/*****************************************************************************
 * telx.c : Minimalistic Teletext subtitles decoder
 *****************************************************************************
 * Copyright (C) 2007 Vincent Penne
 * Some code converted from ProjectX java dvb decoder (c) 2001-2005 by dvb.matt
 * $Id: a0ab9068eb23a7274aa29f9c34cafa9bb4e367c3 $
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/
/*****************************************************************************
 *
 * information on teletext format can be found here :
 * http://pdc.ro.nu/teletext.html
 *
 *****************************************************************************/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <assert.h>
#include <stdint.h>

#include <vlc_common.h>
#include <vlc_plugin.h>
#include <vlc_input.h>

#include "vlc_vout.h"
#include "vlc_bits.h"
#include "vlc_codec.h"

/* #define TELX_DEBUG */
#ifdef TELX_DEBUG
#   define dbg( a ) msg_Dbg a
#else
#   define dbg( a )
#endif

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

#define OVERRIDE_PAGE_TEXT N_("Override page")
#define OVERRIDE_PAGE_LONGTEXT N_("Override the indicated page, try this if " \
        "your subtitles don't appear (-1 = autodetect from TS, " \
        "0 = autodetect from teletext, " \
        ">0 = actual page number, usually 888 or 889).")

#define IGNORE_SUB_FLAG_TEXT N_("Ignore subtitle flag")
#define IGNORE_SUB_FLAG_LONGTEXT N_("Ignore the subtitle flag, try this if " \
        "your subtitles don't appear.")

#define FRENCH_WORKAROUND_TEXT N_("Workaround for France")
#define FRENCH_WORKAROUND_LONGTEXT N_("Some French channels do not flag " \
        "their subtitling pages correctly due to a historical " \
        "interpretation mistake. Try using this wrong interpretation if " \
        "your subtitles don't appear.")

vlc_module_begin();
    set_description( N_("Teletext subtitles decoder") );
    set_shortname( "Teletext" );
    set_capability( "decoder", 50 );
    set_category( CAT_INPUT );
    set_subcategory( SUBCAT_INPUT_SCODEC );
    set_callbacks( Open, Close );

    add_integer( "telx-override-page", -1, NULL,
                 OVERRIDE_PAGE_TEXT, OVERRIDE_PAGE_LONGTEXT, true );
    add_bool( "telx-ignore-subtitle-flag", 0, NULL,
              IGNORE_SUB_FLAG_TEXT, IGNORE_SUB_FLAG_LONGTEXT, true );
    add_bool( "telx-french-workaround", 0, NULL,
              FRENCH_WORKAROUND_TEXT, FRENCH_WORKAROUND_LONGTEXT, true );

vlc_module_end();

/****************************************************************************
 * Local structures
 ****************************************************************************/

struct decoder_sys_t
{
  int         i_align;
  bool        b_is_subtitle[9];
  char        ppsz_lines[32][128];
  char        psz_prev_text[512];
  mtime_t     prev_pts;
  int         i_page[9];
  bool        b_erase[9];
  const uint16_t *  pi_active_national_set[9];
  int         i_wanted_page, i_wanted_magazine;
  bool        b_ignore_sub_flag;
};

/****************************************************************************
 * Local data
 ****************************************************************************/

/*
 * My doc only mentions 13 national characters, but experiments show there
 * are more, in france for example I already found two more (0x9 and 0xb).
 *
 * Conversion is in this order :
 *
 * 0x23 0x24 0x40 0x5b 0x5c 0x5d 0x5e 0x5f 0x60 0x7b 0x7c 0x7d 0x7e
 * (these are the standard ones)
 * 0x08 0x09 0x0a 0x0b 0x0c 0x0d (apparently a control character) 0x0e 0x0f
 */

static const uint16_t ppi_national_subsets[][20] =
{
  { 0x00a3, 0x0024, 0x0040, 0x00ab, 0x00bd, 0x00bb, 0x005e, 0x0023,
    0x002d, 0x00bc, 0x00a6, 0x00be, 0x00f7 }, /* english ,000 */

  { 0x00e9, 0x00ef, 0x00e0, 0x00eb, 0x00ea, 0x00f9, 0x00ee, 0x0023,
    0x00e8, 0x00e2, 0x00f4, 0x00fb, 0x00e7, 0, 0x00eb, 0, 0x00ef }, /* french  ,001 */

  { 0x0023, 0x00a4, 0x00c9, 0x00c4, 0x00d6, 0x00c5, 0x00dc, 0x005f,
    0x00e9, 0x00e4, 0x00f6, 0x00e5, 0x00fc }, /* swedish,finnish,hungarian ,010 */

  { 0x0023, 0x016f, 0x010d, 0x0165, 0x017e, 0x00fd, 0x00ed, 0x0159,
    0x00e9, 0x00e1, 0x011b, 0x00fa, 0x0161 }, /* czech,slovak  ,011 */

  { 0x0023, 0x0024, 0x00a7, 0x00c4, 0x00d6, 0x00dc, 0x005e, 0x005f,
    0x00b0, 0x00e4, 0x00f6, 0x00fc, 0x00df }, /* german ,100 */

  { 0x00e7, 0x0024, 0x00a1, 0x00e1, 0x00e9, 0x00ed, 0x00f3, 0x00fa,
    0x00bf, 0x00fc, 0x00f1, 0x00e8, 0x00e0 }, /* portuguese,spanish ,101 */

  { 0x00a3, 0x0024, 0x00e9, 0x00b0, 0x00e7, 0x00bb, 0x005e, 0x0023,
    0x00f9, 0x00e0, 0x00f2, 0x00e8, 0x00ec }, /* italian  ,110 */

  { 0x0023, 0x00a4, 0x0162, 0x00c2, 0x015e, 0x0102, 0x00ce, 0x0131,
    0x0163, 0x00e2, 0x015f, 0x0103, 0x00ee }, /* rumanian ,111 */

  /* I have these tables too, but I don't know how they can be triggered */
  { 0x0023, 0x0024, 0x0160, 0x0117, 0x0119, 0x017d, 0x010d, 0x016b,
    0x0161, 0x0105, 0x0173, 0x017e, 0x012f }, /* lettish,lithuanian ,1000 */

  { 0x0023, 0x0144, 0x0105, 0x005a, 0x015a, 0x0141, 0x0107, 0x00f3,
    0x0119, 0x017c, 0x015b, 0x0142, 0x017a }, /* polish,  1001 */

  { 0x0023, 0x00cb, 0x010c, 0x0106, 0x017d, 0x0110, 0x0160, 0x00eb,
    0x010d, 0x0107, 0x017e, 0x0111, 0x0161 }, /* serbian,croatian,slovenian, 1010 */

  { 0x0023, 0x00f5, 0x0160, 0x00c4, 0x00d6, 0x017e, 0x00dc, 0x00d5,
    0x0161, 0x00e4, 0x00f6, 0x017e, 0x00fc }, /* estonian  ,1011 */

  { 0x0054, 0x011f, 0x0130, 0x015e, 0x00d6, 0x00c7, 0x00dc, 0x011e,
    0x0131, 0x015f, 0x00f6, 0x00e7, 0x00fc }, /* turkish  ,1100 */
};


/*****************************************************************************
 * 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 = NULL;
    vlc_value_t    val;
    int            i;

    if( p_dec->fmt_in.i_codec != VLC_FOURCC('t','e','l','x'))
    {
        return VLC_EGENERIC;
    }

    p_dec->pf_decode_sub = Decode;
    p_sys = p_dec->p_sys = malloc( sizeof(decoder_sys_t) );
    if( p_sys == NULL )
        return VLC_ENOMEM;

    memset( p_sys, 0, sizeof(decoder_sys_t) );

    p_sys->i_align = 0;
    for ( i = 0; i < 9; i++ )
        p_sys->pi_active_national_set[i] = ppi_national_subsets[1];

    var_Create( p_dec, "telx-override-page",
                VLC_VAR_INTEGER | VLC_VAR_DOINHERIT );
    var_Get( p_dec, "telx-override-page", &val );
    if( val.i_int == -1 && p_dec->fmt_in.subs.dvb.i_id != -1 
          && p_dec->fmt_in.subs.dvb.i_id != (1<<16) ) /* ignore if TS demux wants page 100 (unlikely to be sub) */
    {
        p_sys->i_wanted_magazine = p_dec->fmt_in.subs.dvb.i_id >> 16;
        if( p_sys->i_wanted_magazine == 0 )
            p_sys->i_wanted_magazine = 8;
        p_sys->i_wanted_page = p_dec->fmt_in.subs.dvb.i_id & 0xff;

        var_Create( p_dec, "telx-french-workaround",
                    VLC_VAR_BOOL | VLC_VAR_DOINHERIT );
        var_Get( p_dec, "telx-french-workaround", &val );
        if( p_sys->i_wanted_page < 100 &&
              (val.b_bool || (p_sys->i_wanted_page % 16) >= 10))
        {
            /* See http://www.nada.kth.se/~ragge/vdr/ttxtsubs/TROUBLESHOOTING.txt
             * paragraph about French channels - they mix up decimal and
             * hexadecimal */
            p_sys->i_wanted_page = (p_sys->i_wanted_page / 10) * 16 +
                                   (p_sys->i_wanted_page % 10);
        }
    }
    else if( val.i_int <= 0 )
    {
        p_sys->i_wanted_magazine = -1;
        p_sys->i_wanted_page = -1;
    }
    else
    {
        p_sys->i_wanted_magazine = val.i_int / 100;
        p_sys->i_wanted_page = (((val.i_int % 100) / 10) << 4)
                                | ((val.i_int % 100) % 10);
    }
    var_Create( p_dec, "telx-ignore-subtitle-flag",
                VLC_VAR_BOOL | VLC_VAR_DOINHERIT );
    var_Get( p_dec, "telx-ignore-subtitle-flag", &val );
    p_sys->b_ignore_sub_flag = val.b_bool;

    msg_Dbg( p_dec, "starting telx on magazine %d page %02x flag %d",
             p_sys->i_wanted_magazine, p_sys->i_wanted_page,
             p_sys->b_ignore_sub_flag );

    return VLC_SUCCESS;

/*  error: */
/*     if (p_sys) { */
/*       free(p_sys); */
/*       p_sys = NULL; */
/*     } */
/*     return VLC_EGENERIC; */
}

/*****************************************************************************
 * 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( p_sys );
}

/**************************
 * change bits endianness *
 **************************/
static uint8_t bytereverse( int n )
{
    n = (((n >> 1) & 0x55) | ((n << 1) & 0xaa));
    n = (((n >> 2) & 0x33) | ((n << 2) & 0xcc));
    n = (((n >> 4) & 0x0f) | ((n << 4) & 0xf0));
    return n;
}

static int hamming_8_4( int a )
{
    switch (a) {
    case 0xA8:
        return 0;
    case 0x0B:
        return 1;
    case 0x26:
        return 2;
    case 0x85:
        return 3;
    case 0x92:
        return 4;
    case 0x31:
        return 5;
    case 0x1C:
        return 6;
    case 0xBF:
        return 7;
    case 0x40:
        return 8;
    case 0xE3:
        return 9;
    case 0xCE:
        return 10;
    case 0x6D:
        return 11;
    case 0x7A:
        return 12;
    case 0xD9:
        return 13;
    case 0xF4:
        return 14;
    case 0x57:
        return 15;
    default:
        return -1;     // decoding error , not yet corrected
    }
}

// utc-2 --> utf-8
// this is not a general function, but it's enough for what we do here
// the result buffer need to be at least 4 bytes long
static void to_utf8( char * res, uint16_t ch )
{
    if( ch >= 0x80 )
    {
        if( ch >= 0x800 )
        {
            res[0] = (ch >> 12) | 0xE0;
            res[1] = ((ch >> 6) & 0x3F) | 0x80;
            res[2] = (ch & 0x3F) | 0x80;
            res[3] = 0;
        }
        else
        {
            res[0] = (ch >> 6) | 0xC0;
            res[1] = (ch & 0x3F) | 0x80;
            res[2] = 0;
        }
    }
    else
    {
        res[0] = ch;
        res[1] = 0;
    }
}

static void decode_string( char * res, int res_len,
                           decoder_sys_t *p_sys, int magazine,
                           uint8_t * packet, int len )
{
    char utf8[7];
    char * pt = res;
    int i;

    for ( i = 0; i < len; i++ )
    {
        int in = bytereverse( packet[i] ) & 0x7f;
        uint16_t out = 32;
        size_t l;

        switch ( in )
        {
        /* special national characters */
        case 0x23:
            out = p_sys->pi_active_national_set[magazine][0];
            break;
        case 0x24:
            out = p_sys->pi_active_national_set[magazine][1];
            break;
        case 0x40:
            out = p_sys->pi_active_national_set[magazine][2];
            break;
        case 0x5b:
            out = p_sys->pi_active_national_set[magazine][3];
            break;
        case 0x5c:
            out = p_sys->pi_active_national_set[magazine][4];
            break;
        case 0x5d:
            out = p_sys->pi_active_national_set[magazine][5];
            break;
        case 0x5e:
            out = p_sys->pi_active_national_set[magazine][6];
            break;
        case 0x5f:
            out = p_sys->pi_active_national_set[magazine][7];
            break;
        case 0x60:
            out = p_sys->pi_active_national_set[magazine][8];
            break;
        case 0x7b:
            out = p_sys->pi_active_national_set[magazine][9];
            break;
        case 0x7c:
            out = p_sys->pi_active_national_set[magazine][10];
            break;
        case 0x7d:
            out = p_sys->pi_active_national_set[magazine][11];
            break;
        case 0x7e:
            out = p_sys->pi_active_national_set[magazine][12];
            break;

        /* some special control characters (empirical) */
        case 0x0d:
            /* apparently this starts a sequence that ends with 0xb 0xb */
            while ( i + 1 < len && (bytereverse( packet[i+1] ) & 0x7f) != 0x0b )
                i++;
            i += 2;
            break;
            /* goto skip; */

        default:
            /* non documented national range 0x08 - 0x0f */
            if ( in >= 0x08 && in <= 0x0f )
            {
                out = p_sys->pi_active_national_set[magazine][13 + in - 8];
                break;
            }

            /* normal ascii */
            if ( in > 32 && in < 0x7f )
                out = in;
        }

        /* handle undefined national characters */
        if ( out == 0 )
            out = 32;

        /* convert to utf-8 */
        to_utf8( utf8, out );
        l = strlen( utf8 );
        if ( pt + l < res + res_len - 1 )
        {
            strcpy(pt, utf8);
            pt += l;
        }

        /* skip: ; */
    }
    /* end: */
    *pt++ = 0;
}

/*****************************************************************************
 * 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;
    video_format_t fmt;
    /* int erase = 0; */
    int len, offset;
#if 0
    int i_wanted_magazine = i_conf_wanted_page / 100;
    int i_wanted_page = 0x10 * ((i_conf_wanted_page % 100) / 10)
                         | (i_conf_wanted_page % 10);
#endif
    bool b_update = false;
    char psz_text[512], *pt = psz_text;
    char psz_line[256];
    int i, total;

    if( pp_block == NULL || *pp_block == NULL )
        return NULL;
    p_block = *pp_block;
    if( p_block->i_rate != 0 )
        p_block->i_length = p_block->i_length * p_block->i_rate / INPUT_RATE_DEFAULT;
    *pp_block = NULL;

    dbg((p_dec, "start of telx packet with header %2x\n",
                * (uint8_t *) p_block->p_buffer));
    len = p_block->i_buffer;
    for ( offset = 1; offset + 46 <= len; offset += 46 )
    {
        uint8_t * packet = (uint8_t *) p_block->p_buffer+offset;
//        int vbi = ((0x20 & packet[2]) != 0 ? 0 : 313) + (0x1F & packet[2]);
 
//        dbg((p_dec, "vbi %d header %02x %02x %02x\n", vbi, packet[0], packet[1], packet[2]));
        if ( packet[0] == 0xFF ) continue;

/*      if (packet[1] != 0x2C) { */
/*         printf("wrong header\n"); */
/*         //goto error; */
/*         continue; */
/*       } */

        int mpag = (hamming_8_4( packet[4] ) << 4) | hamming_8_4( packet[5] );
        int row, magazine;
        if ( mpag < 0 )
        {
            /* decode error */
            dbg((p_dec, "mpag hamming error\n"));
            continue;
        }

        row = 0xFF & bytereverse(mpag);
        magazine = (7 & row) == 0 ? 8 : (7 & row);
        row >>= 3;

        if ( p_sys->i_wanted_page != -1
              && magazine != p_sys->i_wanted_magazine )
            continue;

        if ( row == 0 )
        {
            /* row 0 : flags and header line */
            int flag = 0;
            int a;
 
            for ( a = 0; a < 6; a++ )
            {
                flag |= (0xF & (bytereverse( hamming_8_4(packet[8 + a]) ) >> 4))
                          << (a * 4);
            }

    /*         if (!p_sys->b_ignore_sub_flag && !(1 & flag>>15)) */
    /*           continue; */

            p_sys->i_page[magazine] = (0xF0 & bytereverse( hamming_8_4(packet[7]) )) |
                             (0xF & (bytereverse( hamming_8_4(packet[6]) ) >> 4) );

            decode_string( psz_line, sizeof(psz_line), p_sys, magazine,
                           packet + 14, 40 - 14 );

            dbg((p_dec, "mag %d flags %x page %x character set %d subtitles %d", magazine, flag,
                 p_sys->i_page[magazine],
                 7 & flag>>21, 1 & flag>>15, psz_line));

            p_sys->pi_active_national_set[magazine] =
                                 ppi_national_subsets[7 & (flag >> 21)];

            p_sys->b_is_subtitle[magazine] = p_sys->b_ignore_sub_flag
                                              || ( (1 & (flag >> 15))
                                                  && (1 & (flag>>16)) );

            dbg(( p_dec, "FLAGS%s%s%s%s%s%s%s mag_ser %d",
                  (1 & (flag>>14))? " news" : "",
                  (1 & (flag>>15))? " subtitle" : "",
                  (1 & (flag>>7))? " erase" : "",
                  (1 & (flag>>16))? " suppressed_head" : "",
                  (1 & (flag>>17))? " update" : "",
                  (1 & (flag>>18))? " interrupt" : "",
                  (1 & (flag>>19))? " inhibit" : "",
                  (1 & (flag>>20)) ));
 
            if ( (p_sys->i_wanted_page != -1
                   && p_sys->i_page[magazine] != p_sys->i_wanted_page)
                   || !p_sys->b_is_subtitle[magazine] )
                continue;

            p_sys->b_erase[magazine] = (1 & (flag >> 7));

            dbg((p_dec, "%ld --> %ld\n", (long int) p_block->i_pts, (long int)(p_sys->prev_pts+1500000)));
            /* kludge here :
             * we ignore the erase flag if it happens less than 1.5 seconds
             * before last caption
             * TODO   make this time configurable
             * UPDATE the kludge seems to be no more necessary
             *        so it's commented out*/
            if ( /*p_block->i_pts > p_sys->prev_pts + 1500000 && */
                 p_sys->b_erase[magazine] )
            {
                int i;
 
                dbg((p_dec, "ERASE !\n"));

                p_sys->b_erase[magazine] = 0;
                for ( i = 1; i < 32; i++ )
                {
                    if ( !p_sys->ppsz_lines[i][0] ) continue;
                    /* b_update = true; */
                    p_sys->ppsz_lines[i][0] = 0;
                }
            }

            /* replace the row if it's different */
            if ( strcmp(psz_line, p_sys->ppsz_lines[row]) )
            {
                strncpy( p_sys->ppsz_lines[row], psz_line,
                         sizeof(p_sys->ppsz_lines[row]) - 1);
            }
            b_update = true;

        }
        else if ( row < 24 )
        {
            char * t;
            int i;
            /* row 1-23 : normal lines */

            if ( (p_sys->i_wanted_page != -1
                   && p_sys->i_page[magazine] != p_sys->i_wanted_page)
                   || !p_sys->b_is_subtitle[magazine]
                   || (p_sys->i_wanted_page == -1
                        && p_sys->i_page[magazine] > 0x99) )
                continue;

            decode_string( psz_line, sizeof(psz_line), p_sys, magazine,
                           packet + 6, 40 );
            t = psz_line;

            /* remove starting spaces */
            while ( *t == 32 ) t++;

            /* remove trailing spaces */
            for ( i = strlen(t) - 1; i >= 0 && t[i] == 32; i-- );
            t[i + 1] = 0;

            /* replace the row if it's different */
            if ( strcmp( t, p_sys->ppsz_lines[row] ) )
            {
                strncpy( p_sys->ppsz_lines[row], t,
                         sizeof(p_sys->ppsz_lines[row]) - 1 );
                b_update = true;
            }

            if (t[0])
                p_sys->prev_pts = p_block->i_pts;

            dbg((p_dec, "%d %d : ", magazine, row));
            dbg((p_dec, "%s\n", t));

#ifdef TELX_DEBUG
            {
                char dbg[256];
                dbg[0] = 0;
                for ( i = 0; i < 40; i++ )
                {
                    int in = bytereverse(packet[6 + i]) & 0x7f;
                    sprintf(dbg + strlen(dbg), "%02x ", in);
                }
                dbg((p_dec, "%s\n", dbg));
                dbg[0] = 0;
                for ( i = 0; i < 40; i++ )
                {
                    decode_string( psz_line, sizeof(psz_line), p_sys, magazine,
                                   packet + 6 + i, 1 );
                    sprintf( dbg + strlen(dbg), "%s  ", psz_line );
                }
                dbg((p_dec, "%s\n", dbg));
            }
#endif
        }
        else if ( row == 25 )
        {
            /* row 25 : alternate header line */
            if ( (p_sys->i_wanted_page != -1
                   && p_sys->i_page[magazine] != p_sys->i_wanted_page)
                   || !p_sys->b_is_subtitle[magazine] )
                continue;

            decode_string( psz_line, sizeof(psz_line), p_sys, magazine,
                           packet + 6, 40 );

            /* replace the row if it's different */
            if ( strcmp( psz_line, p_sys->ppsz_lines[0] ) )
            {
                strncpy( p_sys->ppsz_lines[0], psz_line,
                         sizeof(p_sys->ppsz_lines[0]) - 1 );
                /* b_update = true; */
            }
        }
/*       else if (row == 26) { */
/*         // row 26 : TV listings */
/*       } else */
/*         dbg((p_dec, "%d %d : %s\n", magazine, row, decode_string(p_sys, magazine, packet+6, 40))); */
    }

    if ( !b_update )
        goto error;

    total = 0;
    for ( i = 1; i < 24; i++ )
    {
        size_t l = strlen( p_sys->ppsz_lines[i] );

        if ( l > sizeof(psz_text) - total - 1 )
            l = sizeof(psz_text) - total - 1;

        if ( l > 0 )
        {
            memcpy( pt, p_sys->ppsz_lines[i], l );
            total += l;
            pt += l;
            if ( sizeof(psz_text) - total - 1 > 0 )
            {
                *pt++ = '\n';
                total++;
            }
        }
    }
    *pt = 0;

    if ( !strcmp(psz_text, p_sys->psz_prev_text) )
        goto error;

    dbg((p_dec, "UPDATE TELETEXT PICTURE\n"));

    assert( sizeof(p_sys->psz_prev_text) >= sizeof(psz_text) );
    strcpy( p_sys->psz_prev_text, psz_text );

    /* Create the subpicture unit */
    p_spu = p_dec->pf_spu_buffer_new( p_dec );
    if( !p_spu )
    {
        msg_Warn( p_dec, "can't get spu buffer" );
        goto error;
    }
 
    /* Create a new subpicture region */
    memset( &fmt, 0, sizeof(video_format_t) );
    fmt.i_chroma = VLC_FOURCC('T','E','X','T');
    fmt.i_aspect = 0;
    fmt.i_width = fmt.i_height = 0;
    fmt.i_x_offset = fmt.i_y_offset = 0;
    p_spu->p_region = subpicture_region_New( &fmt );
    if( p_spu->p_region == NULL )
    {
        msg_Err( p_dec, "cannot allocate SPU region" );
        goto error;
    }

    /* Normal text subs, easy markup */
    p_spu->p_region->i_align = SUBPICTURE_ALIGN_BOTTOM | p_sys->i_align;
    p_spu->p_region->i_x = p_sys->i_align ? 20 : 0;
    p_spu->p_region->i_y = 10;
    p_spu->p_region->psz_text = strdup(psz_text);

    p_spu->i_start = p_block->i_pts;
    p_spu->i_stop = p_block->i_pts + p_block->i_length;
    p_spu->b_ephemer = (p_block->i_length == 0);
    p_spu->b_absolute = false;
    dbg((p_dec, "%ld --> %ld\n", (long int) p_block->i_pts/100000, (long int)p_block->i_length/100000));

    block_Release( p_block );
    return p_spu;

error:
    if ( p_spu != NULL )
    {
        p_dec->pf_spu_buffer_del( p_dec, p_spu );
        p_spu = NULL;
    }

    block_Release( p_block );
    return NULL;
}
