dvbsub.c

video linux conference

/*****************************************************************************
 * dvbsub.c : DVB subtitles decoder
 *            DVB subtitles encoder (developed for Anevia, www.anevia.com)
 *****************************************************************************
 * Copyright (C) 2003 ANEVIA
 * Copyright (C) 2003-2005 VideoLAN
 * $Id: dvbsub.c 10585 2005-04-07 04:58:36Z rocky $
 *
 * Authors: Gildas Bazin <[e-mail]>
 *          Damien LUCAS <[e-mail]>
 *          Laurent Aimar <[e-mail]>
 *
 * 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, or
 * (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., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
 *****************************************************************************/
/*****************************************************************************
 * Preamble
 *
 * FIXME:
 * DVB subtitles coded as strings of characters are not handled correctly.
 * The character codes in the string should actually be indexes refering to a
 * character table identified in the subtitle descriptor.
 *****************************************************************************/
#include <vlc/vlc.h>
#include <vlc/vout.h>
#include <vlc/decoder.h>
#include <vlc/sout.h>

#include "vlc_bits.h"

//#define DEBUG_DVBSUB 1

/*****************************************************************************
 * Module descriptor.
 *****************************************************************************/
static int  Open ( vlc_object_t * );
static void Close( vlc_object_t * );
static subpicture_t *Decode( decoder_t *, block_t ** );

static int OpenEncoder  ( vlc_object_t * );
static void CloseEncoder( vlc_object_t * );
static block_t *Encode  ( encoder_t *, subpicture_t * );

vlc_module_begin();
    set_description( _("DVB subtitles decoder") );
    set_capability( "decoder", 50 );
    set_category( CAT_INPUT );
    set_subcategory( SUBCAT_INPUT_SCODEC );
    set_callbacks( Open, Close );

#   define ENC_CFG_PREFIX "sout-dvbsub-"
    add_submodule();
    set_description( _("DVB subtitles encoder") );
    set_capability( "encoder", 100 );
    set_callbacks( OpenEncoder, CloseEncoder );
vlc_module_end();

static const char *ppsz_enc_options[] = { NULL };

/****************************************************************************
 * Local structures
 ****************************************************************************
 * Those structures refer closely to the ETSI 300 743 Object model
 ****************************************************************************/

/* The object definition gives the position of the object in a region */
typedef struct dvbsub_objectdef_s
{
    int i_id;
    int i_type;
    int i_x;
    int i_y;
    int i_fg_pc;
    int i_bg_pc;
    char *psz_text; /* for string of characters objects */

} dvbsub_objectdef_t;

/* The entry in the palette CLUT */
typedef struct
{
    uint8_t                 Y;
    uint8_t                 Cr;
    uint8_t                 Cb;
    uint8_t                 T;

} dvbsub_color_t;

/* */
typedef struct dvbsub_clut_s
{
    uint8_t                 i_id;
    uint8_t                 i_version;
    dvbsub_color_t          c_2b[4];
    dvbsub_color_t          c_4b[16];
    dvbsub_color_t          c_8b[256];

    struct dvbsub_clut_s    *p_next;

} dvbsub_clut_t;

/* The Region is an aera on the image
 * with a list of the object definitions associated and a CLUT */
typedef struct dvbsub_region_s
{
    int i_id;
    int i_version;
    int i_x;
    int i_y;
    int i_width;
    int i_height;
    int i_level_comp;
    int i_depth;
    int i_clut;

    uint8_t *p_pixbuf;

    int                    i_object_defs;
    dvbsub_objectdef_t     *p_object_defs;

    struct dvbsub_region_s *p_next;

} dvbsub_region_t;

/* The object definition gives the position of the object in a region */
typedef struct dvbsub_regiondef_s
{
    int i_id;
    int i_x;
    int i_y;

} dvbsub_regiondef_t;

/* The page defines the list of regions */
typedef struct
{
    int i_id;
    int i_timeout;
    int i_state;
    int i_version;

    int                i_region_defs;
    dvbsub_regiondef_t *p_region_defs;

} dvbsub_page_t;

struct decoder_sys_t
{
    bs_t            bs;

    /* Decoder internal data */
    int             i_id;
    int             i_ancillary_id;
    mtime_t         i_pts;

    vlc_bool_t      b_page;
    dvbsub_page_t   *p_page;
    dvbsub_region_t *p_regions;
    dvbsub_clut_t   *p_cluts;
    dvbsub_clut_t   default_clut;
};


// List of different SEGMENT TYPES
// According to EN 300-743, table 2
#define DVBSUB_ST_PAGE_COMPOSITION      0x10
#define DVBSUB_ST_REGION_COMPOSITION    0x11
#define DVBSUB_ST_CLUT_DEFINITION       0x12
#define DVBSUB_ST_OBJECT_DATA           0x13
#define DVBSUB_ST_ENDOFDISPLAY          0x80
#define DVBSUB_ST_STUFFING              0xff
// List of different OBJECT TYPES
// According to EN 300-743, table 6
#define DVBSUB_OT_BASIC_BITMAP          0x00
#define DVBSUB_OT_BASIC_CHAR            0x01
#define DVBSUB_OT_COMPOSITE_STRING      0x02
// Pixel DATA TYPES
// According to EN 300-743, table 9
#define DVBSUB_DT_2BP_CODE_STRING       0x10
#define DVBSUB_DT_4BP_CODE_STRING       0x11
#define DVBSUB_DT_8BP_CODE_STRING       0x12
#define DVBSUB_DT_24_TABLE_DATA         0x20
#define DVBSUB_DT_28_TABLE_DATA         0x21
#define DVBSUB_DT_48_TABLE_DATA         0x22
#define DVBSUB_DT_END_LINE              0xf0
// List of different Page Composition Segment state
// According to EN 300-743, 7.2.1 table 3
#define DVBSUB_PCS_STATE_ACQUISITION    0x01
#define DVBSUB_PCS_STATE_CHANGE         0x10

/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
static void decode_segment( decoder_t *, bs_t * );
static void decode_page_composition( decoder_t *, bs_t * );
static void decode_region_composition( decoder_t *, bs_t * );
static void decode_object( decoder_t *, bs_t * );
static void decode_clut( decoder_t *, bs_t * );
static void free_all( decoder_t * );

static void default_clut_init( decoder_t * );

static subpicture_t *render( decoder_t * );

/*****************************************************************************
 * Open: probe the decoder and return score
 *****************************************************************************
 * Tries to launch a decoder and return score so that the interface is able
 * to chose.
 *****************************************************************************/
static int Open( vlc_object_t *p_this )
{
    decoder_t     *p_dec = (decoder_t *) p_this;
    decoder_sys_t *p_sys;

    if( p_dec->fmt_in.i_codec != VLC_FOURCC('d','v','b','s') )
    {
        return VLC_EGENERIC;
    }

    p_dec->pf_decode_sub = Decode;
    p_sys = p_dec->p_sys = malloc( sizeof(decoder_sys_t) );
    memset( p_sys, 0, sizeof(decoder_sys_t) );

    p_sys->i_pts          = 0;
    p_sys->i_id           = p_dec->fmt_in.subs.dvb.i_id & 0xFFFF;
    p_sys->i_ancillary_id = p_dec->fmt_in.subs.dvb.i_id >> 16;

    p_sys->p_regions      = NULL;
    p_sys->p_cluts        = NULL;
    p_sys->p_page         = NULL;

    es_format_Init( &p_dec->fmt_out, SPU_ES, VLC_FOURCC( 'd','v','b','s' ) );

    default_clut_init( p_dec );

    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;

    free_all( p_dec );
    free( p_sys );
}

/*****************************************************************************
 * Decode:
 *****************************************************************************/
static subpicture_t *Decode( decoder_t *p_dec, block_t **pp_block )
{
    decoder_sys_t *p_sys = p_dec->p_sys;
    block_t       *p_block;
    subpicture_t  *p_spu = NULL;

    if( pp_block == NULL || *pp_block == NULL ) return NULL;
    p_block = *pp_block;
    *pp_block = NULL;

    p_sys->i_pts = p_block->i_pts;
    if( p_sys->i_pts <= 0 )
    {
#ifdef DEBUG_DVBSUB
        /* Some DVB channels send stuffing segments in non-dated packets so
         * don't complain too loudly. */
        msg_Warn( p_dec, "non dated subtitle" );
#endif
        block_Release( p_block );
        return NULL;
    }

    bs_init( &p_sys->bs, p_block->p_buffer, p_block->i_buffer );

    if( bs_read( &p_sys->bs, 8 ) != 0x20 ) /* Data identifier */
    {
        msg_Dbg( p_dec, "invalid data identifier" );
        block_Release( p_block );
        return NULL;
    }

    if( bs_read( &p_sys->bs, 8 ) ) /* Subtitle stream id */
    {
        msg_Dbg( p_dec, "invalid subtitle stream id" );
        block_Release( p_block );
        return NULL;
    }

#ifdef DEBUG_DVBSUB
    msg_Dbg( p_dec, "subtitle packet received: "I64Fd, p_sys->i_pts );
#endif

    p_sys->b_page = VLC_FALSE;
    while( bs_show( &p_sys->bs, 8 ) == 0x0f ) /* Sync byte */
    {
        decode_segment( p_dec, &p_sys->bs );
    }

    if( bs_read( &p_sys->bs, 8 ) != 0xff ) /* End marker */
    {
        msg_Warn( p_dec, "end marker not found (corrupted subtitle ?)" );
        block_Release( p_block );
        return NULL;
    }

    /* Check if the page is to be displayed */
    if( p_sys->p_page && p_sys->b_page ) p_spu = render( p_dec );

    block_Release( p_block );

    return p_spu;
}

/* following functions are local */

/*****************************************************************************
 * default_clut_init: default clut as defined in EN 300-743 section 10
 *****************************************************************************/
static void default_clut_init( decoder_t *p_dec )
{
    decoder_sys_t *p_sys = p_dec->p_sys;
    uint8_t i;

#define RGB_TO_Y(r, g, b) ((int16_t) 77 * r + 150 * g + 29 * b) / 256;
#define RGB_TO_U(r, g, b) ((int16_t) -44 * r - 87 * g + 131 * b) / 256;
#define RGB_TO_V(r, g, b) ((int16_t) 131 * r - 110 * g - 21 * b) / 256;

    /* 4 entries CLUT */
    for( i = 0; i < 4; i++ )
    {
        uint8_t R = 0, G = 0, B = 0, T = 0;

        if( !(i & 0x2) && !(i & 0x1) ) T = 0xFF;
        else if( !(i & 0x2) && (i & 0x1) ) R = G = B = 0xFF;
        else if( (i & 0x2) && !(i & 0x1) ) R = G = B = 0;
        else R = G = B = 0x7F;

        p_sys->default_clut.c_2b[i].Y = RGB_TO_Y(R,G,B);
        p_sys->default_clut.c_2b[i].Cr = RGB_TO_U(R,G,B);
        p_sys->default_clut.c_2b[i].Cb = RGB_TO_V(R,G,B);
        p_sys->default_clut.c_2b[i].T = T;
    }

    /* 16 entries CLUT */
    for( i = 0; i < 16; i++ )
    {
        uint8_t R = 0, G = 0, B = 0, T = 0;

        if( !(i & 0x8) )
        {
            if( !(i & 0x4) && !(i & 0x2) && !(i & 0x1) )
            {
                T = 0xFF;
            }
            else
            {
                R = (i & 0x1) ? 0xFF : 0;
                G = (i & 0x2) ? 0xFF : 0;
                B = (i & 0x4) ? 0xFF : 0;
            }
        }
        else
        {
            R = (i & 0x1) ? 0x7F : 0;
            G = (i & 0x2) ? 0x7F : 0;
            B = (i & 0x4) ? 0x7F : 0;
        }

        p_sys->default_clut.c_4b[i].Y = RGB_TO_Y(R,G,B);
        p_sys->default_clut.c_4b[i].Cr = RGB_TO_U(R,G,B);
        p_sys->default_clut.c_4b[i].Cb = RGB_TO_V(R,G,B);
        p_sys->default_clut.c_4b[i].T = T;
    }

    /* 256 entries CLUT (TODO) */
    memset( p_sys->default_clut.c_8b, 0xFF, 256 * sizeof(dvbsub_color_t) );
}

static void decode_segment( decoder_t *p_dec, bs_t *s )
{
    decoder_sys_t *p_sys = p_dec->p_sys;
    int i_type;
    int i_page_id;
    int i_size;

    /* sync_byte (already checked) */
    bs_skip( s, 8 );

    /* segment type */
    i_type = bs_read( s, 8 );

    /* page id */
    i_page_id = bs_read( s, 16 );

    /* segment size */
    i_size = bs_show( s, 16 );

    if( i_page_id != p_sys->i_id && i_page_id != p_sys->i_ancillary_id )
    {
#ifdef DEBUG_DVBSUB
        msg_Dbg( p_dec, "subtitle skipped (page id: %i, %i)",
                 i_page_id, p_sys->i_id );
#endif
        bs_skip( s,  8 * ( 2 + i_size ) );
        return;