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_common.h>
  36 #include <vlc_plugin.h>
  37 #include <vlc_sout.h>
  38 #include <vlc_codec.h>
  39 #include <vlc_block.h>
  40
  41 #include "vlc_block_helper.h"
  42 #include "vlc_bits.h"
  43
  44 /*****************************************************************************
  45  * Module descriptor
  46  *****************************************************************************/
  47 static int  Open ( vlc_object_t * );
  48 static void Close( vlc_object_t * );
  49
  50 vlc_module_begin();
  51     set_category( CAT_SOUT );
  52     set_subcategory( SUBCAT_SOUT_PACKETIZER );
  53     set_description( N_("H.264 video packetizer") );
  54     set_capability( "packetizer", 50 );
  55     set_callbacks( Open, Close );
  56 vlc_module_end();
  57
  58
  59 /****************************************************************************
  60  * Local prototypes
  61  ****************************************************************************/
  62 static block_t *Packetize( decoder_t *, block_t ** );
  63 static block_t *PacketizeAVC1( decoder_t *, block_t ** );
  64
  65 typedef struct
  66 {
  67     int i_nal_type;
  68     int i_nal_ref_idc;
  69
  70     int i_frame_type;
  71     int i_pic_parameter_set_id;
  72     int i_frame_num;
  73
  74     int i_field_pic_flag;
  75     int i_bottom_field_flag;
  76
  77     int i_idr_pic_id;
  78
  79     int i_pic_order_cnt_lsb;
  80     int i_delta_pic_order_cnt_bottom;
  81
  82     int i_delta_pic_order_cnt0;
  83     int i_delta_pic_order_cnt1;
  84 } slice_t;
  85
  86 struct decoder_sys_t
  87 {
  88     block_bytestream_t bytestream;
  89
  90     int     i_state;
  91     size_t  i_offset;
  92     uint8_t startcode[4];
  93
  94     bool b_slice;
  95     block_t    *p_frame;
  96
  97     bool   b_sps;
  98     bool   b_pps;
  99     bool   b_header;
 100
 101     /* avcC data */
 102     int i_avcC_length_size;
 103     block_t *p_sps;
 104     block_t *p_pps;
 105
 106     /* Useful values of the Sequence Parameter Set */
 107     int i_log2_max_frame_num;
 108     int b_frame_mbs_only;
 109     int i_pic_order_cnt_type;
 110     int i_delta_pic_order_always_zero_flag;
 111     int i_log2_max_pic_order_cnt_lsb;
 112
 113     /* Value from Picture Parameter Set */
 114     int i_pic_order_present_flag;
 115
 116     /* Useful values of the Slice Header */
 117     slice_t slice;
 118 };
 119
 120 enum
 121 {
 122     STATE_NOSYNC,
 123     STATE_NEXT_SYNC,
 124 };
 125
 126 enum nal_unit_type_e
 127 {
 128     NAL_UNKNOWN = 0,
 129     NAL_SLICE   = 1,
 130     NAL_SLICE_DPA   = 2,
 131     NAL_SLICE_DPB   = 3,
 132     NAL_SLICE_DPC   = 4,
 133     NAL_SLICE_IDR   = 5,    /* ref_idc != 0 */
 134     NAL_SEI         = 6,    /* ref_idc == 0 */
 135     NAL_SPS         = 7,
 136     NAL_PPS         = 8,
 137     NAL_AU_DELIMITER= 9
 138     /* ref_idc == 0 for 6,9,10,11,12 */
 139 };
 140
 141 enum nal_priority_e
 142 {
 143     NAL_PRIORITY_DISPOSABLE = 0,
 144     NAL_PRIORITY_LOW        = 1,
 145     NAL_PRIORITY_HIGH       = 2,
 146     NAL_PRIORITY_HIGHEST    = 3,
 147 };
 148
 149 static block_t *ParseNALBlock( decoder_t *, block_t * );
 150
 151 static block_t *nal_get_annexeb( decoder_t *, uint8_t *p, int );
 152
 153 /*****************************************************************************
 154  * Open: probe the packetizer and return score
 155  * When opening after demux, the packetizer is only loaded AFTER the decoder
 156  * That means that what you set in fmt_out is ignored by the decoder in this special case
 157  *****************************************************************************/
 158 static int Open( vlc_object_t *p_this )
 159 {
 160     decoder_t     *p_dec = (decoder_t*)p_this;
 161     decoder_sys_t *p_sys;
 162
 163     if( p_dec->fmt_in.i_codec != VLC_FOURCC( 'h', '2', '6', '4') &&
 164         p_dec->fmt_in.i_codec != VLC_FOURCC( 'H', '2', '6', '4') &&
 165         p_dec->fmt_in.i_codec != VLC_FOURCC( 'V', 'S', 'S', 'H') &&
 166         p_dec->fmt_in.i_codec != VLC_FOURCC( 'v', 's', 's', 'h') &&
 167         p_dec->fmt_in.i_codec != VLC_FOURCC( 'D', 'A', 'V', 'C') &&
 168         ( p_dec->fmt_in.i_codec != VLC_FOURCC( 'a', 'v', 'c', '1') ||
 169           p_dec->fmt_in.i_extra < 7 ) )
 170     {
 171         return VLC_EGENERIC;
 172     }
 173
 174     /* Allocate the memory needed to store the decoder's structure */
 175     if( ( p_dec->p_sys = p_sys = malloc( sizeof(decoder_sys_t) ) ) == NULL )
 176     {
 177         return VLC_ENOMEM;
 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 = false;
 187     p_sys->p_frame = NULL;
 188     p_sys->b_sps   = false;
 189     p_sys->b_pps   = false;
 190     p_sys->p_sps   = 0;
 191     p_sys->p_pps   = 0;
 192     p_sys->b_header= 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             uint16_t i_length = GetWBE( p ); p += 2;
 227             if( i_length >
 228                 (uint8_t*)p_dec->fmt_in.p_extra + p_dec->fmt_in.i_extra - p )
 229             {
 230                 return VLC_EGENERIC;
 231             }
 232             block_t *p_sps = nal_get_annexeb( p_dec, p, i_length );
 233             if( !p_sps )
 234                 return VLC_EGENERIC;
 235             p_sys->p_sps = block_Duplicate( p_sps );
 236             p_sps->i_pts = p_sps->i_dts = mdate();
 237             ParseNALBlock( p_dec, p_sps );
 238             p += i_length;
 239         }
 240         /* Read PPS */
 241         i_pps = *p++;
 242         for( i = 0; i < i_pps; i++ )
 243         {
 244             uint16_t i_length = GetWBE( p ); p += 2;
 245             if( i_length >
 246                 (uint8_t*)p_dec->fmt_in.p_extra + p_dec->fmt_in.i_extra - p )
 247             {
 248                 return VLC_EGENERIC;
 249             }
 250             block_t *p_pps = nal_get_annexeb( p_dec, p, i_length );
 251             if( !p_pps )
 252                 return VLC_EGENERIC;
 253             p_sys->p_pps = block_Duplicate( p_pps );
 254             p_pps->i_pts = p_pps->i_dts = mdate();
 255             ParseNALBlock( p_dec, p_pps );
 256             p += i_length;
 257         }
 258         msg_Dbg( p_dec, "avcC length size=%d, sps=%d, pps=%d",
 259                  p_sys->i_avcC_length_size, i_sps, i_pps );
 260
 261         /* FIXME: FFMPEG isn't happy at all if you leave this */
 262         if( p_dec->fmt_out.i_extra > 0 ) free( p_dec->fmt_out.p_extra );
 263         p_dec->fmt_out.i_extra = 0;
 264         p_dec->fmt_out.p_extra = NULL;
 265
 266         /* Set the new extradata */
 267         p_dec->fmt_out.i_extra = p_sys->p_pps->i_buffer + p_sys->p_sps->i_buffer;
 268         p_dec->fmt_out.p_extra = malloc( p_dec->fmt_out.i_extra );
 269         if( p_dec->fmt_out.p_extra )
 270         {
 271             memcpy( (uint8_t*)p_dec->fmt_out.p_extra,
 272                     p_sys->p_sps->p_buffer, p_sys->p_sps->i_buffer);
 273             memcpy( (uint8_t*)p_dec->fmt_out.p_extra+p_sys->p_sps->i_buffer,
 274                     p_sys->p_pps->p_buffer, p_sys->p_pps->i_buffer);
 275             p_sys->b_header = true;
 276         }
 277         else p_dec->fmt_out.i_extra = 0;
 278
 279         /* Set callback */
 280         p_dec->pf_packetize = PacketizeAVC1;
 281     }
 282     else
 283     {
 284         /* This type of stream contains data with 3 of 4 byte startcodes
 285          * The fmt_in.p_extra MAY contain SPS/PPS with 4 byte startcodes
 286          * The fmt_out.p_extra should be the same */
 287
 288         /* Set callback */
 289         p_dec->pf_packetize = Packetize;
 290
 291         /* */
 292         if( p_dec->fmt_in.i_extra > 0 )
 293         {
 294             block_t *p_init = block_New( p_dec, p_dec->fmt_in.i_extra );
 295             block_t *p_pic;
 296
 297             memcpy( p_init->p_buffer, p_dec->fmt_in.p_extra,
 298                     p_dec->fmt_in.i_extra );
 299
 300             while( ( p_pic = Packetize( p_dec, &p_init ) ) )
 301             {
 302                 /* Should not occur because we should only receive SPS/PPS */
 303                 block_Release( p_pic );
 304             }
 305         }
 306     }
 307
 308     return VLC_SUCCESS;
 309 }
 310
 311 /*****************************************************************************
 312  * Close: clean up the packetizer
 313  *****************************************************************************/
 314 static void Close( vlc_object_t *p_this )
 315 {
 316     decoder_t *p_dec = (decoder_t*)p_this;
 317     decoder_sys_t *p_sys = p_dec->p_sys;
 318
 319     if( p_sys->p_frame ) block_ChainRelease( p_sys->p_frame );
 320     if( p_sys->p_sps ) block_Release( p_sys->p_sps );
 321     if( p_sys->p_pps ) block_Release( p_sys->p_pps );
 322     block_BytestreamRelease( &p_sys->bytestream );
 323     free( p_sys );
 324 }
 325
 326 /****************************************************************************
 327  * Packetize: the whole thing
 328  * Search for the startcodes 3 or more bytes
 329  * Feed ParseNALBlock ALWAYS with 4 byte startcode prepended NALs
 330  ****************************************************************************/
 331 static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
 332 {
 333     decoder_sys_t *p_sys = p_dec->p_sys;
 334     block_t       *p_pic;
 335
 336     if( !pp_block || !*pp_block )
 337         return NULL;
 338
 339     if( (*pp_block)->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
 340     {
 341         if( (*pp_block)->i_flags&BLOCK_FLAG_CORRUPTED )
 342         {
 343             p_sys->i_state = STATE_NOSYNC;
 344             block_BytestreamFlush( &p_sys->bytestream );
 345
 346             if( p_sys->p_frame )
 347                 block_ChainRelease( p_sys->p_frame );
 348             p_sys->p_frame = NULL;
 349             p_sys->slice.i_frame_type = 0;
 350             p_sys->b_slice = false;
 351         }
 352         block_Release( *pp_block );
 353         return NULL;
 354     }
 355
 356     block_BytestreamPush( &p_sys->bytestream, *pp_block );
 357
 358     for( ;; )
 359     {
 360         switch( p_sys->i_state )
 361         {
 362             case STATE_NOSYNC:
 363                 /* Skip until 3 byte startcode 0 0 1 */
 364                 if( block_FindStartcodeFromOffset( &p_sys->bytestream,
 365                       &p_sys->i_offset, p_sys->startcode+1, 3 ) == VLC_SUCCESS)
 366                 {
 367                     p_sys->i_state = STATE_NEXT_SYNC;
 368                 }
 369
 370                 if( p_sys->i_offset )
 371                 {
 372                     /* skip the data */
 373                     block_SkipBytes( &p_sys->bytestream, p_sys->i_offset );
 374                     p_sys->i_offset = 0;
 375                     block_BytestreamFlush( &p_sys->bytestream );
 376                 }
 377
 378                 if( p_sys->i_state != STATE_NEXT_SYNC )
 379                 {
 380                     /* Need more data */
 381                     return NULL;
 382                 }
 383
 384                 p_sys->i_offset = 1; /* To find next startcode */
 385
 386             case STATE_NEXT_SYNC:
 387                 /* Find the next 3 byte startcode 0 0 1*/
 388                 if( block_FindStartcodeFromOffset( &p_sys->bytestream,
 389                       &p_sys->i_offset, p_sys->startcode+1, 3 ) != VLC_SUCCESS)
 390                 {
 391                     /* Need more data */
 392                     return NULL;
 393                 }
 394
 395                 /* Get the new fragment and set the pts/dts */
 396                 p_pic = block_New( p_dec, p_sys->i_offset +1 );
 397                 p_pic->i_pts = p_sys->bytestream.p_block->i_pts;
 398                 p_pic->i_dts = p_sys->bytestream.p_block->i_dts;
 399                 /* Force 4 byte startcode 0 0 0 1 */
 400                 p_pic->p_buffer[0] = 0;
 401
 402                 block_GetBytes( &p_sys->bytestream, &p_pic->p_buffer[1],
 403                                 p_pic->i_buffer-1 );
 404
 405                 /* Remove trailing 0 bytes */
 406                 while( p_pic->i_buffer && (!p_pic->p_buffer[p_pic->i_buffer-1] ) )
 407                     p_pic->i_buffer--;
 408                 p_sys->i_offset = 0;
 409
 410                 /* Parse the NAL */
 411                 if( !( p_pic = ParseNALBlock( p_dec, p_pic ) ) )
 412                 {
 413                     p_sys->i_state = STATE_NOSYNC;
 414                     break;
 415                 }
 416 #if 0
 417                 msg_Dbg( p_dec, "pts=%"PRId64" dts=%"PRId64,
 418                          p_pic->i_pts, p_pic->i_dts );
 419 #endif
 420
 421                 /* So p_block doesn't get re-added several times */
 422                 *pp_block = block_BytestreamPop( &p_sys->bytestream );
 423
 424                 p_sys->i_state = STATE_NOSYNC;
 425
 426                 return p_pic;
 427         }
 428     }
 429 }
 430
 431 /****************************************************************************
 432  * PacketizeAVC1: Takes VCL blocks of data and creates annexe B type NAL stream
 433  * Will always use 4 byte 0 0 0 1 startcodes
 434  * Will prepend a SPS and PPS before each keyframe
 435  ****************************************************************************/
 436 static block_t *PacketizeAVC1( decoder_t *p_dec, block_t **pp_block )
 437 {
 438     decoder_sys_t *p_sys = p_dec->p_sys;
 439     block_t       *p_block;
 440     block_t       *p_ret = NULL;
 441     uint8_t       *p;
 442
 443     if( !pp_block || !*pp_block )
 444         return NULL;
 445     if( (*pp_block)->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
 446     {
 447         block_Release( *pp_block );
 448         return NULL;
 449     }
 450
 451     p_block = *pp_block;
 452     *pp_block = NULL;
 453
 454     for( p = p_block->p_buffer; p < &p_block->p_buffer[p_block->i_buffer]; )
 455     {
 456         block_t *p_pic;
 457         int i_size = 0;
 458         int i;
 459
 460         for( i = 0; i < p_sys->i_avcC_length_size; i++ )
 461         {
 462             i_size = (i_size << 8) | (*p++);
 463         }
 464
 465         if( i_size <= 0 ||
 466             i_size > ( p_block->p_buffer + p_block->i_buffer - p ) )
 467         {
 468             msg_Err( p_dec, "Broken frame : size %d is too big", i_size );
 469             break;
 470         }
 471
 472         block_t *p_part = nal_get_annexeb( p_dec, p, i_size );
 473         if( !p_part )
 474             break;
 475         p_part->i_dts = p_block->i_dts;
 476         p_part->i_pts = p_block->i_pts;
 477
 478         /* Parse the NAL */
 479         if( ( p_pic = ParseNALBlock( p_dec, p_part ) ) )
 480         {
 481             block_ChainAppend( &p_ret, p_pic );
 482         }
 483         p += i_size;
 484     }
 485     block_Release( p_block );
 486
 487     return p_ret;
 488 }
 489
 490 static block_t *nal_get_annexeb( decoder_t *p_dec, uint8_t *p, int i_size )
 491 {
 492     block_t *p_nal;
 493
 494     p_nal = block_New( p_dec, 4 + i_size );
 495     if( !p_nal ) return NULL;
 496
 497     /* Add start code */
 498     p_nal->p_buffer[0] = 0x00;
 499     p_nal->p_buffer[1] = 0x00;
 500     p_nal->p_buffer[2] = 0x00;
 501     p_nal->p_buffer[3] = 0x01;
 502
 503     /* Copy nalu */
 504     memcpy( &p_nal->p_buffer[4], p, i_size );
 505
 506     VLC_UNUSED(p_dec);
 507     return p_nal;
 508 }
 509
 510 static void nal_get_decoded( uint8_t **pp_ret, int *pi_ret,
 511                              uint8_t *src, int i_src )
 512 {
 513     uint8_t *end = &src[i_src];
 514     uint8_t *dst = malloc( i_src );
 515
 516     *pp_ret = dst;
 517
 518     if( dst )
 519     {
 520         while( src < end )
 521         {
 522             if( src < end - 3 && src[0] == 0x00 && src[1] == 0x00 &&
 523                 src[2] == 0x03 )
 524             {
 525                 *dst++ = 0x00;
 526                 *dst++ = 0x00;
 527
 528                 src += 3;
 529                 continue;
 530             }
 531             *dst++ = *src++;
 532         }
 533     }
 534     *pi_ret = dst - *pp_ret;
 535 }
 536
 537 static inline int bs_read_ue( bs_t *s )
 538 {
 539     int i = 0;
 540
 541     while( bs_read1( s ) == 0 && s->p < s->p_end && i < 32 )
 542     {
 543         i++;
 544     }
 545     return( ( 1 << i) - 1 + bs_read( s, i ) );
 546 }
 547
 548 static inline int bs_read_se( bs_t *s )
 549 {
 550     int val = bs_read_ue( s );
 551
 552     return val&0x01 ? (val+1)/2 : -(val/2);
 553 }
 554
 555 /*****************************************************************************
 556  * ParseNALBlock: parses annexB type NALs
 557  * All p_frag blocks are required to start with 0 0 0 1 4-byte startcode
 558  *****************************************************************************/
 559 static block_t *OutputPicture( decoder_t *p_dec )
 560 {
 561     decoder_sys_t *p_sys = p_dec->p_sys;
 562     block_t *p_pic;
 563
 564     if( !p_sys->b_header && p_sys->slice.i_frame_type != BLOCK_FLAG_TYPE_I)
 565         return NULL;
 566
 567     if( p_sys->slice.i_frame_type == BLOCK_FLAG_TYPE_I && p_sys->p_sps && p_sys->p_pps )
 568     {
 569         block_t *p_sps = block_Duplicate( p_sys->p_sps );
 570         block_t *p_pps = block_Duplicate( p_sys->p_pps );
 571         p_sps->i_dts = p_sys->p_frame->i_dts;
 572         p_sps->i_pts = p_sys->p_frame->i_pts;
 573         block_ChainAppend( &p_sps, p_pps );
 574         block_ChainAppend( &p_sps, p_sys->p_frame );
 575         p_sys->b_header = true;
 576         p_pic = block_ChainGather( p_sps );
 577     }
 578     else
 579     {
 580         p_pic = block_ChainGather( p_sys->p_frame );
 581     }
 582     p_pic->i_length = 0;    /* FIXME */
 583     p_pic->i_flags |= p_sys->slice.i_frame_type;
 584
 585     p_sys->slice.i_frame_type = 0;
 586     p_sys->p_frame = NULL;
 587     p_sys->b_slice = false;
 588
 589     return p_pic;
 590 }
 591
 592 static block_t *ParseNALBlock( decoder_t *p_dec, block_t *p_frag )
 593 {
 594     decoder_sys_t *p_sys = p_dec->p_sys;
 595     block_t *p_pic = NULL;
 596
 597     const int i_nal_ref_idc = (p_frag->p_buffer[4] >> 5)&0x03;
 598     const int i_nal_type = p_frag->p_buffer[4]&0x1f;
 599
 600     if( p_sys->b_slice && ( !p_sys->b_sps || !p_sys->b_pps ) )
 601     {
 602         block_ChainRelease( p_sys->p_frame );
 603         msg_Warn( p_dec, "waiting for SPS/PPS" );
 604
 605         /* Reset context */
 606         p_sys->slice.i_frame_type = 0;
 607         p_sys->p_frame = NULL;
 608         p_sys->b_slice = false;
 609     }
 610
 611     if( ( !p_sys->b_sps || !p_sys->b_pps ) &&
 612         i_nal_type >= NAL_SLICE && i_nal_type <= NAL_SLICE_IDR )
 613     {
 614         p_sys->b_slice = true;
 615         /* Fragment will be discarded later on */
 616     }
 617     else if( i_nal_type >= NAL_SLICE && i_nal_type <= NAL_SLICE_IDR )
 618     {
 619         uint8_t *dec = NULL;
 620         int i_dec = 0, i_first_mb, i_slice_type;
 621         slice_t slice;
 622         bool b_pic;
 623         bs_t s;
 624
 625         /* do not convert the whole frame */
 626         nal_get_decoded( &dec, &i_dec, &p_frag->p_buffer[5],
 627                          __MIN( p_frag->i_buffer - 5, 60 ) );
 628         bs_init( &s, dec, i_dec );
 629
 630         /* first_mb_in_slice */
 631         i_first_mb = bs_read_ue( &s );
 632
 633         /* slice_type */
 634         switch( (i_slice_type = bs_read_ue( &s )) )
 635         {
 636         case 0: case 5:
 637             slice.i_frame_type = BLOCK_FLAG_TYPE_P;
 638             break;
 639         case 1: case 6:
 640             slice.i_frame_type = BLOCK_FLAG_TYPE_B;
 641             break;
 642         case 2: case 7:
 643             slice.i_frame_type = BLOCK_FLAG_TYPE_I;
 644             break;
 645         case 3: case 8: /* SP */
 646             slice.i_frame_type = BLOCK_FLAG_TYPE_P;
 647             break;
 648         case 4: case 9:
 649             slice.i_frame_type = BLOCK_FLAG_TYPE_I;
 650             break;
 651         default:
 652             slice.i_frame_type = 0;
 653             break;
 654         }
 655
 656         /* */
 657         slice.i_nal_type = i_nal_type;
 658         slice.i_nal_ref_idc = i_nal_ref_idc;
 659
 660         slice.i_pic_parameter_set_id = bs_read_ue( &s );
 661         slice.i_frame_num = bs_read( &s, p_sys->i_log2_max_frame_num + 4 );
 662
 663         slice.i_field_pic_flag = 0;
 664         slice.i_bottom_field_flag = -1;
 665         if( !p_sys->b_frame_mbs_only )
 666         {
 667             /* field_pic_flag */
 668             slice.i_field_pic_flag = bs_read( &s, 1 );
 669             if( slice.i_field_pic_flag )
 670                 slice.i_bottom_field_flag = bs_read( &s, 1 );
 671         }
 672
 673         slice.i_idr_pic_id = p_sys->slice.i_idr_pic_id;
 674         if( slice.i_nal_type == NAL_SLICE_IDR )
 675             slice.i_idr_pic_id = bs_read_ue( &s );
 676
 677         slice.i_pic_order_cnt_lsb = -1;
 678         slice.i_delta_pic_order_cnt_bottom = -1;
 679         slice.i_delta_pic_order_cnt0 = 0;
 680         slice.i_delta_pic_order_cnt1 = 0;
 681         if( p_sys->i_pic_order_cnt_type == 0 )
 682         {
 683             slice.i_pic_order_cnt_lsb = bs_read( &s, p_sys->i_log2_max_pic_order_cnt_lsb + 4 );
 684             if( p_sys->i_pic_order_present_flag && !slice.i_field_pic_flag )
 685                 slice.i_delta_pic_order_cnt_bottom = bs_read_se( &s );
 686         }
 687         else if( (p_sys->i_pic_order_cnt_type == 1) &&
 688                  (!p_sys->i_delta_pic_order_always_zero_flag) )
 689         {
 690             slice.i_delta_pic_order_cnt0 = bs_read_se( &s );
 691             if( p_sys->i_pic_order_present_flag && !slice.i_field_pic_flag )
 692                 slice.i_delta_pic_order_cnt1 = bs_read_se( &s );
 693         }
 694
 695         /* Detection of the first VCL NAL unit of a primary coded picture
 696          * (cf. 7.4.1.2.4) */
 697         b_pic = false;
 698         if( slice.i_frame_num != p_sys->slice.i_frame_num ||
 699             slice.i_pic_parameter_set_id != p_sys->slice.i_pic_parameter_set_id ||
 700             slice.i_field_pic_flag != p_sys->slice.i_field_pic_flag ||
 701             slice.i_nal_ref_idc != p_sys->slice.i_nal_ref_idc )
 702             b_pic = true;
 703         if( (slice.i_bottom_field_flag != -1) &&
 704             (p_sys->slice.i_bottom_field_flag != -1) &&
 705             (slice.i_bottom_field_flag != p_sys->slice.i_bottom_field_flag) )
 706             b_pic = true;
 707         if( p_sys->i_pic_order_cnt_type == 0 &&
 708             ( slice.i_pic_order_cnt_lsb != p_sys->slice.i_pic_order_cnt_lsb ||
 709               slice.i_delta_pic_order_cnt_bottom != p_sys->slice.i_delta_pic_order_cnt_bottom ) )
 710             b_pic = true;
 711         else if( p_sys->i_pic_order_cnt_type == 1 &&
 712                  ( slice.i_delta_pic_order_cnt0 != p_sys->slice.i_delta_pic_order_cnt0 ||
 713                    slice.i_delta_pic_order_cnt1 != p_sys->slice.i_delta_pic_order_cnt1 ) )
 714             b_pic = true;
 715         if( ( slice.i_nal_type == NAL_SLICE_IDR || p_sys->slice.i_nal_type == NAL_SLICE_IDR ) &&
 716             ( slice.i_nal_type != p_sys->slice.i_nal_type || slice.i_idr_pic_id != p_sys->slice.i_idr_pic_id ) )
 717                 b_pic = true;
 718
 719         /* */
 720         p_sys->slice = slice;
 721
 722         if( b_pic && p_sys->b_slice )
 723             p_pic = OutputPicture( p_dec );
 724
 725         p_sys->b_slice = true;
 726
 727         free( dec );
 728     }
 729     else if( i_nal_type == NAL_SPS )
 730     {
 731         uint8_t *dec = NULL;
 732         int     i_dec = 0;
 733         bs_t s;
 734         int i_tmp;
 735
 736         if( !p_sys->b_sps ) msg_Dbg( p_dec, "found NAL_SPS" );
 737
 738         p_sys->b_sps = true;
 739
 740         nal_get_decoded( &dec, &i_dec, &p_frag->p_buffer[5],
 741                          p_frag->i_buffer - 5 );
 742
 743         bs_init( &s, dec, i_dec );
 744         /* Skip profile(8), constraint_set012, reserver(5), level(8) */
 745         bs_skip( &s, 8 + 1+1+1 + 5 + 8 );
 746         /* sps id */
 747         bs_read_ue( &s );
 748         /* Skip i_log2_max_frame_num */
 749         p_sys->i_log2_max_frame_num = bs_read_ue( &s );
 750         if( p_sys->i_log2_max_frame_num > 12)
 751             p_sys->i_log2_max_frame_num = 12;
 752         /* Read poc_type */
 753         p_sys->i_pic_order_cnt_type = bs_read_ue( &s );
 754         if( p_sys->i_pic_order_cnt_type == 0 )
 755         {
 756             /* skip i_log2_max_poc_lsb */
 757             p_sys->i_log2_max_pic_order_cnt_lsb = bs_read_ue( &s );
 758             if( p_sys->i_log2_max_pic_order_cnt_lsb > 12 )
 759                 p_sys->i_log2_max_pic_order_cnt_lsb = 12;
 760         }
 761         else if( p_sys->i_pic_order_cnt_type == 1 )
 762         {
 763             int i_cycle;
 764             /* skip b_delta_pic_order_always_zero */
 765             p_sys->i_delta_pic_order_always_zero_flag = bs_read( &s, 1 );
 766             /* skip i_offset_for_non_ref_pic */
 767             bs_read_se( &s );
 768             /* skip i_offset_for_top_to_bottom_field */
 769             bs_read_se( &s );
 770             /* read i_num_ref_frames_in_poc_cycle */
 771             i_cycle = bs_read_ue( &s );
 772             if( i_cycle > 256 ) i_cycle = 256;
 773             while( i_cycle > 0 )
 774             {
 775                 /* skip i_offset_for_ref_frame */
 776                 bs_read_se(&s );
 777             }
 778         }
 779         /* i_num_ref_frames */
 780         bs_read_ue( &s );
 781         /* b_gaps_in_frame_num_value_allowed */
 782         bs_skip( &s, 1 );
 783
 784         /* Read size */
 785         p_dec->fmt_out.video.i_width  = 16 * ( bs_read_ue( &s ) + 1 );
 786         p_dec->fmt_out.video.i_height = 16 * ( bs_read_ue( &s ) + 1 );
 787
 788         /* b_frame_mbs_only */
 789         p_sys->b_frame_mbs_only = bs_read( &s, 1 );
 790         if( p_sys->b_frame_mbs_only == 0 )
 791         {
 792             bs_skip( &s, 1 );
 793         }
 794         /* b_direct8x8_inference */
 795         bs_skip( &s, 1 );
 796
 797         /* crop */
 798         i_tmp = bs_read( &s, 1 );
 799         if( i_tmp )
 800         {
 801             /* left */
 802             bs_read_ue( &s );
 803             /* right */
 804             bs_read_ue( &s );
 805             /* top */
 806             bs_read_ue( &s );
 807             /* bottom */
 808             bs_read_ue( &s );
 809         }
 810
 811         /* vui */
 812         i_tmp = bs_read( &s, 1 );
 813         if( i_tmp )
 814         {
 815             /* read the aspect ratio part if any FIXME check it */
 816             i_tmp = bs_read( &s, 1 );
 817             if( i_tmp )
 818             {
 819                 static const struct { int w, h; } sar[14] =
 820                 {
 821                     { 0,   0 }, { 1,   1 }, { 12, 11 }, { 10, 11 },
 822                     { 16, 11 }, { 40, 33 }, { 24, 11 }, { 20, 11 },
 823                     { 32, 11 }, { 80, 33 }, { 18, 11 }, { 15, 11 },
 824                     { 64, 33 }, { 160,99 },
 825                 };
 826                 int i_sar = bs_read( &s, 8 );
 827                 int w, h;
 828
 829                 if( i_sar < 14 )
 830                 {
 831                     w = sar[i_sar].w;
 832                     h = sar[i_sar].h;
 833                 }
 834                 else
 835                 {
 836                     w = bs_read( &s, 16 );
 837                     h = bs_read( &s, 16 );
 838                 }
 839                 if( h != 0 )
 840                     p_dec->fmt_out.video.i_aspect = VOUT_ASPECT_FACTOR * w /
 841                         h * p_dec->fmt_out.video.i_width /
 842                         p_dec->fmt_out.video.i_height;
 843                 else
 844                     p_dec->fmt_out.video.i_aspect = VOUT_ASPECT_FACTOR;
 845             }
 846         }
 847
 848         free( dec );
 849
 850         if( p_sys->b_slice )
 851             p_pic = OutputPicture( p_dec );
 852
 853         /* We have a new SPS */
 854         if( p_sys->p_sps ) block_Release( p_sys->p_sps );
 855         p_sys->p_sps = p_frag;
 856
 857         /* Do not append the SPS because we will insert it on keyframes */
 858         return p_pic;
 859     }
 860     else if( i_nal_type == NAL_PPS )
 861     {
 862         bs_t s;
 863
 864         bs_init( &s, &p_frag->p_buffer[5], p_frag->i_buffer - 5 );
 865         bs_read_ue( &s ); // pps id
 866         bs_read_ue( &s ); // sps id
 867         bs_skip( &s, 1 ); // entropy coding mode flag
 868         p_sys->i_pic_order_present_flag = bs_read( &s, 1 );
 869
 870         if( !p_sys->b_pps ) msg_Dbg( p_dec, "found NAL_PPS" );
 871         p_sys->b_pps = true;
 872
 873         /* TODO */
 874
 875         if( p_sys->b_slice )
 876             p_pic = OutputPicture( p_dec );
 877
 878         /* We have a new PPS */
 879         if( p_sys->p_pps ) block_Release( p_sys->p_pps );
 880         p_sys->p_pps = p_frag;
 881
 882         /* Do not append the PPS because we will insert it on keyframes */
 883         return p_pic;
 884     }
 885     else if( i_nal_type == NAL_AU_DELIMITER ||
 886              i_nal_type == NAL_SEI ||
 887              ( i_nal_type >= 13 && i_nal_type <= 18 ) )
 888     {
 889         if( p_sys->b_slice )
 890             p_pic = OutputPicture( p_dec );
 891     }
 892
 893     /* Append the block */
 894     block_ChainAppend( &p_sys->p_frame, p_frag );
 895
 896     return p_pic;
 897 }