dirac.c 49.1 KB
Newer Older
David Flynn's avatar
David Flynn committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
/*****************************************************************************
 * dirac.c
 *****************************************************************************
 * Copyright (C) 2008 the VideoLAN team
 * $Id$
 *
 * Authors: David Flynn <davidf@rd.bbc.co.uk>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

/* Dirac packetizer, formed of three parts:
 *  1) Bitstream synchroniser (dirac_DoSync)
Rémi Duraffort's avatar
Rémi Duraffort committed
26
 *      - Given an arbitrary sequence of bytes, extract whole Dirac Data Units
David Flynn's avatar
David Flynn committed
27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53
 *      - Maps timestamps in supplied block_t's to the extracted Data Unit
 *        A time stamp applies to the next Data Unit to commence at, or after
 *        the first byte of the block_t with the timestamp.
 *  2) Encapsulation Unit generation (dirac_BuildEncapsulationUnit)
 *      - Takes multiple well formed Dirac Data Units and forms them into a
 *        single encapsulation unit, suitable for muxing.
 *      - Sorts out any time stamps so that they only apply to pictures.
 *  3) Timestamp generator (dirac_TimeGenPush)
 *      - Many streams will not be correctly timestamped, ie, DTS&PTS for
 *        every encapsulation unit.  Timestamp generator syncs to avaliable
 *        timestamps and produces DTS&PTS for each encapsulation unit.
 *      - For 'Occasional' missing PTS|DTS:
 *          Missing timestamp is generated using interpolation from last
 *          known good values.
 *      - for All PTS missing:
 *          It is assumed that DTS values are fake, and are actually
 *          in the sequence of the PTS values at the output of a decoder.
 *          Fill in PTS by copying from DTS (accounting for reordering,
 *          by simulating reorder buffer); adjust DTS to provide correct
 *          value.  This is how demuxers like AVI work.
 *      - for All DTS missing:
 *          (Ie, PTS is present), reorder buffer is simulated to determine
 *          PTS for each encapsulation unit.
 *      - NB, doesn't handle all pts missing with real dts. (no way to
 *        distinguish from the fake dts case.)
 *
 *  DIRAC_NON_DATED is used to show a block should not have a time stamp
Rémi Denis-Courmont's avatar
Rémi Denis-Courmont committed
54
 *  associated (ie, don't interpolate a counter).  At the output, these
David Flynn's avatar
David Flynn committed
55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72
 *  blocks get dated with the last used timestamp (or are merged with
 *  another encapsulation unit).
 */

/*****************************************************************************
 * Preamble
 *****************************************************************************/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <assert.h>
#include <vlc_common.h>
#include <vlc_plugin.h>
#include <vlc_codec.h>
#include <vlc_block.h>

73 74
#include <vlc_bits.h>
#include <vlc_block_helper.h>
David Flynn's avatar
David Flynn committed
75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187

#define SANITIZE_PREV_PARSE_OFFSET 1

/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
static int  Open ( vlc_object_t * );
static void Close( vlc_object_t * );

vlc_module_begin()
    set_category( CAT_SOUT )
    set_subcategory( SUBCAT_SOUT_PACKETIZER )
    set_description( N_("Dirac packetizer") )
    set_capability( "packetizer", 50 )
    set_callbacks( Open, Close )
vlc_module_end()

/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
struct decoder_sys_t
{
    /* sync state */
    block_bytestream_t bytestream;
    int i_state;
    size_t i_offset;
    uint32_t u_last_npo;
    /* recovered timestamp from bytesteram for use
     * by synchroniser: should only get reset by the
     * synchronizer upon a discontinuity sentinel */
    mtime_t i_sync_pts;
    mtime_t i_sync_dts;

    /* build encapsulation unit state */
    block_t *p_eu; /*< Current encapsulation unit being built */
    block_t **pp_eu_last;
    uint32_t u_eu_last_npo; /* last next_parse_offset at input to encapsulation */
    mtime_t i_eu_pts;
    mtime_t i_eu_dts;

    /* timestamp generator state */
    date_t dts; /*< timegen decode clock, increments at picture rate */
    bool b_dts; /*< timegen decode clock valid */

    bool b_pts; /*< timegen presentation time valid */
    mtime_t i_pts; /*< timegen presentation time of picture u_pts_picnum */
    uint32_t u_pts_picnum; /*< picture number of timegen presentation time */

    mtime_t i_pts_offset; /*< maximum time between pts and dts */

    /* p_outqueue is the list of encapsulation units that have been
     * fed to the timegenerator.  the timegenerator stamps them in
     * the order it solves the time.  the main packetizer loop removes
     * completed encapsulation units from the front */
    block_t *p_outqueue;
    block_t **pp_outqueue_last;
    /* p_out_dts points to an element in p_outqueue.  It is used for VLC's
     * fake pts hidden in DTS hack, as used by AVI */
    block_t *p_out_dts;

    uint32_t u_tg_last_picnum; /*< most recent picturenumber output from RoB */
    bool b_tg_last_picnum; /*< u_tg_last_picnum valid */

    struct dirac_reorder_buffer {
        int u_size_max;
        int u_size;
        struct dirac_reorder_entry {
            struct dirac_reorder_entry *p_next;
            block_t *p_eu;
            uint32_t u_picnum;
        } p_entries[32], *p_head, *p_empty;
    } reorder_buf; /*< reorder buffer, used by timegenerator */

    /* packetizer state */
    mtime_t i_pts_last_out; /*< last output [from packetizer] pts */
    mtime_t i_dts_last_out; /*< last output [from packetizer] dts */

    struct seq_hdr_t {
        uint32_t u_width;
        uint32_t u_height;
        uint32_t u_fps_num;
        uint32_t u_fps_den;
        enum picture_coding_mode_t {
            DIRAC_FRAME_CODING=0,
            DIRAC_FIELD_CODING=1,
        } u_picture_coding_mode;
    } seq_hdr; /*< sequence header */
    bool b_seen_seq_hdr; /* sequence header valid */
    bool b_seen_eos; /* last data unit to be handled was an EOS */
};

typedef struct {
    uint32_t u_next_offset;
    uint32_t u_prev_offset;
    int i_parse_code;
} parse_info_t;

typedef struct {
    block_free_t pf_blk_release;
    /*> next_parse_offset of the final data unit in associated block_t */
    uint32_t u_last_next_offset;
    /*> picture number is invalid if block has flags DIRAC_NON_DATED */
    uint32_t u_picture_number;
} dirac_block_encap_t;

enum {
    NOT_SYNCED=0,
    TRY_SYNC,
    SYNCED,
    SYNCED_INCOMPLETEDU,
};

enum {
188 189
    DIRAC_NON_DATED = (1 << BLOCK_FLAG_PRIVATE_SHIFT),
    DIRAC_DISCARD   = (2 << BLOCK_FLAG_PRIVATE_SHIFT),
David Flynn's avatar
David Flynn committed
190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224
};

enum {
    DIRAC_DU_IN_EU,
    DIRAC_DU_ENDS_EU,
};

/***
 * Block encapsulation functions.
 * Things are greately simplified by associating some metadata
 * with a block as it passes through the packetizer (saves having
 * to determine it again)
 *
 * unfortunately p_block doesn't have a p_priv, so some fakage
 * needs to happen:
 *   - Create a dummy block that has some extra storage, set up
 *     members to be identical to the actual block
 *   - Store private data there and pointer to orig block
 *   - modify block pointer to point to fake block
 *
 * NB, the add/new functions must not be used to blocks
 * that are referenced in lists, etc., [in this code, this is ok]
 * NB, don't call add on the same block multiple times (will leak)
 *
 * davidf has a patch that reverts this to use a p_priv in block_t.
 */
typedef struct {
    block_t fake;
    block_t *p_orig;
    void *p_priv;
} fake_block_t;

static dirac_block_encap_t *dirac_RemoveBlockEncap( block_t *p_block )
{
    fake_block_t *p_fake = (fake_block_t *)p_block;
Laurent Aimar's avatar
Laurent Aimar committed
225 226
    dirac_block_encap_t *p_dbe = p_fake->p_priv;
    if( !p_dbe ) return NULL;
David Flynn's avatar
David Flynn committed
227
    p_fake->p_priv = NULL;
Laurent Aimar's avatar
Laurent Aimar committed
228 229
    p_dbe->pf_blk_release = NULL;
    return p_dbe;
David Flynn's avatar
David Flynn committed
230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254
}

static void dirac_ReleaseBlockAndEncap( block_t *p_block )
{
    fake_block_t *p_fake = (fake_block_t *)p_block;
    free( dirac_RemoveBlockEncap( p_block ) );
    p_fake->p_orig->pf_release( p_fake->p_orig );
    free( p_fake );
}

static void dirac_AddBlockEncap( block_t **pp_block, dirac_block_encap_t *p_dbe )
{
    fake_block_t *p_fake = calloc( 1, sizeof( *p_fake ) );
    assert( p_fake ); /* must not fail, fixby: adding a p_priv to block_t */
    p_fake->p_orig = *pp_block;
    memcpy( &p_fake->fake, *pp_block, sizeof( block_t ) );
    *pp_block = &p_fake->fake;

    p_fake->p_priv = p_dbe;
    p_dbe->pf_blk_release = p_fake->p_orig->pf_release;
    p_fake->fake.pf_release = dirac_ReleaseBlockAndEncap;
}

static dirac_block_encap_t *dirac_NewBlockEncap( block_t **pp_block )
{
Laurent Aimar's avatar
Laurent Aimar committed
255 256 257
    dirac_block_encap_t *p_dbe = calloc( 1, sizeof( *p_dbe ) );
    if( p_dbe ) dirac_AddBlockEncap( pp_block, p_dbe );
    return p_dbe;
David Flynn's avatar
David Flynn committed
258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277
}

static dirac_block_encap_t *dirac_GetBlockEncap( block_t *p_block )
{
    return (dirac_block_encap_t*) ((fake_block_t *)p_block)->p_priv;
}

/***
 * General utility funcions
 */

/**
 * given a chain of block_t, allocate and return an array containing
 * pointers to all the blocks. (Acts as a replacement for the old p_prev
 * member of block_t) */
static int block_ChainToArray( block_t *p_block, block_t ***ppp_array)
{
    if( !ppp_array )
        return 0;

Laurent Aimar's avatar
Laurent Aimar committed
278 279
    int i_num_blocks;
    block_ChainProperties( p_block, &i_num_blocks, NULL, NULL );
David Flynn's avatar
David Flynn committed
280

Laurent Aimar's avatar
Laurent Aimar committed
281
    *ppp_array = calloc( i_num_blocks, sizeof( block_t* ) );
282
    if( !*ppp_array ) return 0;
David Flynn's avatar
David Flynn committed
283

Laurent Aimar's avatar
Laurent Aimar committed
284
    for( int i = 0; i < i_num_blocks; i++ )
David Flynn's avatar
David Flynn committed
285 286 287 288 289
    {
        (*ppp_array)[i] = p_block;
        p_block = p_block->p_next;
    }

Laurent Aimar's avatar
Laurent Aimar committed
290
    return i_num_blocks;
David Flynn's avatar
David Flynn committed
291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313
}

/**
 * Destructively find and recover the earliest timestamp from start of
 * bytestream, upto i_length.
 */
static void dirac_RecoverTimestamps ( decoder_t *p_dec, size_t i_length )
{
    decoder_sys_t *p_sys = p_dec->p_sys;
    block_t *p_block = p_sys->bytestream.p_block;

    /* Find the block with first non-flushed data */
    size_t i_offset = p_sys->bytestream.i_offset;
    for(; p_block != NULL; p_block = p_block->p_next )
    {
        if( i_offset < p_block->i_buffer )
            break;
        i_offset -= p_block->i_buffer;
    }

    i_offset += i_length;
    for(; p_block != NULL; p_block = p_block->p_next )
    {
314
        if( p_sys->i_sync_pts <= VLC_TS_INVALID && p_sys->i_sync_dts <= VLC_TS_INVALID )
David Flynn's avatar
David Flynn committed
315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340
        {
            /* oldest timestamp wins */
            p_sys->i_sync_pts = p_block->i_pts;
            p_sys->i_sync_dts = p_block->i_dts;
        }
        /* clear timestamps -- more than one data unit can come from a block */
        p_block->i_flags = 0;
        p_block->i_pts = p_block->i_dts = VLC_TS_INVALID;
        if( i_offset < p_block->i_buffer )
            break;
        i_offset -= p_block->i_buffer;
    }
}

/* backdate the list [p_block .. p_block->p_next where p_next == p_last] */
static void dirac_BackdateDTS( block_t *p_block, block_t *p_last, date_t *p_dts )
{
    /* Transverse p_last backwards.  (no p_prev anymore) */
    block_t **pp_array = NULL;
    int n = block_ChainToArray( p_block, &pp_array );
    while( n ) if( pp_array[--n] == p_last ) break;
    /* want to start at p_last->p_prev */
    while( n-- )
    {
        if( pp_array[n]->i_flags & DIRAC_NON_DATED )
            continue;
341
        if( pp_array[n]->i_dts <= VLC_TS_INVALID )
David Flynn's avatar
David Flynn committed
342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358
            pp_array[n]->i_dts = date_Decrement( p_dts, 1 );
    }
    free( pp_array );
}

/* backdate the list [p_block .. p_block->p_next where p_next == p_last] */
static void dirac_BackdatePTS( block_t *p_block, block_t *p_last, date_t *p_pts, uint32_t u_pts_picnum )
{
    /* Transverse p_last backwards.  (no p_prev anymore) */
    block_t **pp_array = NULL;
    int n = block_ChainToArray( p_block, &pp_array );
    while( n ) if( pp_array[--n] == p_last ) break;
    /* want to start at p_last->p_prev */
    while( n-- )
    {
        if( pp_array[n]->i_flags & DIRAC_NON_DATED )
            continue;
359
        if( pp_array[n]->i_dts > VLC_TS_INVALID )
David Flynn's avatar
David Flynn committed
360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399
            continue;
        dirac_block_encap_t *dbe = dirac_GetBlockEncap( pp_array[n] );
        int32_t u_pic_num = dbe ? dbe->u_picture_number : 0;
        int32_t i_dist = u_pic_num - u_pts_picnum;
        date_t pts = *p_pts;
        if( i_dist >= 0 )
            pp_array[n]->i_pts = date_Increment( &pts, i_dist );
        else
            pp_array[n]->i_pts = date_Decrement( &pts, -i_dist );
    }
    free( pp_array );
}

/***
 * Dirac spec defined relations
 */

static bool dirac_isEOS( uint8_t u_parse_code ) { return 0x10 == u_parse_code; }
static bool dirac_isSeqHdr( uint8_t u_parse_code ) { return 0 == u_parse_code; }
static bool dirac_isPicture( uint8_t u_parse_code ) { return 0x08 & u_parse_code; }
static int dirac_numRefs( uint8_t u_parse_code ) { return 0x3 & u_parse_code; }

static inline bool dirac_PictureNbeforeM( uint32_t u_n, uint32_t u_m )
{
    /* specified as: u_n occurs before u_m if:
     *   (u_m - u_n) mod (1<<32) < D */
    return (uint32_t)(u_m - u_n) < (1u<<31);
}

/***
 * Reorder buffer model
 */

static void dirac_ReorderInit( struct dirac_reorder_buffer *p_rb )
{
    memset( p_rb, 0, sizeof(*p_rb) );
    p_rb->u_size_max = 2;
    p_rb->p_empty = p_rb->p_entries;
    p_rb->p_entries[31].p_next = NULL;

Laurent Aimar's avatar
Laurent Aimar committed
400
    for( int i = 0; i < 31; i++ )
David Flynn's avatar
David Flynn committed
401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488
        p_rb->p_entries[i].p_next = &p_rb->p_entries[i+1];
}

/* simulate the dirac picture reorder buffer */
static block_t *dirac_Reorder( decoder_t *p_dec, block_t *p_block_in, uint32_t u_picnum )
{
    decoder_sys_t *p_sys = p_dec->p_sys;

    if( !p_sys->reorder_buf.u_size_max )
        /* reorder buffer disabled */
        return p_block_in;

    /* Modeling the reorder buffer:
     * 1. If the reorder buffer is not full, insert picture for reordering.
     *    No picture is output by the system this picture period
     * 2. If the reorder buffer is full:
     *    a. The picture decoded this period (u_picnum) bypasses the reorder
     *       buffer if it has a lower picture number than any entry in the
     *       reorder buffer. This picture is output by the system.
     *    b. Otherwise, the lowest picture number in the reorder buffer is
     *       removed from the buffer and output by the system.  The current
     *       decoded picture (u_picnum) is inserted into the reorder buffer
     */

    block_t *p_block = NULL;
    /* Determine if the picture needs to be inserted */
    if( p_sys->reorder_buf.u_size == p_sys->reorder_buf.u_size_max )
    {
        /* (2) reorder buffer is full */
        if( !p_sys->reorder_buf.u_size_max ||
            dirac_PictureNbeforeM( u_picnum, p_sys->reorder_buf.p_head->u_picnum ) )
        {
            /* (2a) current picture is first in order */
            return p_block_in;
        }

        /* (2b) extract the youngest picture in the buffer */
        p_block = p_sys->reorder_buf.p_head->p_eu;

        struct dirac_reorder_entry *p_tmp = p_sys->reorder_buf.p_head;
        p_sys->reorder_buf.p_head = p_tmp->p_next;
        p_tmp->p_next = p_sys->reorder_buf.p_empty;
        p_sys->reorder_buf.p_empty = p_tmp;

        p_sys->reorder_buf.u_size--;
    }

    /* (1) and (2b) both require u_picnum to be inserted */
    struct dirac_reorder_entry *p_current = p_sys->reorder_buf.p_empty;
    p_sys->reorder_buf.p_empty = p_current->p_next;
    p_sys->reorder_buf.u_size++;

    /* insertion sort to keep p_head always sorted, earliest first */
    struct dirac_reorder_entry **pp_at = &p_sys->reorder_buf.p_head;
    for( ; *pp_at; pp_at = &(*pp_at)->p_next )
        if( dirac_PictureNbeforeM( u_picnum, (*pp_at)->u_picnum ) )
            break;

    p_current->u_picnum = u_picnum;
    p_current->p_eu = p_block_in;
    p_current->p_next = *pp_at;
    *pp_at = p_current;

    return p_block;
}

/***
 * bytestream parsing and unmarshalling functions
 */

static bool dirac_UnpackParseInfo( parse_info_t *p_pi, block_bytestream_t *p_bs,
                                   size_t u_offset )
{
    uint8_t p_d[13];
    if( VLC_SUCCESS != block_PeekOffsetBytes( p_bs, u_offset, p_d, 13 ) )
        return false;

    if( p_d[0] != 'B' || p_d[1] != 'B' || p_d[2] != 'C' || p_d[3] != 'D' )
        return false;

    p_pi->i_parse_code = p_d[4];
    p_pi->u_next_offset = p_d[5] << 24 | p_d[6] << 16 | p_d[7] << 8 | p_d[8];
    p_pi->u_prev_offset = p_d[9] << 24 | p_d[10] << 16 | p_d[11] << 8 | p_d[12];
    return true;
}

static uint32_t dirac_uint( bs_t *p_bs )
{
Laurent Aimar's avatar
Laurent Aimar committed
489 490 491 492 493 494 495 496
    uint32_t u_count = 0, u_value = 0;
    while( !bs_eof( p_bs ) && !bs_read( p_bs, 1 ) )
    {
        u_count++;
        u_value <<= 1;
        u_value |= bs_read( p_bs, 1 );
    }
    return (1 << u_count) - 1 + u_value;
David Flynn's avatar
David Flynn committed
497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647
}

static int dirac_bool( bs_t *p_bs )
{
    return bs_read( p_bs, 1 );
}

/* read in useful bits from sequence header */
static bool dirac_UnpackSeqHdr( struct seq_hdr_t *p_sh, block_t *p_block )
{
    bs_t bs;
    bs_init( &bs, p_block->p_buffer, p_block->i_buffer );
    bs_skip( &bs, 13*8 ); /* parse_info_header */
    dirac_uint( &bs ); /* major_version */
    dirac_uint( &bs ); /* minor_version */
    dirac_uint( &bs ); /* profile */
    dirac_uint( &bs ); /* level */

    uint32_t u_video_format = dirac_uint( &bs ); /* index */
    if( u_video_format > 20 )
    {
        /* dont know how to parse this header */
        return false;
    }

    static const struct {
        uint32_t u_w, u_h;
    } dirac_size_tbl[] = {
        {640,480}, {176,120}, {176,144}, {352,240}, {352,288}, {704,480},
        {704,576}, {720,480}, {720,576}, {1280,720}, {1280,720}, {1920,1080},
        {1920,1080}, {1920,1080}, {1920,1080}, {2048,1080}, {4096,2160},
        {3840,2160}, {3840,2160}, {7680,4320}, {7680,4320},
    };

    p_sh->u_width = dirac_size_tbl[u_video_format].u_w;
    p_sh->u_height = dirac_size_tbl[u_video_format].u_h;
    if( dirac_bool( &bs ) )
    {
        p_sh->u_width = dirac_uint( &bs ); /* frame_width */
        p_sh->u_height = dirac_uint( &bs ); /* frame_height */
    }

    if( dirac_bool( &bs ) )
    {
        dirac_uint( &bs ); /* chroma_format */
    }

    if( dirac_bool( &bs ) )
    {
        dirac_uint( &bs ); /* scan_format */
    }

    static const struct {
        uint32_t u_n /* numerator */, u_d /* denominator */;
    } dirac_frate_tbl[] = { /* table 10.3 */
        {1, 1}, /* this value is not used */
        {24000,1001}, {24,1}, {25,1}, {30000,1001}, {30,1},
        {50,1}, {60000,1001}, {60,1}, {15000,1001}, {25,2},
    };

    const unsigned dirac_frate_tbl_size =
        sizeof( dirac_frate_tbl ) / sizeof( *dirac_frate_tbl );

    static const uint32_t dirac_vidfmt_frate[] = { /* table C.1 */
        1, 9, 10, 9, 10, 9, 10, 4, 3, 7, 6, 4, 3, 7, 6, 2, 2, 7, 6, 7, 6,
    };

    p_sh->u_fps_num = dirac_frate_tbl[dirac_vidfmt_frate[u_video_format]].u_n;
    p_sh->u_fps_den = dirac_frate_tbl[dirac_vidfmt_frate[u_video_format]].u_d;
    if( dirac_bool( &bs ) )
    {
        uint32_t frame_rate_index = dirac_uint( &bs );
        p_sh->u_fps_num = dirac_frate_tbl[frame_rate_index].u_n;
        p_sh->u_fps_den = dirac_frate_tbl[frame_rate_index].u_d;
        if( frame_rate_index >= dirac_frate_tbl_size )
        {
            /* invalid header */
            return false;
        }
        if( frame_rate_index == 0 )
        {
            p_sh->u_fps_num = dirac_uint( &bs ); /* frame_rate_numerator */
            p_sh->u_fps_den = dirac_uint( &bs ); /* frame_rate_denominator */
        }
    }

    /* must have a valid framerate */
    if( !p_sh->u_fps_num || !p_sh->u_fps_den )
        return false;

    if( dirac_bool( &bs ) )
    {
        uint32_t par_index = dirac_uint( &bs );
        if( !par_index )
        {
            dirac_uint( &bs ); /* par_num */
            dirac_uint( &bs ); /* par_den */
        }
    }

    if( dirac_bool( &bs ) )
    {
        dirac_uint( &bs ); /* clean_width */
        dirac_uint( &bs ); /* clean_height */
        dirac_uint( &bs ); /* clean_left_offset */
        dirac_uint( &bs ); /* clean_top_offset */
    }

    if( dirac_bool( &bs ) )
    {
        uint32_t signal_range_index = dirac_uint( &bs );
        if( !signal_range_index )
        {
            dirac_uint( &bs ); /* luma_offset */
            dirac_uint( &bs ); /* luma_excursion */
            dirac_uint( &bs ); /* chroma_offset */
            dirac_uint( &bs ); /* chroma_excursion */
        }
    }

    if( dirac_bool( &bs ) )
    {
        uint32_t colour_spec_index = dirac_uint( &bs );
        if( !colour_spec_index )
        {
            if( dirac_bool( &bs ) )
            {
                dirac_uint( &bs ); /* colour_primaries_index */
            }
            if( dirac_bool( &bs ) )
            {
                dirac_uint( &bs ); /* colour_matrix_index */
            }
            if( dirac_bool( &bs ) )
            {
                dirac_uint( &bs ); /* transfer_function_index */
            }
        }
    }

    p_sh->u_picture_coding_mode = dirac_uint( &bs );

    return true;
}

/***
 * Data Unit marshalling functions
 */

static block_t *dirac_EmitEOS( decoder_t *p_dec, uint32_t i_prev_parse_offset )
{
Laurent Aimar's avatar
Laurent Aimar committed
648
    const uint8_t p_eos[] = { 'B','B','C','D',0x10,0,0,0,13,0,0,0,0 };
David Flynn's avatar
David Flynn committed
649 650 651
    block_t *p_block = block_New( p_dec, 13 );
    if( !p_block )
        return NULL;
Laurent Aimar's avatar
Laurent Aimar committed
652
    memcpy( p_block->p_buffer, p_eos, 13 );
David Flynn's avatar
David Flynn committed
653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675

    SetDWBE( p_block->p_buffer + 9, i_prev_parse_offset );

    p_block->i_flags = DIRAC_NON_DATED;

    return p_block;

    (void) p_dec;
}

/***
 * Bytestream synchronizer
 * maps [Bytes] -> DataUnit
 */
static block_t *dirac_DoSync( decoder_t *p_dec )
{
    decoder_sys_t *p_sys = p_dec->p_sys;
    parse_info_t pu;

    static const uint8_t p_parsecode[4] = {'B','B','C','D'};
    do {
        switch( p_sys->i_state )
        {
Laurent Aimar's avatar
Laurent Aimar committed
676 677
        case NOT_SYNCED:
        {
David Flynn's avatar
David Flynn committed
678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735
            if( VLC_SUCCESS !=
                block_FindStartcodeFromOffset( &p_sys->bytestream, &p_sys->i_offset, p_parsecode, 4 ) )
            {
                /* p_sys->i_offset will have been set to:
                 *   end of bytestream - amount of prefix found
                 * can resume search from this point when more data arrives */
                return NULL;
            }
            /* candidate parse_code_prefix has been found at p_sys->i_offset */
            if( VLC_SUCCESS != block_PeekOffsetBytes( &p_sys->bytestream, p_sys->i_offset + 12, NULL, 0 ) )
            {
                /* insufficient data has been accumulated to fully extract
                 * a parse_info header. exit for now in the hope of more
                 * data later to retry at exactly the same point */
                return NULL;
            }
            p_sys->i_state = TRY_SYNC;
            break; /* candidate found, try to sync */
        }
        case SYNCED: /* -> TRY_SYNC | NOT_SYNCED */
            /* sanity: can only reach this after having extracted a DU,
             * which causes data to be consumed and local i_offset to be reset */
            assert( p_sys->i_offset == 0 );
            if( VLC_SUCCESS != block_PeekOffsetBytes( &p_sys->bytestream, 12, NULL, 0 ) )
            {
                /* insufficient data has been accumulated to fully extract
                 * a parse_info header, retry later */
                return NULL;
            }
            if( !dirac_UnpackParseInfo( &pu, &p_sys->bytestream, 0 )
             || !pu.u_next_offset || (p_sys->u_last_npo != pu.u_prev_offset) )
            {
                /* !a: not a valid parse info.
                 * !pu.u_next_offset: don't know the length of the data unit
                 *                    search for the next one that points back
                 *                    to this one to determine length.
                 * (p_sys->u_last_npo != pu.u_prev_offset): some desync
                 */
                p_sys->i_state = NOT_SYNCED;
                break;
            }
            if( pu.u_next_offset > 1024*1024 )
            {
                /* sanity check for erronious hugs next_parse_offsets
                 * (eg, 2^32-1) that would cause a very long wait
                 * and large space consumption: fall back to try sync */
                p_sys->i_state = TRY_SYNC;
                break;
            }
            /* check that the start of the next data unit is avaliable */
            if( VLC_SUCCESS !=
                block_PeekOffsetBytes( &p_sys->bytestream, pu.u_next_offset + 12, NULL, 0 ) )
            {
                return NULL; /* retry later */
            }
            /* attempt to syncronise backwards from pu.u_next_offset */
            p_sys->i_offset = pu.u_next_offset;
            /* fall through */
Laurent Aimar's avatar
Laurent Aimar committed
736 737 738
        case TRY_SYNC: /* -> SYNCED | NOT_SYNCED */
        {
            if( !p_sys->i_offset )
David Flynn's avatar
David Flynn committed
739 740 741 742
                goto sync_fail; /* if a is at start of bytestream, b can't be in buffer */

            parse_info_t pu_a;
            bool a = dirac_UnpackParseInfo( &pu_a, &p_sys->bytestream, p_sys->i_offset );
Laurent Aimar's avatar
Laurent Aimar committed
743
            if( !a || (pu_a.u_prev_offset > p_sys->i_offset) )
David Flynn's avatar
David Flynn committed
744 745
                goto sync_fail; /* b lies beyond start of bytestream: can't sync */

Laurent Aimar's avatar
Laurent Aimar committed
746 747
            if( !pu_a.u_prev_offset )
            {
David Flynn's avatar
David Flynn committed
748 749 750 751 752 753 754 755 756 757 758 759
                if( p_sys->i_state == TRY_SYNC )
                {
                    goto sync_fail; /* can't find different pu_b from pu_a */
                }
                /* state == SYNCED: already know where pu_b is.
                 * pu_a has probably been inserted by something that doesn't
                 * know what the last next_parse_offset was */
                pu_a.u_prev_offset = pu.u_next_offset;
            }

            parse_info_t *pu_b = &pu;
            bool b = dirac_UnpackParseInfo( pu_b, &p_sys->bytestream, p_sys->i_offset - pu_a.u_prev_offset );
Laurent Aimar's avatar
Laurent Aimar committed
760 761
            if( !b || (pu_b->u_next_offset && pu_a.u_prev_offset != pu_b->u_next_offset) )
            {
David Flynn's avatar
David Flynn committed
762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808
                /* if pu_b->u_next_offset = 0, have to assume we've synced, ie,
                 * just rely on finding a valid pu_b from pu_a. */
                goto sync_fail;
            }
            p_sys->u_last_npo = pu_b->u_next_offset;
            if( !pu_b->u_next_offset ) pu_b->u_next_offset = pu_a.u_prev_offset;
            /* offset was pointing at pu_a, rewind to point at pu_b */
            p_sys->i_offset -= pu_a.u_prev_offset;
            p_sys->i_state = SYNCED;
            break;
        }
sync_fail:
            if( p_sys->i_state == SYNCED ) p_sys->i_offset = 0;
            p_sys->i_offset++;
            p_sys->i_state = NOT_SYNCED;
            break; /* find somewhere else to try again */
        default:;
        }
    } while( SYNCED != p_sys->i_state );

    /*
     * synced, attempt to extract a data unit
     */

    /* recover any timestamps from the data that is about to be flushed */
    dirac_RecoverTimestamps( p_dec, p_sys->i_offset );

    /* flush everything upto the start of the DU */
    block_SkipBytes( &p_sys->bytestream, p_sys->i_offset );
    block_BytestreamFlush( &p_sys->bytestream );
    p_sys->i_offset = 0;

    /* setup the data unit buffer */
    block_t *p_block = block_New( p_dec, pu.u_next_offset );
    if( !p_block )
        return NULL;

    p_block->i_pts = p_sys->i_sync_pts;
    p_block->i_dts = p_sys->i_sync_dts;
    p_sys->i_sync_pts = p_sys->i_sync_dts = VLC_TS_INVALID;

    /* recover any new timestamps from the data that is about to be consumed */
    dirac_RecoverTimestamps( p_dec, p_sys->i_offset );

    block_GetBytes( &p_sys->bytestream, p_block->p_buffer, p_block->i_buffer );

    /* save parse offset in private area for later use */
Laurent Aimar's avatar
Laurent Aimar committed
809 810
    dirac_block_encap_t *p_dbe = dirac_NewBlockEncap( &p_block );
    if( p_dbe ) p_dbe->u_last_next_offset = pu.u_next_offset;
David Flynn's avatar
David Flynn committed
811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835

    return p_block;
}

/***
 * Packet (Data Unit) inspection, learns parameters from sequence
 * headers, sets up flags, drops unwanted data units, sets
 * encapsulation unit termination policy
 */
static int dirac_InspectDataUnit( decoder_t *p_dec, block_t **pp_block, block_t *p_eu )
{
    decoder_sys_t *p_sys = p_dec->p_sys;
    block_t *p_block = *pp_block;
    uint8_t u_parse_code = p_block->p_buffer[4];

    if( dirac_isEOS( u_parse_code ) )
    {
        if( p_sys->b_seen_eos )
        {
            /* remove duplicate EOS packets */
            block_Release( p_block );
            *pp_block = NULL;
            return DIRAC_DU_IN_EU;
        }
        /* p_block is an EOS packet */
836
        p_eu->i_flags |= BLOCK_FLAG_END_OF_SEQUENCE;
David Flynn's avatar
David Flynn committed
837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876
        /* for the moment, let this end an encapsulation unit */
        /* seeing an eos packet requires a flush of the packetizer
         * this is detected by the caller of this function */
        p_sys->b_seen_seq_hdr = false;
        p_sys->b_seen_eos = true;
        return DIRAC_DU_ENDS_EU;
#if 0
        /* let anything down streem know too */
        /*
        Actually, this is a bad idea:
         - It sets the discontinuity for every dirac EOS packet
           which doesnt imply a time discontinuity.
         - When the syncronizer detects a real discontinuity, it
           should copy the flags through.
        p_eu->i_flags |= BLOCK_FLAG_DISCONTINUITY;
        */
#endif
    }
    p_sys->b_seen_eos = false;

    if( dirac_isPicture( u_parse_code ) )
    {
        /* timestamps apply to pictures only */
        p_eu->i_dts = p_sys->i_eu_dts;
        p_eu->i_pts = p_sys->i_eu_pts;
        p_sys->i_eu_dts = p_sys->i_eu_pts = VLC_TS_INVALID;

        if( !p_sys->b_seen_seq_hdr )
        {
            /* can't timestamp in this case, discard later
             * so that the timestamps aren't lost */
            p_eu->i_flags |= DIRAC_DISCARD;
        }
        /* p_block is a picture -- it ends the 'encapsulation unit' */
        if( dirac_numRefs( u_parse_code ) )
        {
            /* if this picture is not an I frame, ensure that the
             * random access point flags are not set */
            p_eu->i_flags &= ~BLOCK_FLAG_TYPE_I;
        }
Laurent Aimar's avatar
Laurent Aimar committed
877 878
        dirac_block_encap_t *p_dbe = dirac_GetBlockEncap( p_block );
        if( p_dbe && p_block->i_buffer > 13+4 )
David Flynn's avatar
David Flynn committed
879 880 881
        {
            /* record the picture number to save the time gen functions
             * from having to inspect the data for it */
Laurent Aimar's avatar
Laurent Aimar committed
882
            p_dbe->u_picture_number = GetDWBE( p_block->p_buffer + 13 );
David Flynn's avatar
David Flynn committed
883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908
        }
        return DIRAC_DU_ENDS_EU;
    }

    if( dirac_isSeqHdr( u_parse_code ) )
    {
        if( !dirac_UnpackSeqHdr( &p_sys->seq_hdr, p_block ) )
        {
            /* couldn't parse the sequence header, just ignore it */
            return DIRAC_DU_IN_EU;
        }
        p_sys->b_seen_seq_hdr = true;

       /* a sequence header followed by an I frame is a random
        * access point; assume that this is the case */
        p_eu->i_flags |= BLOCK_FLAG_TYPE_I;

        es_format_t *p_es = &p_dec->fmt_out;

        p_es->video.i_width  = p_sys->seq_hdr.u_width;
        p_es->video.i_height = p_sys->seq_hdr.u_height;

        vlc_ureduce( &p_es->video.i_frame_rate, &p_es->video.i_frame_rate_base
                   , p_sys->seq_hdr.u_fps_num, p_sys->seq_hdr.u_fps_den, 0 );

        /* when field coding, dts needs to be incremented in terms of field periods */
Laurent Aimar's avatar
Laurent Aimar committed
909 910
        unsigned u_pics_per_sec = p_sys->seq_hdr.u_fps_num;
        if( p_sys->seq_hdr.u_picture_coding_mode == DIRAC_FIELD_CODING )
David Flynn's avatar
David Flynn committed
911 912 913 914 915 916 917 918 919 920 921 922 923 924
        {
            u_pics_per_sec *= 2;
        }
        date_Change( &p_sys->dts, u_pics_per_sec, p_sys->seq_hdr.u_fps_den );

        /* TODO: set p_sys->reorder_buf.u_size_max */
        p_sys->i_pts_offset = p_sys->reorder_buf.u_size_max
                            * 1000000
                            * p_es->video.i_frame_rate_base / p_es->video.i_frame_rate + 1;

        /* stash a copy of the seqhdr
         *  - required for ogg muxing
         *  - useful for error checking
         *  - it isn't allowed to change until an eos */
925
        free( p_es->p_extra );
David Flynn's avatar
David Flynn committed
926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958
        p_es->p_extra = calloc( 1, p_block->i_buffer + 13 );
        if( !p_es->p_extra )
        {
            p_es->i_extra = 0;
            return DIRAC_DU_IN_EU;
        }
        p_es->i_extra = p_block->i_buffer;
        memcpy( p_es->p_extra, p_block->p_buffer, p_block->i_buffer );
        /* append EOS as per Ogg guidelines */
        p_block = dirac_EmitEOS( p_dec, p_block->i_buffer );
        if( p_block )
        {
            memcpy( (uint8_t*)p_es->p_extra + p_es->i_extra, p_block->p_buffer, 13 );
            p_es->i_extra += 13;
        }

        return DIRAC_DU_IN_EU;
    }

    /* doesn't end an encapsulation unit */
    return DIRAC_DU_IN_EU;
}

/***
 * Encapsulation (packetization) suitable for all muxing standards
 * maps [DataUnit] -> EncapsulationUnit
 */
static block_t *dirac_BuildEncapsulationUnit( decoder_t *p_dec, block_t *p_block )
{
    decoder_sys_t *p_sys = p_dec->p_sys;

    assert(p_block->i_buffer >= 13 && 0x42424344 == GetDWBE( p_block->p_buffer ));

959
    if( p_sys->i_eu_pts <= VLC_TS_INVALID && p_sys->i_eu_dts <= VLC_TS_INVALID )
David Flynn's avatar
David Flynn committed
960 961 962 963
    {
        /* earliest block with pts/dts gets to set the pts/dts for the dated
         * encapsulation unit as a whole */
        /* NB, the 'earliest block' criteria is aribtary */
964
        if( p_block->i_pts > VLC_TS_INVALID || p_block->i_dts > VLC_TS_INVALID )
David Flynn's avatar
David Flynn committed
965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989
        {
            p_sys->i_eu_pts = p_block->i_pts;
            p_sys->i_eu_dts = p_block->i_dts;
        }
    }

    /* inpectdataunit also updates flags for the EU.
     *  - if this is the first block in the EU, then it hasn't been added
     *    to the chain yet (so, p_block will become the front of the chain
     *  - otherwise, use the flags of the chain (first block) */
    block_t *p_eu = p_sys->p_eu ? p_sys->p_eu : p_block;
    int i_block = dirac_InspectDataUnit( p_dec, &p_block, p_eu);

    if( !p_block )
    {
        /* block has been discarded during inspection */
        /* becareful, don't discard anything that is dated,
         * as this needs to go into the timegen loop.  set
         * the DIRAC_DISCARD block flag, and it'll be dropped
         * at output time */
        return NULL;
    }

    block_ChainLastAppend( &p_sys->pp_eu_last, p_block );

Laurent Aimar's avatar
Laurent Aimar committed
990
    dirac_block_encap_t *p_dbe = dirac_GetBlockEncap( p_block );
David Flynn's avatar
David Flynn committed
991 992 993
#ifdef SANITIZE_PREV_PARSE_OFFSET
    /* fixup prev_parse_offset to point to the last data unit
     * to arrive */
Laurent Aimar's avatar
Laurent Aimar committed
994
    if( p_dbe )
David Flynn's avatar
David Flynn committed
995 996
    {
        SetDWBE( p_block->p_buffer + 9, p_sys->u_eu_last_npo );
Laurent Aimar's avatar
Laurent Aimar committed
997
        p_sys->u_eu_last_npo = p_dbe->u_last_next_offset;
David Flynn's avatar
David Flynn committed
998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009
    }
#endif

    if( i_block != DIRAC_DU_ENDS_EU )
    {
        /* encapsulation unit not ended */
        return NULL;
    }

    /* gather up encapsulation unit, reassociating the final
     * private state with the gathered block */
    block_t *p_eu_last = (block_t*) p_sys->pp_eu_last - offsetof( block_t, p_next );
Laurent Aimar's avatar
Laurent Aimar committed
1010
    p_dbe = dirac_RemoveBlockEncap( p_eu_last );
David Flynn's avatar
David Flynn committed
1011 1012 1013 1014 1015 1016 1017 1018

    uint8_t u_parse_code = p_block->p_buffer[4];

    /* gather up the encapsulation unit */
    p_block = block_ChainGather( p_sys->p_eu );
    assert( p_block ); /* block_ChainGather doesn't define when it frees chain */

    p_block->i_flags |= DIRAC_NON_DATED;
Laurent Aimar's avatar
Laurent Aimar committed
1019
    if( p_dbe )
David Flynn's avatar
David Flynn committed
1020
    {
Laurent Aimar's avatar
Laurent Aimar committed
1021
        dirac_AddBlockEncap( &p_block, p_dbe );
David Flynn's avatar
David Flynn committed
1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041
        if( dirac_isPicture( u_parse_code ) ) p_block->i_flags &= ~DIRAC_NON_DATED;
    }
    p_sys->p_eu = NULL;
    p_sys->pp_eu_last = &p_sys->p_eu;
    return p_block;
}

/**
 * dirac_TimeGenPush:
 * @p_dec: vlc object
 * @p_block_in: whole encapsulation unit to generate timestamps for
 *
 * Returns:
 *  0: everything ok
 *  1: EOS occured, please flush and reset
 *  2: picture number discontinuity, please flush and reset
 */
static int dirac_TimeGenPush( decoder_t *p_dec, block_t *p_block_in )
{
    decoder_sys_t *p_sys = p_dec->p_sys;
Laurent Aimar's avatar
Laurent Aimar committed
1042
    dirac_block_encap_t *p_dbe;
David Flynn's avatar
David Flynn committed
1043

1044
    if( p_block_in->i_flags & BLOCK_FLAG_END_OF_SEQUENCE )
David Flynn's avatar
David Flynn committed
1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057
    {
        /* NB, this test occurs after the timegen push, so as to
         * push the block into the output queue */
        return 1;
    }

    if( p_block_in->i_flags & DIRAC_NON_DATED )
    {
        /* no picture found, which means p_block_in is a non-dated EU,
         * do not try and put a date on it */
        return 0;
    }

Laurent Aimar's avatar
Laurent Aimar committed
1058 1059
    p_dbe = dirac_GetBlockEncap( p_block_in );
    uint32_t u_picnum = p_dbe ? p_dbe->u_picture_number : 0;
David Flynn's avatar
David Flynn committed
1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080
    /*
     * Simple DTS regeneration:
     *  - DTS values linearly increase in stream order.
     *  - Every time a DTS occurs at the input, sync to it
     *    - If this is the first DTS seen, backdate all the previous ones that are undated
     *  - If a DTS is missing, guess that it increases by one picture period
     *  - If never seen DTS, don't do anything
     */
    /*
     * Simple PTS regeneration
     *  - PTS values do not linearly increase in stream order.
     *  - Every time a PTS occurs at the input, sync to it and record picture number
     *  - If a PTS is missing, guess that it differs by the product of picture
     *    period and difference between picture number of sync point and current picture
     *  - If this is the first PTS seen, backdate all previous ones that are undated
     *  - If never seen PTS, don't do anything
     */
    /*
     * Stage 1, sync to input timestamps, backdate timestamps for old
     * EUs that are in the outqueue with missing dates
     */
1081
    if( p_block_in->i_dts > VLC_TS_INVALID )
David Flynn's avatar
David Flynn committed
1082 1083 1084 1085 1086 1087 1088 1089 1090 1091
    do {
        /* if timestamps exist, sync to them */
        if( p_sys->b_dts )
            break;
        /* first dts seen, backdate any packets in outqueue */
        p_sys->b_dts = true;
        date_t dts = p_sys->dts;
        dirac_BackdateDTS( p_sys->p_outqueue, p_block_in, &dts );
    } while( 0 );

1092
    if( p_block_in->i_pts > VLC_TS_INVALID )
David Flynn's avatar
David Flynn committed
1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117
    do {
        /* if timestamps exist, sync to them */
        p_sys->u_pts_picnum = u_picnum;
        p_sys->i_pts = p_block_in->i_pts;
        if( p_sys->b_pts )
            break;
        /* first pts seen, backdate any packets in outqueue */
        p_sys->b_pts = true;
        date_t pts = p_sys->dts;
        date_Set( &pts, p_sys->i_pts );
        dirac_BackdatePTS( p_sys->p_outqueue, p_block_in, &pts, p_sys->u_pts_picnum );
    } while( 0 );

    /*
     * Stage 2, don't attempt to forwards interpolate timestamps for
     * blocks if the picture rates aren't known
     */
    if( !p_sys->b_seen_seq_hdr )
    {
        return 0;
    }

    /*
     * Stage 3, for block_in, interpolate any missing timestamps
     */
1118
    if( p_sys->b_dts && p_block_in->i_dts <= VLC_TS_INVALID )
David Flynn's avatar
David Flynn committed
1119 1120 1121 1122 1123
    {
        /* dts has previously been seen, but not this time, interpolate */
        p_block_in->i_dts = date_Increment( &p_sys->dts, 1 );
    }

1124
    if( p_sys->b_pts && p_block_in->i_pts <= VLC_TS_INVALID )
David Flynn's avatar
David Flynn committed
1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153
    {
        /* pts has previously been seen, but not this time, interpolate */
        date_t pts = p_sys->dts;
        date_Set( &pts, p_sys->i_pts );
        int32_t i_dist = u_picnum - p_sys->u_pts_picnum;
        if( i_dist >= 0 )
            p_block_in->i_pts = date_Increment( &pts, i_dist );
        else
            p_block_in->i_pts = date_Decrement( &pts, -i_dist );
    }

    /* If pts and dts have been seen, there is no need to simulate operation
     * of the decoder reorder buffer */
    /* If neither have been seen, there is little point in simulating */
    if( p_sys->b_dts == p_sys->b_pts )
        return 0;

    if( !p_sys->p_out_dts )
        p_sys->p_out_dts = p_sys->p_outqueue;

    /* model the reorder buffer */
    block_t *p_block = dirac_Reorder( p_dec, p_block_in, u_picnum );
    if( !p_block )
        return 0;

    /* A future ehancement is to stop modeling the reorder buffer as soon as
     * the first packet is output -- interpolate the past and freewheel for
     * the future */

Laurent Aimar's avatar
Laurent Aimar committed
1154 1155
    p_dbe = dirac_GetBlockEncap( p_block );
    u_picnum = p_dbe ? p_dbe->u_picture_number : 0;
David Flynn's avatar
David Flynn committed
1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166
    if( p_sys->b_tg_last_picnum )
    {
        if( dirac_PictureNbeforeM( u_picnum, p_sys->u_tg_last_picnum ) )
        {
            msg_Warn( p_dec, "stream jumped? %d < %d: resetting"
                    , u_picnum, p_sys->u_tg_last_picnum );
            /* pictures only emerge from the reorder buffer in sequence
             * if a stream suddenly jumped backwards without a signaling
             * a discontinuity, some pictures will get stuck in the RoB.
             * flush the RoB. */
            /* this could be a bit less indiscriminate */
Laurent Aimar's avatar
Laurent Aimar committed
1167 1168
            p_dbe = dirac_GetBlockEncap( p_sys->p_outqueue );
            uint32_t u_prev_parse_offset = p_dbe ? p_dbe->u_last_next_offset : 0;
David Flynn's avatar
David Flynn committed
1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210
            block_ChainRelease( p_sys->p_outqueue );
            p_sys->p_outqueue = dirac_EmitEOS( p_dec, u_prev_parse_offset );
            if( p_sys->p_outqueue )
                p_sys->p_outqueue->i_flags = BLOCK_FLAG_DISCONTINUITY | DIRAC_NON_DATED;
            /* return 2, so as not to reset the b_dts flags -- needed if
             * using the rawdirac demuxer with broken stream */
            return 2;
        }
    }
    p_sys->b_tg_last_picnum = true;
    p_sys->u_tg_last_picnum = u_picnum;

    if( !p_sys->b_pts )
    {
        /* some demuxers (eg, AVI) will provide a series of fake dts values,
         * which are actually inorder pts values (ie, what should be seen at
         * the output of a decoder.  A main reason for simulating the reorder
         * buffer is to turn the inorder fakedts into an out-of-order pts */
        p_block->i_pts = p_sys->p_out_dts->i_dts;
        p_sys->p_out_dts->i_dts = VLC_TS_INVALID;
    }

    /* If pts was copied from dts, the dts needs to be corrected to account for reordering*/
    /* If dts has never been seen, the same needs to happen */
    p_sys->p_out_dts->i_dts = p_block->i_pts - p_sys->i_pts_offset;

    /* move dts pointer */
    if( p_sys->p_out_dts )
        p_sys->p_out_dts = p_sys->p_out_dts->p_next;

    return 0;
}

/*****************************************************************************
 * Packetize: form dated encapsulation units from anything
 *****************************************************************************/
static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
{
    decoder_sys_t *p_sys = p_dec->p_sys;
    block_t *p_block = NULL;
    int i_flushing = 0;

1211
    if( pp_block && *pp_block )
David Flynn's avatar
David Flynn committed
1212 1213
    {
        p_block = *pp_block;
1214
        *pp_block = NULL;
David Flynn's avatar
David Flynn committed
1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228

        if( p_block->i_flags & BLOCK_FLAG_DISCONTINUITY )
        {
            /* pre-emptively insert an EOS at a discontinuity, protects
             * any decoders from any sudden changes */
            block_Release( p_block );
            p_block = dirac_EmitEOS( p_dec, 0 );
            if( p_block )
            {
                p_block->p_next = dirac_EmitEOS( p_dec, 13 );
                /* need two EOS to ensure it gets detected by syncro
                 * duplicates get discarded in forming encapsulation unit */
            }
        }
1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239
        else if( p_block->i_flags & BLOCK_FLAG_CORRUPTED )
        {
            /* silently discard corruption sentinels,
             * synchronizer will then discard affected data units.
             * do not produce an EOS data unit as this is very
             * disruptive to the stream (and may make a larger error). */
            block_Release( p_block );
            p_block = NULL;
        }
        if( p_block )
            block_BytestreamPush( &p_sys->bytestream, p_block );
David Flynn's avatar
David Flynn committed
1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260
    }

    /* form as many encapsulation units as possible, give up
     * when the syncronizer runs out of input data */
    while( ( p_block = dirac_DoSync( p_dec ) ) )
    {
        p_block = dirac_BuildEncapsulationUnit( p_dec, p_block );
        if( !p_block )
            continue;
        /* add to tail of output queue (ie, not reordered) */
        block_ChainLastAppend( &p_sys->pp_outqueue_last, p_block );
        /* insert encapsulation unit into timestamp generator
         * which then calculates some timestamps if required */
        i_flushing = dirac_TimeGenPush( p_dec, p_block );
        if( i_flushing )
            break;
    }

    block_t *p_output = NULL;
    block_t **pp_output = &p_output;

Rémi Denis-Courmont's avatar
Rémi Denis-Courmont committed
1261
    /* extract all the dated packets from the head of the output queue */
David Flynn's avatar
David Flynn committed
1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278
    /* explicitly nondated packets repeat the previous timestamps to
     * stop vlc discarding them */
    while( (p_block = p_sys->p_outqueue) )
    {
        if( p_block->i_flags & DIRAC_DISCARD )
        {
            p_sys->p_outqueue = p_block->p_next;
            p_block->p_next = NULL;
            block_Release( p_block );
            continue;
        }

        if( i_flushing || p_block->i_flags & DIRAC_NON_DATED )
        {
            p_block->i_dts = p_sys->i_dts_last_out;
            p_block->i_pts = p_sys->i_pts_last_out;
        }
1279 1280
        else if( p_block->i_pts <= VLC_TS_INVALID ) break;
        else if( p_block->i_dts <= VLC_TS_INVALID ) break;
David Flynn's avatar
David Flynn committed
1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320

        p_sys->i_dts_last_out = p_block->i_dts;
        p_sys->i_pts_last_out = p_block->i_pts;

        p_sys->p_outqueue = p_block->p_next;
        p_block->p_next = NULL;
        /* clear any flags we set */
        p_block->i_flags &= ~BLOCK_FLAG_PRIVATE_MASK;
        block_ChainLastAppend( &pp_output, p_block );

        mtime_t i_delay = p_block->i_pts - p_block->i_dts;
        if( i_delay < 0 )
            msg_Err( p_dec, "pts - dts is negative(%"PRId64"): incorrect RoB size", i_delay );
    }

    if( i_flushing )
    {
        p_sys->i_eu_dts = p_sys->i_eu_pts = VLC_TS_INVALID;

        /* reset timegen state (except synchronizer) */
        p_sys->b_seen_seq_hdr = false;
        if( i_flushing < 2 )
        {
            /* this state isn't safe to loose if there was
             * an unsignalled discontinuity */
            p_sys->b_pts = p_sys->b_dts = false;
        }
        p_sys->b_tg_last_picnum = false;
        dirac_ReorderInit( &p_sys->reorder_buf );

        assert( p_sys->p_outqueue == NULL );
        p_sys->p_out_dts = NULL;
    }

    /* perform sanity check:
     *  if there were a block at the front of outqueue that never
     *  satisfied the extraction criteria, but all blocks after did,
     *  the output queue would grow bounded by the stream length.
     * If there are 10 data units in the output queue, assume this
     * has happened and purge all blocks that fail extraction criteria */
Laurent Aimar's avatar
Laurent Aimar committed
1321 1322 1323
    int i_count;
    block_ChainProperties( p_sys->p_outqueue, &i_count, NULL, NULL );
    if( i_count > 9 )
David Flynn's avatar
David Flynn committed
1324 1325 1326 1327 1328
    {
        p_block = p_sys->p_outqueue;
        while( p_block )
        {
            block_t *p_block_next = p_block->p_next;
1329
            if( p_block->i_pts > VLC_TS_INVALID && p_block->i_dts > VLC_TS_INVALID )
David Flynn's avatar
David Flynn committed
1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350
                break;
            block_Release( p_block );
            p_sys->p_outqueue = p_block = p_block_next;
        }
    }

    if( !p_sys->p_outqueue )
    {
        p_sys->pp_outqueue_last = &p_sys->p_outqueue;
    }
    return p_output;
}

/*****************************************************************************
 * Open: probe the packetizer and return score
 *****************************************************************************/
static int Open( vlc_object_t *p_this )
{
    decoder_t     *p_dec = (decoder_t*)p_this;
    decoder_sys_t *p_sys;

1351
    if( p_dec->fmt_in.i_codec !=  VLC_CODEC_DIRAC )
David Flynn's avatar
David Flynn committed
1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367
        return VLC_EGENERIC;

    p_dec->pf_packetize = Packetize;

    /* Create the output format */
    es_format_Copy( &p_dec->fmt_out, &p_dec->fmt_in );
    p_dec->p_sys = p_sys = calloc( 1, sizeof( decoder_sys_t ) );

    if( !p_sys )
        return VLC_ENOMEM;

    p_sys->i_eu_pts = p_sys->i_eu_dts = VLC_TS_INVALID;
    p_sys->i_sync_pts = p_sys->i_sync_dts = VLC_TS_INVALID;
    p_sys->i_dts_last_out = p_sys->i_pts_last_out = VLC_TS_INVALID;

    p_sys->i_state = NOT_SYNCED;
1368
    block_BytestreamInit( &p_sys->bytestream );
David Flynn's avatar
David Flynn committed
1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423

    p_sys->pp_outqueue_last = &p_sys->p_outqueue;
    p_sys->pp_eu_last = &p_sys->p_eu;

    date_Init( &p_sys->dts, 1, 1 );
    dirac_ReorderInit( &p_sys->reorder_buf );

    if( p_dec->fmt_in.i_extra > 0 )
    {
        /* handle hacky systems like ogg that dump some headers
         * in p_extra. and packetizers that expect it to be filled
         * in before real startup */
        block_t *p_init = block_New( p_dec, p_dec->fmt_in.i_extra );
        if( !p_init )
        {
            /* memory might be avaliable soon.  it isn't the end of
             * the world that fmt_in.i_extra isn't handled */
            return VLC_SUCCESS;
        }
        memcpy( p_init->p_buffer, p_dec->fmt_in.p_extra, p_dec->fmt_in.i_extra );
        /* in theory p_extra should contain just a seqhdr&EOS.  if just a
         * seqhdr, ensure it is extracted by appending an EOS with
         * prev_offset = seqhdr length, ie i_extra.  If all were actually
         * ok, this won't do anything bad */
        if( ( p_init->p_next = dirac_EmitEOS( p_dec, p_dec->fmt_in.i_extra ) ) )
        {
            /* to ensure that one of these two EOS dataunits gets extracted,
             * send a second one */
            p_init->p_next->p_next = dirac_EmitEOS( p_dec, 13 );
        }

        block_t *p_block;
        while( ( p_block = Packetize( p_dec, &p_init ) ) )
            block_Release( p_block );
    }

    return VLC_SUCCESS;
}

/*****************************************************************************
 * Close:
 *****************************************************************************/
static void Close( vlc_object_t *p_this )
{
    decoder_t     *p_dec = (decoder_t*)p_this;
    decoder_sys_t *p_sys = p_dec->p_sys;

    block_BytestreamRelease( &p_sys->bytestream );
    if( p_sys->p_outqueue )
        block_ChainRelease( p_sys->p_outqueue );
    if( p_sys->p_eu )
        block_ChainRelease( p_sys->p_eu );
    free( p_sys );
}