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