dvbsub.c

video linux conference

    }

    if( p_sys->i_ancillary_id != p_sys->i_id &&
        i_type == DVBSUB_ST_PAGE_COMPOSITION &&
        i_page_id == p_sys->i_ancillary_id )
    {
#ifdef DEBUG_DVBSUB
        msg_Dbg( p_dec, "skipped invalid ancillary subtitle packet" );
#endif
        bs_skip( s,  8 * ( 2 + i_size ) );
        return;
    }

#ifdef DEBUG_DVBSUB
    if( i_page_id == p_sys->i_id )
        msg_Dbg( p_dec, "segment (id: %i)", i_page_id );
    else
        msg_Dbg( p_dec, "ancillary segment (id: %i)", i_page_id );
#endif

    switch( i_type )
    {
    case DVBSUB_ST_PAGE_COMPOSITION:
#ifdef DEBUG_DVBSUB
        msg_Dbg( p_dec, "decode_page_composition" );
#endif
        decode_page_composition( p_dec, s );
        break;

    case DVBSUB_ST_REGION_COMPOSITION:
#ifdef DEBUG_DVBSUB
        msg_Dbg( p_dec, "decode_region_composition" );
#endif
        decode_region_composition( p_dec, s );
        break;

    case DVBSUB_ST_CLUT_DEFINITION:
#ifdef DEBUG_DVBSUB
        msg_Dbg( p_dec, "decode_clut" );
#endif
        decode_clut( p_dec, s );
        break;

    case DVBSUB_ST_OBJECT_DATA:
#ifdef DEBUG_DVBSUB
        msg_Dbg( p_dec, "decode_object" );
#endif
        decode_object( p_dec, s );
        break;

    case DVBSUB_ST_ENDOFDISPLAY:
#ifdef DEBUG_DVBSUB
        msg_Dbg( p_dec, "end of display" );
#endif
        bs_skip( s,  8 * ( 2 + i_size ) );
        break;

    case DVBSUB_ST_STUFFING:
#ifdef DEBUG_DVBSUB
        msg_Dbg( p_dec, "skip stuffing" );
#endif
        bs_skip( s,  8 * ( 2 + i_size ) );
        break;

    default:
        msg_Warn( p_dec, "unsupported segment type: (%04x)", i_type );
        bs_skip( s,  8 * ( 2 + i_size ) );
        break;
    }
}

static void decode_clut( decoder_t *p_dec, bs_t *s )
{
    decoder_sys_t *p_sys = p_dec->p_sys;
    uint16_t      i_segment_length;
    uint16_t      i_processed_length;
    dvbsub_clut_t *p_clut, *p_next;
    int           i_id, i_version;

    i_segment_length = bs_read( s, 16 );
    i_id             = bs_read( s, 8 );
    i_version        = bs_read( s, 4 );

    /* Check if we already have this clut */
    for( p_clut = p_sys->p_cluts; p_clut != NULL; p_clut = p_clut->p_next )
    {
        if( p_clut->i_id == i_id ) break;
    }

    /* Check version number */
    if( p_clut && p_clut->i_version == i_version )
    {
        /* Nothing to do */
        bs_skip( s, 8 * i_segment_length - 12 );
        return;
    }

    if( !p_clut )
    {
#ifdef DEBUG_DVBSUB
        msg_Dbg( p_dec, "new clut: %i", i_id );
#endif
        p_clut = malloc( sizeof(dvbsub_clut_t) );
        p_clut->p_next = p_sys->p_cluts;
        p_sys->p_cluts = p_clut;
    }

    /* Initialize to default clut */
    p_next = p_clut->p_next;
    *p_clut = p_sys->default_clut;
    p_clut->p_next = p_next;

    /* We don't have this version of the CLUT: Parse it */
    p_clut->i_version = i_version;
    p_clut->i_id = i_id;
    bs_skip( s, 4 ); /* Reserved bits */
    i_processed_length = 2;
    while( i_processed_length < i_segment_length )
    {
        uint8_t y, cb, cr, t;
        uint8_t i_id;
        uint8_t i_type;

        i_id = bs_read( s, 8 );
        i_type = bs_read( s, 3 );

        bs_skip( s, 4 );

        if( bs_read( s, 1 ) )
        {
            y  = bs_read( s, 8 );
            cr = bs_read( s, 8 );
            cb = bs_read( s, 8 );
            t  = bs_read( s, 8 );
            i_processed_length += 6;
        }
        else
        {
            y  = bs_read( s, 6 ) << 2;
            cr = bs_read( s, 4 ) << 4;
            cb = bs_read( s, 4 ) << 4;
            t  = bs_read( s, 2 ) << 6;
            i_processed_length += 4;
        }

        /* We are not entirely compliant here as full transparency is indicated
         * with a luma value of zero, not a transparency value of 0xff
         * (full transparency would actually be 0xff + 1). */

        if( y == 0 )
        {
            cr = cb = 0;
            t  = 0xff;
        }

        /* According to EN 300-743 section 7.2.3 note 1, type should
         * not have more than 1 bit set to one, but some streams don't
         * respect this note. */

        if( i_type & 0x04 && i_id < 4 )
        {
            p_clut->c_2b[i_id].Y = y;
            p_clut->c_2b[i_id].Cr = cr;
            p_clut->c_2b[i_id].Cb = cb;
            p_clut->c_2b[i_id].T = t;
        }
        if( i_type & 0x02 && i_id < 16 )
        {
            p_clut->c_4b[i_id].Y = y;
            p_clut->c_4b[i_id].Cr = cr;
            p_clut->c_4b[i_id].Cb = cb;
            p_clut->c_4b[i_id].T = t;
        }
        if( i_type & 0x01 )
        {
            p_clut->c_8b[i_id].Y = y;
            p_clut->c_8b[i_id].Cr = cr;
            p_clut->c_8b[i_id].Cb = cb;
            p_clut->c_8b[i_id].T = t;
        }
    }
}

static void decode_page_composition( decoder_t *p_dec, bs_t *s )
{
    decoder_sys_t *p_sys = p_dec->p_sys;
    int i_version, i_state, i_segment_length, i_timeout, i;

    /* A page is composed by 0 or more region */

    i_segment_length = bs_read( s, 16 );
    i_timeout = bs_read( s, 8 );
    i_version = bs_read( s, 4 );
    i_state = bs_read( s, 2 );
    bs_skip( s, 2 ); /* Reserved */

    if( i_state == DVBSUB_PCS_STATE_CHANGE )
    {
        /* End of an epoch, reset decoder buffer */
#ifdef DEBUG_DVBSUB
        msg_Dbg( p_dec, "page composition mode change" );
#endif
        free_all( p_dec );
    }
    else if( !p_sys->p_page && i_state != DVBSUB_PCS_STATE_ACQUISITION &&
             i_state != DVBSUB_PCS_STATE_CHANGE )
    {
        /* Not a full PCS, we need to wait for one */
        msg_Dbg( p_dec, "didn't receive an acquisition page yet" );

#if 0 /* Try to start decoding even without an acquisition page */
        bs_skip( s,  8 * (i_segment_length - 2) );
        return;
#endif
    }

#ifdef DEBUG_DVBSUB
    if( i_state == DVBSUB_PCS_STATE_ACQUISITION )
        msg_Dbg( p_dec, "acquisition page composition" );
#endif

    /* Check version number */
    if( p_sys->p_page && p_sys->p_page->i_version == i_version )
    {
        bs_skip( s,  8 * (i_segment_length - 2) );
        return;
    }
    else if( p_sys->p_page )
    {
        if( p_sys->p_page->i_region_defs )
            free( p_sys->p_page->p_region_defs );
        p_sys->p_page->i_region_defs = 0;
    }

    if( !p_sys->p_page )
    {
#ifdef DEBUG_DVBSUB
        msg_Dbg( p_dec, "new page" );
#endif
        /* Allocate a new page */
        p_sys->p_page = malloc( sizeof(dvbsub_page_t) );
    }

    p_sys->p_page->i_version = i_version;
    p_sys->p_page->i_timeout = i_timeout;
    p_sys->b_page = VLC_TRUE;

    /* Number of regions */
    p_sys->p_page->i_region_defs = (i_segment_length - 2) / 6;

    if( p_sys->p_page->i_region_defs == 0 ) return;

    p_sys->p_page->p_region_defs =
        malloc( p_sys->p_page->i_region_defs * sizeof(dvbsub_region_t) );
    for( i = 0; i < p_sys->p_page->i_region_defs; i++ )
    {
        p_sys->p_page->p_region_defs[i].i_id = bs_read( s, 8 );
        bs_skip( s, 8 ); /* Reserved */
        p_sys->p_page->p_region_defs[i].i_x = bs_read( s, 16 );
        p_sys->p_page->p_region_defs[i].i_y = bs_read( s, 16 );

#ifdef DEBUG_DVBSUB
        msg_Dbg( p_dec, "page_composition, region %i (%i,%i)",
                 i, p_sys->p_page->p_region_defs[i].i_x,
                 p_sys->p_page->p_region_defs[i].i_y );
#endif
    }
}

static void decode_region_composition( decoder_t *p_dec, bs_t *s )
{
    decoder_sys_t *p_sys = p_dec->p_sys;
    dvbsub_region_t *p_region, **pp_region = &p_sys->p_regions;
    int i_segment_length, i_processed_length, i_id, i_version;
    int i_width, i_height, i_level_comp, i_depth, i_clut;
    int i_8_bg, i_4_bg, i_2_bg;
    vlc_bool_t b_fill;

    i_segment_length = bs_read( s, 16 );
    i_id = bs_read( s, 8 );
    i_version = bs_read( s, 4 );

    /* Check if we already have this region */
    for( p_region = p_sys->p_regions; p_region != NULL;
         p_region = p_region->p_next )
    {
        pp_region = &p_region->p_next;
        if( p_region->i_id == i_id ) break;
    }

    /* Check version number */
    if( p_region && p_region->i_version == i_version )
    {
        bs_skip( s, 8 * (i_segment_length - 1) - 4 );
        return;
    }

    if( !p_region )
    {
#ifdef DEBUG_DVBSUB
        msg_Dbg( p_dec, "new region: %i", i_id );
#endif
        p_region = *pp_region = malloc( sizeof(dvbsub_region_t) );
        memset( p_region, 0, sizeof(dvbsub_region_t) );
        p_region->p_object_defs = NULL;
        p_region->p_pixbuf = NULL;
        p_region->p_next = NULL;
    }

    /* Region attributes */
    p_region->i_id = i_id;
    p_region->i_version = i_version;
    b_fill = bs_read( s, 1 );
    bs_skip( s, 3 ); /* Reserved */

    i_width = bs_read( s, 16 );
    i_height = bs_read( s, 16 );
    i_level_comp = bs_read( s, 3 );
    i_depth = bs_read( s, 3 );
    bs_skip( s, 2 ); /* Reserved */
    i_clut = bs_read( s, 8 );

    i_8_bg = bs_read( s, 8 );
    i_4_bg = bs_read( s, 4 );
    i_2_bg = bs_read( s, 2 );
    bs_skip( s, 2 ); /* Reserved */

    /* Free old object defs */
    while( p_region->i_object_defs )
    {
        int i = p_region->i_object_defs - 1;
        if( p_region->p_object_defs[i].psz_text )
            free( p_region->p_object_defs[i].psz_text );
        if( !i ) free( p_region->p_object_defs );

        p_region->i_object_defs--;
    }
    p_region->p_object_defs = NULL;

    /* Extra sanity checks */
    if( p_region->i_width != i_width || p_region->i_height != i_height )
    {
        if( p_region->p_pixbuf )
        {
            msg_Dbg( p_dec, "region size changed (not allowed)" );
            free( p_region->p_pixbuf );
        }

        p_region->p_pixbuf = malloc( i_height * i_width );
        p_region->i_depth = 0;
        b_fill = VLC_TRUE;
    }
    if( p_region->i_depth && (p_region->i_depth != i_depth ||
        p_region->i_level_comp != i_level_comp || p_region->i_clut != i_clut) )
    {
        msg_Dbg( p_dec, "region parameters changed (not allowed)" );
    }

    /* Erase background of region */
    if( b_fill )
    {
        int i_background = (p_region->i_depth == 1) ? i_2_bg :
            (p_region->i_depth == 2) ? i_4_bg : i_8_bg;
        memset( p_region->p_pixbuf, i_background, i_width * i_height );
    }

    p_region->i_width = i_width;
    p_region->i_height = i_height;
    p_region->i_level_comp = i_level_comp;
    p_region->i_depth = i_depth;
    p_region->i_clut = i_clut;

    /* List of objects in the region */
    i_processed_length = 10;
    while( i_processed_length < i_segment_length )
    {
        dvbsub_objectdef_t *p_obj;

        /* We create a new object */
        p_region->i_object_defs++;
        p_region->p_object_defs =
            realloc( p_region->p_object_defs,
                     sizeof(dvbsub_objectdef_t) * p_region->i_object_defs );

        /* We parse object properties */
        p_obj = &p_region->p_object_defs[p_region->i_object_defs - 1];
        p_obj->i_id         = bs_read( s, 16 );
        p_obj->i_type       = bs_read( s, 2 );
        bs_skip( s, 2 ); /* Provider */
        p_obj->i_x          = bs_read( s, 12 );
        bs_skip( s, 4 ); /* Reserved */
        p_obj->i_y          = bs_read( s, 12 );
        p_obj->psz_text     = 0;

        i_processed_length += 6;

        if( p_obj->i_type == DVBSUB_OT_BASIC_CHAR ||
            p_obj->i_type == DVBSUB_OT_COMPOSITE_STRING )
        {
            p_obj->i_fg_pc =  bs_read( s, 8 );
            p_obj->i_bg_pc =  bs_read( s, 8 );
            i_processed_length += 2;
        }
    }
}

static void dvbsub_render_pdata( decoder_t *, dvbsub_region_t *, int, int,
                                 uint8_t *, int );
static void dvbsub_pdata2bpp( bs_t *, uint8_t *, int, int * );
static void dvbsub_pdata4bpp( bs_t *, uint8_t *, int, int * );
static void dvbsub_pdata8bpp( bs_t *, uint8_t *, int, int * );

static void decode_object( decoder_t *p_dec, bs_t *s )
{
    decoder_sys_t *p_sys = p_dec->p_sys;
    dvbsub_region_t *p_region;
    int i_segment_length, i_coding_method, i_version, i_id, i;
    vlc_bool_t b_non_modify_color;

    i_segment_length = bs_read( s, 16 );