* another 1st string review, refs #438
[vlc.git] / modules / packetizer / mpegvideo.c
1 /*****************************************************************************
2  * mpegvideo.c: parse and packetize an MPEG1/2 video stream
3  *****************************************************************************
4  * Copyright (C) 2001-2006 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  *          Jean-Paul Saman <jpsaman #_at_# m2x dot nl>
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  * Problem with this implementation:
29  *
30  * Although we should time-stamp each picture with a PTS, this isn't possible
31  * with the current implementation.
32  * The problem comes from the fact that for non-low-delay streams we can't
33  * calculate the PTS of pictures used as backward reference. Even the temporal
34  * reference number doesn't help here because all the pictures don't
35  * necessarily have the same duration (eg. 3:2 pulldown).
36  *
37  * However this doesn't really matter as far as the MPEG muxers are concerned
38  * because they allow having empty PTS fields. --gibalou
39  *****************************************************************************/
40
41 /*****************************************************************************
42  * Preamble
43  *****************************************************************************/
44 #include <stdlib.h>                                      /* malloc(), free() */
45
46 #include <vlc/vlc.h>
47 #include <vlc/decoder.h>
48 #include <vlc/input.h>
49
50 #include "vlc_block_helper.h"
51
52 #define SYNC_INTRAFRAME_TEXT N_("Sync on Intra Frame")
53 #define SYNC_INTRAFRAME_LONGTEXT N_("Normally the packetizer would " \
54     "sync on the next full frame. This flags instructs the packetizer " \
55     "to sync on the first Intra Frame found.")
56
57 /*****************************************************************************
58  * Module descriptor
59  *****************************************************************************/
60 static int  Open ( vlc_object_t * );
61 static void Close( vlc_object_t * );
62
63 vlc_module_begin();
64     set_category( CAT_SOUT );
65     set_subcategory( SUBCAT_SOUT_PACKETIZER );
66     set_description( _("MPEG-I/II video packetizer") );
67     set_capability( "packetizer", 50 );
68     set_callbacks( Open, Close );
69
70     add_bool( "packetizer-mpegvideo-sync-iframe", 0, NULL, SYNC_INTRAFRAME_TEXT,
71               SYNC_INTRAFRAME_LONGTEXT, VLC_TRUE );
72 vlc_module_end();
73
74 /*****************************************************************************
75  * Local prototypes
76  *****************************************************************************/
77 static block_t *Packetize( decoder_t *, block_t ** );
78 static block_t *ParseMPEGBlock( decoder_t *, block_t * );
79
80 struct decoder_sys_t
81 {
82     /*
83      * Input properties
84      */
85     block_bytestream_t bytestream;
86     int i_state;
87     int i_offset;
88     uint8_t p_startcode[3];
89
90     /* Sequence header and extension */
91     block_t *p_seq;
92     block_t *p_ext;
93
94     /* Current frame being built */
95     block_t    *p_frame;
96     block_t    **pp_last;
97
98     vlc_bool_t b_frame_slice;
99     mtime_t i_pts;
100     mtime_t i_dts;
101
102     /* Sequence properties */
103     int         i_frame_rate;
104     int         i_frame_rate_base;
105     vlc_bool_t  b_seq_progressive;
106     vlc_bool_t  b_low_delay;
107     int         i_aspect_ratio_info;
108     vlc_bool_t  b_inited;
109
110     /* Picture properties */
111     int i_temporal_ref;
112     int i_picture_type;
113     int i_picture_structure;
114     int i_top_field_first;
115     int i_repeat_first_field;
116     int i_progressive_frame;
117
118     mtime_t i_interpolated_dts;
119     mtime_t i_old_duration;
120     mtime_t i_last_ref_pts;
121
122     /* Number of pictures since last sequence header */
123     int i_seq_old;
124
125     /* Sync behaviour */
126     vlc_bool_t  b_sync_on_intra_frame;
127     vlc_bool_t  b_discontinuity;
128 };
129
130 enum {
131     STATE_NOSYNC,
132     STATE_NEXT_SYNC
133 };
134
135 /*****************************************************************************
136  * Open:
137  *****************************************************************************/
138 static int Open( vlc_object_t *p_this )
139 {
140     decoder_t *p_dec = (decoder_t*)p_this;
141     decoder_sys_t *p_sys;
142
143     if( p_dec->fmt_in.i_codec != VLC_FOURCC( 'm', 'p', 'g', '1' ) &&
144         p_dec->fmt_in.i_codec != VLC_FOURCC( 'm', 'p', 'g', '2' ) &&
145         p_dec->fmt_in.i_codec != VLC_FOURCC( 'm', 'p', 'g', 'v' ) )
146     {
147         return VLC_EGENERIC;
148     }
149
150     es_format_Init( &p_dec->fmt_out, VIDEO_ES, VLC_FOURCC('m','p','g','v') );
151     p_dec->pf_packetize = Packetize;
152
153     p_dec->p_sys = p_sys = malloc( sizeof( decoder_sys_t ) );
154
155     /* Misc init */
156     p_sys->i_state = STATE_NOSYNC;
157     p_sys->bytestream = block_BytestreamInit( p_dec );
158     p_sys->p_startcode[0] = 0;
159     p_sys->p_startcode[1] = 0;
160     p_sys->p_startcode[2] = 1;
161     p_sys->i_offset = 0;
162
163     p_sys->p_seq = NULL;
164     p_sys->p_ext = NULL;
165     p_sys->p_frame = NULL;
166     p_sys->pp_last = &p_sys->p_frame;
167     p_sys->b_frame_slice = VLC_FALSE;
168
169     p_sys->i_dts = p_sys->i_pts = 0;
170
171     p_sys->i_frame_rate = 1;
172     p_sys->i_frame_rate_base = 1;
173     p_sys->b_seq_progressive = VLC_TRUE;
174     p_sys->b_low_delay = VLC_TRUE;
175     p_sys->i_seq_old = 0;
176
177     p_sys->i_temporal_ref = 0;
178     p_sys->i_picture_type = 0;
179     p_sys->i_picture_structure = 0x03; /* frame */
180     p_sys->i_top_field_first = 0;
181     p_sys->i_repeat_first_field = 0;
182     p_sys->i_progressive_frame = 0;
183     p_sys->b_inited = 0;
184
185     p_sys->i_interpolated_dts = 0;
186     p_sys->i_old_duration = 0;
187     p_sys->i_last_ref_pts = 0;
188
189     p_sys->b_discontinuity = VLC_FALSE;
190     p_sys->b_sync_on_intra_frame = var_CreateGetBool( p_dec, "packetizer-mpegvideo-sync-iframe" );
191     if( p_sys->b_sync_on_intra_frame )
192         msg_Dbg( p_dec, "syncing on intra frame now" );
193
194     return VLC_SUCCESS;
195 }
196
197 /*****************************************************************************
198  * Close:
199  *****************************************************************************/
200 static void Close( vlc_object_t *p_this )
201 {
202     decoder_t     *p_dec = (decoder_t*)p_this;
203     decoder_sys_t *p_sys = p_dec->p_sys;
204
205     block_BytestreamRelease( &p_sys->bytestream );
206
207     if( p_sys->p_seq )
208     {
209         block_Release( p_sys->p_seq );
210     }
211     if( p_sys->p_ext )
212     {
213         block_Release( p_sys->p_ext );
214     }
215     if( p_sys->p_frame )
216     {
217         block_ChainRelease( p_sys->p_frame );
218     }
219
220     var_Destroy( p_dec, "packetizer-mpegvideo-sync-iframe" );
221
222     free( p_sys );
223 }
224
225 /*****************************************************************************
226  * Packetize:
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 == NULL || *pp_block == NULL )
234     {
235         return NULL;
236     }
237
238     if( (*pp_block)->i_flags & (BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
239     {
240         p_sys->i_state = STATE_NOSYNC;
241         p_sys->b_discontinuity = VLC_TRUE;
242         if( p_sys->p_frame )
243             block_ChainRelease( p_sys->p_frame );
244         p_sys->p_frame = NULL;
245         p_sys->pp_last = &p_sys->p_frame;
246         p_sys->b_frame_slice = VLC_FALSE;
247         block_Release( *pp_block );
248         return NULL;
249     }
250
251     block_BytestreamPush( &p_sys->bytestream, *pp_block );
252
253     while( 1 )
254     {
255         switch( p_sys->i_state )
256         {
257
258         case STATE_NOSYNC:
259             if( block_FindStartcodeFromOffset( &p_sys->bytestream,
260                     &p_sys->i_offset, p_sys->p_startcode, 3 ) == VLC_SUCCESS )
261             {
262                 p_sys->i_state = STATE_NEXT_SYNC;
263             }
264
265             if( p_sys->i_offset )
266             {
267                 block_SkipBytes( &p_sys->bytestream, p_sys->i_offset );
268                 p_sys->i_offset = 0;
269                 block_BytestreamFlush( &p_sys->bytestream );
270             }
271
272             if( p_sys->i_state != STATE_NEXT_SYNC )
273             {
274                 /* Need more data */
275                 return NULL;
276             }
277
278             p_sys->i_offset = 1; /* To find next startcode */
279
280         case STATE_NEXT_SYNC:
281             /* TODO: If p_block == NULL, flush the buffer without checking the
282              * next sync word */
283
284             /* Find the next startcode */
285             if( block_FindStartcodeFromOffset( &p_sys->bytestream,
286                     &p_sys->i_offset, p_sys->p_startcode, 3 ) != VLC_SUCCESS )
287             {
288                 /* Need more data */
289                 return NULL;
290             }
291
292             /* Get the new fragment and set the pts/dts */
293             p_pic = block_New( p_dec, p_sys->i_offset );
294             block_BytestreamFlush( &p_sys->bytestream );
295             p_pic->i_pts = p_sys->bytestream.p_block->i_pts;
296             p_pic->i_dts = p_sys->bytestream.p_block->i_dts;
297
298             block_GetBytes( &p_sys->bytestream, p_pic->p_buffer,
299                             p_pic->i_buffer );
300
301             /* don't reuse the same timestamps several times */
302             if( p_pic->i_buffer >= 4 && p_pic->p_buffer[3] == 0x00 )
303             {
304                 /* We have a picture start code */
305                 p_sys->bytestream.p_block->i_pts = 0;
306                 p_sys->bytestream.p_block->i_dts = 0;
307             }
308
309             p_sys->i_offset = 0;
310
311             /* Get picture if any */
312             if( !( p_pic = ParseMPEGBlock( p_dec, p_pic ) ) )
313             {
314                 p_sys->i_state = STATE_NOSYNC;
315                 break;
316             }
317
318             /* If a discontinuity has been encountered, then wait till
319              * the next Intra frame before continuing with packetizing */
320             if( p_sys->b_discontinuity &&
321                 p_sys->b_sync_on_intra_frame )
322             {
323                 if( p_pic->i_flags & BLOCK_FLAG_TYPE_I )
324                 {
325                     msg_Dbg( p_dec, "synced on intra frame" );
326                     p_sys->b_discontinuity = VLC_FALSE;
327                     p_pic->i_flags |= BLOCK_FLAG_DISCONTINUITY;
328                 }
329                 else
330                 {
331                     msg_Dbg( p_dec, "waiting on intra frame" );
332                     p_sys->i_state = STATE_NOSYNC;
333                     block_Release( p_pic );
334                     break;
335                 }
336             }
337
338             /* We've just started the stream, wait for the first PTS.
339              * We discard here so we can still get the sequence header. */
340             if( p_sys->i_dts <= 0 && p_sys->i_pts <= 0 &&
341                 p_sys->i_interpolated_dts <= 0 )
342             {
343                 msg_Dbg( p_dec, "need a starting pts/dts" );
344                 p_sys->i_state = STATE_NOSYNC;
345                 block_Release( p_pic );
346                 break;
347             }
348
349             /* When starting the stream we can have the first frame with
350              * a null DTS (i_interpolated_pts is initialized to 0) */
351             if( !p_pic->i_dts ) p_pic->i_dts = p_pic->i_pts;
352
353             /* So p_block doesn't get re-added several times */
354             *pp_block = block_BytestreamPop( &p_sys->bytestream );
355
356             p_sys->i_state = STATE_NOSYNC;
357
358             return p_pic;
359         }
360     }
361 }
362
363 /*****************************************************************************
364  * ParseMPEGBlock: Re-assemble fragments into a block containing a picture
365  *****************************************************************************/
366 static block_t *ParseMPEGBlock( decoder_t *p_dec, block_t *p_frag )
367 {
368     decoder_sys_t *p_sys = p_dec->p_sys;
369     block_t *p_pic = NULL;
370
371     /*
372      * Check if previous picture is finished
373      */
374     if( ( p_sys->b_frame_slice &&
375           (p_frag->p_buffer[3] == 0x00 || p_frag->p_buffer[3] > 0xaf) ) &&
376           p_sys->p_seq == NULL )
377     {
378         /* We have a picture but without a sequence header we can't
379          * do anything */
380         msg_Dbg( p_dec, "waiting for sequence start" );
381         if( p_sys->p_frame ) block_ChainRelease( p_sys->p_frame );
382         p_sys->p_frame = NULL;
383         p_sys->pp_last = &p_sys->p_frame;
384         p_sys->b_frame_slice = VLC_FALSE;
385
386     }
387     else if( p_sys->b_frame_slice &&
388              (p_frag->p_buffer[3] == 0x00 || p_frag->p_buffer[3] > 0xaf) )
389     {
390         mtime_t i_duration;
391
392         p_pic = block_ChainGather( p_sys->p_frame );
393
394         i_duration = (mtime_t)( 1000000 * p_sys->i_frame_rate_base /
395                                 p_sys->i_frame_rate );
396
397         if( !p_sys->b_seq_progressive && p_sys->i_picture_structure != 0x03 )
398         {
399             i_duration /= 2;
400         }
401
402         if( p_sys->b_seq_progressive )
403         {
404             if( p_sys->i_top_field_first == 0 &&
405                 p_sys->i_repeat_first_field == 1 )
406             {
407                 i_duration *= 2;
408             }
409             else if( p_sys->i_top_field_first == 1 &&
410                      p_sys->i_repeat_first_field == 1 )
411             {
412                 i_duration *= 3;
413             }
414         }
415         else
416         {
417             if( p_sys->i_picture_structure == 0x03 )
418             {
419                 if( p_sys->i_progressive_frame && p_sys->i_repeat_first_field )
420                 {
421                     i_duration += i_duration / 2;
422                 }
423             }
424         }
425
426         if( p_sys->b_low_delay || p_sys->i_picture_type == 0x03 )
427         {
428             /* Trivial case (DTS == PTS) */
429             /* Correct interpolated dts when we receive a new pts/dts */
430             if( p_sys->i_pts > 0 ) p_sys->i_interpolated_dts = p_sys->i_pts;
431             if( p_sys->i_dts > 0 ) p_sys->i_interpolated_dts = p_sys->i_dts;
432         }
433         else
434         {
435             /* Correct interpolated dts when we receive a new pts/dts */
436             if( p_sys->i_last_ref_pts > 0 )
437                 p_sys->i_interpolated_dts = p_sys->i_last_ref_pts;
438             if( p_sys->i_dts > 0 ) p_sys->i_interpolated_dts = p_sys->i_dts;
439
440             p_sys->i_last_ref_pts = p_sys->i_pts;
441         }
442
443         p_pic->i_dts = p_sys->i_interpolated_dts;
444
445         /* Set PTS only if we have a B frame or if it comes from the stream */
446         if( p_sys->i_pts > 0 )
447         {
448             p_pic->i_pts = p_sys->i_pts;
449         }
450         else if( p_sys->i_picture_type == 0x03 )
451         {
452             p_pic->i_pts = p_pic->i_dts;
453         }
454         else
455         {
456             p_pic->i_pts = 0;
457         }
458
459         if( p_sys->b_low_delay || p_sys->i_picture_type == 0x03 )
460         {
461             /* Trivial case (DTS == PTS) */
462             p_sys->i_interpolated_dts += i_duration;
463         }
464         else
465         {
466             p_sys->i_interpolated_dts += p_sys->i_old_duration;
467             p_sys->i_old_duration = i_duration;
468         }
469
470         switch ( p_sys->i_picture_type )
471         {
472         case 0x01:
473             p_pic->i_flags |= BLOCK_FLAG_TYPE_I;
474             break;
475         case 0x02:
476             p_pic->i_flags |= BLOCK_FLAG_TYPE_P;
477             break;
478         case 0x03:
479             p_pic->i_flags |= BLOCK_FLAG_TYPE_B;
480             break;
481         }
482
483         p_pic->i_length = p_sys->i_interpolated_dts - p_pic->i_dts;
484
485 #if 0
486         msg_Dbg( p_dec, "pic: type=%d dts="I64Fd" pts-dts="I64Fd,
487         p_sys->i_picture_type, p_pic->i_dts, p_pic->i_pts - p_pic->i_dts);
488 #endif
489
490         /* Reset context */
491         p_sys->p_frame = NULL;
492         p_sys->pp_last = &p_sys->p_frame;
493         p_sys->b_frame_slice = VLC_FALSE;
494     }
495
496     /*
497      * Check info of current fragment
498      */
499     if( p_frag->p_buffer[3] == 0xb8 )
500     {
501         /* Group start code */
502         if( p_sys->p_seq &&
503             p_sys->i_seq_old > p_sys->i_frame_rate/p_sys->i_frame_rate_base )
504         {
505             /* Usefull for mpeg1: repeat sequence header every second */
506             block_ChainLastAppend( &p_sys->pp_last, block_Duplicate( p_sys->p_seq ) );
507             if( p_sys->p_ext )
508             {
509                 block_ChainLastAppend( &p_sys->pp_last, block_Duplicate( p_sys->p_ext ) );
510             }
511
512             p_sys->i_seq_old = 0;
513         }
514     }
515     else if( p_frag->p_buffer[3] == 0xb3 && p_frag->i_buffer >= 8 )
516     {
517         /* Sequence header code */
518         static const int code_to_frame_rate[16][2] =
519         {
520             { 1, 1 },  /* invalid */
521             { 24000, 1001 }, { 24, 1 }, { 25, 1 },       { 30000, 1001 },
522             { 30, 1 },       { 50, 1 }, { 60000, 1001 }, { 60, 1 },
523             /* Unofficial 15fps from Xing*/
524             { 15, 1001 },
525             /* Unofficial economy rates from libmpeg3 */
526             { 5, 1001 }, { 10, 1001 }, { 12, 1001 }, { 15, 1001 },
527             { 1, 1 },  { 1, 1 }  /* invalid */
528         };
529
530         if( p_sys->p_seq ) block_Release( p_sys->p_seq );
531         if( p_sys->p_ext ) block_Release( p_sys->p_ext );
532
533         p_sys->p_seq = block_Duplicate( p_frag );
534         p_sys->i_seq_old = 0;
535         p_sys->p_ext = NULL;
536
537         p_dec->fmt_out.video.i_width =
538             ( p_frag->p_buffer[4] << 4)|(p_frag->p_buffer[5] >> 4 );
539         p_dec->fmt_out.video.i_height =
540             ( (p_frag->p_buffer[5]&0x0f) << 8 )|p_frag->p_buffer[6];
541         p_sys->i_aspect_ratio_info = p_frag->p_buffer[7] >> 4;
542
543         /* TODO: MPEG1 aspect ratio */
544
545         p_sys->i_frame_rate = code_to_frame_rate[p_frag->p_buffer[7]&0x0f][0];
546         p_sys->i_frame_rate_base =
547             code_to_frame_rate[p_frag->p_buffer[7]&0x0f][1];
548
549         p_dec->fmt_out.video.i_frame_rate = p_sys->i_frame_rate;
550         p_dec->fmt_out.video.i_frame_rate_base = p_sys->i_frame_rate_base;
551
552         p_sys->b_seq_progressive = VLC_TRUE;
553         p_sys->b_low_delay = VLC_TRUE;
554
555         if ( !p_sys->b_inited )
556         {
557             msg_Dbg( p_dec, "size %dx%d fps=%.3f",
558                  p_dec->fmt_out.video.i_width, p_dec->fmt_out.video.i_height,
559                  p_sys->i_frame_rate / (float)p_sys->i_frame_rate_base );
560             p_sys->b_inited = 1;
561         }
562     }
563     else if( p_frag->p_buffer[3] == 0xb5 )
564     {
565         int i_type = p_frag->p_buffer[4] >> 4;
566
567         /* Extention start code */
568         if( i_type == 0x01 )
569         {
570 #if 0
571             static const int mpeg2_aspect[16][2] =
572             {
573                 {0,1}, {1,1}, {4,3}, {16,9}, {221,100},
574                 {0,1}, {0,1}, {0,1}, {0,1}, {0,1}, {0,1}, {0,1}, {0,1}, {0,1},
575                 {0,1}, {0,1}
576             };
577 #endif
578
579             /* sequence extention */
580             if( p_sys->p_ext) block_Release( p_sys->p_ext );
581             p_sys->p_ext = block_Duplicate( p_frag );
582
583             if( p_frag->i_buffer >= 10 )
584             {
585                 p_sys->b_seq_progressive =
586                     p_frag->p_buffer[5]&0x08 ? VLC_TRUE : VLC_FALSE;
587                 p_sys->b_low_delay =
588                     p_frag->p_buffer[9]&0x80 ? VLC_TRUE : VLC_FALSE;
589             }
590
591             /* Do not set aspect ratio : in case we're transcoding,
592              * transcode will take our fmt_out as a fmt_in to libmpeg2.
593              * libmpeg2.c will then believe that the user has requested
594              * a specific aspect ratio, which she hasn't. Thus in case
595              * of aspect ratio change, we're screwed. --Meuuh
596              */
597 #if 0
598             p_dec->fmt_out.video.i_aspect =
599                 mpeg2_aspect[p_sys->i_aspect_ratio_info][0] *
600                 VOUT_ASPECT_FACTOR /
601                 mpeg2_aspect[p_sys->i_aspect_ratio_info][1];
602 #endif
603
604         }
605         else if( i_type == 0x08 )
606         {
607             /* picture extention */
608             p_sys->i_picture_structure = p_frag->p_buffer[6]&0x03;
609             p_sys->i_top_field_first   = p_frag->p_buffer[7] >> 7;
610             p_sys->i_repeat_first_field= (p_frag->p_buffer[7]>>1)&0x01;
611             p_sys->i_progressive_frame = p_frag->p_buffer[8] >> 7;
612         }
613     }
614     else if( p_frag->p_buffer[3] == 0x00 )
615     {
616         /* Picture start code */
617         p_sys->i_seq_old++;
618
619         if( p_frag->i_buffer >= 6 )
620         {
621             p_sys->i_temporal_ref =
622                 ( p_frag->p_buffer[4] << 2 )|(p_frag->p_buffer[5] >> 6);
623             p_sys->i_picture_type = ( p_frag->p_buffer[5] >> 3 ) & 0x03;
624         }
625
626         p_sys->i_dts = p_frag->i_dts;
627         p_sys->i_pts = p_frag->i_pts;
628     }
629     else if( p_frag->p_buffer[3] >= 0x01 && p_frag->p_buffer[3] <= 0xaf )
630     {
631         /* Slice start code */
632         p_sys->b_frame_slice = VLC_TRUE;
633     }
634
635     /* Append the block */
636     block_ChainLastAppend( &p_sys->pp_last, p_frag );
637
638     return p_pic;
639 }