modules/codec/stl.c

   1 /*****************************************************************************
   2  * stl.c: EBU STL decoder
   3  *****************************************************************************
   4  * Copyright (C) 2010 Laurent Aimar
   5  * $Id$
   6  *
   7  * Authors: Laurent Aimar <fenrir _AT_ videolan _DOT_ org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  22  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27 #ifdef HAVE_CONFIG_H
  28 # include "config.h"
  29 #endif
  30 #include <assert.h>
  31
  32 #include <vlc_common.h>
  33 #include <vlc_plugin.h>
  34 #include <vlc_codec.h>
  35 #include <vlc_memory.h>
  36 #include <vlc_charset.h>
  37
  38 /*****************************************************************************
  39  * Module descriptor
  40  *****************************************************************************/
  41 static int  Open (vlc_object_t *);
  42 static void Close(vlc_object_t *);
  43
  44 vlc_module_begin()
  45     set_description(N_("EBU STL subtitles decoder"))
  46     set_category(CAT_INPUT)
  47     set_subcategory(SUBCAT_INPUT_SCODEC)
  48     set_capability("decoder", 10)
  49     set_callbacks(Open, Close)
  50 vlc_module_end()
  51
  52 /*****************************************************************************
  53  * Local definitions/prototypes
  54  *****************************************************************************/
  55 #define GSI_BLOCK_SIZE 1024
  56
  57 typedef enum {
  58     CCT_ISO_6937_2 = 0x3030, CCT_BEGIN = CCT_ISO_6937_2,
  59     CCT_ISO_8859_5 = 0x3031,
  60     CCT_ISO_8859_6 = 0x3032,
  61     CCT_ISO_8859_7 = 0x3033,
  62     CCT_ISO_8859_8 = 0x3034, CCT_END = CCT_ISO_8859_8
  63 } cct_number_value_t;
  64
  65 typedef struct {
  66     cct_number_value_t value;
  67     const char *str;
  68 } cct_number_t;
  69
  70 struct decoder_sys_t {
  71     cct_number_value_t cct;
  72 };
  73
  74 static cct_number_t cct_nums[] = { {CCT_ISO_6937_2, "ISO_6937-2"},
  75                                    {CCT_ISO_8859_5, "ISO_8859-5"},
  76                                    {CCT_ISO_8859_6, "ISO_8859-6"},
  77                                    {CCT_ISO_8859_7, "ISO_8859-7"},
  78                                    {CCT_ISO_8859_8, "ISO_8859-8"} };
  79
  80
  81 static char *ParseText(uint8_t *data, int size, const char *charset)
  82 {
  83     char *text = strdup("");
  84     int  text_size = 0;
  85
  86     for (int i = 0; i < size; i++) {
  87         uint8_t code = data[i];
  88
  89         if (code == 0x8f)
  90             break;
  91
  92         char tmp[16] = "";
  93         char *t = tmp;
  94         if ((code >= 0x20 && code <= 0x7e) ||
  95             (code >= 0xa0 && code <= 0xff) )
  96             snprintf(tmp, sizeof(tmp), "%c", code);
  97 #if 0
  98         else if (code == 0x80)
  99             snprintf(tmp, sizeof(tmp), "<i>");
 100         else if (code == 0x81)
 101             snprintf(tmp, sizeof(tmp), "</i>");
 102         else if (code == 0x82)
 103             snprintf(tmp, sizeof(tmp), "<u>");
 104         else if (code == 0x83)
 105             snprintf(tmp, sizeof(tmp), "</u>");
 106         else if (code == 0x8a)
 107             snprintf(tmp, sizeof(tmp), "\n");
 108 #endif
 109         else {
 110             t = NULL;
 111         }
 112
 113         if (!t)
 114             continue;
 115         size_t t_size = strlen(t);
 116         text = realloc_or_free(text, t_size + text_size + 1);
 117         if (!text)
 118             continue;
 119         memcpy(&text[text_size], t, t_size);
 120         text_size += t_size;
 121         text[text_size]   = '\0';
 122     }
 123     return FromCharset(charset, text, text_size);
 124 }
 125
 126 static subpicture_t *Decode(decoder_t *dec, block_t **block)
 127 {
 128     if (block == NULL || *block == NULL)
 129         return NULL;
 130
 131     subpicture_t *sub = NULL;
 132
 133     block_t *b = *block; *block = NULL;
 134     if (b->i_flags & (BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED))
 135         goto exit;
 136     if (b->i_buffer < 128)
 137         goto exit;
 138
 139     int     payload_size = (b->i_buffer / 128) * 112;
 140     uint8_t *payload = malloc(payload_size);
 141     if (!payload)
 142         goto exit;
 143     for (int i = 0; i < b->i_buffer / 128; i++)
 144         memcpy(&payload[112 * i], &b->p_buffer[128 * i + 16], 112);
 145
 146     sub = decoder_NewSubpicture(dec, NULL);
 147     if (!sub) {
 148         free(payload);
 149         goto exit;
 150     }
 151     sub->i_start    = b->i_pts;
 152     sub->i_stop     = b->i_pts + b->i_length;
 153     sub->b_ephemer  = b->i_length == 0;
 154     sub->b_absolute = false;
 155     //sub->i_original_picture_width  = 0;
 156     //sub->i_original_picture_height = 0;
 157
 158     video_format_t fmt;
 159     video_format_Init(&fmt, VLC_CODEC_TEXT);
 160     sub->p_region = subpicture_region_New(&fmt);
 161     video_format_Clean(&fmt);
 162
 163     if (sub->p_region) {
 164         sub->p_region->psz_text = ParseText(payload,
 165                                             payload_size,
 166                                             cct_nums[dec->p_sys->cct - CCT_BEGIN].str);
 167         sub->p_region->psz_html = NULL;
 168     }
 169
 170     free(payload);
 171
 172 exit:
 173     block_Release(b);
 174     return sub;
 175 }
 176
 177 static int ExtractCCT(const decoder_t *dec, cct_number_value_t *cct_number)
 178 {
 179     uint8_t *header = dec->fmt_in.p_extra;
 180     if (!header) {
 181         msg_Err(dec, "NULL EBU header (GSI block)\n");
 182         return VLC_EGENERIC;
 183     }
 184
 185     if (GSI_BLOCK_SIZE != dec->fmt_in.i_extra) {
 186         msg_Err(dec, "EBU header is not in expected size (%d)\n", dec->fmt_in.i_extra);
 187         return VLC_EGENERIC;
 188     }
 189
 190     int cct = (header[12] << 8) | header[13];
 191     if (CCT_BEGIN > cct || CCT_END < cct) {
 192         msg_Err(dec, "EBU header contains illegal CCT (0x%x)\n", cct);
 193         return VLC_EGENERIC;
 194     }
 195
 196     *cct_number = cct;
 197
 198     return VLC_SUCCESS;
 199 }
 200
 201 static int Open(vlc_object_t *object)
 202 {
 203     decoder_t *dec = (decoder_t*)object;
 204
 205     if (dec->fmt_in.i_codec != VLC_CODEC_EBU_STL)
 206         return VLC_EGENERIC;
 207
 208     cct_number_value_t cct;
 209     int rc = ExtractCCT(dec, &cct);
 210     if (VLC_SUCCESS != rc)
 211         return rc;
 212
 213     msg_Dbg(dec, "CCT=0x%x", cct);
 214
 215     decoder_sys_t *sys = malloc(sizeof(*sys));
 216     if (!sys)
 217         return VLC_ENOMEM;
 218
 219     sys->cct = cct;
 220
 221     dec->p_sys = sys;
 222     dec->pf_decode_sub = Decode;
 223     dec->fmt_out.i_cat = SPU_ES;
 224     dec->fmt_out.i_codec = 0;
 225     return VLC_SUCCESS;
 226 }
 227
 228 static void Close(vlc_object_t *object)
 229 {
 230     decoder_t *dec = (decoder_t*)object;
 231     decoder_sys_t *sys = dec->p_sys;
 232
 233     free(sys);
 234 }