dvbsub.c

VLC Player Source Code

    /* 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) );
        if( p_region )
        {
            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 );
#ifdef DEBUG_DVBSUB
    msg_Dbg( p_dec, " width=%d height=%d", i_width, i_height );
#endif
    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 )
        free( p_region->p_object_defs[--p_region->i_object_defs].psz_text );

    free( p_region->p_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 (%dx%d->%dx%d)",
                     p_region->i_width, p_region->i_height, i_width, i_height );
            free( p_region->p_pixbuf );
        }

        p_region->p_pixbuf = malloc( i_height * i_width );
        p_region->i_depth = 0;
        b_fill = 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;
        }
    }
}

/* ETSI 300 743 [7.2.1] */
static void decode_display_definition( 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 = 40;
    dvbsub_display_t *p_display;
    dvbsub_display_t *p_old = p_sys->p_display;
    int           i_version;

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

    /* Check version number */
    if( p_old && ( p_old->i_version == i_version ) )
    {
        /* The definition did not change */
        bs_skip( s, 8*i_segment_length - 4 );
        return;
    }

#ifdef DEBUG_DVBSUB
    msg_Dbg( p_dec, "new display definition: %i", i_version );
#endif
    p_display = malloc( sizeof(dvbsub_display_t) );
    if( p_display )
    {
        /* We don't have this version of the display definition: Parse it */
        p_display->i_version = i_version;
        p_display->b_windowed = bs_read( s, 1 );
        bs_skip( s, 3 ); /* Reserved bits */
        p_display->i_width = bs_read( s, 16 )+1;
        p_display->i_height = bs_read( s, 16 )+1;

        if( p_display->b_windowed )
        {
#ifdef DEBUG_DVBSUB
            msg_Dbg( p_dec, "display definition with offsets (windowed)" );
#endif
            /* Coordinates are measured from the top left corner */
            p_display->i_x     = bs_read( s, 16 );
            p_display->i_max_x = bs_read( s, 16 );
            p_display->i_y     = bs_read( s, 16 );
            p_display->i_max_y = bs_read( s, 16 );
            i_processed_length += 64;
        }
    }

    p_sys->p_display = p_display;
    free( p_old );

    if( i_processed_length != i_segment_length*8 )
    {
        msg_Err( p_dec, "processed length %d != segment length %d",
                 i_processed_length, i_segment_length );
    }

#ifdef DEBUG_DVBSUB
    msg_Dbg( p_dec, "version: %d, width: %d, height: %d",
             p_display->i_version, p_display->i_width, p_display->i_height );
    if( p_display->b_windowed )
        msg_Dbg( p_dec, "xmin: %d, xmax: %d, ymin: %d, ymax: %d",
                 p_display->i_x, p_display->i_max_x, p_display->i_y, p_display->i_max_y );
#endif
}

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;
    bool b_non_modify_color;

    /* ETSI 300-743 paragraph 7.2.4
     * sync_byte, segment_type and page_id have already been processed.
     */
    i_segment_length = bs_read( s, 16 );
    i_id             = bs_read( s, 16 );
    i_version        = bs_read( s, 4 );
    i_coding_method  = bs_read( s, 2 );

    if( i_coding_method > 1 )
    {
        msg_Dbg( p_dec, "unknown DVB subtitling coding %d is not handled!", i_coding_method );
        bs_skip( s, 8 * (i_segment_length - 2) - 6 );
        return;
    }

    /* Check if the object needs to be rendered in at least one
     * of the regions */
    for( p_region = p_sys->p_regions; p_region != NULL;
         p_region = p_region->p_next )
    {
        for( i = 0; i < p_region->i_object_defs; i++ )
            if( p_region->p_object_defs[i].i_id == i_id ) break;

        if( i != p_region->i_object_defs ) break;
    }
    if( !p_region )
    {
        bs_skip( s, 8 * (i_segment_length - 2) - 6 );
        return;
    }

#ifdef DEBUG_DVBSUB
    msg_Dbg( p_dec, "new object: %i", i_id );
#endif

    b_non_modify_color = bs_read( s, 1 );
    bs_skip( s, 1 ); /* Reserved */

    if( i_coding_method == 0x00 )
    {
        int i_topfield, i_bottomfield;
        uint8_t *p_topfield, *p_bottomfield;

        i_topfield    = bs_read( s, 16 );
        i_bottomfield = bs_read( s, 16 );
        p_topfield    = s->p_start + bs_pos( s ) / 8;
        p_bottomfield = p_topfield + i_topfield;

        bs_skip( s, 8 * (i_segment_length - 7) );

        /* Sanity check */
        if( ( i_segment_length < ( i_topfield + i_bottomfield + 7 ) ) ||
            ( ( p_topfield + i_topfield + i_bottomfield ) > s->p_end ) )
        {
            msg_Dbg( p_dec, "corrupted object data" );
            return;
        }

        for( p_region = p_sys->p_regions; p_region != NULL;
             p_region = p_region->p_next )
        {
            for( i = 0; i < p_region->i_object_defs; i++ )
            {
                if( p_region->p_object_defs[i].i_id != i_id ) continue;

                dvbsub_render_pdata( p_dec, p_region,
                                     p_region->p_object_defs[i].i_x,
                                     p_region->p_object_defs[i].i_y,
                                     p_topfield, i_topfield );

                if( i_bottomfield )
                {
                    dvbsub_render_pdata( p_dec, p_region,
                                         p_region->p_object_defs[i].i_x,
                                         p_region->p_object_defs[i].i_y + 1,
                                         p_bottomfield, i_bottomfield );
                }
                else
                {
                    /* Duplicate the top field */
                    dvbsub_render_pdata( p_dec, p_region,
                                         p_region->p_object_defs[i].i_x,
                                         p_region->p_object_defs[i].i_y + 1,
                                         p_topfield, i_topfield );
                }
            }
        }
    }
    else
    {
        /* DVB subtitling as characters */
        int i_number_of_codes = bs_read( s, 8 );
        uint8_t* p_start = s->p_start + bs_pos( s ) / 8;

        /* Sanity check */
        if( ( i_segment_length < ( i_number_of_codes*2 + 4 ) ) ||
            ( ( p_start + i_number_of_codes*2 ) > s->p_end ) )
        {
            msg_Dbg( p_dec, "corrupted object data" );
            return;
        }

        for( p_region = p_sys->p_regions; p_region != NULL;
             p_region = p_region->p_next )
        {
            for( i = 0; i < p_region->i_object_defs; i++ )
            {
                int j;

                if( p_region->p_object_defs[i].i_id != i_id ) continue;

                p_region->p_object_defs[i].psz_text =
                    realloc( p_region->p_object_defs[i].psz_text,
                             i_number_of_codes + 1 );

                /* FIXME 16bits -> char ??? See Preamble */
                for( j = 0; j < i_number_of_codes; j++ )
                {
                    p_region->p_object_defs[i].psz_text[j] = (char)(bs_read( s, 16 ) & 0xFF);
                }
                /* Null terminate the string */
                p_region->p_object_defs[i].psz_text[j] = 0;
            }
        }
    }

#ifdef DEBUG_DVBSUB
    msg_Dbg( p_dec, "end object: %i", i_id );
#endif
}

static void dvbsub_render_pdata( decoder_t *p_dec, dvbsub_region_t *p_region,
                                 int i_x, int i_y,
                                 uint8_t *p_field, int i_field )
{
    uint8_t *p_pixbuf;
    int i_offset = 0;
    bs_t bs;

    /* Sanity check */
    if( !p_region->p_pixbuf )
    {
        msg_Err( p_dec, "region %i has no pixel buffer!", p_region->i_id );
        return;
    }
    if( i_y < 0 || i_x < 0 || i_y >= p_region->i_height ||
        i_x >= p_region->i_width )
    {
        msg_Dbg( p_dec, "invalid offset (%i,%i)", i_x, i_y );
        return;
    }

    p_pixbuf = p_region->p_pixbuf + i_y * p_region->i_width;
    bs_init( &bs, p_field, i_field );

    while( !bs_eof( &bs ) )
    {
        /* Sanity check */
        if( i_y >= p_region->i_height ) return;

        switch( bs_read( &bs, 8 ) )
        {
        case 0x10:
            dvbsub_pdata2bpp( &bs, p_pixbuf + i_x, p_region->i_width - i_x,
                              &i_offset );
            break;

        case 0x11:
            dvbsub_pdata4bpp( &bs, p_pixbuf + i_x, p_region->i_width - i_x,
                              &i_offset );
            break;

        case 0x12:
            dvbsub_pdata8bpp( &bs, p_pixbuf + i_x, p_region->i_width - i_x,
                              &i_offset );
            break;

        case 0x20:
        case 0x21:
        case 0x22:
            /* We don't use map tables */
            break;

        case 0xf0: /* End of line code */
            p_pixbuf += 2*p_region->i_width;
            i_offset = 0; i_y += 2;
            break;
        }
    }
}

static void dvbsub_pdata2bpp( bs_t *s, uint8_t *p, int i_width, int *pi_off )
{
    bool b_stop = false;

    while( !b_stop && !bs_eof( s ) )
    {
        int i_count = 0, i_color = 0;

        i_color = bs_read( s, 2 );
        if( i_color != 0x00 )
        {
            i_count = 1;
        }
        else
        {
            if( bs_read( s, 1 ) == 0x01 )         // Switch1
            {
                i_count = 3 + bs_read( s, 3 );
                i_color = bs_read( s, 2 );
            }
            else