include/input_ext-dec.h

   1 /*****************************************************************************
   2  * input_ext-dec.h: structures exported to the VideoLAN decoders
   3  *****************************************************************************
   4  * Copyright (C) 1999-2001 VideoLAN
   5  * $Id: input_ext-dec.h,v 1.78 2003/01/07 21:49:01 fenrir Exp $
   6  *
   7  * Authors: Christophe Massiot <massiot@via.ecp.fr>
   8  *          Michel Kaempf <maxx@via.ecp.fr>
   9  *
  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.
  14  *
  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.
  19  *
  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  *****************************************************************************/
  24
  25 #ifndef _VLC_INPUT_EXT_DEC_H
  26 #define _VLC_INPUT_EXT_DEC_H 1
  27
  28 /* Structures exported to the decoders */
  29
  30 /*****************************************************************************
  31  * data_packet_t
  32  *****************************************************************************
  33  * Describe a data packet.
  34  *****************************************************************************/
  35 struct data_packet_t
  36 {
  37     /* Used to chain the packets that carry data for a same PES or PSI */
  38     data_packet_t *  p_next;
  39
  40     /* start of the PS or TS packet */
  41     byte_t *         p_demux_start;
  42     /* start of the PES payload in this packet */
  43     byte_t *         p_payload_start;
  44     byte_t *         p_payload_end; /* guess ? :-) */
  45     /* is the packet messed up ? */
  46     vlc_bool_t       b_discard_payload;
  47
  48     /* pointer to the real data */
  49     data_buffer_t *  p_buffer;
  50 };
  51
  52 /*****************************************************************************
  53  * pes_packet_t
  54  *****************************************************************************
  55  * Describes an PES packet, with its properties, and pointers to the TS packets
  56  * containing it.
  57  *****************************************************************************/
  58 struct pes_packet_t
  59 {
  60     /* Chained list to the next PES packet (depending on the context) */
  61     pes_packet_t *  p_next;
  62
  63     /* PES properties */
  64     vlc_bool_t      b_data_alignment;          /* used to find the beginning of
  65                                                 * a video or audio unit */
  66     vlc_bool_t      b_discontinuity;          /* This packet doesn't follow the
  67                                                * previous one */
  68
  69     mtime_t         i_pts;            /* PTS for this packet (zero if unset) */
  70     mtime_t         i_dts;            /* DTS for this packet (zero if unset) */
  71     int             i_rate;   /* current reading pace (see stream_control.h) */
  72
  73     unsigned int    i_pes_size;            /* size of the current PES packet */
  74
  75     /* Chained list to packets */
  76     data_packet_t * p_first;              /* The first packet contained by this
  77                                            * PES (used by decoders). */
  78     data_packet_t * p_last;            /* The last packet contained by this
  79                                         * PES (used by the buffer allocator) */
  80     unsigned int    i_nb_data; /* Number of data packets in the chained list */
  81 };
  82
  83 /*****************************************************************************
  84  * decoder_fifo_t
  85  *****************************************************************************
  86  * This rotative FIFO contains PES packets that are to be decoded.
  87  *****************************************************************************/
  88 struct decoder_fifo_t
  89 {
  90     VLC_COMMON_MEMBERS
  91
  92     /* Thread structures */
  93     vlc_mutex_t         data_lock;                         /* fifo data lock */
  94     vlc_cond_t          data_wait;         /* fifo data conditional variable */
  95
  96     /* Data */
  97     pes_packet_t *      p_first;
  98     pes_packet_t **     pp_last;
  99     int                 i_depth;       /* number of PES packets in the stack */
 100
 101     /* Communication interface between input and decoders */
 102     input_buffers_t    *p_packets_mgt;   /* packets management services data */
 103
 104     /* Standard pointers given to the decoders as a toolbox. */
 105     uint16_t            i_id;
 106     vlc_fourcc_t        i_fourcc;
 107     es_sys_t *          p_demux_data;
 108     stream_ctrl_t *     p_stream_ctrl;
 109     sout_instance_t *   p_sout;
 110     void *              p_waveformatex;
 111     void *              p_bitmapinfoheader;
 112
 113     /* Module properties */
 114     module_t *              p_module;
 115     int                 ( * pf_run ) ( decoder_fifo_t * );
 116 };
 117
 118 /*****************************************************************************
 119  * bit_fifo_t : bit fifo descriptor
 120  *****************************************************************************
 121  * This type describes a bit fifo used to store bits while working with the
 122  * input stream at the bit level.
 123  *****************************************************************************/
 124 typedef uint32_t    WORD_TYPE;
 125
 126 typedef struct bit_fifo_t
 127 {
 128     /* This unsigned integer allows us to work at the bit level. This buffer
 129      * can contain 32 bits, and the used space can be found on the MSb's side
 130      * and the available space on the LSb's side. */
 131     WORD_TYPE           buffer;
 132
 133     /* Number of bits available in the bit buffer */
 134     int                 i_available;
 135
 136 } bit_fifo_t;
 137
 138 /*****************************************************************************
 139  * bit_stream_t : bit stream descriptor
 140  *****************************************************************************
 141  * This type, based on a PES stream, includes all the structures needed to
 142  * handle the input stream like a bit stream.
 143  *****************************************************************************/
 144 struct bit_stream_t
 145 {
 146     /*
 147      * Bit structures
 148      */
 149     bit_fifo_t       fifo;
 150
 151     /*
 152      * Input structures
 153      */
 154     /* The decoder fifo contains the data of the PES stream */
 155     decoder_fifo_t * p_decoder_fifo;
 156
 157     /* Callback to the decoder used when changing data packets ; set
 158      * to NULL if your decoder doesn't need it. */
 159     void          (* pf_bitstream_callback)( bit_stream_t *, vlc_bool_t );
 160     /* Optional argument to the callback */
 161     void *           p_callback_arg;
 162
 163     /*
 164      * PTS retrieval
 165      */
 166     mtime_t          i_pts, i_dts;
 167     byte_t *         p_pts_validity;
 168
 169     /*
 170      * Byte structures
 171      */
 172     /* Current PES packet (extracted from the PES stream) */
 173     pes_packet_t *          p_pes;
 174     /* Current data packet (in the current PES packet) */
 175     data_packet_t *         p_data;
 176     /* Pointer to the next byte that is to be read (in the current packet) */
 177     byte_t *                p_byte;
 178     /* Pointer to the last byte that is to be read (in the current packet */
 179     byte_t *                p_end;
 180     /* Temporary buffer in case we're not aligned when changing data packets */
 181     WORD_TYPE               i_showbits_buffer;
 182     data_packet_t           showbits_data;
 183 };
 184
 185 /*****************************************************************************
 186  * Inline functions used by the decoders to read bit_stream_t
 187  *****************************************************************************/
 188
 189 /*
 190  * DISCUSSION : How to use the bit_stream structures
 191  *
 192  * sizeof(WORD_TYPE) (usually 32) bits are read at the same time, thus
 193  * minimizing the number of p_byte changes.
 194  * Bits are read via GetBits() or ShowBits.
 195  *
 196  * XXX : Be aware that if, in the forthcoming functions, i_bits > 24,
 197  * the data have to be already aligned on an 8-bit boundary, or wrong
 198  * results will be returned. Use RealignBits() if unsure.
 199  */
 200
 201 #if (WORD_TYPE == uint32_t)
 202 #   define WORD_AT      U32_AT
 203 #   define WORD_SIGNED  int32_t
 204 #elif (WORD_TYPE == uint64_t)
 205 #   define WORD_AT      U64_AT
 206 #   define WORD_SIGNED  int64_t
 207 #else
 208 #   error Unsupported WORD_TYPE
 209 #endif
 210
 211 /*****************************************************************************
 212  * Prototypes from input_ext-dec.c
 213  *****************************************************************************/
 214 VLC_EXPORT( int, InitBitstream, ( bit_stream_t *, decoder_fifo_t *, void ( * )( bit_stream_t *, vlc_bool_t ), void * p_callback_arg ) );
 215 VLC_EXPORT( vlc_bool_t, NextDataPacket,    ( decoder_fifo_t *, bit_stream_t * ) );
 216 VLC_EXPORT( void, BitstreamNextDataPacket, ( bit_stream_t * ) );
 217 VLC_EXPORT( uint32_t, UnalignedShowBits,   ( bit_stream_t *, unsigned int ) );
 218 VLC_EXPORT( void, UnalignedRemoveBits,     ( bit_stream_t * ) );
 219 VLC_EXPORT( uint32_t, UnalignedGetBits,    ( bit_stream_t *, unsigned int ) );
 220 VLC_EXPORT( void, CloseBitstream,          ( bit_stream_t * ) );
 221 VLC_EXPORT( void, CurrentPTS,              ( bit_stream_t *, mtime_t *, mtime_t * ) );
 222 VLC_EXPORT( void, NextPTS,                 ( bit_stream_t *, mtime_t *, mtime_t * ) );
 223
 224 /*****************************************************************************
 225  * AlignWord : fill in the bit buffer so that the byte pointer be aligned
 226  * on a word boundary (XXX: there must be at least sizeof(WORD_TYPE) - 1
 227  * empty bytes in the bit buffer)
 228  *****************************************************************************/
 229 static inline void AlignWord( bit_stream_t * p_bit_stream )
 230 {
 231     while( (ptrdiff_t)p_bit_stream->p_byte
 232              & (sizeof(WORD_TYPE) - 1) )
 233     {
 234         if( p_bit_stream->p_byte < p_bit_stream->p_end )
 235         {
 236             p_bit_stream->fifo.buffer |= *(p_bit_stream->p_byte++)
 237                 << (8 * sizeof(WORD_TYPE) - 8
 238                      - p_bit_stream->fifo.i_available);
 239             p_bit_stream->fifo.i_available += 8;
 240         }
 241         else
 242         {
 243             BitstreamNextDataPacket( p_bit_stream );
 244             p_bit_stream->fifo.buffer |= *(p_bit_stream->p_byte++)
 245                 << (8 * sizeof(WORD_TYPE) - 8
 246                      - p_bit_stream->fifo.i_available);
 247             p_bit_stream->fifo.i_available += 8;
 248         }
 249     }
 250 }
 251
 252 /*****************************************************************************
 253  * ShowBits : return i_bits bits from the bit stream
 254  *****************************************************************************/
 255 static inline uint32_t ShowBits( bit_stream_t * p_bit_stream,
 256                                  unsigned int i_bits )
 257 {
 258     if( (unsigned int)p_bit_stream->fifo.i_available >= i_bits )
 259     {
 260         return( p_bit_stream->fifo.buffer >> (8 * sizeof(WORD_TYPE) - i_bits) );
 261     }
 262
 263     if( p_bit_stream->p_byte <= p_bit_stream->p_end - sizeof(WORD_TYPE) )
 264     {
 265         return( (p_bit_stream->fifo.buffer |
 266                     (WORD_AT( p_bit_stream->p_byte )
 267                         >> p_bit_stream->fifo.i_available))
 268                     >> (8 * sizeof(WORD_TYPE) - i_bits) );
 269     }
 270
 271     return( UnalignedShowBits( p_bit_stream, i_bits ) );
 272 }
 273
 274 /*****************************************************************************
 275  * ShowSignedBits : return i_bits bits from the bit stream, using signed
 276  *                  arithmetic
 277  *****************************************************************************/
 278 static inline int32_t ShowSignedBits( bit_stream_t * p_bit_stream,
 279                                       unsigned int i_bits )
 280 {
 281     if( (unsigned int)p_bit_stream->fifo.i_available >= i_bits )
 282     {
 283         return( (WORD_SIGNED)p_bit_stream->fifo.buffer
 284                     >> (8 * sizeof(WORD_TYPE) - i_bits) );
 285     }
 286
 287     /* You can probably do something a little faster, but now I'm tired. */
 288     return( (WORD_SIGNED)(ShowBits( p_bit_stream, i_bits ) << (32 - i_bits))
 289              >> (32 - i_bits) );
 290 }
 291
 292 /*****************************************************************************
 293  * RemoveBits : removes i_bits bits from the bit buffer
 294  *              XXX: do not use for 32 bits, see RemoveBits32
 295  *****************************************************************************/
 296 static inline void RemoveBits( bit_stream_t * p_bit_stream,
 297                                unsigned int i_bits )
 298 {
 299     p_bit_stream->fifo.i_available -= i_bits;
 300
 301     if( p_bit_stream->fifo.i_available >= 0 )
 302     {
 303         p_bit_stream->fifo.buffer <<= i_bits;
 304         return;
 305     }
 306
 307     if( p_bit_stream->p_byte <= p_bit_stream->p_end - sizeof(WORD_TYPE) )
 308     {
 309         p_bit_stream->fifo.buffer = WORD_AT( p_bit_stream->p_byte )
 310                                         << ( -p_bit_stream->fifo.i_available );
 311         p_bit_stream->p_byte =
 312                    (byte_t *) ( ((WORD_TYPE *)p_bit_stream->p_byte) + 1 );
 313         p_bit_stream->fifo.i_available += sizeof(WORD_TYPE) * 8;
 314         return;
 315     }
 316
 317     UnalignedRemoveBits( p_bit_stream );
 318 }
 319
 320 /*****************************************************************************
 321  * RemoveBits32 : removes 32 bits from the bit buffer (and as a side effect,
 322  *                refill it)
 323  *****************************************************************************/
 324 #if (WORD_TYPE == uint32_t)
 325 static inline void RemoveBits32( bit_stream_t * p_bit_stream )
 326 {
 327     if( p_bit_stream->p_byte <= p_bit_stream->p_end - sizeof(WORD_TYPE) )
 328     {
 329         if( p_bit_stream->fifo.i_available )
 330         {
 331             p_bit_stream->fifo.buffer = WORD_AT( p_bit_stream->p_byte )
 332                             << (32 - p_bit_stream->fifo.i_available);
 333             p_bit_stream->p_byte =
 334                        (byte_t *) ( ((WORD_TYPE *)p_bit_stream->p_byte) + 1 );
 335             return;
 336         }
 337
 338         p_bit_stream->p_byte =
 339                    (byte_t *) ( ((WORD_TYPE *)p_bit_stream->p_byte) + 1 );
 340         return;
 341     }
 342
 343     p_bit_stream->fifo.i_available -= 32;
 344     UnalignedRemoveBits( p_bit_stream );
 345 }
 346 #else
 347 #   define RemoveBits32( p_bit_stream )     RemoveBits( p_bit_stream, 32 )
 348 #endif
 349
 350 /*****************************************************************************
 351  * GetBits : returns i_bits bits from the bit stream and removes them
 352  *           XXX: do not use for 32 bits, see GetBits32
 353  *****************************************************************************/
 354 static inline uint32_t GetBits( bit_stream_t * p_bit_stream,
 355                                 unsigned int i_bits )
 356 {
 357     uint32_t        i_result;
 358
 359     p_bit_stream->fifo.i_available -= i_bits;
 360
 361     if( p_bit_stream->fifo.i_available >= 0 )
 362     {
 363         i_result = p_bit_stream->fifo.buffer
 364                         >> (8 * sizeof(WORD_TYPE) - i_bits);
 365         p_bit_stream->fifo.buffer <<= i_bits;
 366         return( i_result );
 367     }
 368
 369     if( p_bit_stream->p_byte <= p_bit_stream->p_end - sizeof(WORD_TYPE) )
 370     {
 371         i_result = p_bit_stream->fifo.buffer
 372                         >> (8 * sizeof(WORD_TYPE) - i_bits);
 373         p_bit_stream->fifo.buffer = WORD_AT( p_bit_stream->p_byte );
 374         p_bit_stream->p_byte =
 375                    (byte_t *) ( ((WORD_TYPE *)p_bit_stream->p_byte) + 1 );
 376         i_result |= p_bit_stream->fifo.buffer
 377                         >> (8 * sizeof(WORD_TYPE)
 378                                      + p_bit_stream->fifo.i_available);
 379         p_bit_stream->fifo.buffer <<= ( -p_bit_stream->fifo.i_available );
 380         p_bit_stream->fifo.i_available += sizeof(WORD_TYPE) * 8;
 381         return( i_result );
 382     }
 383
 384     return UnalignedGetBits( p_bit_stream, i_bits );
 385 }
 386
 387 /*****************************************************************************
 388  * GetSignedBits : returns i_bits bits from the bit stream and removes them,
 389  *                 using signed arithmetic
 390  *                 XXX: do not use for 32 bits
 391  *****************************************************************************/
 392 static inline int32_t GetSignedBits( bit_stream_t * p_bit_stream,
 393                                      unsigned int i_bits )
 394 {
 395     if( (unsigned int)p_bit_stream->fifo.i_available >= i_bits )
 396     {
 397         int32_t         i_result;
 398
 399         p_bit_stream->fifo.i_available -= i_bits;
 400         i_result = (WORD_SIGNED)p_bit_stream->fifo.buffer
 401                         >> (8 * sizeof(WORD_TYPE) - i_bits);
 402         p_bit_stream->fifo.buffer <<= i_bits;
 403         return( i_result );
 404     }
 405
 406     /* You can probably do something a little faster, but now I'm tired. */
 407     return( (WORD_SIGNED)(GetBits( p_bit_stream, i_bits ) << (32 - i_bits))
 408              >> (32 - i_bits) );
 409 }
 410
 411 /*****************************************************************************
 412  * GetBits32 : returns 32 bits from the bit stream and removes them
 413  *****************************************************************************/
 414 #if (WORD_TYPE == uint32_t)
 415 static inline uint32_t GetBits32( bit_stream_t * p_bit_stream )
 416 {
 417     uint32_t        i_result;
 418
 419     if( p_bit_stream->fifo.i_available == 32 )
 420     {
 421         p_bit_stream->fifo.i_available = 0;
 422         i_result = p_bit_stream->fifo.buffer;
 423         p_bit_stream->fifo.buffer = 0;
 424         return( i_result );
 425     }
 426
 427     if( p_bit_stream->p_byte <= p_bit_stream->p_end - sizeof(WORD_TYPE) )
 428     {
 429         if( p_bit_stream->fifo.i_available )
 430         {
 431             i_result = p_bit_stream->fifo.buffer;
 432             p_bit_stream->fifo.buffer = WORD_AT( p_bit_stream->p_byte );
 433             p_bit_stream->p_byte =
 434                        (byte_t *) ( ((WORD_TYPE *)p_bit_stream->p_byte) + 1 );
 435             i_result |= p_bit_stream->fifo.buffer
 436                              >> (p_bit_stream->fifo.i_available);
 437             p_bit_stream->fifo.buffer <<= (32 - p_bit_stream->fifo.i_available);
 438             return( i_result );
 439         }
 440
 441         i_result = WORD_AT( p_bit_stream->p_byte );
 442         p_bit_stream->p_byte =
 443                    (byte_t *) ( ((WORD_TYPE *)p_bit_stream->p_byte) + 1 );
 444         return( i_result );
 445     }
 446
 447     p_bit_stream->fifo.i_available -= 32;
 448     return UnalignedGetBits( p_bit_stream, 32 );
 449 }
 450 #else
 451 #   define GetBits32( p_bit_stream )    GetBits( p_bit_stream, 32 )
 452 #endif
 453
 454 /*****************************************************************************
 455  * RealignBits : realigns the bit buffer on an 8-bit boundary
 456  *****************************************************************************/
 457 static inline void RealignBits( bit_stream_t * p_bit_stream )
 458 {
 459     p_bit_stream->fifo.buffer <<= (p_bit_stream->fifo.i_available & 0x7);
 460     p_bit_stream->fifo.i_available &= ~0x7;
 461 }
 462
 463
 464 /*****************************************************************************
 465  * GetChunk : reads a large chunk of data
 466  *****************************************************************************
 467  * The position in the stream must be byte-aligned, if unsure call
 468  * RealignBits(). p_buffer must point to a buffer at least as big as i_buf_len
 469  * otherwise your code will crash.
 470  *****************************************************************************/
 471 static inline void GetChunk( bit_stream_t * p_bit_stream,
 472                              byte_t * p_buffer, size_t i_buf_len )
 473 {
 474     ptrdiff_t           i_available;
 475
 476     /* We need to take care because i_buf_len may be < 4. */
 477     while( p_bit_stream->fifo.i_available > 0 && i_buf_len )
 478     {
 479         *p_buffer = p_bit_stream->fifo.buffer >> (8 * sizeof(WORD_TYPE) - 8);
 480         p_buffer++;
 481         i_buf_len--;
 482         p_bit_stream->fifo.buffer <<= 8;
 483         p_bit_stream->fifo.i_available -= 8;
 484     }
 485
 486     i_available = p_bit_stream->p_end - p_bit_stream->p_byte;
 487     if( i_available >= (ptrdiff_t)i_buf_len )
 488     {
 489         p_bit_stream->p_decoder_fifo->p_vlc->pf_memcpy( p_buffer,
 490                                            p_bit_stream->p_byte, i_buf_len );
 491         p_bit_stream->p_byte += i_buf_len;
 492     }
 493     else
 494     {
 495         do
 496         {
 497             p_bit_stream->p_decoder_fifo->p_vlc->pf_memcpy( p_buffer,
 498                                            p_bit_stream->p_byte, i_available );
 499             p_bit_stream->p_byte = p_bit_stream->p_end;
 500             p_buffer += i_available;
 501             i_buf_len -= i_available;
 502             BitstreamNextDataPacket( p_bit_stream );
 503             if( p_bit_stream->p_decoder_fifo->b_die )
 504                 return;
 505         }
 506         while( (i_available = p_bit_stream->p_end - p_bit_stream->p_byte)
 507                 <= (ptrdiff_t)i_buf_len );
 508
 509         if( i_buf_len )
 510         {
 511             p_bit_stream->p_decoder_fifo->p_vlc->pf_memcpy( p_buffer,
 512                                            p_bit_stream->p_byte, i_buf_len );
 513             p_bit_stream->p_byte += i_buf_len;
 514         }
 515     }
 516
 517     if( p_bit_stream->p_byte <= p_bit_stream->p_end - sizeof(WORD_TYPE) )
 518     {
 519         AlignWord( p_bit_stream );
 520     }
 521 }
 522
 523
 524 /*
 525  * Communication interface between input and decoders
 526  */
 527
 528 /*****************************************************************************
 529  * Prototypes from input_dec.c
 530  *****************************************************************************/
 531 VLC_EXPORT( void, DecoderError, ( decoder_fifo_t * p_fifo ) );
 532
 533 #endif /* "input_ext-dec.h" */