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

   1 /*****************************************************************************
   2  * h264.c: h264/avc video packetizer
   3  *****************************************************************************
   4  * Copyright (C) 2001, 2002 VideoLAN
   5  * $Id$
   6  *
   7  * Authors: Laurent Aimar <fenrir@via.ecp.fr>
   8  *          Eric Petit <titer@videolan.org>
   9  *          Gildas Bazin <gbazin@videolan.org>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  24  *****************************************************************************/
  25
  26 /*****************************************************************************
  27  * Preamble
  28  *****************************************************************************/
  29 #include <stdlib.h>                                      /* malloc(), free() */
  30
  31 #include <vlc/vlc.h>
  32 #include <vlc/decoder.h>
  33 #include <vlc/sout.h>
  34
  35 #include "vlc_block_helper.h"
  36 #include "vlc_bits.h"
  37
  38 /*****************************************************************************
  39  * Module descriptor
  40  *****************************************************************************/
  41 static int  Open ( vlc_object_t * );
  42 static void Close( vlc_object_t * );
  43
  44 vlc_module_begin();
  45     set_category( CAT_SOUT );
  46     set_subcategory( SUBCAT_SOUT_PACKETIZER );
  47     set_description( _("H264 video packetizer") );
  48     set_capability( "packetizer", 50 );
  49     set_callbacks( Open, Close );
  50 vlc_module_end();
  51
  52
  53 /****************************************************************************
  54  * Local prototypes
  55  ****************************************************************************/
  56 static block_t *Packetize( decoder_t *, block_t ** );
  57 static block_t *PacketizeAVC1( decoder_t *, block_t ** );
  58
  59 struct decoder_sys_t
  60 {
  61     block_bytestream_t bytestream;
  62
  63     int     i_state;
  64     int     i_offset;
  65     uint8_t startcode[4];
  66
  67     vlc_bool_t b_slice;
  68     block_t    *p_frame;
  69
  70     vlc_bool_t   b_sps;
  71     vlc_bool_t   b_pps;
  72
  73     /* avcC data */
  74     int i_avcC_length_size;
  75
  76     /* Useful values of the Sequence Parameter Set */
  77     int i_log2_max_frame_num;
  78     int b_frame_mbs_only;
  79
  80     /* Useful values of the Slice Header */
  81     int i_nal_type;
  82     int i_nal_ref_idc;
  83     int i_idr_pic_id;
  84     int i_frame_num;
  85 };
  86
  87 enum
  88 {
  89     STATE_NOSYNC,
  90     STATE_NEXT_SYNC,
  91 };
  92
  93 enum nal_unit_type_e
  94 {
  95     NAL_UNKNOWN = 0,
  96     NAL_SLICE   = 1,
  97     NAL_SLICE_DPA   = 2,
  98     NAL_SLICE_DPB   = 3,
  99     NAL_SLICE_DPC   = 4,
 100     NAL_SLICE_IDR   = 5,    /* ref_idc != 0 */
 101     NAL_SEI         = 6,    /* ref_idc == 0 */
 102     NAL_SPS         = 7,
 103     NAL_PPS         = 8,
 104     NAL_AU_DELIMITER= 9
 105     /* ref_idc == 0 for 6,9,10,11,12 */
 106 };
 107
 108 enum nal_priority_e
 109 {
 110     NAL_PRIORITY_DISPOSABLE = 0,
 111     NAL_PRIORITY_LOW        = 1,
 112     NAL_PRIORITY_HIGH       = 2,
 113     NAL_PRIORITY_HIGHEST    = 3,
 114 };
 115
 116 static block_t *ParseNALBlock( decoder_t *, block_t * );
 117
 118 static block_t *nal_get_annexeb( decoder_t *, uint8_t *p, int );
 119
 120 /*****************************************************************************
 121  * Open: probe the packetizer and return score
 122  *****************************************************************************/
 123 static int Open( vlc_object_t *p_this )
 124 {
 125     decoder_t     *p_dec = (decoder_t*)p_this;
 126     decoder_sys_t *p_sys;
 127
 128     if( p_dec->fmt_in.i_codec != VLC_FOURCC( 'h', '2', '6', '4') &&
 129         p_dec->fmt_in.i_codec != VLC_FOURCC( 'H', '2', '6', '4') &&
 130         p_dec->fmt_in.i_codec != VLC_FOURCC( 'V', 'S', 'S', 'H') &&
 131         p_dec->fmt_in.i_codec != VLC_FOURCC( 'v', 's', 's', 'h') &&
 132         ( p_dec->fmt_in.i_codec != VLC_FOURCC( 'a', 'v', 'c', '1') ||
 133           p_dec->fmt_in.i_extra < 7 ) )
 134     {
 135         return VLC_EGENERIC;
 136     }
 137
 138     /* Allocate the memory needed to store the decoder's structure */
 139     if( ( p_dec->p_sys = p_sys = malloc( sizeof(decoder_sys_t) ) ) == NULL )
 140     {
 141         msg_Err( p_dec, "out of memory" );
 142         return VLC_EGENERIC;
 143     }
 144     p_sys->i_state = STATE_NOSYNC;
 145     p_sys->i_offset = 0;
 146     p_sys->startcode[0] = 0;
 147     p_sys->startcode[1] = 0;
 148     p_sys->startcode[2] = 0;
 149     p_sys->startcode[3] = 1;
 150     p_sys->bytestream = block_BytestreamInit( p_dec );
 151     p_sys->b_slice = VLC_FALSE;
 152     p_sys->p_frame = NULL;
 153     p_sys->b_sps   = VLC_FALSE;
 154     p_sys->b_pps   = VLC_FALSE;
 155
 156     p_sys->i_nal_type = -1;
 157     p_sys->i_nal_ref_idc = -1;
 158     p_sys->i_idr_pic_id = -1;
 159     p_sys->i_frame_num = -1;
 160
 161     /* Setup properties */
 162     es_format_Copy( &p_dec->fmt_out, &p_dec->fmt_in );
 163     p_dec->fmt_out.i_codec = VLC_FOURCC( 'h', '2', '6', '4' );
 164     /* FIXME: FFMPEG isn't happy at all if you leave this */
 165     if( p_dec->fmt_out.i_extra ) free( p_dec->fmt_out.p_extra );
 166     p_dec->fmt_out.i_extra = 0; p_dec->fmt_out.p_extra = 0;
 167
 168     if( p_dec->fmt_in.i_codec == VLC_FOURCC( 'a', 'v', 'c', '1' ) )
 169     {
 170         uint8_t *p = &((uint8_t*)p_dec->fmt_in.p_extra)[4];
 171         int i_sps, i_pps;
 172         int i;
 173
 174         /* Parse avcC */
 175         p_sys->i_avcC_length_size = 1 + ((*p++)&0x03);
 176
 177         /* Read SPS */
 178         i_sps = (*p++)&0x1f;
 179
 180         for( i = 0; i < i_sps; i++ )
 181         {
 182             int i_length = GetWBE( p );
 183             block_t *p_sps = nal_get_annexeb( p_dec, p + 2, i_length );
 184
 185             ParseNALBlock( p_dec, p_sps );
 186             p += 2 + i_length;
 187         }
 188         /* Read PPS */
 189         i_pps = *p++;
 190         for( i = 0; i < i_pps; i++ )
 191         {
 192             int i_length = GetWBE( p );
 193             block_t *p_pps = nal_get_annexeb( p_dec, p + 2, i_length );
 194
 195             ParseNALBlock( p_dec, p_pps );
 196             p += 2 + i_length;
 197         }
 198         msg_Dbg( p_dec, "avcC length size=%d sps=%d pps=%d",
 199                  p_sys->i_avcC_length_size, i_sps, i_pps );
 200
 201         /* Set callback */
 202         p_dec->pf_packetize = PacketizeAVC1;
 203     }
 204     else
 205     {
 206         /* Set callback */
 207         p_dec->pf_packetize = Packetize;
 208     }
 209
 210     return VLC_SUCCESS;
 211 }
 212
 213 /*****************************************************************************
 214  * Close: clean up the packetizer
 215  *****************************************************************************/
 216 static void Close( vlc_object_t *p_this )
 217 {
 218     decoder_t *p_dec = (decoder_t*)p_this;
 219     decoder_sys_t *p_sys = p_dec->p_sys;
 220
 221     block_BytestreamRelease( &p_sys->bytestream );
 222     free( p_sys );
 223 }
 224
 225 /****************************************************************************
 226  * Packetize: the whole thing
 227  ****************************************************************************/
 228 static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
 229 {
 230     decoder_sys_t *p_sys = p_dec->p_sys;
 231     block_t       *p_pic;
 232
 233     if( !pp_block || !*pp_block ) return NULL;
 234
 235     block_BytestreamPush( &p_sys->bytestream, *pp_block );
 236
 237     for( ;; )
 238     {
 239         switch( p_sys->i_state )
 240         {
 241             case STATE_NOSYNC:
 242                 if( block_FindStartcodeFromOffset( &p_sys->bytestream,
 243                       &p_sys->i_offset, p_sys->startcode+1, 3 ) == VLC_SUCCESS)
 244                 {
 245                     p_sys->i_state = STATE_NEXT_SYNC;
 246                 }
 247
 248                 if( p_sys->i_offset )
 249                 {
 250                     block_SkipBytes( &p_sys->bytestream, p_sys->i_offset );
 251                     p_sys->i_offset = 0;
 252                     block_BytestreamFlush( &p_sys->bytestream );
 253                 }
 254
 255                 if( p_sys->i_state != STATE_NEXT_SYNC )
 256                 {
 257                     /* Need more data */
 258                     return NULL;
 259                 }
 260
 261                 p_sys->i_offset = 1; /* To find next startcode */
 262
 263             case STATE_NEXT_SYNC:
 264                 /* Find the next startcode */
 265                 if( block_FindStartcodeFromOffset( &p_sys->bytestream,
 266                       &p_sys->i_offset, p_sys->startcode, 3 ) != VLC_SUCCESS)
 267                 {
 268                     if( block_FindStartcodeFromOffset( &p_sys->bytestream,
 269                           &p_sys->i_offset, p_sys->startcode+1, 3 ) !=
 270                         VLC_SUCCESS )
 271                     {
 272                         /* Need more data */
 273                         return NULL;
 274                     }
 275                 }
 276
 277                 /* Get the new fragment and set the pts/dts */
 278                 p_pic = block_New( p_dec, p_sys->i_offset );
 279                 p_pic->i_pts = p_sys->bytestream.p_block->i_pts;
 280                 p_pic->i_dts = p_sys->bytestream.p_block->i_dts;
 281
 282                 block_GetBytes( &p_sys->bytestream, p_pic->p_buffer,
 283                                 p_pic->i_buffer );
 284
 285                 p_sys->i_offset = 0;
 286
 287                 /* Parse the NAL */
 288                 if( !( p_pic = ParseNALBlock( p_dec, p_pic ) ) )
 289                 {
 290                     p_sys->i_state = STATE_NOSYNC;
 291                     break;
 292                 }
 293 #if 0
 294                 msg_Dbg( p_dec, "pts="I64Fd" dts="I64Fd,
 295                          p_pic->i_pts, p_pic->i_dts );
 296 #endif
 297
 298                 /* So p_block doesn't get re-added several times */
 299                 *pp_block = block_BytestreamPop( &p_sys->bytestream );
 300
 301                 p_sys->i_state = STATE_NOSYNC;
 302
 303                 return p_pic;
 304         }
 305     }
 306 }
 307
 308 /****************************************************************************
 309  * PacketizeAVC1: the whole thing
 310  ****************************************************************************/
 311 static block_t *PacketizeAVC1( decoder_t *p_dec, block_t **pp_block )
 312 {
 313     decoder_sys_t *p_sys = p_dec->p_sys;
 314     block_t       *p_block;
 315     block_t       *p_ret = NULL;
 316     uint8_t       *p;
 317
 318     if( !pp_block || !*pp_block ) return NULL;
 319
 320     p_block = *pp_block;
 321     *pp_block = NULL;
 322
 323     for( p = p_block->p_buffer; p < &p_block->p_buffer[p_block->i_buffer]; )
 324     {
 325         block_t *p_pic;
 326         int i_size = 0;
 327         int i;
 328
 329         for( i = 0; i < p_sys->i_avcC_length_size; i++ )
 330         {
 331             i_size = (i_size << 8) | (*p++);
 332         }
 333
 334         if( i_size > 0 )
 335         {
 336             block_t *p_part = nal_get_annexeb( p_dec, p, i_size );
 337
 338             p_part->i_dts = p_block->i_dts;
 339             p_part->i_pts = p_block->i_pts;
 340
 341             /* Parse the NAL */
 342             if( ( p_pic = ParseNALBlock( p_dec, p_part ) ) )
 343             {
 344                 block_ChainAppend( &p_ret, p_pic );
 345             }
 346         }
 347         p += i_size;
 348     }
 349
 350     return p_ret;
 351 }
 352
 353 static block_t *nal_get_annexeb( decoder_t *p_dec, uint8_t *p, int i_size )
 354 {
 355     block_t *p_nal;
 356
 357     p_nal = block_New( p_dec, 3 + i_size );
 358
 359     /* Add start code */
 360     p_nal->p_buffer[0] = 0x00;
 361     p_nal->p_buffer[1] = 0x00;
 362     p_nal->p_buffer[2] = 0x01;
 363
 364     /* Copy nalu */
 365     memcpy( &p_nal->p_buffer[3], p, i_size );
 366
 367     return p_nal;
 368 }
 369
 370 static void nal_get_decoded( uint8_t **pp_ret, int *pi_ret,
 371                              uint8_t *src, int i_src )
 372 {
 373     uint8_t *end = &src[i_src];
 374     uint8_t *dst = malloc( i_src );
 375
 376     *pp_ret = dst;
 377
 378     while( src < end )
 379     {
 380         if( src < end - 3 && src[0] == 0x00 && src[1] == 0x00 &&
 381             src[2] == 0x03 )
 382         {
 383             *dst++ = 0x00;
 384             *dst++ = 0x00;
 385
 386             src += 3;
 387             continue;
 388         }
 389         *dst++ = *src++;
 390     }
 391
 392     *pi_ret = dst - *pp_ret;
 393 }
 394
 395 static inline int bs_read_ue( bs_t *s )
 396 {
 397     int i = 0;
 398
 399     while( bs_read1( s ) == 0 && s->p < s->p_end && i < 32 )
 400     {
 401         i++;
 402     }
 403     return( ( 1 << i) - 1 + bs_read( s, i ) );
 404 }
 405
 406 static inline int bs_read_se( bs_t *s )
 407 {
 408     int val = bs_read_ue( s );
 409
 410     return val&0x01 ? (val+1)/2 : -(val/2);
 411 }
 412
 413
 414 static block_t *ParseNALBlock( decoder_t *p_dec, block_t *p_frag )
 415 {
 416     decoder_sys_t *p_sys = p_dec->p_sys;
 417     block_t *p_pic = NULL;
 418
 419     const int i_nal_ref_idc = (p_frag->p_buffer[3] >> 5)&0x03;
 420     const int i_nal_type = p_frag->p_buffer[3]&0x1f;
 421
 422 #define OUTPUT \
 423     do {                                                \
 424         p_pic = block_ChainGather( p_sys->p_frame );    \
 425         p_pic->i_length = 0;    /* FIXME */             \
 426                                                         \
 427         p_sys->p_frame = NULL;                          \
 428         p_sys->b_slice = VLC_FALSE;                     \
 429     } while(0)
 430
 431
 432     if( p_sys->b_slice && !p_sys->b_sps )
 433     {
 434         block_ChainRelease( p_sys->p_frame );
 435         msg_Warn( p_dec, "waiting for SPS" );
 436
 437         /* Reset context */
 438         p_sys->p_frame = NULL;
 439         p_sys->b_slice = VLC_FALSE;
 440     }
 441
 442     if( !p_sys->b_sps &&
 443         i_nal_type >= NAL_SLICE && i_nal_type <= NAL_SLICE_IDR )
 444     {
 445         p_sys->b_slice = VLC_TRUE;
 446         /* Fragment will be discarded later on */
 447     }
 448     else if( i_nal_type >= NAL_SLICE && i_nal_type <= NAL_SLICE_IDR )
 449     {
 450         uint8_t *dec;
 451         int i_dec, i_first_mb, i_slice_type, i_frame_num, i_pic_flags = 0;
 452         vlc_bool_t b_pic = VLC_FALSE;
 453         bs_t s;
 454
 455         /* do not convert the whole frame */
 456         nal_get_decoded( &dec, &i_dec, &p_frag->p_buffer[4],
 457                          __MIN( p_frag->i_buffer - 4, 60 ) );
 458         bs_init( &s, dec, i_dec );
 459
 460         /* first_mb_in_slice */
 461         i_first_mb = bs_read_ue( &s );
 462
 463         /* slice_type */
 464         switch( (i_slice_type = bs_read_ue( &s )) )
 465         {
 466             case 0: case 5:
 467                 i_pic_flags = BLOCK_FLAG_TYPE_P;
 468                 break;
 469             case 1: case 6:
 470                 i_pic_flags = BLOCK_FLAG_TYPE_B;
 471                 break;
 472             case 2: case 7:
 473                 i_pic_flags = BLOCK_FLAG_TYPE_I;
 474                 break;
 475             case 3: case 8: /* SP */
 476                 i_pic_flags = BLOCK_FLAG_TYPE_P;
 477                 break;
 478             case 4: case 9:
 479                 i_pic_flags = BLOCK_FLAG_TYPE_I;
 480                 break;
 481         }
 482
 483         /* pic_parameter_set_id */
 484         bs_read_ue( &s );
 485         /* frame_num */
 486         i_frame_num = bs_read( &s, p_sys->i_log2_max_frame_num + 4 );
 487
 488         /* Detection of the first VCL NAL unit of a primary coded picture
 489          * (cf. 7.4.1.2.4) */
 490         if( i_frame_num != p_sys->i_frame_num ||
 491             ( (i_nal_ref_idc != p_sys->i_nal_ref_idc) &&
 492               (!i_nal_ref_idc || !p_sys->i_nal_ref_idc) ) )
 493         {
 494             b_pic = VLC_TRUE;
 495         }
 496         p_sys->i_frame_num = i_frame_num;
 497         p_sys->i_nal_ref_idc = i_nal_ref_idc;
 498
 499         if( !p_sys->b_frame_mbs_only )
 500         {
 501             /* field_pic_flag */
 502             if( bs_read( &s, 1 ) )
 503             {
 504                 /* bottom_field_flag */
 505                 bs_read( &s, 1 );
 506             }
 507         }
 508
 509         if( i_nal_type == NAL_SLICE_IDR )
 510         {
 511             /* id_pic_id */
 512             int i_idr_pic_id = bs_read_ue( &s );
 513             if( p_sys->i_nal_type != i_nal_type ) b_pic = VLC_TRUE;
 514             if( p_sys->i_idr_pic_id != i_idr_pic_id ) b_pic = VLC_TRUE;
 515             p_sys->i_idr_pic_id = i_idr_pic_id;
 516         }
 517         p_sys->i_nal_type = i_nal_type;
 518
 519         if( b_pic && p_sys->b_slice )
 520             OUTPUT;
 521
 522         p_sys->b_slice = VLC_TRUE;
 523
 524         free( dec );
 525     }
 526     else if( i_nal_type == NAL_SPS )
 527     {
 528         uint8_t *dec;
 529         int     i_dec;
 530         bs_t s;
 531         int i_tmp;
 532
 533         if( !p_sys->b_sps )
 534             msg_Dbg( p_dec, "found NAL_SPS" );
 535
 536         p_sys->b_sps = VLC_TRUE;
 537
 538         nal_get_decoded( &dec, &i_dec, &p_frag->p_buffer[4],
 539                          p_frag->i_buffer - 4 );
 540
 541         bs_init( &s, dec, i_dec );
 542         /* Skip profile(8), constraint_set012, reserver(5), level(8) */
 543         bs_skip( &s, 8 + 1+1+1 + 5 + 8 );
 544         /* sps id */
 545         bs_read_ue( &s );
 546         /* Skip i_log2_max_frame_num */
 547         p_sys->i_log2_max_frame_num = bs_read_ue( &s );
 548         /* Read poc_type */
 549         i_tmp = bs_read_ue( &s );
 550         if( i_tmp == 0 )
 551         {
 552             /* skip i_log2_max_poc_lsb */
 553             bs_read_ue( &s );
 554         }
 555         else if( i_tmp == 1 )
 556         {
 557             int i_cycle;
 558             /* skip b_delta_pic_order_always_zero */
 559             bs_skip( &s, 1 );
 560             /* skip i_offset_for_non_ref_pic */
 561             bs_read_se( &s );
 562             /* skip i_offset_for_top_to_bottom_field */
 563             bs_read_se( &s );
 564             /* read i_num_ref_frames_in_poc_cycle */
 565             i_cycle = bs_read_ue( &s );
 566             if( i_cycle > 256 ) i_cycle = 256;
 567             while( i_cycle > 0 )
 568             {
 569                 /* skip i_offset_for_ref_frame */
 570                 bs_read_se(&s );
 571             }
 572         }
 573         /* i_num_ref_frames */
 574         bs_read_ue( &s );
 575         /* b_gaps_in_frame_num_value_allowed */
 576         bs_skip( &s, 1 );
 577
 578         /* Read size */
 579         p_dec->fmt_out.video.i_width  = 16 * ( bs_read_ue( &s ) + 1 );
 580         p_dec->fmt_out.video.i_height = 16 * ( bs_read_ue( &s ) + 1 );
 581
 582         /* b_frame_mbs_only */
 583         p_sys->b_frame_mbs_only = bs_read( &s, 1 );
 584         if( p_sys->b_frame_mbs_only == 0 )
 585         {
 586             bs_skip( &s, 1 );
 587         }
 588         /* b_direct8x8_inference */
 589         bs_skip( &s, 1 );
 590
 591         /* crop */
 592         i_tmp = bs_read( &s, 1 );
 593         if( i_tmp )
 594         {
 595             /* left */
 596             bs_read_ue( &s );
 597             /* right */
 598             bs_read_ue( &s );
 599             /* top */
 600             bs_read_ue( &s );
 601             /* bottom */
 602             bs_read_ue( &s );
 603         }
 604
 605         /* vui */
 606         i_tmp = bs_read( &s, 1 );
 607         if( i_tmp )
 608         {
 609             /* read the aspect ratio part if any FIXME check it */
 610             i_tmp = bs_read( &s, 1 );
 611             if( i_tmp )
 612             {
 613                 static const struct { int w, h; } sar[14] =
 614                 {
 615                     { 0,   0 }, { 1,   1 }, { 12, 11 }, { 10, 11 },
 616                     { 16, 11 }, { 40, 33 }, { 24, 11 }, { 20, 11 },
 617                     { 32, 11 }, { 80, 33 }, { 18, 11 }, { 15, 11 },
 618                     { 64, 33 }, { 160,99 },
 619                 };
 620                 int i_sar = bs_read( &s, 8 );
 621                 int w, h;
 622
 623                 if( i_sar < 14 )
 624                 {
 625                     w = sar[i_sar].w;
 626                     h = sar[i_sar].h;
 627                 }
 628                 else
 629                 {
 630                     w = bs_read( &s, 16 );
 631                     h = bs_read( &s, 16 );
 632                 }
 633                 p_dec->fmt_out.video.i_aspect =
 634                     VOUT_ASPECT_FACTOR * w / h * p_dec->fmt_out.video.i_width /
 635                     p_dec->fmt_out.video.i_height;
 636             }
 637         }
 638
 639         free( dec );
 640
 641
 642         if( p_sys->b_slice )
 643             OUTPUT;
 644     }
 645     else if( i_nal_type == NAL_PPS )
 646     {
 647         bs_t s;
 648         bs_init( &s, &p_frag->p_buffer[4], p_frag->i_buffer - 4 );
 649
 650         if( !p_sys->b_pps )
 651             msg_Dbg( p_dec, "found NAL_PPS" );
 652         p_sys->b_pps = VLC_TRUE;
 653
 654         /* TODO */
 655
 656         if( p_sys->b_slice )
 657             OUTPUT;
 658     }
 659     else if( i_nal_type == NAL_AU_DELIMITER ||
 660              i_nal_type == NAL_SEI ||
 661              ( i_nal_type >= 13 && i_nal_type <= 18 ) )
 662     {
 663         if( p_sys->b_slice )
 664             OUTPUT;
 665     }
 666
 667 #undef OUTPUT
 668
 669     /* Append the block */
 670     block_ChainAppend( &p_sys->p_frame, p_frag );
 671
 672     return p_pic;
 673 }