git.sesse.net Git - vlc/blob - modules/packetizer/h264.c

   1 /*****************************************************************************
   2  * h264.c: h264/avc video packetizer
   3  *****************************************************************************
   4  * Copyright (C) 2001, 2002, 2006 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Laurent Aimar <fenrir@via.ecp.fr>
   8  *          Eric Petit <titer@videolan.org>
   9  *          Gildas Bazin <gbazin@videolan.org>
  10  *          Derk-Jan Hartman <hartman at videolan dot org>
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  25  *****************************************************************************/
  26
  27 /*****************************************************************************
  28  * Preamble
  29  *****************************************************************************/
  30
  31 #ifdef HAVE_CONFIG_H
  32 # include "config.h"
  33 #endif
  34
  35 #include <vlc/vlc.h>
  36 #include <vlc_sout.h>
  37 #include <vlc_codec.h>
  38 #include <vlc_block.h>
  39
  40 #include "vlc_block_helper.h"
  41 #include "vlc_bits.h"
  42
  43 /*****************************************************************************
  44  * Module descriptor
  45  *****************************************************************************/
  46 static int  Open ( vlc_object_t * );
  47 static void Close( vlc_object_t * );
  48
  49 vlc_module_begin();
  50     set_category( CAT_SOUT );
  51     set_subcategory( SUBCAT_SOUT_PACKETIZER );
  52     set_description( _("H.264 video packetizer") );
  53     set_capability( "packetizer", 50 );
  54     set_callbacks( Open, Close );
  55 vlc_module_end();
  56
  57
  58 /****************************************************************************
  59  * Local prototypes
  60  ****************************************************************************/
  61 static block_t *Packetize( decoder_t *, block_t ** );
  62 static block_t *PacketizeAVC1( decoder_t *, block_t ** );
  63
  64 typedef struct
  65 {
  66     int i_nal_type;
  67     int i_nal_ref_idc;
  68
  69     int i_frame_type;
  70     int i_pic_parameter_set_id;
  71     int i_frame_num;
  72
  73     int i_field_pic_flag;
  74     int i_bottom_field_flag;
  75
  76     int i_idr_pic_id;
  77
  78     int i_pic_order_cnt_lsb;
  79     int i_delta_pic_order_cnt_bottom;
  80
  81     int i_delta_pic_order_cnt0;
  82     int i_delta_pic_order_cnt1;
  83 } slice_t;
  84
  85 struct decoder_sys_t
  86 {
  87     block_bytestream_t bytestream;
  88
  89     int     i_state;
  90     size_t  i_offset;
  91     uint8_t startcode[4];
  92
  93     vlc_bool_t b_slice;
  94     block_t    *p_frame;
  95
  96     vlc_bool_t   b_sps;
  97     vlc_bool_t   b_pps;
  98     vlc_bool_t   b_header;
  99
 100     /* avcC data */
 101     int i_avcC_length_size;
 102     block_t *p_sps;
 103     block_t *p_pps;
 104
 105     /* Useful values of the Sequence Parameter Set */
 106     int i_log2_max_frame_num;
 107     int b_frame_mbs_only;
 108     int i_pic_order_cnt_type;
 109     int i_delta_pic_order_always_zero_flag;
 110     int i_log2_max_pic_order_cnt_lsb;
 111
 112     /* Value from Picture Parameter Set */
 113     int i_pic_order_present_flag;
 114
 115     /* Useful values of the Slice Header */
 116     slice_t slice;
 117 };
 118
 119 enum
 120 {
 121     STATE_NOSYNC,
 122     STATE_NEXT_SYNC,
 123 };
 124
 125 enum nal_unit_type_e
 126 {
 127     NAL_UNKNOWN = 0,
 128     NAL_SLICE   = 1,
 129     NAL_SLICE_DPA   = 2,
 130     NAL_SLICE_DPB   = 3,
 131     NAL_SLICE_DPC   = 4,
 132     NAL_SLICE_IDR   = 5,    /* ref_idc != 0 */
 133     NAL_SEI         = 6,    /* ref_idc == 0 */
 134     NAL_SPS         = 7,
 135     NAL_PPS         = 8,
 136     NAL_AU_DELIMITER= 9
 137     /* ref_idc == 0 for 6,9,10,11,12 */
 138 };
 139
 140 enum nal_priority_e
 141 {
 142     NAL_PRIORITY_DISPOSABLE = 0,
 143     NAL_PRIORITY_LOW        = 1,
 144     NAL_PRIORITY_HIGH       = 2,
 145     NAL_PRIORITY_HIGHEST    = 3,
 146 };
 147
 148 static block_t *ParseNALBlock( decoder_t *, block_t * );
 149
 150 static block_t *nal_get_annexeb( decoder_t *, uint8_t *p, int );
 151
 152 /*****************************************************************************
 153  * Open: probe the packetizer and return score
 154  * When opening after demux, the packetizer is only loaded AFTER the decoder
 155  * That means that what you set in fmt_out is ignored by the decoder in this special case
 156  *****************************************************************************/
 157 static int Open( vlc_object_t *p_this )
 158 {
 159     decoder_t     *p_dec = (decoder_t*)p_this;
 160     decoder_sys_t *p_sys;
 161
 162     if( p_dec->fmt_in.i_codec != VLC_FOURCC( 'h', '2', '6', '4') &&
 163         p_dec->fmt_in.i_codec != VLC_FOURCC( 'H', '2', '6', '4') &&
 164         p_dec->fmt_in.i_codec != VLC_FOURCC( 'V', 'S', 'S', 'H') &&
 165         p_dec->fmt_in.i_codec != VLC_FOURCC( 'v', 's', 's', 'h') &&
 166         p_dec->fmt_in.i_codec != VLC_FOURCC( 'D', 'A', 'V', 'C') &&
 167         ( p_dec->fmt_in.i_codec != VLC_FOURCC( 'a', 'v', 'c', '1') ||
 168           p_dec->fmt_in.i_extra < 7 ) )
 169     {
 170         return VLC_EGENERIC;
 171     }
 172
 173     /* Allocate the memory needed to store the decoder's structure */
 174     if( ( p_dec->p_sys = p_sys = malloc( sizeof(decoder_sys_t) ) ) == NULL )
 175     {
 176         msg_Err( p_dec, "out of memory" );
 177         return VLC_EGENERIC;
 178     }
 179     p_sys->i_state = STATE_NOSYNC;
 180     p_sys->i_offset = 0;
 181     p_sys->startcode[0] = 0;
 182     p_sys->startcode[1] = 0;
 183     p_sys->startcode[2] = 0;
 184     p_sys->startcode[3] = 1;
 185     p_sys->bytestream = block_BytestreamInit();
 186     p_sys->b_slice = VLC_FALSE;
 187     p_sys->p_frame = NULL;
 188     p_sys->b_sps   = VLC_FALSE;
 189     p_sys->b_pps   = VLC_FALSE;
 190     p_sys->p_sps   = 0;
 191     p_sys->p_pps   = 0;
 192     p_sys->b_header= VLC_FALSE;
 193
 194     p_sys->slice.i_nal_type = -1;
 195     p_sys->slice.i_nal_ref_idc = -1;
 196     p_sys->slice.i_idr_pic_id = -1;
 197     p_sys->slice.i_frame_num = -1;
 198     p_sys->slice.i_frame_type = 0;
 199     p_sys->slice.i_pic_parameter_set_id = -1;
 200     p_sys->slice.i_field_pic_flag = 0;
 201     p_sys->slice.i_bottom_field_flag = -1;
 202     p_sys->slice.i_pic_order_cnt_lsb = -1;
 203     p_sys->slice.i_delta_pic_order_cnt_bottom = -1;
 204
 205     /* Setup properties */
 206     es_format_Copy( &p_dec->fmt_out, &p_dec->fmt_in );
 207     p_dec->fmt_out.i_codec = VLC_FOURCC( 'h', '2', '6', '4' );
 208
 209     if( p_dec->fmt_in.i_codec == VLC_FOURCC( 'a', 'v', 'c', '1' ) )
 210     {
 211         /* This type of stream is produced by mp4 and matroska
 212          * when we want to store it in another streamformat, you need to convert
 213          * The fmt_in.p_extra should ALWAYS contain the avcC
 214          * The fmt_out.p_extra should contain all the SPS and PPS with 4 byte startcodes */
 215         uint8_t *p = &((uint8_t*)p_dec->fmt_in.p_extra)[4];
 216         int i_sps, i_pps;
 217         int i;
 218
 219         /* Parse avcC */
 220         p_sys->i_avcC_length_size = 1 + ((*p++)&0x03);
 221
 222         /* Read SPS */
 223         i_sps = (*p++)&0x1f;
 224         for( i = 0; i < i_sps; i++ )
 225         {
 226             int i_length = GetWBE( p );
 227             block_t *p_sps = nal_get_annexeb( p_dec, p + 2, i_length );
 228
 229             p_sys->p_sps = block_Duplicate( p_sps );
 230             p_sps->i_pts = p_sps->i_dts = mdate();
 231             ParseNALBlock( p_dec, p_sps );
 232             p += 2 + i_length;
 233         }
 234         /* Read PPS */
 235         i_pps = *p++;
 236         for( i = 0; i < i_pps; i++ )
 237         {
 238             int i_length = GetWBE( p );
 239             block_t *p_pps = nal_get_annexeb( p_dec, p + 2, i_length );
 240
 241             p_sys->p_pps = block_Duplicate( p_pps );
 242             p_pps->i_pts = p_pps->i_dts = mdate();
 243             ParseNALBlock( p_dec, p_pps );
 244             p += 2 + i_length;
 245         }
 246         msg_Dbg( p_dec, "avcC length size=%d, sps=%d, pps=%d",
 247                  p_sys->i_avcC_length_size, i_sps, i_pps );
 248
 249         /* FIXME: FFMPEG isn't happy at all if you leave this */
 250         if( p_dec->fmt_out.i_extra ) free( p_dec->fmt_out.p_extra );
 251         p_dec->fmt_out.i_extra = 0; p_dec->fmt_out.p_extra = NULL;
 252
 253         /* Set the new extradata */
 254         p_dec->fmt_out.i_extra = p_sys->p_pps->i_buffer + p_sys->p_sps->i_buffer;
 255         p_dec->fmt_out.p_extra = (uint8_t*)malloc( p_dec->fmt_out.i_extra );
 256         if( p_dec->fmt_out.p_extra )
 257         {
 258             memcpy( (uint8_t*)p_dec->fmt_out.p_extra, p_sys->p_sps->p_buffer, p_sys->p_sps->i_buffer);
 259             memcpy( (uint8_t*)p_dec->fmt_out.p_extra+p_sys->p_sps->i_buffer, p_sys->p_pps->p_buffer, p_sys->p_pps->i_buffer);
 260             p_sys->b_header = VLC_TRUE;
 261         }
 262         else p_dec->fmt_out.i_extra = 0;
 263
 264         /* Set callback */
 265         p_dec->pf_packetize = PacketizeAVC1;
 266     }
 267     else
 268     {
 269         /* This type of stream contains data with 3 of 4 byte startcodes
 270          * The fmt_in.p_extra MAY contain SPS/PPS with 4 byte startcodes
 271          * The fmt_out.p_extra should be the same */
 272
 273         /* Set callback */
 274         p_dec->pf_packetize = Packetize;
 275
 276         /* */
 277         if( p_dec->fmt_in.i_extra > 0 )
 278         {
 279             block_t *p_init = block_New( p_dec, p_dec->fmt_in.i_extra );
 280             block_t *p_pic;
 281
 282             memcpy( p_init->p_buffer, p_dec->fmt_in.p_extra,
 283                     p_dec->fmt_in.i_extra );
 284
 285             while( ( p_pic = Packetize( p_dec, &p_init ) ) )
 286             {
 287                 /* Should not occur because we should only receive SPS/PPS */
 288                 block_Release( p_pic );
 289             }
 290         }
 291     }
 292
 293     return VLC_SUCCESS;
 294 }
 295
 296 /*****************************************************************************
 297  * Close: clean up the packetizer
 298  *****************************************************************************/
 299 static void Close( vlc_object_t *p_this )
 300 {
 301     decoder_t *p_dec = (decoder_t*)p_this;
 302     decoder_sys_t *p_sys = p_dec->p_sys;
 303
 304     if( p_sys->p_frame ) block_ChainRelease( p_sys->p_frame );
 305     if( p_sys->p_sps ) block_Release( p_sys->p_sps );
 306     if( p_sys->p_pps ) block_Release( p_sys->p_pps );
 307     block_BytestreamRelease( &p_sys->bytestream );
 308     free( p_sys );
 309 }
 310
 311 /****************************************************************************
 312  * Packetize: the whole thing
 313  * Search for the startcodes 3 or more bytes
 314  * Feed ParseNALBlock ALWAYS with 4 byte startcode prepended NALs
 315  ****************************************************************************/
 316 static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
 317 {
 318     decoder_sys_t *p_sys = p_dec->p_sys;
 319     block_t       *p_pic;
 320
 321     if( !pp_block || !*pp_block )
 322         return NULL;
 323
 324     if( (*pp_block)->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
 325     {
 326         if( (*pp_block)->i_flags&BLOCK_FLAG_CORRUPTED )
 327         {
 328             p_sys->i_state = STATE_NOSYNC;
 329             block_BytestreamFlush( &p_sys->bytestream );
 330
 331             if( p_sys->p_frame )
 332                 block_ChainRelease( p_sys->p_frame );
 333             p_sys->p_frame = NULL;
 334             p_sys->slice.i_frame_type = 0;
 335             p_sys->b_slice = VLC_FALSE;
 336         }
 337         block_Release( *pp_block );
 338         return NULL;
 339     }
 340
 341     block_BytestreamPush( &p_sys->bytestream, *pp_block );
 342
 343     for( ;; )
 344     {
 345         switch( p_sys->i_state )
 346         {
 347             case STATE_NOSYNC:
 348                 /* Skip until 3 byte startcode 0 0 1 */
 349                 if( block_FindStartcodeFromOffset( &p_sys->bytestream,
 350                       &p_sys->i_offset, p_sys->startcode+1, 3 ) == VLC_SUCCESS)
 351                 {
 352                     p_sys->i_state = STATE_NEXT_SYNC;
 353                 }
 354
 355                 if( p_sys->i_offset )
 356                 {
 357                     /* skip the data */
 358                     block_SkipBytes( &p_sys->bytestream, p_sys->i_offset );
 359                     p_sys->i_offset = 0;
 360                     block_BytestreamFlush( &p_sys->bytestream );
 361                 }
 362
 363                 if( p_sys->i_state != STATE_NEXT_SYNC )
 364                 {
 365                     /* Need more data */
 366                     return NULL;
 367                 }
 368
 369                 p_sys->i_offset = 1; /* To find next startcode */
 370
 371             case STATE_NEXT_SYNC:
 372                 /* Find the next 3 byte startcode 0 0 1*/
 373                 if( block_FindStartcodeFromOffset( &p_sys->bytestream,
 374                       &p_sys->i_offset, p_sys->startcode+1, 3 ) != VLC_SUCCESS)
 375                 {
 376                     /* Need more data */
 377                     return NULL;
 378                 }
 379
 380                 /* Get the new fragment and set the pts/dts */
 381                 p_pic = block_New( p_dec, p_sys->i_offset +1 );
 382                 p_pic->i_pts = p_sys->bytestream.p_block->i_pts;
 383                 p_pic->i_dts = p_sys->bytestream.p_block->i_dts;
 384                 /* Force 4 byte startcode 0 0 0 1 */
 385                 p_pic->p_buffer[0] = 0;
 386
 387                 block_GetBytes( &p_sys->bytestream, &p_pic->p_buffer[1],
 388                                 p_pic->i_buffer-1 );
 389
 390                 /* Remove trailing 0 bytes */
 391                 while( p_pic->i_buffer && (!p_pic->p_buffer[p_pic->i_buffer-1] ) )
 392                     p_pic->i_buffer--;
 393                 p_sys->i_offset = 0;
 394
 395                 /* Parse the NAL */
 396                 if( !( p_pic = ParseNALBlock( p_dec, p_pic ) ) )
 397                 {
 398                     p_sys->i_state = STATE_NOSYNC;
 399                     break;
 400                 }
 401 #if 0
 402                 msg_Dbg( p_dec, "pts="I64Fd" dts="I64Fd,
 403                          p_pic->i_pts, p_pic->i_dts );
 404 #endif
 405
 406                 /* So p_block doesn't get re-added several times */
 407                 *pp_block = block_BytestreamPop( &p_sys->bytestream );
 408
 409                 p_sys->i_state = STATE_NOSYNC;
 410
 411                 return p_pic;
 412         }
 413     }
 414 }
 415
 416 /****************************************************************************
 417  * PacketizeAVC1: Takes VCL blocks of data and creates annexe B type NAL stream
 418  * Will always use 4 byte 0 0 0 1 startcodes
 419  * Will prepend a SPS and PPS before each keyframe
 420  ****************************************************************************/
 421 static block_t *PacketizeAVC1( decoder_t *p_dec, block_t **pp_block )
 422 {
 423     decoder_sys_t *p_sys = p_dec->p_sys;
 424     block_t       *p_block;
 425     block_t       *p_ret = NULL;
 426     uint8_t       *p;
 427
 428     if( !pp_block || !*pp_block )
 429         return NULL;
 430     if( (*pp_block)->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
 431     {
 432         block_Release( *pp_block );
 433         return NULL;
 434     }
 435
 436     p_block = *pp_block;
 437     *pp_block = NULL;
 438
 439     for( p = p_block->p_buffer; p < &p_block->p_buffer[p_block->i_buffer]; )
 440     {
 441         block_t *p_pic;
 442         int i_size = 0;
 443         int i;
 444
 445         for( i = 0; i < p_sys->i_avcC_length_size; i++ )
 446         {
 447             i_size = (i_size << 8) | (*p++);
 448         }
 449
 450         if( i_size > 0 && i_size < p_block->i_buffer )
 451         {
 452             block_t *p_part = nal_get_annexeb( p_dec, p, i_size );
 453             if( !p_part )
 454             {
 455                 block_Release( p_block );
 456                 return NULL;
 457             }
 458             p_part->i_dts = p_block->i_dts;
 459             p_part->i_pts = p_block->i_pts;
 460
 461             /* Parse the NAL */
 462             if( ( p_pic = ParseNALBlock( p_dec, p_part ) ) )
 463             {
 464                 block_ChainAppend( &p_ret, p_pic );
 465             }
 466         }
 467         p += i_size;
 468     }
 469     block_Release( p_block );
 470
 471     return p_ret;
 472 }
 473
 474 static block_t *nal_get_annexeb( decoder_t *p_dec, uint8_t *p, int i_size )
 475 {
 476     block_t *p_nal;
 477
 478     p_nal = block_New( p_dec, 4 + i_size );
 479     if( !p_nal ) return NULL;
 480
 481     /* Add start code */
 482     p_nal->p_buffer[0] = 0x00;
 483     p_nal->p_buffer[1] = 0x00;
 484     p_nal->p_buffer[2] = 0x00;
 485     p_nal->p_buffer[3] = 0x01;
 486
 487     /* Copy nalu */
 488     memcpy( &p_nal->p_buffer[4], p, i_size );
 489
 490     return p_nal;
 491 }
 492
 493 static void nal_get_decoded( uint8_t **pp_ret, int *pi_ret,
 494                              uint8_t *src, int i_src )
 495 {
 496     uint8_t *end = &src[i_src];
 497     uint8_t *dst = malloc( i_src );
 498
 499     *pp_ret = dst;
 500
 501     if( dst )
 502     {
 503         while( src < end )
 504         {
 505             if( src < end - 3 && src[0] == 0x00 && src[1] == 0x00 &&
 506                 src[2] == 0x03 )
 507             {
 508                 *dst++ = 0x00;
 509                 *dst++ = 0x00;
 510
 511                 src += 3;
 512                 continue;
 513             }
 514             *dst++ = *src++;
 515         }
 516     }
 517     *pi_ret = dst - *pp_ret;
 518 }
 519
 520 static inline int bs_read_ue( bs_t *s )
 521 {
 522     int i = 0;
 523
 524     while( bs_read1( s ) == 0 && s->p < s->p_end && i < 32 )
 525     {
 526         i++;
 527     }
 528     return( ( 1 << i) - 1 + bs_read( s, i ) );
 529 }
 530
 531 static inline int bs_read_se( bs_t *s )
 532 {
 533     int val = bs_read_ue( s );
 534
 535     return val&0x01 ? (val+1)/2 : -(val/2);
 536 }
 537
 538 /*****************************************************************************
 539  * ParseNALBlock: parses annexB type NALs
 540  * All p_frag blocks are required to start with 0 0 0 1 4-byte startcode
 541  *****************************************************************************/
 542 static block_t *ParseNALBlock( decoder_t *p_dec, block_t *p_frag )
 543 {
 544     decoder_sys_t *p_sys = p_dec->p_sys;
 545     block_t *p_pic = NULL;
 546
 547     const int i_nal_ref_idc = (p_frag->p_buffer[4] >> 5)&0x03;
 548     const int i_nal_type = p_frag->p_buffer[4]&0x1f;
 549
 550 #define OUTPUT \
 551     do {                                                      \
 552         if( !p_sys->b_header && p_sys->slice.i_frame_type != BLOCK_FLAG_TYPE_I) \
 553             break;                                            \
 554                                                               \
 555         if( p_sys->slice.i_frame_type == BLOCK_FLAG_TYPE_I && p_sys->p_sps && p_sys->p_pps ) \
 556         { \
 557             block_t *p_sps = block_Duplicate( p_sys->p_sps ); \
 558             block_t *p_pps = block_Duplicate( p_sys->p_pps ); \
 559             p_sps->i_dts = p_sys->p_frame->i_dts;           \
 560             p_sps->i_pts = p_sys->p_frame->i_pts;           \
 561             block_ChainAppend( &p_sps, p_pps );               \
 562             block_ChainAppend( &p_sps, p_sys->p_frame );      \
 563             p_sys->b_header = VLC_TRUE;                       \
 564             p_pic = block_ChainGather( p_sps );               \
 565         } else { \
 566             p_pic = block_ChainGather( p_sys->p_frame ); \
 567         } \
 568         p_pic->i_length = 0;    /* FIXME */                   \
 569         p_pic->i_flags |= p_sys->slice.i_frame_type;          \
 570             \
 571         p_sys->slice.i_frame_type = 0;                        \
 572         p_sys->p_frame = NULL;                                \
 573         p_sys->b_slice = VLC_FALSE;                           \
 574     } while(0)
 575
 576     if( p_sys->b_slice && ( !p_sys->b_sps || !p_sys->b_pps ) )
 577     {
 578         block_ChainRelease( p_sys->p_frame );
 579         msg_Warn( p_dec, "waiting for SPS/PPS" );
 580
 581         /* Reset context */
 582         p_sys->slice.i_frame_type = 0;
 583         p_sys->p_frame = NULL;
 584         p_sys->b_slice = VLC_FALSE;
 585     }
 586
 587     if( ( !p_sys->b_sps || !p_sys->b_pps ) &&
 588         i_nal_type >= NAL_SLICE && i_nal_type <= NAL_SLICE_IDR )
 589     {
 590         p_sys->b_slice = VLC_TRUE;
 591         /* Fragment will be discarded later on */
 592     }
 593     else if( i_nal_type >= NAL_SLICE && i_nal_type <= NAL_SLICE_IDR )
 594     {
 595         uint8_t *dec = NULL;
 596         int i_dec = 0, i_first_mb, i_slice_type;
 597         slice_t slice;
 598         vlc_bool_t b_pic;
 599         bs_t s;
 600
 601         /* do not convert the whole frame */
 602         nal_get_decoded( &dec, &i_dec, &p_frag->p_buffer[5],
 603                          __MIN( p_frag->i_buffer - 5, 60 ) );
 604         bs_init( &s, dec, i_dec );
 605
 606         /* first_mb_in_slice */
 607         i_first_mb = bs_read_ue( &s );
 608
 609         /* slice_type */
 610         switch( (i_slice_type = bs_read_ue( &s )) )
 611         {
 612         case 0: case 5:
 613             slice.i_frame_type = BLOCK_FLAG_TYPE_P;
 614             break;
 615         case 1: case 6:
 616             slice.i_frame_type = BLOCK_FLAG_TYPE_B;
 617             break;
 618         case 2: case 7:
 619             slice.i_frame_type = BLOCK_FLAG_TYPE_I;
 620             break;
 621         case 3: case 8: /* SP */
 622             slice.i_frame_type = BLOCK_FLAG_TYPE_P;
 623             break;
 624         case 4: case 9:
 625             slice.i_frame_type = BLOCK_FLAG_TYPE_I;
 626             break;
 627         default:
 628             slice.i_frame_type = 0;
 629             break;
 630         }
 631
 632         /* */
 633         slice.i_nal_type = i_nal_type;
 634         slice.i_nal_ref_idc = i_nal_ref_idc;
 635
 636         slice.i_pic_parameter_set_id = bs_read_ue( &s );
 637         slice.i_frame_num = bs_read( &s, p_sys->i_log2_max_frame_num + 4 );
 638
 639         slice.i_field_pic_flag = 0;
 640         slice.i_bottom_field_flag = -1;
 641         if( !p_sys->b_frame_mbs_only )
 642         {
 643             /* field_pic_flag */
 644             slice.i_field_pic_flag = bs_read( &s, 1 );
 645             if( slice.i_field_pic_flag )
 646                 slice.i_bottom_field_flag = bs_read( &s, 1 );
 647         }
 648
 649         slice.i_idr_pic_id = p_sys->slice.i_idr_pic_id;
 650         if( slice.i_nal_type == NAL_SLICE_IDR )
 651             slice.i_idr_pic_id = bs_read_ue( &s );
 652
 653         slice.i_pic_order_cnt_lsb = -1;
 654         slice.i_delta_pic_order_cnt_bottom = -1;
 655         slice.i_delta_pic_order_cnt0 = 0;
 656         slice.i_delta_pic_order_cnt1 = 0;
 657         if( p_sys->i_pic_order_cnt_type == 0 )
 658         {
 659             slice.i_pic_order_cnt_lsb = bs_read( &s, p_sys->i_log2_max_pic_order_cnt_lsb + 4 );
 660             if( p_sys->i_pic_order_present_flag && !slice.i_field_pic_flag )
 661                 slice.i_delta_pic_order_cnt_bottom = bs_read_se( &s );
 662         }
 663         else if( (p_sys->i_pic_order_cnt_type == 1) &&
 664                  (!p_sys->i_delta_pic_order_always_zero_flag) )
 665         {
 666             slice.i_delta_pic_order_cnt0 = bs_read_se( &s );
 667             if( p_sys->i_pic_order_present_flag && !slice.i_field_pic_flag )
 668                 slice.i_delta_pic_order_cnt1 = bs_read_se( &s );
 669         }
 670
 671         /* Detection of the first VCL NAL unit of a primary coded picture
 672          * (cf. 7.4.1.2.4) */
 673         b_pic = VLC_FALSE;
 674         if( slice.i_frame_num != p_sys->slice.i_frame_num ||
 675             slice.i_pic_parameter_set_id != p_sys->slice.i_pic_parameter_set_id ||
 676             slice.i_field_pic_flag != p_sys->slice.i_field_pic_flag ||
 677             slice.i_nal_ref_idc != p_sys->slice.i_nal_ref_idc )
 678             b_pic = VLC_TRUE;
 679         if( (slice.i_bottom_field_flag != -1) &&
 680             (p_sys->slice.i_bottom_field_flag != -1) &&
 681             (slice.i_bottom_field_flag != p_sys->slice.i_bottom_field_flag) )
 682             b_pic = VLC_TRUE;
 683         if( p_sys->i_pic_order_cnt_type == 0 &&
 684             ( slice.i_pic_order_cnt_lsb != p_sys->slice.i_pic_order_cnt_lsb ||
 685               slice.i_delta_pic_order_cnt_bottom != p_sys->slice.i_delta_pic_order_cnt_bottom ) )
 686             b_pic = VLC_TRUE;
 687         else if( p_sys->i_pic_order_cnt_type == 1 &&
 688                  ( slice.i_delta_pic_order_cnt0 != p_sys->slice.i_delta_pic_order_cnt0 ||
 689                    slice.i_delta_pic_order_cnt1 != p_sys->slice.i_delta_pic_order_cnt1 ) )
 690             b_pic = VLC_TRUE;
 691         if( ( slice.i_nal_type == NAL_SLICE_IDR || p_sys->slice.i_nal_type == NAL_SLICE_IDR ) &&
 692             ( slice.i_nal_type != p_sys->slice.i_nal_type || slice.i_idr_pic_id != p_sys->slice.i_idr_pic_id ) )
 693                 b_pic = VLC_TRUE;
 694
 695         /* */
 696         p_sys->slice = slice;
 697
 698         if( b_pic && p_sys->b_slice )
 699             OUTPUT;
 700
 701         p_sys->b_slice = VLC_TRUE;
 702
 703         free( dec );
 704     }
 705     else if( i_nal_type == NAL_SPS )
 706     {
 707         uint8_t *dec = NULL;
 708         int     i_dec = 0;
 709         bs_t s;
 710         int i_tmp;
 711
 712         if( !p_sys->b_sps ) msg_Dbg( p_dec, "found NAL_SPS" );
 713
 714         p_sys->b_sps = VLC_TRUE;
 715
 716         nal_get_decoded( &dec, &i_dec, &p_frag->p_buffer[5],
 717                          p_frag->i_buffer - 5 );
 718
 719         bs_init( &s, dec, i_dec );
 720         /* Skip profile(8), constraint_set012, reserver(5), level(8) */
 721         bs_skip( &s, 8 + 1+1+1 + 5 + 8 );
 722         /* sps id */
 723         bs_read_ue( &s );
 724         /* Skip i_log2_max_frame_num */
 725         p_sys->i_log2_max_frame_num = bs_read_ue( &s );
 726         if( p_sys->i_log2_max_frame_num > 12)
 727             p_sys->i_log2_max_frame_num = 12;
 728         /* Read poc_type */
 729         p_sys->i_pic_order_cnt_type = bs_read_ue( &s );
 730         if( p_sys->i_pic_order_cnt_type == 0 )
 731         {
 732             /* skip i_log2_max_poc_lsb */
 733             p_sys->i_log2_max_pic_order_cnt_lsb = bs_read_ue( &s );
 734             if( p_sys->i_log2_max_pic_order_cnt_lsb > 12 )
 735                 p_sys->i_log2_max_pic_order_cnt_lsb = 12;
 736         }
 737         else if( p_sys->i_pic_order_cnt_type == 1 )
 738         {
 739             int i_cycle;
 740             /* skip b_delta_pic_order_always_zero */
 741             p_sys->i_delta_pic_order_always_zero_flag = bs_read( &s, 1 );
 742             /* skip i_offset_for_non_ref_pic */
 743             bs_read_se( &s );
 744             /* skip i_offset_for_top_to_bottom_field */
 745             bs_read_se( &s );
 746             /* read i_num_ref_frames_in_poc_cycle */
 747             i_cycle = bs_read_ue( &s );
 748             if( i_cycle > 256 ) i_cycle = 256;
 749             while( i_cycle > 0 )
 750             {
 751                 /* skip i_offset_for_ref_frame */
 752                 bs_read_se(&s );
 753             }
 754         }
 755         /* i_num_ref_frames */
 756         bs_read_ue( &s );
 757         /* b_gaps_in_frame_num_value_allowed */
 758         bs_skip( &s, 1 );
 759
 760         /* Read size */
 761         p_dec->fmt_out.video.i_width  = 16 * ( bs_read_ue( &s ) + 1 );
 762         p_dec->fmt_out.video.i_height = 16 * ( bs_read_ue( &s ) + 1 );
 763
 764         /* b_frame_mbs_only */
 765         p_sys->b_frame_mbs_only = bs_read( &s, 1 );
 766         if( p_sys->b_frame_mbs_only == 0 )
 767         {
 768             bs_skip( &s, 1 );
 769         }
 770         /* b_direct8x8_inference */
 771         bs_skip( &s, 1 );
 772
 773         /* crop */
 774         i_tmp = bs_read( &s, 1 );
 775         if( i_tmp )
 776         {
 777             /* left */
 778             bs_read_ue( &s );
 779             /* right */
 780             bs_read_ue( &s );
 781             /* top */
 782             bs_read_ue( &s );
 783             /* bottom */
 784             bs_read_ue( &s );
 785         }
 786
 787         /* vui */
 788         i_tmp = bs_read( &s, 1 );
 789         if( i_tmp )
 790         {
 791             /* read the aspect ratio part if any FIXME check it */
 792             i_tmp = bs_read( &s, 1 );
 793             if( i_tmp )
 794             {
 795                 static const struct { int w, h; } sar[14] =
 796                 {
 797                     { 0,   0 }, { 1,   1 }, { 12, 11 }, { 10, 11 },
 798                     { 16, 11 }, { 40, 33 }, { 24, 11 }, { 20, 11 },
 799                     { 32, 11 }, { 80, 33 }, { 18, 11 }, { 15, 11 },
 800                     { 64, 33 }, { 160,99 },
 801                 };
 802                 int i_sar = bs_read( &s, 8 );
 803                 int w, h;
 804
 805                 if( i_sar < 14 )
 806                 {
 807                     w = sar[i_sar].w;
 808                     h = sar[i_sar].h;
 809                 }
 810                 else
 811                 {
 812                     w = bs_read( &s, 16 );
 813                     h = bs_read( &s, 16 );
 814                 }
 815                 if( h != 0 )
 816                     p_dec->fmt_out.video.i_aspect = VOUT_ASPECT_FACTOR * w /
 817                         h * p_dec->fmt_out.video.i_width /
 818                         p_dec->fmt_out.video.i_height;
 819                 else
 820                     p_dec->fmt_out.video.i_aspect = VOUT_ASPECT_FACTOR;
 821             }
 822         }
 823
 824         free( dec );
 825
 826         if( p_sys->b_slice ) OUTPUT;
 827
 828         /* We have a new SPS */
 829         if( p_sys->p_sps ) block_Release( p_sys->p_sps );
 830         p_sys->p_sps = p_frag;
 831
 832         /* Do not append the SPS because we will insert it on keyframes */
 833         return p_pic;
 834     }
 835     else if( i_nal_type == NAL_PPS )
 836     {
 837         bs_t s;
 838
 839         bs_init( &s, &p_frag->p_buffer[5], p_frag->i_buffer - 5 );
 840         bs_read_ue( &s ); // pps id
 841         bs_read_ue( &s ); // sps id
 842         bs_skip( &s, 1 ); // entropy coding mode flag
 843         p_sys->i_pic_order_present_flag = bs_read( &s, 1 );
 844
 845         if( !p_sys->b_pps ) msg_Dbg( p_dec, "found NAL_PPS" );
 846         p_sys->b_pps = VLC_TRUE;
 847
 848         /* TODO */
 849
 850         if( p_sys->b_slice ) OUTPUT;
 851
 852         /* We have a new PPS */
 853         if( p_sys->p_pps ) block_Release( p_sys->p_pps );
 854         p_sys->p_pps = p_frag;
 855
 856         /* Do not append the PPS because we will insert it on keyframes */
 857         return p_pic;
 858     }
 859     else if( i_nal_type == NAL_AU_DELIMITER ||
 860              i_nal_type == NAL_SEI ||
 861              ( i_nal_type >= 13 && i_nal_type <= 18 ) )
 862     {
 863         if( p_sys->b_slice ) OUTPUT;
 864     }
 865
 866 #undef OUTPUT
 867
 868     /* Append the block */
 869     block_ChainAppend( &p_sys->p_frame, p_frag );
 870
 871     return p_pic;
 872 }