1 /*****************************************************************************
2 * mpegvideo.c: parse and packetize an MPEG1/2 video stream
3 *****************************************************************************
4 * Copyright (C) 2001-2006 the VideoLAN team
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>
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.
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.
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 *****************************************************************************/
27 /*****************************************************************************
28 * Problem with this implementation:
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).
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 *****************************************************************************/
41 /*****************************************************************************
43 *****************************************************************************/
46 #include <vlc_block.h>
47 #include <vlc_codec.h>
48 #include <vlc_block_helper.h>
49 #include "../codec/cc.h"
51 #define SYNC_INTRAFRAME_TEXT N_("Sync on Intra Frame")
52 #define SYNC_INTRAFRAME_LONGTEXT N_("Normally the packetizer would " \
53 "sync on the next full frame. This flags instructs the packetizer " \
54 "to sync on the first Intra Frame found.")
56 /*****************************************************************************
58 *****************************************************************************/
59 static int Open ( vlc_object_t * );
60 static void Close( vlc_object_t * );
63 set_category( CAT_SOUT );
64 set_subcategory( SUBCAT_SOUT_PACKETIZER );
65 set_description( _("MPEG-I/II video packetizer") );
66 set_capability( "packetizer", 50 );
67 set_callbacks( Open, Close );
69 add_bool( "packetizer-mpegvideo-sync-iframe", 0, NULL, SYNC_INTRAFRAME_TEXT,
70 SYNC_INTRAFRAME_LONGTEXT, VLC_TRUE );
73 /*****************************************************************************
75 *****************************************************************************/
76 static block_t *Packetize( decoder_t *, block_t ** );
77 static block_t *ParseMPEGBlock( decoder_t *, block_t * );
78 static block_t *GetCc( decoder_t *p_dec, vlc_bool_t pb_present[4] );
85 block_bytestream_t bytestream;
88 uint8_t p_startcode[3];
90 /* Sequence header and extension */
94 /* Current frame being built */
98 vlc_bool_t b_frame_slice;
102 /* Sequence properties */
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;
110 /* Picture properties */
113 int i_picture_structure;
114 int i_top_field_first;
115 int i_repeat_first_field;
116 int i_progressive_frame;
118 mtime_t i_interpolated_dts;
119 mtime_t i_last_ref_pts;
120 vlc_bool_t b_second_field;
122 /* Number of pictures since last sequence header */
126 vlc_bool_t b_sync_on_intra_frame;
127 vlc_bool_t b_discontinuity;
130 vlc_bool_t b_cc_reset;
142 /*****************************************************************************
144 *****************************************************************************/
145 static int Open( vlc_object_t *p_this )
147 decoder_t *p_dec = (decoder_t*)p_this;
148 decoder_sys_t *p_sys;
150 if( p_dec->fmt_in.i_codec != VLC_FOURCC( 'm', 'p', 'g', '1' ) &&
151 p_dec->fmt_in.i_codec != VLC_FOURCC( 'm', 'p', 'g', '2' ) &&
152 p_dec->fmt_in.i_codec != VLC_FOURCC( 'm', 'p', 'g', 'v' ) )
157 es_format_Init( &p_dec->fmt_out, VIDEO_ES, VLC_FOURCC('m','p','g','v') );
158 p_dec->pf_packetize = Packetize;
159 p_dec->pf_get_cc = GetCc;
161 p_dec->p_sys = p_sys = malloc( sizeof( decoder_sys_t ) );
164 p_sys->i_state = STATE_NOSYNC;
165 p_sys->bytestream = block_BytestreamInit( p_dec );
166 p_sys->p_startcode[0] = 0;
167 p_sys->p_startcode[1] = 0;
168 p_sys->p_startcode[2] = 1;
173 p_sys->p_frame = NULL;
174 p_sys->pp_last = &p_sys->p_frame;
175 p_sys->b_frame_slice = VLC_FALSE;
177 p_sys->i_dts = p_sys->i_pts = 0;
179 p_sys->i_frame_rate = 1;
180 p_sys->i_frame_rate_base = 1;
181 p_sys->b_seq_progressive = VLC_TRUE;
182 p_sys->b_low_delay = VLC_TRUE;
183 p_sys->i_seq_old = 0;
185 p_sys->i_temporal_ref = 0;
186 p_sys->i_picture_type = 0;
187 p_sys->i_picture_structure = 0x03; /* frame */
188 p_sys->i_top_field_first = 0;
189 p_sys->i_repeat_first_field = 0;
190 p_sys->i_progressive_frame = 0;
193 p_sys->i_interpolated_dts = 0;
194 p_sys->i_last_ref_pts = 0;
195 p_sys->b_second_field = 0;
197 p_sys->b_discontinuity = VLC_FALSE;
198 p_sys->b_sync_on_intra_frame = var_CreateGetBool( p_dec, "packetizer-mpegvideo-sync-iframe" );
199 if( p_sys->b_sync_on_intra_frame )
200 msg_Dbg( p_dec, "syncing on intra frame now" );
202 p_sys->b_cc_reset = VLC_FALSE;
205 p_sys->i_cc_flags = 0;
206 cc_Init( &p_sys->cc );
211 /*****************************************************************************
213 *****************************************************************************/
214 static void Close( vlc_object_t *p_this )
216 decoder_t *p_dec = (decoder_t*)p_this;
217 decoder_sys_t *p_sys = p_dec->p_sys;
219 block_BytestreamRelease( &p_sys->bytestream );
223 block_Release( p_sys->p_seq );
227 block_Release( p_sys->p_ext );
231 block_ChainRelease( p_sys->p_frame );
234 var_Destroy( p_dec, "packetizer-mpegvideo-sync-iframe" );
239 /*****************************************************************************
241 *****************************************************************************/
242 static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
244 decoder_sys_t *p_sys = p_dec->p_sys;
247 if( pp_block == NULL || *pp_block == NULL )
252 if( (*pp_block)->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
254 if( (*pp_block)->i_flags&BLOCK_FLAG_CORRUPTED )
256 p_sys->i_state = STATE_NOSYNC;
257 block_BytestreamFlush( &p_sys->bytestream );
259 p_sys->b_discontinuity = VLC_TRUE;
261 block_ChainRelease( p_sys->p_frame );
262 p_sys->p_frame = NULL;
263 p_sys->pp_last = &p_sys->p_frame;
264 p_sys->b_frame_slice = VLC_FALSE;
266 // p_sys->i_interpolated_dts =
267 // p_sys->i_last_ref_pts = 0;
269 block_Release( *pp_block );
274 block_BytestreamPush( &p_sys->bytestream, *pp_block );
278 switch( p_sys->i_state )
282 if( block_FindStartcodeFromOffset( &p_sys->bytestream,
283 &p_sys->i_offset, p_sys->p_startcode, 3 ) == VLC_SUCCESS )
285 p_sys->i_state = STATE_NEXT_SYNC;
288 if( p_sys->i_offset )
290 block_SkipBytes( &p_sys->bytestream, p_sys->i_offset );
292 block_BytestreamFlush( &p_sys->bytestream );
295 if( p_sys->i_state != STATE_NEXT_SYNC )
301 p_sys->i_offset = 1; /* To find next startcode */
303 case STATE_NEXT_SYNC:
304 /* TODO: If p_block == NULL, flush the buffer without checking the
307 /* Find the next startcode */
308 if( block_FindStartcodeFromOffset( &p_sys->bytestream,
309 &p_sys->i_offset, p_sys->p_startcode, 3 ) != VLC_SUCCESS )
315 /* Get the new fragment and set the pts/dts */
316 p_pic = block_New( p_dec, p_sys->i_offset );
317 block_BytestreamFlush( &p_sys->bytestream );
318 p_pic->i_pts = p_sys->bytestream.p_block->i_pts;
319 p_pic->i_dts = p_sys->bytestream.p_block->i_dts;
321 block_GetBytes( &p_sys->bytestream, p_pic->p_buffer,
324 /* don't reuse the same timestamps several times */
325 if( p_pic->i_buffer >= 4 && p_pic->p_buffer[3] == 0x00 )
327 /* We have a picture start code */
328 p_sys->bytestream.p_block->i_pts = 0;
329 p_sys->bytestream.p_block->i_dts = 0;
334 /* Get picture if any */
335 if( !( p_pic = ParseMPEGBlock( p_dec, p_pic ) ) )
337 p_sys->i_state = STATE_NOSYNC;
341 /* If a discontinuity has been encountered, then wait till
342 * the next Intra frame before continuing with packetizing */
343 if( p_sys->b_discontinuity &&
344 p_sys->b_sync_on_intra_frame )
346 if( p_pic->i_flags & BLOCK_FLAG_TYPE_I )
348 msg_Dbg( p_dec, "synced on intra frame" );
349 p_sys->b_discontinuity = VLC_FALSE;
350 p_pic->i_flags |= BLOCK_FLAG_DISCONTINUITY;
354 msg_Dbg( p_dec, "waiting on intra frame" );
355 p_sys->i_state = STATE_NOSYNC;
356 block_Release( p_pic );
361 /* We've just started the stream, wait for the first PTS.
362 * We discard here so we can still get the sequence header. */
363 if( p_sys->i_dts <= 0 && p_sys->i_pts <= 0 &&
364 p_sys->i_interpolated_dts <= 0 )
366 msg_Dbg( p_dec, "need a starting pts/dts" );
367 p_sys->i_state = STATE_NOSYNC;
368 block_Release( p_pic );
372 /* When starting the stream we can have the first frame with
373 * a null DTS (i_interpolated_pts is initialized to 0) */
374 if( !p_pic->i_dts ) p_pic->i_dts = p_pic->i_pts;
376 /* So p_block doesn't get re-added several times */
377 *pp_block = block_BytestreamPop( &p_sys->bytestream );
379 p_sys->i_state = STATE_NOSYNC;
386 /*****************************************************************************
388 *****************************************************************************/
389 static block_t *GetCc( decoder_t *p_dec, vlc_bool_t pb_present[4] )
391 decoder_sys_t *p_sys = p_dec->p_sys;
395 for( i = 0; i < 4; i++ )
396 pb_present[i] = p_sys->cc.pb_present[i];
398 if( p_sys->cc.i_data <= 0 )
401 p_cc = block_New( p_dec, p_sys->cc.i_data);
404 memcpy( p_cc->p_buffer, p_sys->cc.p_data, p_sys->cc.i_data );
406 p_cc->i_pts = p_sys->cc.b_reorder ? p_sys->i_cc_pts : p_sys->i_cc_dts;
407 p_cc->i_flags = ( p_sys->cc.b_reorder ? p_sys->i_cc_flags : BLOCK_FLAG_TYPE_P ) & ( BLOCK_FLAG_TYPE_I|BLOCK_FLAG_TYPE_P|BLOCK_FLAG_TYPE_B);
409 cc_Flush( &p_sys->cc );
413 /*****************************************************************************
414 * ParseMPEGBlock: Re-assemble fragments into a block containing a picture
415 *****************************************************************************/
416 static block_t *ParseMPEGBlock( decoder_t *p_dec, block_t *p_frag )
418 decoder_sys_t *p_sys = p_dec->p_sys;
419 block_t *p_pic = NULL;
422 * Check if previous picture is finished
424 if( ( p_sys->b_frame_slice &&
425 (p_frag->p_buffer[3] == 0x00 || p_frag->p_buffer[3] > 0xaf) ) &&
426 p_sys->p_seq == NULL )
428 /* We have a picture but without a sequence header we can't
430 msg_Dbg( p_dec, "waiting for sequence start" );
431 if( p_sys->p_frame ) block_ChainRelease( p_sys->p_frame );
432 p_sys->p_frame = NULL;
433 p_sys->pp_last = &p_sys->p_frame;
434 p_sys->b_frame_slice = VLC_FALSE;
437 else if( p_sys->b_frame_slice &&
438 (p_frag->p_buffer[3] == 0x00 || p_frag->p_buffer[3] > 0xaf) )
442 p_pic = block_ChainGather( p_sys->p_frame );
444 i_duration = (mtime_t)( 1000000 * p_sys->i_frame_rate_base /
445 p_sys->i_frame_rate );
447 if( !p_sys->b_seq_progressive && p_sys->i_picture_structure != 0x03 )
452 if( p_sys->b_seq_progressive )
454 if( p_sys->i_top_field_first == 0 &&
455 p_sys->i_repeat_first_field == 1 )
459 else if( p_sys->i_top_field_first == 1 &&
460 p_sys->i_repeat_first_field == 1 )
467 if( p_sys->i_picture_structure == 0x03 )
469 if( p_sys->i_progressive_frame && p_sys->i_repeat_first_field )
471 i_duration += i_duration / 2;
476 if( p_sys->b_low_delay || p_sys->i_picture_type == 0x03 )
478 /* Trivial case (DTS == PTS) */
479 /* Correct interpolated dts when we receive a new pts/dts */
480 if( p_sys->i_pts > 0 ) p_sys->i_interpolated_dts = p_sys->i_pts;
481 if( p_sys->i_dts > 0 ) p_sys->i_interpolated_dts = p_sys->i_dts;
485 /* Correct interpolated dts when we receive a new pts/dts */
486 if( p_sys->i_last_ref_pts > 0 && !p_sys->b_second_field )
487 p_sys->i_interpolated_dts = p_sys->i_last_ref_pts;
488 if( p_sys->i_dts > 0 ) p_sys->i_interpolated_dts = p_sys->i_dts;
490 if( !p_sys->b_second_field )
491 p_sys->i_last_ref_pts = p_sys->i_pts;
494 p_pic->i_dts = p_sys->i_interpolated_dts;
495 p_sys->i_interpolated_dts += i_duration;
497 /* Set PTS only if we have a B frame or if it comes from the stream */
498 if( p_sys->i_pts > 0 )
500 p_pic->i_pts = p_sys->i_pts;
502 else if( p_sys->i_picture_type == 0x03 )
504 p_pic->i_pts = p_pic->i_dts;
511 switch ( p_sys->i_picture_type )
514 p_pic->i_flags |= BLOCK_FLAG_TYPE_I;
517 p_pic->i_flags |= BLOCK_FLAG_TYPE_P;
520 p_pic->i_flags |= BLOCK_FLAG_TYPE_B;
524 p_pic->i_length = p_sys->i_interpolated_dts - p_pic->i_dts;
527 msg_Dbg( p_dec, "pic: type=%d dts="I64Fd" pts-dts="I64Fd,
528 p_sys->i_picture_type, p_pic->i_dts, p_pic->i_pts - p_pic->i_dts);
532 p_sys->p_frame = NULL;
533 p_sys->pp_last = &p_sys->p_frame;
534 p_sys->b_frame_slice = VLC_FALSE;
536 if( p_sys->i_picture_structure != 0x03 )
538 p_sys->b_second_field = !p_sys->b_second_field;
542 p_sys->b_second_field = 0;
546 p_sys->b_cc_reset = VLC_TRUE;
547 p_sys->i_cc_pts = p_pic->i_pts;
548 p_sys->i_cc_dts = p_pic->i_dts;
549 p_sys->i_cc_flags = p_pic->i_flags;
552 if( !p_pic && p_sys->b_cc_reset )
554 p_sys->b_cc_reset = VLC_FALSE;
555 cc_Flush( &p_sys->cc );
559 * Check info of current fragment
561 if( p_frag->p_buffer[3] == 0xb8 )
563 /* Group start code */
565 p_sys->i_seq_old > p_sys->i_frame_rate/p_sys->i_frame_rate_base )
567 /* Usefull for mpeg1: repeat sequence header every second */
568 block_ChainLastAppend( &p_sys->pp_last, block_Duplicate( p_sys->p_seq ) );
571 block_ChainLastAppend( &p_sys->pp_last, block_Duplicate( p_sys->p_ext ) );
574 p_sys->i_seq_old = 0;
577 else if( p_frag->p_buffer[3] == 0xb3 && p_frag->i_buffer >= 8 )
579 /* Sequence header code */
580 static const int code_to_frame_rate[16][2] =
582 { 1, 1 }, /* invalid */
583 { 24000, 1001 }, { 24, 1 }, { 25, 1 }, { 30000, 1001 },
584 { 30, 1 }, { 50, 1 }, { 60000, 1001 }, { 60, 1 },
585 /* Unofficial 15fps from Xing*/
587 /* Unofficial economy rates from libmpeg3 */
588 { 5, 1001 }, { 10, 1001 }, { 12, 1001 }, { 15, 1001 },
589 { 1, 1 }, { 1, 1 } /* invalid */
592 if( p_sys->p_seq ) block_Release( p_sys->p_seq );
593 if( p_sys->p_ext ) block_Release( p_sys->p_ext );
595 p_sys->p_seq = block_Duplicate( p_frag );
596 p_sys->i_seq_old = 0;
599 p_dec->fmt_out.video.i_width =
600 ( p_frag->p_buffer[4] << 4)|(p_frag->p_buffer[5] >> 4 );
601 p_dec->fmt_out.video.i_height =
602 ( (p_frag->p_buffer[5]&0x0f) << 8 )|p_frag->p_buffer[6];
603 p_sys->i_aspect_ratio_info = p_frag->p_buffer[7] >> 4;
605 /* TODO: MPEG1 aspect ratio */
607 p_sys->i_frame_rate = code_to_frame_rate[p_frag->p_buffer[7]&0x0f][0];
608 p_sys->i_frame_rate_base =
609 code_to_frame_rate[p_frag->p_buffer[7]&0x0f][1];
611 p_dec->fmt_out.video.i_frame_rate = p_sys->i_frame_rate;
612 p_dec->fmt_out.video.i_frame_rate_base = p_sys->i_frame_rate_base;
614 p_sys->b_seq_progressive = VLC_TRUE;
615 p_sys->b_low_delay = VLC_TRUE;
617 if ( !p_sys->b_inited )
619 msg_Dbg( p_dec, "size %dx%d fps=%.3f",
620 p_dec->fmt_out.video.i_width, p_dec->fmt_out.video.i_height,
621 p_sys->i_frame_rate / (float)p_sys->i_frame_rate_base );
625 else if( p_frag->p_buffer[3] == 0xb5 )
627 int i_type = p_frag->p_buffer[4] >> 4;
629 /* Extension start code */
633 static const int mpeg2_aspect[16][2] =
635 {0,1}, {1,1}, {4,3}, {16,9}, {221,100},
636 {0,1}, {0,1}, {0,1}, {0,1}, {0,1}, {0,1}, {0,1}, {0,1}, {0,1},
641 /* sequence extension */
642 if( p_sys->p_ext) block_Release( p_sys->p_ext );
643 p_sys->p_ext = block_Duplicate( p_frag );
645 if( p_frag->i_buffer >= 10 )
647 p_sys->b_seq_progressive =
648 p_frag->p_buffer[5]&0x08 ? VLC_TRUE : VLC_FALSE;
650 p_frag->p_buffer[9]&0x80 ? VLC_TRUE : VLC_FALSE;
653 /* Do not set aspect ratio : in case we're transcoding,
654 * transcode will take our fmt_out as a fmt_in to libmpeg2.
655 * libmpeg2.c will then believe that the user has requested
656 * a specific aspect ratio, which she hasn't. Thus in case
657 * of aspect ratio change, we're screwed. --Meuuh
660 p_dec->fmt_out.video.i_aspect =
661 mpeg2_aspect[p_sys->i_aspect_ratio_info][0] *
663 mpeg2_aspect[p_sys->i_aspect_ratio_info][1];
667 else if( i_type == 0x08 )
669 /* picture extension */
670 p_sys->i_picture_structure = p_frag->p_buffer[6]&0x03;
671 p_sys->i_top_field_first = p_frag->p_buffer[7] >> 7;
672 p_sys->i_repeat_first_field= (p_frag->p_buffer[7]>>1)&0x01;
673 p_sys->i_progressive_frame = p_frag->p_buffer[8] >> 7;
676 else if( p_frag->p_buffer[3] == 0xb2 && p_frag->i_buffer > 4 )
678 cc_Extract( &p_sys->cc, &p_frag->p_buffer[4], p_frag->i_buffer - 4 );
680 else if( p_frag->p_buffer[3] == 0x00 )
682 /* Picture start code */
685 if( p_frag->i_buffer >= 6 )
687 p_sys->i_temporal_ref =
688 ( p_frag->p_buffer[4] << 2 )|(p_frag->p_buffer[5] >> 6);
689 p_sys->i_picture_type = ( p_frag->p_buffer[5] >> 3 ) & 0x03;
692 p_sys->i_dts = p_frag->i_dts;
693 p_sys->i_pts = p_frag->i_pts;
695 else if( p_frag->p_buffer[3] >= 0x01 && p_frag->p_buffer[3] <= 0xaf )
697 /* Slice start code */
698 p_sys->b_frame_slice = VLC_TRUE;
701 /* Append the block */
702 block_ChainLastAppend( &p_sys->pp_last, p_frag );