1 /*****************************************************************************
2 * ps.c: MPEG PS (ISO/IEC 13818-1) / MPEG SYSTEM (ISO/IEC 1172-1)
3 * multiplexer module for vlc
4 *****************************************************************************
5 * Copyright (C) 2001, 2002 the VideoLAN team
8 * Authors: Laurent Aimar <fenrir@via.ecp.fr>
9 * Eric Petit <titer@videolan.org>
10 * Gildas Bazin <gbazin@videolan.org>
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 /*****************************************************************************
29 *****************************************************************************/
35 #include <vlc_common.h>
36 #include <vlc_plugin.h>
38 #include <vlc_block.h>
43 #include <vlc_iso_lang.h>
45 /*****************************************************************************
47 *****************************************************************************/
48 #define DTS_TEXT N_("DTS delay (ms)")
49 #define DTS_LONGTEXT N_("Delay the DTS (decoding time " \
50 "stamps) and PTS (presentation timestamps) of the data in the " \
51 "stream, compared to the SCRs. This allows for some buffering inside " \
52 "the client decoder.")
54 #define PES_SIZE_TEXT N_("PES maximum size")
55 #define PES_SIZE_LONGTEXT N_("Set the maximum allowed PES "\
56 "size when producing the MPEG PS streams.")
58 static int Open ( vlc_object_t * );
59 static void Close ( vlc_object_t * );
61 #define SOUT_CFG_PREFIX "sout-ps-"
64 set_description( N_("PS muxer") )
65 set_shortname( "MPEG-PS" )
66 set_category( CAT_SOUT )
67 set_subcategory( SUBCAT_SOUT_MUX )
68 set_capability( "sout mux", 50 )
70 add_shortcut( "mpeg1" )
72 set_callbacks( Open, Close )
74 add_integer( SOUT_CFG_PREFIX "dts-delay", 200, NULL, DTS_TEXT,
76 add_integer( SOUT_CFG_PREFIX "pes-max-size", PES_PAYLOAD_SIZE_MAX, NULL,
77 PES_SIZE_TEXT, PES_SIZE_LONGTEXT, true )
80 /*****************************************************************************
82 *****************************************************************************/
83 static int Control ( sout_mux_t *, int, va_list );
84 static int AddStream( sout_mux_t *, sout_input_t * );
85 static int DelStream( sout_mux_t *, sout_input_t * );
86 static int Mux ( sout_mux_t * );
88 /*****************************************************************************
90 *****************************************************************************/
92 static void MuxWritePackHeader ( sout_mux_t *, block_t **, mtime_t );
93 static void MuxWriteSystemHeader( sout_mux_t *, block_t **, mtime_t );
94 static void MuxWritePSM ( sout_mux_t *, block_t **, mtime_t );
96 static void StreamIdInit ( bool *id, int i_range );
97 static int StreamIdGet ( bool *id, int i_id_min, int i_id_max );
98 static void StreamIdRelease ( bool *id, int i_id_min, int i_id );
100 typedef struct ps_stream_s
104 int i_max_buff_size; /* used in system header */
106 /* Language is iso639-2T */
111 struct sout_mux_sys_t
113 /* Which id are unused */
114 bool stream_id_mpga[16]; /* 0xc0 -> 0xcf */
115 bool stream_id_mpgv[16]; /* 0xe0 -> 0xef */
116 bool stream_id_a52[8]; /* 0x80 -> 0x87 <- FIXME I'm not sure */
117 bool stream_id_spu[32]; /* 0x20 -> 0x3f */
118 bool stream_id_dts[8]; /* 0x88 -> 0x8f */
119 bool stream_id_lpcm[16]; /* 0xa0 -> 0xaf */
126 int i_rate_bound; /* units of 50 bytes/second */
128 int64_t i_instant_bitrate;
129 int64_t i_instant_size;
130 int64_t i_instant_dts;
137 uint32_t crc32_table[256];
140 static const char *const ppsz_sout_options[] = {
141 "dts-delay", "pes-max-size", NULL
144 /*****************************************************************************
146 *****************************************************************************/
147 static int Open( vlc_object_t *p_this )
149 sout_mux_t *p_mux = (sout_mux_t*)p_this;
150 sout_mux_sys_t *p_sys;
153 msg_Info( p_mux, "Open" );
154 config_ChainParse( p_mux, SOUT_CFG_PREFIX, ppsz_sout_options, p_mux->p_cfg );
156 p_mux->pf_control = Control;
157 p_mux->pf_addstream = AddStream;
158 p_mux->pf_delstream = DelStream;
160 p_mux->p_sys = p_sys = malloc( sizeof( sout_mux_sys_t ) );
162 /* Init free stream id */
163 StreamIdInit( p_sys->stream_id_a52, 8 );
164 StreamIdInit( p_sys->stream_id_dts, 8 );
165 StreamIdInit( p_sys->stream_id_mpga, 16 );
166 StreamIdInit( p_sys->stream_id_mpgv, 16 );
167 StreamIdInit( p_sys->stream_id_lpcm, 16 );
168 StreamIdInit( p_sys->stream_id_spu, 32 );
170 p_sys->i_audio_bound = 0;
171 p_sys->i_video_bound = 0;
172 p_sys->i_system_header = 0;
173 p_sys->i_pes_count = 0;
175 p_sys->i_psm_version = 0;
177 p_sys->i_instant_bitrate = 0;
178 p_sys->i_instant_size = 0;
179 p_sys->i_instant_dts = 0;
180 p_sys->i_rate_bound = 0;
181 p_sys->b_mpeg2 = !(p_mux->psz_mux && !strcmp( p_mux->psz_mux, "mpeg1" ));
183 var_Get( p_mux, SOUT_CFG_PREFIX "dts-delay", &val );
184 p_sys->i_dts_delay = (int64_t)val.i_int * 1000;
186 var_Get( p_mux, SOUT_CFG_PREFIX "pes-max-size", &val );
187 p_sys->i_pes_max_size = (int64_t)val.i_int;
189 /* Initialise CRC32 table */
194 for( i = 0; i < 256; i++ )
197 for( j = (i << 24) | 0x800000; j != 0x80000000; j <<= 1 )
198 k = (k << 1) ^ (((k ^ j) & 0x80000000) ? 0x04c11db7 : 0);
200 p_sys->crc32_table[i] = k;
207 /*****************************************************************************
209 *****************************************************************************/
210 static void Close( vlc_object_t * p_this )
212 sout_mux_t *p_mux = (sout_mux_t*)p_this;
213 sout_mux_sys_t *p_sys = p_mux->p_sys;
217 msg_Info( p_mux, "Close" );
219 p_end = block_New( p_mux, 4 );
220 p_end->p_buffer[0] = 0x00; p_end->p_buffer[1] = 0x00;
221 p_end->p_buffer[2] = 0x01; p_end->p_buffer[3] = 0xb9;
223 sout_AccessOutWrite( p_mux->p_access, p_end );
228 /*****************************************************************************
230 *****************************************************************************/
231 static int Control( sout_mux_t *p_mux, int i_query, va_list args )
239 case MUX_CAN_ADD_STREAM_WHILE_MUXING:
240 pb_bool = (bool*)va_arg( args, bool * );
244 case MUX_GET_ADD_STREAM_WAIT:
245 pb_bool = (bool*)va_arg( args, bool * );
250 ppsz = (char**)va_arg( args, char ** );
251 *ppsz = strdup( "video/mpeg" );
259 /*****************************************************************************
261 *****************************************************************************/
262 static int AddStream( sout_mux_t *p_mux, sout_input_t *p_input )
264 sout_mux_sys_t *p_sys = p_mux->p_sys;
265 ps_stream_t *p_stream;
268 msg_Dbg( p_mux, "adding input codec=%4.4s",
269 (char*)&p_input->p_fmt->i_codec );
271 p_input->p_sys = p_stream = malloc( sizeof( ps_stream_t ) );
272 p_stream->i_stream_type = 0x81;
274 /* Init this new stream */
275 switch( p_input->p_fmt->i_codec )
278 p_stream->i_stream_id =
279 StreamIdGet( p_sys->stream_id_mpgv, 0xe0, 0xef );
280 p_stream->i_stream_type = 0x02; /* ISO/IEC 13818 Video */
283 p_stream->i_stream_id =
284 StreamIdGet( p_sys->stream_id_mpgv, 0xe0, 0xef );
285 p_stream->i_stream_type = 0x10;
288 p_stream->i_stream_id =
289 StreamIdGet( p_sys->stream_id_mpgv, 0xe0, 0xef );
290 p_stream->i_stream_type = 0x1b;
292 case VLC_CODEC_DVD_LPCM:
293 p_stream->i_stream_id =
294 0xbd00 | StreamIdGet( p_sys->stream_id_lpcm, 0xa0, 0xaf );
297 p_stream->i_stream_id =
298 0xbd00 | StreamIdGet( p_sys->stream_id_dts, 0x88, 0x8f );
301 p_stream->i_stream_id =
302 0xbd00 | StreamIdGet( p_sys->stream_id_a52, 0x80, 0x87 );
305 p_stream->i_stream_id =
306 StreamIdGet( p_sys->stream_id_mpga, 0xc0, 0xcf );
307 p_stream->i_stream_type = 0x03; /* ISO/IEC 11172 Audio */
310 p_stream->i_stream_id =
311 StreamIdGet( p_sys->stream_id_mpga, 0xc0, 0xcf );
312 p_stream->i_stream_type = 0x0f;
315 p_stream->i_stream_id =
316 0xbd00 | StreamIdGet( p_sys->stream_id_spu, 0x20, 0x3f );
322 if( p_stream->i_stream_id < 0 ) goto error;
324 if( p_input->p_fmt->i_cat == AUDIO_ES )
326 p_sys->i_audio_bound++;
327 p_stream->i_max_buff_size = 4 * 1024;
329 else if( p_input->p_fmt->i_cat == VIDEO_ES )
331 p_sys->i_video_bound++;
332 p_stream->i_max_buff_size = 400 * 1024; /* FIXME -- VCD uses 46, SVCD
333 uses 230, ffmpeg has 230 with a note that it is small */
336 { /* FIXME -- what's valid for not audio or video? */
337 p_stream->i_max_buff_size = 4 * 1024;
340 /* Try to set a sensible default value for the instant bitrate */
341 p_sys->i_instant_bitrate += p_input->p_fmt->i_bitrate + 1000/* overhead */;
343 /* FIXME -- spec requires an upper limit rate boundary in the system header;
344 our codecs are VBR; using 2x nominal rate, convert to 50 bytes/sec */
345 p_sys->i_rate_bound += p_input->p_fmt->i_bitrate * 2 / (8 * 50);
346 p_sys->i_psm_version++;
348 p_stream->lang[0] = p_stream->lang[1] = p_stream->lang[2] = 0;
349 if( p_input->p_fmt->psz_language )
351 char *psz = p_input->p_fmt->psz_language;
352 const iso639_lang_t *pl = NULL;
354 if( strlen( psz ) == 2 )
356 pl = GetLang_1( psz );
358 else if( strlen( psz ) == 3 )
360 pl = GetLang_2B( psz );
361 if( !strcmp( pl->psz_iso639_1, "??" ) )
363 pl = GetLang_2T( psz );
366 if( pl && strcmp( pl->psz_iso639_1, "??" ) )
368 p_stream->lang[0] = pl->psz_iso639_2T[0];
369 p_stream->lang[1] = pl->psz_iso639_2T[1];
370 p_stream->lang[2] = pl->psz_iso639_2T[2];
372 msg_Dbg( p_mux, " - lang=%c%c%c",
373 p_stream->lang[0], p_stream->lang[1], p_stream->lang[2] );
383 /*****************************************************************************
385 *****************************************************************************/
386 static int DelStream( sout_mux_t *p_mux, sout_input_t *p_input )
388 sout_mux_sys_t *p_sys = p_mux->p_sys;
389 ps_stream_t *p_stream =(ps_stream_t*)p_input->p_sys;
391 msg_Dbg( p_mux, "removing input" );
392 switch( p_input->p_fmt->i_codec )
395 StreamIdRelease( p_sys->stream_id_mpgv, 0xe0,
396 p_stream->i_stream_id );
398 case VLC_CODEC_DVD_LPCM:
399 StreamIdRelease( p_sys->stream_id_lpcm, 0xa0,
400 p_stream->i_stream_id&0xff );
403 StreamIdRelease( p_sys->stream_id_dts, 0x88,
404 p_stream->i_stream_id&0xff );
407 StreamIdRelease( p_sys->stream_id_a52, 0x80,
408 p_stream->i_stream_id&0xff );
411 StreamIdRelease( p_sys->stream_id_mpga, 0xc0,
412 p_stream->i_stream_id );
415 StreamIdRelease( p_sys->stream_id_spu, 0x20,
416 p_stream->i_stream_id&0xff );
423 if( p_input->p_fmt->i_cat == AUDIO_ES )
425 p_sys->i_audio_bound--;
427 else if( p_input->p_fmt->i_cat == VIDEO_ES )
429 p_sys->i_video_bound--;
432 /* Try to set a sensible default value for the instant bitrate */
433 p_sys->i_instant_bitrate -= (p_input->p_fmt->i_bitrate + 1000);
434 /* rate_bound is in units of 50 bytes/second */
435 p_sys->i_rate_bound -= (p_input->p_fmt->i_bitrate * 2)/(8 * 50);
437 p_sys->i_psm_version++;
443 /*****************************************************************************
444 * Mux: Call each time there is new data for at least one stream
445 *****************************************************************************/
446 static int Mux( sout_mux_t *p_mux )
448 sout_mux_sys_t *p_sys = p_mux->p_sys;
452 sout_input_t *p_input;
453 ps_stream_t *p_stream;
455 block_t *p_ps, *p_data;
459 /* Choose which stream to mux */
460 int i_stream = sout_MuxGetStream( p_mux, 1, &i_dts );
466 p_input = p_mux->pp_inputs[i_stream];
467 p_stream = (ps_stream_t*)p_input->p_sys;
470 /* Write regulary PackHeader */
471 if( p_sys->i_pes_count % 30 == 0)
473 /* Update the instant bitrate every second or so */
474 if( p_sys->i_instant_size &&
475 i_dts - p_sys->i_instant_dts > 1000000 )
477 int64_t i_instant_bitrate = p_sys->i_instant_size * 8000000 /
478 ( i_dts - p_sys->i_instant_dts );
480 p_sys->i_instant_bitrate += i_instant_bitrate;
481 p_sys->i_instant_bitrate /= 2;
483 p_sys->i_instant_size = 0;
484 p_sys->i_instant_dts = i_dts;
486 else if( !p_sys->i_instant_size )
488 p_sys->i_instant_dts = i_dts;
491 MuxWritePackHeader( p_mux, &p_ps, i_dts );
494 /* Write regulary SystemHeader */
495 if( p_sys->i_pes_count % 300 == 0 )
499 MuxWriteSystemHeader( p_mux, &p_ps, i_dts );
501 /* For MPEG1 streaming, set HEADER flag */
502 for( p_pk = p_ps; p_pk != NULL; p_pk = p_pk->p_next )
504 p_pk->i_flags |= BLOCK_FLAG_HEADER;
508 /* Write regulary ProgramStreamMap */
509 if( p_sys->b_mpeg2 && p_sys->i_pes_count % 300 == 0 )
511 MuxWritePSM( p_mux, &p_ps, i_dts );
514 /* Get and mux a packet */
515 p_data = block_FifoGet( p_input->p_fifo );
516 EStoPES ( p_mux->p_sout, &p_data, p_data,
517 p_input->p_fmt, p_stream->i_stream_id,
518 p_sys->b_mpeg2, 0, 0, p_sys->i_pes_max_size );
520 block_ChainAppend( &p_ps, p_data );
522 /* Get size of output data so we can calculate the instant bitrate */
523 for( p_data = p_ps; p_data; p_data = p_data->p_next )
525 p_sys->i_instant_size += p_data->i_buffer;
528 sout_AccessOutWrite( p_mux->p_access, p_ps );
530 /* Increase counter */
531 p_sys->i_pes_count++;
537 /*****************************************************************************
539 *****************************************************************************/
540 static void StreamIdInit( bool *id, int i_range )
544 for( i = 0; i < i_range; i++ )
549 static int StreamIdGet( bool *id, int i_id_min, int i_id_max )
553 for( i = 0; i <= i_id_max - i_id_min; i++ )
564 static void StreamIdRelease( bool *id, int i_id_min, int i_id )
566 id[i_id - i_id_min] = true;
569 static void MuxWritePackHeader( sout_mux_t *p_mux, block_t **p_buf,
572 sout_mux_sys_t *p_sys = p_mux->p_sys;
578 i_scr = (i_dts - p_sys->i_dts_delay) * 9 / 100;
580 p_hdr = block_New( p_mux, 18 );
581 p_hdr->i_pts = p_hdr->i_dts = i_dts;
582 bits_initwrite( &bits, 14, p_hdr->p_buffer );
583 bits_write( &bits, 32, 0x01ba );
585 /* The spec specifies that the mux rate must be rounded upwards */
586 i_mux_rate = (p_sys->i_instant_bitrate + 8 * 50 - 1 ) / (8 * 50);
590 bits_write( &bits, 2, 0x01 );
594 bits_write( &bits, 4, 0x02 );
597 bits_write( &bits, 3, ( i_scr >> 30 )&0x07 );
598 bits_write( &bits, 1, 1 ); // marker
599 bits_write( &bits, 15, ( i_scr >> 15 )&0x7fff );
600 bits_write( &bits, 1, 1 ); // marker
601 bits_write( &bits, 15, i_scr&0x7fff );
602 bits_write( &bits, 1, 1 ); // marker
606 bits_write( &bits, 9, 0 ); // src extension
608 bits_write( &bits, 1, 1 ); // marker
610 bits_write( &bits, 22, i_mux_rate);
611 bits_write( &bits, 1, 1 ); // marker
615 bits_write( &bits, 1, 1 ); // marker
616 bits_write( &bits, 5, 0x1f ); // reserved
617 bits_write( &bits, 3, 0 ); // stuffing bytes
620 p_hdr->i_buffer = p_sys->b_mpeg2 ? 14: 12;
622 block_ChainAppend( p_buf, p_hdr );
625 static void MuxWriteSystemHeader( sout_mux_t *p_mux, block_t **p_buf,
628 sout_mux_sys_t *p_sys = p_mux->p_sys;
634 int i_nb_private, i_nb_stream;
637 /* Count the number of private stream */
638 for( i = 0, i_nb_private = 0; i < p_mux->i_nb_inputs; i++ )
640 ps_stream_t *p_stream;
642 p_stream = (ps_stream_t*)p_mux->pp_inputs[i]->p_sys;
644 if( ( p_stream->i_stream_id&0xff00 ) == 0xbd00 )
650 /* Private stream are declared only one time */
651 i_nb_stream = p_mux->i_nb_inputs -
652 ( i_nb_private > 0 ? i_nb_private - 1 : 0 );
654 p_hdr = block_New( p_mux, 12 + i_nb_stream * 3 );
655 p_hdr->i_dts = p_hdr->i_pts = i_dts;
657 /* The spec specifies that the reported rate_bound must be upper limit */
658 i_rate_bound = (p_sys->i_rate_bound);
660 bits_initwrite( &bits, 12 + i_nb_stream * 3, p_hdr->p_buffer );
661 bits_write( &bits, 32, 0x01bb );
662 bits_write( &bits, 16, 12 - 6 + i_nb_stream * 3 );
663 bits_write( &bits, 1, 1 ); // marker bit
664 bits_write( &bits, 22, i_rate_bound);
665 bits_write( &bits, 1, 1 ); // marker bit
667 bits_write( &bits, 6, p_sys->i_audio_bound );
668 bits_write( &bits, 1, 0 ); // fixed flag
669 bits_write( &bits, 1, 0 ); // CSPS flag
670 bits_write( &bits, 1, 0 ); // system audio lock flag
671 bits_write( &bits, 1, 0 ); // system video lock flag
673 bits_write( &bits, 1, 1 ); // marker bit
675 bits_write( &bits, 5, p_sys->i_video_bound );
676 bits_write( &bits, 1, 1 ); // packet rate restriction flag (1 for mpeg1)
677 bits_write( &bits, 7, 0xff ); // reserved bits
679 /* stream_id table */
680 for( i = 0, b_private = false; i < p_mux->i_nb_inputs; i++ )
682 sout_input_t *p_input;
683 ps_stream_t *p_stream;
685 p_input = p_mux->pp_inputs[i];
686 p_stream = (ps_stream_t *)p_input->p_sys;
688 if( ( p_stream->i_stream_id&0xff00 ) == 0xbd00 )
695 /* Write stream id */
696 bits_write( &bits, 8, 0xbd );
700 /* Write stream id */
701 bits_write( &bits, 8, p_stream->i_stream_id&0xff );
704 bits_write( &bits, 2, 0x03 ); /* reserved */
705 if( p_input->p_fmt->i_cat == AUDIO_ES )
707 bits_write( &bits, 1, 0 );
708 bits_write( &bits, 13, p_stream->i_max_buff_size / 128 );
710 else if( p_input->p_fmt->i_cat == VIDEO_ES )
712 bits_write( &bits, 1, 1 );
713 bits_write( &bits, 13, p_stream->i_max_buff_size / 1024);
717 /* FIXME -- the scale of 0 means do a /128 */
718 bits_write( &bits, 1, 0 );
719 bits_write( &bits, 13, p_stream->i_max_buff_size / 128 );
723 block_ChainAppend( p_buf, p_hdr );
726 static void MuxWritePSM( sout_mux_t *p_mux, block_t **p_buf, mtime_t i_dts )
728 sout_mux_sys_t *p_sys = p_mux->p_sys;
731 int i, i_psm_size = 16, i_es_map_size = 0;
733 for( i = 0; i < p_mux->i_nb_inputs; i++ )
735 sout_input_t *p_input = p_mux->pp_inputs[i];
736 ps_stream_t *p_stream = p_input->p_sys;
739 if( p_stream->lang[0] != 0 ) i_es_map_size += 6;
742 i_psm_size += i_es_map_size;
744 p_hdr = block_New( p_mux, i_psm_size );
745 p_hdr->i_dts = p_hdr->i_pts = i_dts;
747 memset( p_hdr->p_buffer, 0, p_hdr->i_buffer );
748 bits_initwrite( &bits, i_psm_size, p_hdr->p_buffer );
749 bits_write( &bits, 32, 0x01bc );
750 bits_write( &bits, 16, i_psm_size - 6 );
751 bits_write( &bits, 1, 1 ); /* current_next_indicator */
752 bits_write( &bits, 2, 0xF ); /* reserved */
753 bits_write( &bits, 5, p_sys->i_psm_version );
754 bits_write( &bits, 7, 0xFF ); /* reserved */
755 bits_write( &bits, 1, 1 ); /* marker */
757 bits_write( &bits, 16, 0 ); /* program_stream_info_length */
760 bits_write( &bits, 16, i_es_map_size ); /* elementary_stream_map_length */
761 for( i = 0; i < p_mux->i_nb_inputs; i++ )
763 sout_input_t *p_input = p_mux->pp_inputs[i];
764 ps_stream_t *p_stream = p_input->p_sys;
766 bits_write( &bits, 8, p_stream->i_stream_type ); /* stream_type */
767 bits_write( &bits, 8, p_stream->i_stream_id ); /* elementary_stream_id */
769 /* ISO639 language descriptor */
770 if( p_stream->lang[0] != 0 )
772 bits_write( &bits, 16, 6 ); /* elementary_stream_info_length */
774 bits_write( &bits, 8, 0x0a ); /* descriptor_tag */
775 bits_write( &bits, 8, 4 ); /* descriptor_length */
777 bits_write( &bits, 8, p_stream->lang[0] );
778 bits_write( &bits, 8, p_stream->lang[1] );
779 bits_write( &bits, 8, p_stream->lang[2] );
780 bits_write( &bits, 8, 0 ); /* audio type: 0x00 undefined */
784 bits_write( &bits, 16, 0 ); /* elementary_stream_info_length */
790 uint32_t i_crc = 0xffffffff;
791 for( i = 0; (size_t)i < p_hdr->i_buffer; i++ )
792 i_crc = (i_crc << 8) ^
793 p_sys->crc32_table[((i_crc >> 24) ^ p_hdr->p_buffer[i]) & 0xff];
795 bits_write( &bits, 32, i_crc );
798 block_ChainAppend( p_buf, p_hdr );