit buffer. */
 349         AlignWord( p_bit_stream );
 350     }
 351 }
 352