]> git.sesse.net Git - vlc/blob - modules/packetizer/h264.c
Packetizers should trash all blocks with DISCONTINUITY or CORRUPTED flag set.
[vlc] / 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 )
315         return NULL;
316     if( (*pp_block)->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
317     {
318         p_sys->i_state = STATE_NOSYNC;
319         block_Release( *pp_block );
320         return NULL;
321     }
322
323     block_BytestreamPush( &p_sys->bytestream, *pp_block );
324
325     for( ;; )
326     {
327         switch( p_sys->i_state )
328         {
329             case STATE_NOSYNC:
330                 /* Skip until 3 byte startcode 0 0 1 */
331                 if( block_FindStartcodeFromOffset( &p_sys->bytestream,
332                       &p_sys->i_offset, p_sys->startcode+1, 3 ) == VLC_SUCCESS)
333                 {
334                     p_sys->i_state = STATE_NEXT_SYNC;
335                 }
336
337                 if( p_sys->i_offset )
338                 {
339                     /* skip the data */
340                     block_SkipBytes( &p_sys->bytestream, p_sys->i_offset );
341                     p_sys->i_offset = 0;
342                     block_BytestreamFlush( &p_sys->bytestream );
343                 }
344
345                 if( p_sys->i_state != STATE_NEXT_SYNC )
346                 {
347                     /* Need more data */
348                     return NULL;
349                 }
350
351                 p_sys->i_offset = 1; /* To find next startcode */
352
353             case STATE_NEXT_SYNC:
354                 /* Find the next 3 byte startcode 0 0 1*/
355                 if( block_FindStartcodeFromOffset( &p_sys->bytestream,
356                       &p_sys->i_offset, p_sys->startcode+1, 3 ) != VLC_SUCCESS)
357                 {
358                     /* Need more data */
359                     return NULL;
360                 }
361
362                 /* Get the new fragment and set the pts/dts */
363                 p_pic = block_New( p_dec, p_sys->i_offset +1 );
364                 p_pic->i_pts = p_sys->bytestream.p_block->i_pts;
365                 p_pic->i_dts = p_sys->bytestream.p_block->i_dts;
366                 /* Force 4 byte startcode 0 0 0 1 */
367                 p_pic->p_buffer[0] = 0;
368
369                 block_GetBytes( &p_sys->bytestream, &p_pic->p_buffer[1],
370                                 p_pic->i_buffer-1 );
371
372                 /* Remove trailing 0 bytes */
373                 while( p_pic->i_buffer && (!p_pic->p_buffer[p_pic->i_buffer-1] ) )
374                     p_pic->i_buffer--;
375                 p_sys->i_offset = 0;
376
377                 /* Parse the NAL */
378                 if( !( p_pic = ParseNALBlock( p_dec, p_pic ) ) )
379                 {
380                     p_sys->i_state = STATE_NOSYNC;
381                     break;
382                 }
383 #if 0
384                 msg_Dbg( p_dec, "pts="I64Fd" dts="I64Fd,
385                          p_pic->i_pts, p_pic->i_dts );
386 #endif
387
388                 /* So p_block doesn't get re-added several times */
389                 *pp_block = block_BytestreamPop( &p_sys->bytestream );
390
391                 p_sys->i_state = STATE_NOSYNC;
392
393                 return p_pic;
394         }
395     }
396 }
397
398 /****************************************************************************
399  * PacketizeAVC1: Takes VCL blocks of data and creates annexe B type NAL stream
400  * Will always use 4 byte 0 0 0 1 startcodes
401  * Will prepend a SPS and PPS before each keyframe
402  ****************************************************************************/
403 static block_t *PacketizeAVC1( decoder_t *p_dec, block_t **pp_block )
404 {
405     decoder_sys_t *p_sys = p_dec->p_sys;
406     block_t       *p_block;
407     block_t       *p_ret = NULL;
408     uint8_t       *p;
409
410     if( !pp_block || !*pp_block )
411         return NULL;
412     if( (*pp_block)->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
413     {
414         block_Release( *pp_block );
415         return NULL;
416     }
417
418     p_block = *pp_block;
419     *pp_block = NULL;
420
421     for( p = p_block->p_buffer; p < &p_block->p_buffer[p_block->i_buffer]; )
422     {
423         block_t *p_pic;
424         int i_size = 0;
425         int i;
426
427         for( i = 0; i < p_sys->i_avcC_length_size; i++ )
428         {
429             i_size = (i_size << 8) | (*p++);
430         }
431
432         if( i_size > 0 )
433         {
434             block_t *p_part = nal_get_annexeb( p_dec, p, i_size );
435
436             p_part->i_dts = p_block->i_dts;
437             p_part->i_pts = p_block->i_pts;
438
439             /* Parse the NAL */
440             if( ( p_pic = ParseNALBlock( p_dec, p_part ) ) )
441             {
442                 block_ChainAppend( &p_ret, p_pic );
443             }
444         }
445         p += i_size;
446     }
447     block_Release( p_block );
448
449     return p_ret;
450 }
451
452 static block_t *nal_get_annexeb( decoder_t *p_dec, uint8_t *p, int i_size )
453 {
454     block_t *p_nal;
455
456     p_nal = block_New( p_dec, 4 + i_size );
457
458     /* Add start code */
459     p_nal->p_buffer[0] = 0x00;
460     p_nal->p_buffer[1] = 0x00;
461     p_nal->p_buffer[2] = 0x00;
462     p_nal->p_buffer[3] = 0x01;
463
464     /* Copy nalu */
465     memcpy( &p_nal->p_buffer[4], p, i_size );
466
467     return p_nal;
468 }
469
470 static void nal_get_decoded( uint8_t **pp_ret, int *pi_ret,
471                              uint8_t *src, int i_src )
472 {
473     uint8_t *end = &src[i_src];
474     uint8_t *dst = malloc( i_src );
475
476     *pp_ret = dst;
477
478     while( src < end )
479     {
480         if( src < end - 3 && src[0] == 0x00 && src[1] == 0x00 &&
481             src[2] == 0x03 )
482         {
483             *dst++ = 0x00;
484             *dst++ = 0x00;
485
486             src += 3;
487             continue;
488         }
489         *dst++ = *src++;
490     }
491
492     *pi_ret = dst - *pp_ret;
493 }
494
495 static inline int bs_read_ue( bs_t *s )
496 {
497     int i = 0;
498
499     while( bs_read1( s ) == 0 && s->p < s->p_end && i < 32 )
500     {
501         i++;
502     }
503     return( ( 1 << i) - 1 + bs_read( s, i ) );
504 }
505
506 static inline int bs_read_se( bs_t *s )
507 {
508     int val = bs_read_ue( s );
509
510     return val&0x01 ? (val+1)/2 : -(val/2);
511 }
512
513
514 /*****************************************************************************
515  * ParseNALBlock: parses annexB type NALs
516  * All p_frag blocks are required to start with 0 0 0 1 4-byte startcode 
517  *****************************************************************************/
518 static block_t *ParseNALBlock( decoder_t *p_dec, block_t *p_frag )
519 {
520     decoder_sys_t *p_sys = p_dec->p_sys;
521     block_t *p_pic = NULL;
522
523     const int i_nal_ref_idc = (p_frag->p_buffer[4] >> 5)&0x03;
524     const int i_nal_type = p_frag->p_buffer[4]&0x1f;
525
526 #define OUTPUT \
527     do {                                                      \
528         if( !p_sys->b_header && p_sys->slice.i_frame_type != BLOCK_FLAG_TYPE_I) \
529             break;                                            \
530                                                               \
531         if( p_sys->slice.i_frame_type == BLOCK_FLAG_TYPE_I && p_sys->p_sps && p_sys->p_pps && !p_sys->b_header ) \
532         { \
533             block_t *p_sps = block_Duplicate( p_sys->p_sps ); \
534             block_t *p_pps = block_Duplicate( p_sys->p_pps ); \
535             p_sps->i_dts = p_sys->p_frame->i_dts;           \
536             p_sps->i_pts = p_sys->p_frame->i_pts;           \
537             block_ChainAppend( &p_sps, p_pps );               \
538             block_ChainAppend( &p_sps, p_sys->p_frame );      \
539             p_sys->b_header = VLC_TRUE;                       \
540             p_pic = block_ChainGather( p_sps );               \
541         } else { \
542             p_pic = block_ChainGather( p_sys->p_frame ); \
543         } \
544         p_pic->i_length = 0;    /* FIXME */                   \
545         p_pic->i_flags |= p_sys->slice.i_frame_type;          \
546             \
547         p_sys->slice.i_frame_type = 0;                        \
548         p_sys->p_frame = NULL;                                \
549         p_sys->b_slice = VLC_FALSE;                           \
550     } while(0)
551
552     if( p_sys->b_slice && ( !p_sys->b_sps || !p_sys->b_pps ) )
553     {
554         block_ChainRelease( p_sys->p_frame );
555         msg_Warn( p_dec, "waiting for SPS/PPS" );
556
557         /* Reset context */
558         p_sys->slice.i_frame_type = 0;
559         p_sys->p_frame = NULL;
560         p_sys->b_slice = VLC_FALSE;
561     }
562
563     if( ( !p_sys->b_sps || !p_sys->b_pps ) &&
564         i_nal_type >= NAL_SLICE && i_nal_type <= NAL_SLICE_IDR )
565     {
566         p_sys->b_slice = VLC_TRUE;
567         /* Fragment will be discarded later on */
568     }
569     else if( i_nal_type >= NAL_SLICE && i_nal_type <= NAL_SLICE_IDR )
570     {
571         uint8_t *dec;
572         int i_dec, i_first_mb, i_slice_type;
573         slice_t slice;
574         vlc_bool_t b_pic;
575         bs_t s;
576
577         /* do not convert the whole frame */
578         nal_get_decoded( &dec, &i_dec, &p_frag->p_buffer[5],
579                          __MIN( p_frag->i_buffer - 5, 60 ) );
580         bs_init( &s, dec, i_dec );
581
582         /* first_mb_in_slice */
583         i_first_mb = bs_read_ue( &s );
584
585         /* slice_type */
586         switch( (i_slice_type = bs_read_ue( &s )) )
587         {
588         case 0: case 5:
589             slice.i_frame_type = BLOCK_FLAG_TYPE_P;
590             break;
591         case 1: case 6:
592             slice.i_frame_type = BLOCK_FLAG_TYPE_B;
593             break;
594         case 2: case 7:
595             slice.i_frame_type = BLOCK_FLAG_TYPE_I;
596             break;
597         case 3: case 8: /* SP */
598             slice.i_frame_type = BLOCK_FLAG_TYPE_P;
599             break;
600         case 4: case 9:
601             slice.i_frame_type = BLOCK_FLAG_TYPE_I;
602             break;
603         default:
604             slice.i_frame_type = 0;
605             break;
606         }
607
608         /* */
609         slice.i_nal_type = i_nal_type;
610         slice.i_nal_ref_idc = i_nal_ref_idc;
611
612         slice.i_pic_parameter_set_id = bs_read_ue( &s );
613         slice.i_frame_num = bs_read( &s, p_sys->i_log2_max_frame_num + 4 );
614
615         slice.i_field_pic_flag = 0;
616         slice.i_bottom_field_flag = -1;
617         if( !p_sys->b_frame_mbs_only )
618         {
619             /* field_pic_flag */
620             slice.i_field_pic_flag = bs_read( &s, 1 );
621             if( slice.i_field_pic_flag )
622                 slice.i_bottom_field_flag = bs_read( &s, 1 );
623         }
624
625         slice.i_idr_pic_id = p_sys->slice.i_idr_pic_id;
626         if( slice.i_nal_type == NAL_SLICE_IDR )
627             slice.i_idr_pic_id = bs_read_ue( &s );
628
629         slice.i_pic_order_cnt_lsb = -1;
630         slice.i_delta_pic_order_cnt_bottom = -1;
631         slice.i_delta_pic_order_cnt0 = 0;
632         slice.i_delta_pic_order_cnt1 = 0;
633         if( p_sys->i_pic_order_cnt_type == 0 )
634         {
635             slice.i_pic_order_cnt_lsb = bs_read( &s, p_sys->i_log2_max_pic_order_cnt_lsb + 4 );
636             if( p_sys->i_pic_order_present_flag && !slice.i_field_pic_flag )
637                 slice.i_delta_pic_order_cnt_bottom = bs_read_se( &s );
638         }
639         else if( p_sys->i_pic_order_cnt_type == 1 && !p_sys->i_delta_pic_order_always_zero_flag )
640         {
641             slice.i_delta_pic_order_cnt0 = bs_read_se( &s );
642             if( p_sys->i_pic_order_present_flag && !slice.i_field_pic_flag )
643                 slice.i_delta_pic_order_cnt1 = bs_read_se( &s );
644         }
645
646         /* Detection of the first VCL NAL unit of a primary coded picture
647          * (cf. 7.4.1.2.4) */
648         b_pic = VLC_FALSE;
649         if( slice.i_frame_num != p_sys->slice.i_frame_num ||
650             slice.i_pic_parameter_set_id != p_sys->slice.i_pic_parameter_set_id ||
651             slice.i_field_pic_flag != p_sys->slice.i_field_pic_flag ||
652             slice.i_nal_ref_idc != p_sys->slice.i_nal_ref_idc )
653             b_pic = VLC_TRUE;
654         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 )
655             b_pic = VLC_TRUE;
656         if( p_sys->i_pic_order_cnt_type == 0 &&
657             ( slice.i_pic_order_cnt_lsb != p_sys->slice.i_pic_order_cnt_lsb ||
658               slice.i_delta_pic_order_cnt_bottom != p_sys->slice.i_delta_pic_order_cnt_bottom ) )
659             b_pic = VLC_TRUE;
660         else if( p_sys->i_pic_order_cnt_type == 1 &&
661                  ( slice.i_delta_pic_order_cnt0 != p_sys->slice.i_delta_pic_order_cnt0 ||
662                    slice.i_delta_pic_order_cnt1 != p_sys->slice.i_delta_pic_order_cnt1 ) )
663             b_pic = VLC_TRUE;
664         if( ( slice.i_nal_type == NAL_SLICE_IDR || p_sys->slice.i_nal_type == NAL_SLICE_IDR ) &&
665             ( slice.i_nal_type != p_sys->slice.i_nal_type || slice.i_idr_pic_id != p_sys->slice.i_idr_pic_id ) )
666                 b_pic = VLC_TRUE;
667
668         /* */
669         p_sys->slice = slice;
670
671         if( b_pic && p_sys->b_slice )
672             OUTPUT;
673
674         p_sys->b_slice = VLC_TRUE;
675
676         free( dec );
677     }
678     else if( i_nal_type == NAL_SPS )
679     {
680         uint8_t *dec;
681         int     i_dec;
682         bs_t s;
683         int i_tmp;
684
685         if( !p_sys->b_sps ) msg_Dbg( p_dec, "found NAL_SPS" );
686
687         p_sys->b_sps = VLC_TRUE;
688
689         nal_get_decoded( &dec, &i_dec, &p_frag->p_buffer[5],
690                          p_frag->i_buffer - 5 );
691
692         bs_init( &s, dec, i_dec );
693         /* Skip profile(8), constraint_set012, reserver(5), level(8) */
694         bs_skip( &s, 8 + 1+1+1 + 5 + 8 );
695         /* sps id */
696         bs_read_ue( &s );
697         /* Skip i_log2_max_frame_num */
698         p_sys->i_log2_max_frame_num = bs_read_ue( &s );
699         if( p_sys->i_log2_max_frame_num > 12)
700             p_sys->i_log2_max_frame_num = 12;
701         /* Read poc_type */
702         p_sys->i_pic_order_cnt_type = bs_read_ue( &s );
703         if( p_sys->i_pic_order_cnt_type == 0 )
704         {
705             /* skip i_log2_max_poc_lsb */
706             p_sys->i_log2_max_pic_order_cnt_lsb = bs_read_ue( &s );
707             if( p_sys->i_log2_max_pic_order_cnt_lsb > 12 )
708                 p_sys->i_log2_max_pic_order_cnt_lsb = 12;
709         }
710         else if( p_sys->i_pic_order_cnt_type == 1 )
711         {
712             int i_cycle;
713             /* skip b_delta_pic_order_always_zero */
714             p_sys->i_delta_pic_order_always_zero_flag = bs_read( &s, 1 );
715             /* skip i_offset_for_non_ref_pic */
716             bs_read_se( &s );
717             /* skip i_offset_for_top_to_bottom_field */
718             bs_read_se( &s );
719             /* read i_num_ref_frames_in_poc_cycle */
720             i_cycle = bs_read_ue( &s );
721             if( i_cycle > 256 ) i_cycle = 256;
722             while( i_cycle > 0 )
723             {
724                 /* skip i_offset_for_ref_frame */
725                 bs_read_se(&s );
726             }
727         }
728         /* i_num_ref_frames */
729         bs_read_ue( &s );
730         /* b_gaps_in_frame_num_value_allowed */
731         bs_skip( &s, 1 );
732
733         /* Read size */
734         p_dec->fmt_out.video.i_width  = 16 * ( bs_read_ue( &s ) + 1 );
735         p_dec->fmt_out.video.i_height = 16 * ( bs_read_ue( &s ) + 1 );
736
737         /* b_frame_mbs_only */
738         p_sys->b_frame_mbs_only = bs_read( &s, 1 );
739         if( p_sys->b_frame_mbs_only == 0 )
740         {
741             bs_skip( &s, 1 );
742         }
743         /* b_direct8x8_inference */
744         bs_skip( &s, 1 );
745
746         /* crop */
747         i_tmp = bs_read( &s, 1 );
748         if( i_tmp )
749         {
750             /* left */
751             bs_read_ue( &s );
752             /* right */
753             bs_read_ue( &s );
754             /* top */
755             bs_read_ue( &s );
756             /* bottom */
757             bs_read_ue( &s );
758         }
759
760         /* vui */
761         i_tmp = bs_read( &s, 1 );
762         if( i_tmp )
763         {
764             /* read the aspect ratio part if any FIXME check it */
765             i_tmp = bs_read( &s, 1 );
766             if( i_tmp )
767             {
768                 static const struct { int w, h; } sar[14] =
769                 {
770                     { 0,   0 }, { 1,   1 }, { 12, 11 }, { 10, 11 },
771                     { 16, 11 }, { 40, 33 }, { 24, 11 }, { 20, 11 },
772                     { 32, 11 }, { 80, 33 }, { 18, 11 }, { 15, 11 },
773                     { 64, 33 }, { 160,99 },
774                 };
775                 int i_sar = bs_read( &s, 8 );
776                 int w, h;
777
778                 if( i_sar < 14 )
779                 {
780                     w = sar[i_sar].w;
781                     h = sar[i_sar].h;
782                 }
783                 else
784                 {
785                     w = bs_read( &s, 16 );
786                     h = bs_read( &s, 16 );
787                 }
788                 if( h != 0 )
789                     p_dec->fmt_out.video.i_aspect = VOUT_ASPECT_FACTOR * w /
790                         h * p_dec->fmt_out.video.i_width /
791                         p_dec->fmt_out.video.i_height;
792                 else
793                     p_dec->fmt_out.video.i_aspect = VOUT_ASPECT_FACTOR;
794             }
795         }
796
797         free( dec );
798
799         if( p_sys->b_slice ) OUTPUT;
800
801         /* We have a new SPS */
802         if( p_sys->p_sps ) block_Release( p_sys->p_sps );
803         p_sys->p_sps = p_frag;
804
805         /* Do not append the SPS because we will insert it on keyframes */
806         return p_pic;
807     }
808     else if( i_nal_type == NAL_PPS )
809     {
810         bs_t s;
811
812         bs_init( &s, &p_frag->p_buffer[5], p_frag->i_buffer - 5 );
813         bs_read_ue( &s ); // pps id
814         bs_read_ue( &s ); // sps id
815         bs_skip( &s, 1 ); // entropy coding mode flag
816         p_sys->i_pic_order_present_flag = bs_read( &s, 1 );
817
818         if( !p_sys->b_pps ) msg_Dbg( p_dec, "found NAL_PPS" );
819         p_sys->b_pps = VLC_TRUE;
820
821         /* TODO */
822
823         if( p_sys->b_slice ) OUTPUT;
824
825         /* We have a new PPS */
826         if( p_sys->p_pps ) block_Release( p_sys->p_pps );
827         p_sys->p_pps = p_frag;
828
829         /* Do not append the PPS because we will insert it on keyframes */
830         return p_pic;
831     }
832     else if( i_nal_type == NAL_AU_DELIMITER ||
833              i_nal_type == NAL_SEI ||
834              ( i_nal_type >= 13 && i_nal_type <= 18 ) )
835     {
836         if( p_sys->b_slice ) OUTPUT;
837     }
838
839 #undef OUTPUT
840
841     /* Append the block */
842     block_ChainAppend( &p_sys->p_frame, p_frag );
843
844     return p_pic;
845 }