subsusf.c

VLC Player Source Code

/*****************************************************************************
 * subsusf.c : USF subtitles decoder
 *****************************************************************************
 * Copyright (C) 2000-2006 the VideoLAN team
 * $Id: ff8e3d77113758e888ebe8eabf2728f59f33a439 $
 *
 * Authors: Bernie Purcell <[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., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include "subsdec.h"
#include <vlc_plugin.h>

/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
static int  OpenDecoder   ( vlc_object_t * );
static void CloseDecoder  ( vlc_object_t * );

static subpicture_t *DecodeBlock   ( decoder_t *, block_t ** );
static char         *CreatePlainText( char * );
static int           ParseImageAttachments( decoder_t *p_dec );

static subpicture_t        *ParseText     ( decoder_t *, block_t * );
static void                 ParseUSFHeader( decoder_t * );
static subpicture_region_t *ParseUSFString( decoder_t *, char *, subpicture_t * );
static subpicture_region_t *LoadEmbeddedImage( decoder_t *p_dec, subpicture_t *p_spu, const char *psz_filename, int i_transparent_color );

/*****************************************************************************
 * Module descriptor.
 *****************************************************************************/

vlc_module_begin();
    set_capability( "decoder", 40 );
    set_shortname( N_("USFSubs"));
    set_description( N_("USF subtitles decoder") );
    set_callbacks( OpenDecoder, CloseDecoder );
    set_category( CAT_INPUT );
    set_subcategory( SUBCAT_INPUT_SCODEC );
    /* We inherit subsdec-align and subsdec-formatted from subsdec.c */
vlc_module_end();

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

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

    p_dec->pf_decode_sub = DecodeBlock;

    /* Allocate the memory needed to store the decoder's structure */
    if( ( p_dec->p_sys = p_sys =
          (decoder_sys_t *)calloc(1, sizeof(decoder_sys_t)) ) == NULL )
    {
        return VLC_ENOMEM;
    }

    /* Unused fields of p_sys - not needed for USF decoding */
    p_sys->b_ass = false;
    p_sys->iconv_handle = (vlc_iconv_t)-1;
    p_sys->b_autodetect_utf8 = false;

    /* init of p_sys */
    p_sys->i_align = 0;
    p_sys->i_original_height = -1;
    p_sys->i_original_width = -1;
    TAB_INIT( p_sys->i_ssa_styles, p_sys->pp_ssa_styles );
    TAB_INIT( p_sys->i_images, p_sys->pp_images );

    /* USF subtitles are mandated to be UTF-8, so don't need vlc_iconv */

    var_Create( p_dec, "subsdec-align", VLC_VAR_INTEGER | VLC_VAR_DOINHERIT );
    var_Get( p_dec, "subsdec-align", &val );
    p_sys->i_align = val.i_int;

    ParseImageAttachments( p_dec );

    if( var_CreateGetBool( p_dec, "subsdec-formatted" ) )
    {
        if( p_dec->fmt_in.i_extra > 0 )
            ParseUSFHeader( p_dec );
    }

    return VLC_SUCCESS;
}

/****************************************************************************
 * DecodeBlock: the whole thing
 ****************************************************************************
 * This function must be fed with complete subtitles units.
 ****************************************************************************/
static subpicture_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
{
    subpicture_t *p_spu;
    block_t *p_block;

    if( !pp_block || *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;

    p_spu = ParseText( p_dec, p_block );

    block_Release( p_block );
    *pp_block = NULL;

    return p_spu;
}

/*****************************************************************************
 * CloseDecoder: clean up the decoder
 *****************************************************************************/
static void CloseDecoder( vlc_object_t *p_this )
{
    decoder_t *p_dec = (decoder_t *)p_this;
    decoder_sys_t *p_sys = p_dec->p_sys;

    if( p_sys->pp_ssa_styles )
    {
        int i;
        for( i = 0; i < p_sys->i_ssa_styles; i++ )
        {
            if( !p_sys->pp_ssa_styles[i] )
                continue;

            free( p_sys->pp_ssa_styles[i]->psz_stylename );
            free( p_sys->pp_ssa_styles[i]->font_style.psz_fontname );
            free( p_sys->pp_ssa_styles[i] );
        }
        TAB_CLEAN( p_sys->i_ssa_styles, p_sys->pp_ssa_styles );
    }
    if( p_sys->pp_images )
    {
        int i;
        for( i = 0; i < p_sys->i_images; i++ )
        {
            if( !p_sys->pp_images[i] )
                continue;

            if( p_sys->pp_images[i]->p_pic )
                picture_Release( p_sys->pp_images[i]->p_pic );
            free( p_sys->pp_images[i]->psz_filename );

            free( p_sys->pp_images[i] );
        }
        TAB_CLEAN( p_sys->i_images, p_sys->pp_images );
    }

    free( p_sys );
}

/*****************************************************************************
 * ParseText: parse an text subtitle packet and send it to the video output
 *****************************************************************************/
static subpicture_t *ParseText( decoder_t *p_dec, block_t *p_block )
{
    decoder_sys_t *p_sys = p_dec->p_sys;
    subpicture_t *p_spu = NULL;
    char *psz_subtitle = NULL;

    /* We cannot display a subpicture with no date */
    if( p_block->i_pts == 0 )
    {
        msg_Warn( p_dec, "subtitle without a date" );
        return NULL;
    }

    /* Check validity of packet data */
    /* An "empty" line containing only \0 can be used to force
       and ephemer picture from the screen */
    if( p_block->i_buffer < 1 )
    {
        msg_Warn( p_dec, "no subtitle data" );
        return NULL;
    }

    /* Should be resiliant against bad subtitles */
    psz_subtitle = strndup( (const char *)p_block->p_buffer,
                            p_block->i_buffer );
    if( psz_subtitle == NULL )
        return NULL;

    /* USF Subtitles are mandated to be UTF-8 -- make sure it is */
    if (EnsureUTF8( psz_subtitle ) == NULL)
    {
        msg_Err( p_dec, "USF subtitles must be in UTF-8 format.\n"
                 "This stream contains USF subtitles which aren't." );
    }

    /* 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" );
        free( psz_subtitle );
        return NULL;
    }

    p_spu->b_pausable = true;

    /* Decode USF strings */
    p_spu->p_region = ParseUSFString( p_dec, psz_subtitle, p_spu );

    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;
    p_spu->i_original_picture_width = p_sys->i_original_width;
    p_spu->i_original_picture_height = p_sys->i_original_height;

    free( psz_subtitle );

    return p_spu;
}

static char *GrabAttributeValue( const char *psz_attribute,
                                 const char *psz_tag_start )
{
    if( psz_attribute && psz_tag_start )
    {
        char *psz_tag_end = strchr( psz_tag_start, '>' );
        char *psz_found   = strcasestr( psz_tag_start, psz_attribute );

        if( psz_found )
        {
            psz_found += strlen( psz_attribute );

            if(( *(psz_found++) == '=' ) &&
               ( *(psz_found++) == '\"' ))
            {
                if( psz_found < psz_tag_end )
                {
                    int   i_len = strcspn( psz_found, "\"" );
                    return strndup( psz_found, i_len );
                }
            }
        }
    }
    return NULL;
}

static ssa_style_t *ParseStyle( decoder_sys_t *p_sys, char *psz_subtitle )
{
    ssa_style_t *p_style   = NULL;
    char        *psz_style = GrabAttributeValue( "style", psz_subtitle );

    if( psz_style )
    {
        int i;

        for( i = 0; i < p_sys->i_ssa_styles; i++ )
        {
            if( !strcmp( p_sys->pp_ssa_styles[i]->psz_stylename, psz_style ) )
                p_style = p_sys->pp_ssa_styles[i];
        }
        free( psz_style );
    }
    return p_style;
}

static int ParsePositionAttributeList( char *psz_subtitle, int *i_align,
                                       int *i_x, int *i_y )
{
    int   i_mask = 0;

    char *psz_align    = GrabAttributeValue( "alignment", psz_subtitle );
    char *psz_margin_x = GrabAttributeValue( "horizontal-margin", psz_subtitle );
    char *psz_margin_y = GrabAttributeValue( "vertical-margin", psz_subtitle );
    /* -- UNSUPPORTED
    char *psz_relative = GrabAttributeValue( "relative-to", psz_subtitle );
    char *psz_rotate_x = GrabAttributeValue( "rotate-x", psz_subtitle );
    char *psz_rotate_y = GrabAttributeValue( "rotate-y", psz_subtitle );
    char *psz_rotate_z = GrabAttributeValue( "rotate-z", psz_subtitle );
    */

    *i_align = SUBPICTURE_ALIGN_BOTTOM;
    *i_x = 0;
    *i_y = 0;

    if( psz_align )
    {
        if( !strcasecmp( "TopLeft", psz_align ) )
            *i_align = SUBPICTURE_ALIGN_TOP | SUBPICTURE_ALIGN_LEFT;
        else if( !strcasecmp( "TopCenter", psz_align ) )
            *i_align = SUBPICTURE_ALIGN_TOP;
        else if( !strcasecmp( "TopRight", psz_align ) )
            *i_align = SUBPICTURE_ALIGN_TOP | SUBPICTURE_ALIGN_RIGHT;